JPH06242522A - Method for correcting gray balance - Google Patents

Abstract

PURPOSE:To provide a method for correcting gray balance capable of eliminating the influence of a failure without degrading the correction capacity of the color balance for the images photographed by different light sources. CONSTITUTION:The images recorded on a negative film are divided to many pieces of regions and the density values of C, M, Y are respectively measured by each of the respective regions. Conversion relations are determied in order to make the values after conversion of the max. reference values of the respective colors coincide with each other and to make the values after conversion of the min. reference values coincide with each other. The measured values are converted by using these conversion relations. The data obtd. by the conversion are plotted on color coordinates (see (A)). The average value within the prescribed regions (see (B).) inclusive of a straight line L running the max. reference value Dmax and min. reference value Dmin after the conversion is determined in accordance with the distribution on the color coordinates. The conversion relations of the respective colors are corrected in accordance with a quadratic curve Pc, Py (see (C)) running Dmax, Dmin and the average value. The measured values of C, M, Y are converted by using the corrected conversion relations.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gray balance correction method for correcting the gray balance of an image recorded on a negative film.

[0002]

2. Description of the Related Art An image recorded on a color negative film is displayed on the entire screen as B
Transmits three colors of light (blue), G (green), and R (red),
It is empirically known that the transmission rates of these three color lights are generally equal or constant (Evans' theory). Therefore, most photographic printers determine the exposure condition based on the following basic formula called the integral neutral system.

LogEj = Kj + Aj.Dj (1) where logEj is the logarithm of the exposure amount, Kj is the photosensitive material,
A constant determined by a photographic printer, Dj is an integrated transmission density (LATD) of the image, Aj is a correction coefficient, j is R, G,
It represents one of the colored lights of B. According to the above formula (1), for example, for an image with a small amount of transmitted light of R (high integrated transmission density of R), the exposure amount of R is increased.
When printing is performed on the photographic paper based on the above-obtained exposure amount, the R, G, and B exposure lights, which are transmitted through the negative film and are irradiated on the photographic paper, have the same total light amount. Therefore, the integrated value of the R, G, and B density values of the image printed on the photographic paper becomes constant, and the gray balance can be achieved for the entire image.

By the way, in the case of a negative film, the densities of the R, G, and B colors when the exposure amount at the time of photographing is changed theoretically change with a constant density difference as shown in FIG. 19 (A). . In the integral neutral method, the cumulative transmission density is, for example, R
_{In the case of 0} , G ₀ , and B ₀ , the exposure amount is determined so that they coincide with each other. Therefore, theoretically, the exposure amount can be determined so that the characteristics of the density change of each color coincide with each other. The gray balance should be balanced from the lowest density to the highest density in the printed image.

However, in reality, due to the influence of processing conditions such as development, the density change characteristics of the negative film have different slopes for each color (see FIG. 19B). When the gradient of the density change characteristic is different for each color, even if the exposure amount is determined by the integral neutral method so that the integrated transmission densities of the respective colors match, a region having a density higher than the integrated transmission density by a predetermined value or more (for example, In the area A in FIG. 19C and the area where the density is lower than a predetermined value (for example, the area B in FIG. 19C), the density change characteristics of each color are deviated, so that the gray balance is deviated and the image is printed on photographic paper. There is an inconvenience that the color of the portion corresponding to the area of the captured image is different from the color of the subject at the time of shooting.

Also, in an image in which the background area of the main subject is large and the density of the background area is extremely high or low, the cumulative transmission density is significantly different from the density of the main object. This is called density ferria, and when the image is printed on photographic paper with an exposure amount determined by applying the integral neutral method, the main subject portion of the image printed on the photographic paper is exposed due to the influence of the density ferria. Insufficient or overexposure.

Further, in an image in which the area of the background portion of the main subject is large and the color of the background portion is a specific color remarkably different from the color of the main subject (for example, grass green, sea blue, etc.), The specific color has a high cumulative transmission density, and the color balance of the entire screen is largely deviated from the color balance of the main subject. This is called a color feria, and when the image is printed on photographic paper with an exposure amount determined by applying the integral neutral method, the color of the main subject part in the image printed on the photographic paper is affected by the color feria. The balance is lost. These are the same problems that occur when the average transmission density of the entire screen is used instead of the integrated transmission density of the equation (1).

On the other hand, in the conventional photographic printer, the so-called lower correction for reducing the correction amount of the exposure amount prevents the occurrence of the density and color ferrias. However, in this lower collection, the ability to correct the color balance for an image captured by a different light source other than sunlight (for example, a fluorescent lamp, a tungsten lamp, etc.) is lowered, and an appropriate print result cannot be obtained.

Further, a method of removing the data of a portion of the image predicted to have high saturation and obtaining the integrated transmission density (or average density) of the entire image to determine the exposure amount (Japanese Patent Publication No. 59-29847).
(See Japanese Laid-Open Patent Publication No. 59-298), or a method of determining exposure amount after converting high-saturation photometric data into achromatic color (Japanese Patent Laid-Open No. 59-298).
(See Japanese Patent No. 47), etc., but it is difficult to accurately determine whether it is actually high saturation or an image captured by different light sources, and it is necessary to perform complicated processing. There was a problem.

The present invention has been made in consideration of the above facts, and the gray balance capable of eliminating the influence of ferria without deteriorating the ability to correct the color balance for images photographed by different light sources. The purpose is to obtain a correction method.

[0011]

In order to achieve the above object, a gray balance correction method according to the present invention divides an image recorded on a negative film into a large number of areas and densities of three colors in each area. Each value is measured, the maximum reference value and the minimum reference value are obtained for each color based on the measured value of the density value, and the converted values of the maximum reference value of each color are matched with each other and after the conversion of the minimum reference value. A conversion relationship for matching the values is determined, the measured values of the three colors are converted using the conversion relationship obtained above, and the maximum standard after conversion is based on the distribution of the density data obtained by the conversion on the color coordinates. Value and the average value of the density data in a predetermined area including a line passing through the converted minimum reference value, and the conversion relationship of each color according to the maximum density value after conversion, the minimum density value after conversion and the curve passing through the average value. And use the modified conversion relationship To correct the gray balance by performing the conversion again Te.

[0012]

[Function] In photography, almost all objects include white or a part close to white. This is because not only when the color of the subject is white, but also the part where the light from the light source is reflected appears white. Since white is the color with the highest lightness, in an image formed by shooting a subject on a negative film, a region corresponding to white or a portion close to white of the subject has density values of three colors in the image. It is the highest area. It should be noted that when the image is taken with a different light source, the color of the light from the light source is reflected and the image is slightly deviated from white. For example, when shooting with a fluorescent lamp as a light source, a little green component is added to the color of the subject as a whole, and a magenta component is added to the color of a predetermined area in the image of the negative film corresponding to the part where the subject reflects light. However, it is highly probable that the predetermined area is a portion where the density values of the three colors are the highest in the image.

Therefore, in the present invention, the image recorded on the negative film is divided into a large number of areas, the density values of the three colors are measured for each area, and the color values are measured for each color based on the measured density values. Determine the maximum and minimum standard values. As the maximum reference value and the minimum reference value, for example, the maximum value or the minimum value of the measured value of each color is used as it is, or the reference value is approximated to the maximum value or the minimum value, and the image is divided into a predetermined number of areas. The maximum or minimum density value is calculated for each area, and the weighted average of the maximum values calculated for each area is used as the maximum reference value. A weighted average of the values can be used as the minimum reference value.

Further, as the maximum reference value and the minimum reference value,
For example, use the average value of the upper specific or lower specific measurement values in the descending order of the measured values, use the density value of a specific rank close to the maximum value or the minimum value, or set the maximum or minimum value. It is also possible to use the average value of the measured values in the order of the close predetermined range. The base density of the negative film may be used as the minimum reference value.

Next, in the present invention, a conversion relationship for matching the converted values of the maximum reference value of each color with each other and the converted values of the minimum reference value with each other is obtained, and this conversion relationship is used. Convert the three color measurements. This is done so that the two points of the maximum reference value of each color corresponding to white and the minimum reference value of each color corresponding to black match, that is, as shown in FIG.
FIG. 1B shows the density change characteristics of each color as shown in FIG.
As each match at two points of a predetermined value D _{ma x} and a predetermined value D _min as shown in, it is to correct the color balance,
Even in images taken with different light sources, the color of the area corresponding to white or a portion close to white of the subject is white, and the color of the area corresponding to black or a portion close to black included in most of the subject is The density data corrected to be black is obtained.

Further, the magnitudes of the maximum reference value and the minimum reference value fluctuate under the influence of a large area occupied by the background portion in the image and a large difference in density or color from the main subject. There is nothing to do. Therefore, even if the image has density ferria or color ferria,
Concentration data that eliminates these effects can be obtained. It should be noted that even in the case of an image obtained by shooting a subject having no white or a portion close to white, the maximum density value of each color in the image is substantially equal to the density value of the white or a portion close to white. Known to be. Therefore, if the correction is performed on the basis of the maximum reference value and the minimum reference value, it is possible to correct the color balance even in the image of the subject as described above.

By the way, for example, the color of the light source in the maximum density portion of the image and the color of the light source in the intermediate density portion,
In the case of images with different values, even if the gray balance is corrected so that the two points of the maximum reference value and the minimum reference value match as described above, there is a problem that the gray balance collapses in the intermediate density part. is there. For example, in an image captured using a strobe with backlight, the light source in the maximum density part is sunlight and the light source in the intermediate density part is strobe light, and the light source colors are different.

The above correction is to correct the gray balance on the basis of a portion having the maximum density in the subject, that is, a portion which reflects the sunlight and becomes white or close to white. The gray balance may be lost in the intermediate density area. Further, as shown in FIG. 1 (A), since the density change characteristics of each color of the negative film are not linear changes, the maximum reference density and the minimum reference density match as shown in FIG. 1 (B). With such a correction, the gray balance slightly shifts at the intermediate density.

Therefore, according to the present invention, further, based on the distribution of the density data obtained by the conversion on the color coordinates, a predetermined area including a line passing through the maximum reference value after conversion and the minimum reference value after conversion is provided. Obtain the average value of the density data, correct the conversion relationship of each color according to the curve passing through the maximum density value after conversion, the minimum density value after conversion and the average value, and perform conversion again using the corrected conversion relationship. Correct the gray balance. In a general image, the density data is distributed on a line passing through the maximum reference value after conversion and the minimum reference value after conversion on the color coordinates, or in the vicinity of the line. However, for example, in the image in which the color ferria is generated, the distribution is generated even in the part greatly separated from the line. This distribution corresponds to the high-saturation portion of the image and can be determined to be the distribution that represents the background portion.

For this reason, the average value of the density data in the predetermined area represents the gray balance of the intermediate density portion between the maximum reference value and the minimum reference value after conversion, excluding the influence of color ferria and the like. Therefore, a curve that passes through the maximum density value after conversion, the minimum density value after conversion, and the average value serves as an index representing an appropriate balance between the conversion relationships of the respective colors. Therefore, if the conversion relation of each color is corrected according to the curve and the conversion is performed again using the corrected conversion relation, for example, the color of the light source of the maximum density portion and the color of the light source of the intermediate density portion are different. With respect to an image such as the image having the intermediate density, the color of the light source in the intermediate density portion is corrected to be gray, so that the gray balance is obtained as a whole from the maximum density to the minimum density.

As described above, according to the present invention, the effects of color ferria can be eliminated without deteriorating the ability to correct color balance even for images taken by a plurality of types of light sources.

[0022]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 2 shows a photo processing system 10 according to this embodiment. A large number of negative films 12 having a predetermined number of images taken by a camera (not shown) are brought into the photo processing system 10. The many negative films 12 brought in are connected by a splicing tape or the like, wound in layers, and then set in the film processor 14 of the photographic processing system 10.

The film processor 14 is internally provided with a color developing tank 20, a bleaching tank 22, a bleach-fixing tank 24, a washing tank 26,
28 and a stabilizing tank 30 are arranged in this order, and a predetermined processing liquid is stored in each of these processing tanks. The negative film 12 set in the film processor 14 is sequentially fed into the inside of each processing tank, immersed in each processing solution, and subjected to color development, bleaching, bleach-fixing, washing, and stabilizing. As a result, the negative image recorded as a latent image on the negative film 12 is visualized.

A drying section 32 is provided downstream of the stabilizing tank 30.
Are arranged. The drying unit 32 includes a fan and a heater (not shown). The air flow generated by the fan is heated by the heater to generate hot air, and the hot air is supplied to the negative film 12 so that the moisture adhering to the surface of the negative film 12 is absorbed. To dry. The negative film 12 processed by the film processor 14 is once wound into layers and set in the film image reading device 16.

As shown in FIG. 3, inside the film image reading device 16, a prescan section 36 and a fine scan section 38 are sequentially arranged along the film transport path. The scanning units 36 and 38 respectively scan and read the image recorded on the negative film 12, as described later. An insertion detection sensor 40 is provided on the upstream side of the film transport path. The insertion detection sensor 40 includes a light emitting element 40.
A pair of A and the light receiving element 40B is arranged so as to be opposed to each other with the film transport path interposed therebetween. The light receiving element 40B is connected to the control circuit 42. The control circuit 42 includes the light receiving element 4
Based on the change in the level of the signal output from 0B, it is determined whether or not the negative film 12 is inserted in the film transport path of the film image reading device 16.

Insertion detection sensor 40 and prescan unit 36
, A pair of rollers 44 for nipping and conveying the negative film 12, a reading head 46, a frame number detection sensor 48,
The screen detection sensors 50 are sequentially arranged. Read head 46, frame number detection sensor 48, and screen detection sensor 50
Are each connected to the control circuit 42. In the negative film 12 set in the film image reading device 16,
A transparent magnetic material is applied to the back surface to form a magnetic layer,
Information such as frame numbers, film types, and DX codes may be magnetically recorded on this magnetic layer. The read head 46 is arranged at a position where the information magnetically recorded on the magnetic layer can be read, and reads the information and outputs it to the control circuit 42.

The frame number detecting sensor 48 and the screen detecting sensor 50 are composed of a pair of a light emitting element and a light receiving element, like the insertion detecting sensor 40 described above. Negative film 1
Some of the information 2 includes information such as a frame number that is optically recorded (for example, by a bar code). The frame number detection sensor 48 is arranged at a position where the optically recorded information such as the frame number can be detected, and outputs the detected information such as the frame number to the control circuit 42.

The screen detection sensor 50 is arranged at a position corresponding to the widthwise center of the negative film 12.
Since the density of the non-image portion between the images recorded on the negative film 12 is the density of the base of the negative film 12, the transmitted light amount is larger than that of the portion where the image is recorded. The control circuit 42 monitors the level of the signal output from the light receiving element of the screen detection sensor 50, and when the level increases to a predetermined level corresponding to the base density, and when the level drops from the level corresponding to the base density. Then, it is determined that the edge of the image recorded on the negative film 12 corresponds to the screen detection sensor 50, and the position (and size) of the screen recorded on the negative film 12 is determined based on the timing of edge detection. .

On the other hand, the prescan section 36 is provided with a lamp 52 arranged to emit light toward the negative film 12 passing through the prescan section 36. The lamp 52 is connected to the control circuit 42 via a driver 54, and the magnitude of the voltage supplied from the driver 54 is controlled by the control circuit 42 so that the amount of emitted light reaches a predetermined value. It Three of C (cyan), M (magenta), and Y (yellow) are provided on the light emitting side of the lamp 52.
A CC filter group 56 composed of one CC filter and a light diffusing box 58 are arranged in order, and an image forming lens 60 and a CCD line sensor 62 with a film conveying path interposed therebetween.
Are arranged in order.

Each CC filter of the CC filter group 56 is
The amount of insertion into the optical path is adjusted in advance in order to correct variations in the sensitivity of the three colors R, G, B in the CCD line sensor 62. The light sequentially transmitted through the CC filter group 56, the light diffusion box 58, the negative film 12, and the imaging lens 60 is applied to the light receiving surface of the CCD line sensor 62. The CCD line sensor 62 has a large number of sensor units each including a sensor for detecting the light amount of R light, a sensor for detecting the light amount of G light, and a sensor for detecting the light amount of B light. Are arranged at a predetermined interval along the width direction of the.

Accordingly, the CCD line sensor 62 divides the image into a large number of pixels each having a space of one side of the sensor unit, and detects the amount of transmitted light for each pixel.
The area of each of the pixels divided into a large number in the CCD line sensor 62 is set to 200 μm or less. The image forming lens 60 has one pixel row (hereinafter, referred to as a pixel row) which intersects the optical axis of the light emitted from the lamp 52 among the light transmitted through the negative film 12 and extends in the width direction of the negative film 12. The light transmitted through the position is called CC
An image is formed on the light receiving surface of the D line sensor 62.

An amplifier 64, a LOG converter 66, and an A / D converter 68 are sequentially connected to the output side of the CCD line sensor 62. The signal output from the CCD line sensor 62 is amplified by the amplifier 64, logarithmically converted by the LOG converter 66 (converted to a level corresponding to the density value), and then the A / D converter 68 corresponds to the signal level. Value is converted to digital data. The A / D converter 68 is connected to the control circuit 42, and the converted digital data is input to the control circuit 42 as density value data. The control circuit 42 includes an image buffer 70 capable of holding density data of images on several surfaces, and stores the inputted density value data in the image buffer 70. In addition, the control circuit 4
A CRT display 72 is connected to 2 and performs a process using the input density value data to display a positive image on the display 72.

Further, between the prescan section 36 and the fine scan section 38, a roller group composed of a conveying roller pair 74 and a driven roller 76, and driven rollers 78A and 78 are provided.
A roller group composed of B and 78C is arranged at a predetermined interval. A loop of the negative film 12 is formed between the two roller groups. By this loop, the conveyance speed of the negative film 12 in the prescan unit 36,
The difference between the conveyance speed of the negative film 12 in the fine scan section 38 and the conveyance speed is absorbed. A pulse motor 80 is connected to the transport roller pair 74. Pulse motor 80
Is connected to the control circuit 42 via a driver 82. The control circuit 42 drives the pulse motor 80 via the driver 82 to convey the negative film 12.

On the other hand, the fine scan section 38 has substantially the same structure as the prescan section 36. That is,
The fine scan unit 38 includes a lamp 84 that emits light toward the negative film 12. The lamp 84 is connected to the control circuit 42 via the driver 86, and the magnitude of the voltage supplied from the driver 86 is controlled by the control circuit 42 so that the emitted light has a predetermined light amount. On the light emitting side of the lamp 84, C composed of three CC filters is used.
A C filter group 88 and a light diffusing box 90 are sequentially arranged, and the imaging lens 9 is further sandwiched across the film transport path.
2. The CCD line sensor 94 is sequentially arranged.

Each CC filter of the CC filter group 88 is also
The amount of insertion into the optical path is adjusted in advance in order to correct variations in the sensitivity of the three colors R, G, B in the CCD line sensor 94. The imaging lens 92 includes the CC filter group 8
8. Of the light transmitted through the light diffusion box 90 and the negative film 12, the light transmitted through the pixel array located at the reading position is imaged on the light receiving surface of the CCD line sensor 94. CC
The D line sensor 94 has the same structure as the CCD line sensor 62, but the interval between the sensor units is smaller than that of the CCD line sensor 62. Therefore, CC
Compared to the CCD line sensor 62, the D line sensor 94 divides the image into more finely divided pixels,
The amount of transmitted light is detected for each pixel.

An amplifier 96, a LOG converter 98, and an A / D converter 100 are sequentially connected to the output side of the CCD line sensor 94. The signal output from the CCD line sensor 94 is amplified by the amplifier 96 and the LOG converter 98.
After being converted into a level corresponding to the density value in step A, it is converted into digital data by the A / D converter 100. A /
The D converter 100 is connected to the control circuit 42, and the converted digital data is used as density value data in the control circuit 4.
Entered in 2.

The input density value data is stored in the image buffer 70 as described above. Further, the control circuit 42 calculates the exposure amounts of R, G, and B colors on the printing paper based on the density value data. The control circuit 42 is connected to the printer section 110 of the printer processor 18 described later,
The data representing the calculated exposure amount is transferred to the control circuit 122. Further, a conveyance roller pair 102 is arranged on the downstream side of the fine scan unit 38. Conveyor roller pair 10
A pulse motor 104 is also connected to 2. The pulse motor 104 is connected to the control circuit 42 via the driver 106. The control circuit 42 drives the pulse motor 104 via the driver 106 to convey the negative film 12.

On the other hand, the printer processor 18 is provided with a magazine 114 for accommodating the photographic paper 112 wound in layers. The photographic paper 112 is pulled out from the magazine 114, and the printer unit 110 is passed through the cutter unit 116.
Sent to. When the exposure amount data is transferred from the control circuit 42 of the film image reading device 16, the printer unit 110 exposes the image on the photographic printing paper 112 based on the exposure amount data.

As shown in FIG. 4, the printer unit 110 has an R
Semiconductor laser 118R that emits a laser beam with a wavelength of
Is equipped with. On the beam emission side of the semiconductor laser 118R, a collimator lens 124R and an acousto-optical element (AO
M) A dichroic mirror 134G that reflects only the light of wavelengths 133R and G, a dichroic mirror 134B that reflects only the light of wavelength B, and a polygon mirror 126 are sequentially arranged.

The AOM 133 is provided with an acousto-optic medium, and a transducer which outputs an ultrasonic wave according to an inputted high frequency signal and an ultrasonic wave which has passed through the acousto-optic medium are absorbed on the opposing surfaces of the acousto-optic element. The sound absorber to be used is attached. The transducer of AOM133R is connected to AOM driver 120R,
When a high frequency signal is input from the M driver 120R, one laser beam is diffracted from the incident laser beam, and this laser beam is emitted as a recording laser beam. This recording laser beam is incident on the polygon mirror 126 via the dichroic mirrors 134G and 134B.

The AOM driver 120R has a control circuit 122.
It is connected to the. The control circuit 122 outputs to the AOM driver 120R an exposure amount control signal corresponding to the R exposure amount data of the input exposure amount data. This exposure amount control signal is a pulse signal with a cycle t ₀ as shown in FIG. 9, and the pulse width d is changed according to the exposure amount for each pixel of the R exposure amount data. AOM driver 120R
When the level of the input exposure amount control signal is high, a high frequency signal is output to the AOM 133R, and the recording laser beam is emitted from the AOM 133R accordingly.
Therefore, based on the R exposure amount data, the light amount of the laser beam of the R wavelength with which the photographic printing paper 112 is irradiated is changed every period t ₀ .

Further, the printer section 110 has semiconductor lasers 118G and 118 which emit a laser beam having a predetermined wavelength.
It has B. The wavelength conversion element 124G and the collimator lens 124 are provided on the beam emission side of the semiconductor laser 118G.
G, AOM 133G, and total reflection mirror 136G are sequentially arranged. AOM133G is AOM driver 120G
It is connected to the control circuit 122 via. Control circuit 1
22 outputs an exposure amount control signal corresponding to the G exposure amount data to the AOM driver 120G. AOM driver 120
Similarly to the AOM driver 120R, G outputs a high frequency signal when the exposure amount control signal is at high level.

As a result, the laser beam emitted from the semiconductor laser 118G is converted into the G wavelength by the wavelength conversion element 124G and is incident on the AOM 133G, and the AO 133G is emitted.
When a high frequency signal is input from the M driver 120G, a recording laser beam is emitted from the AOM 133G, is reflected by the total reflection mirror 136G, is reflected by the dichroic mirror 134G, and is combined with the laser beam emitted from the semiconductor laser 118R. To be done.

The wavelength conversion element 124B and the collimator lens 12 are also provided on the beam emission side of the semiconductor laser 118B.
4B, AOM 133B, and total reflection mirror 136B are sequentially arranged. AOM133B also AOM driver 120
It is connected to the control circuit 122 via B. The control circuit 122 outputs an exposure amount control signal according to the B exposure amount data to the AOM driver 120B. Semiconductor laser 118
The laser beam emitted from B is the wavelength conversion element 124.
The recording laser beam, which is converted into the wavelength of B by B, is incident on the AOM 133B, and is emitted from the AOM 133G when the high-frequency signal is input from the AOM driver 120G, is reflected by the total reflection mirror 136B and reflected by the dichroic mirror 134B. Then, the semiconductor laser 11
Laser beam emitted from 8R and semiconductor laser 11
It is combined with the laser beam emitted from 8G.

Dichroic mirrors 134G, 134B
The combined laser beam is incident on the polygon mirror 126. The polygon mirror 126 is connected to the control circuit 122 via a polygon mirror driver 128, and is rotationally driven by the polygon mirror driver 128 and its rotational speed is controlled. Polygon mirror 1
The laser beam incident on 26 is reflected by the polygon mirror 12
The rotation of 6 sequentially changes the emission direction, and scanning is performed along the horizontal direction in FIG. A mirror 130 is arranged on the laser beam emitting side of the polygon mirror 126. The laser beam reflected by the polygon mirror 126 is reflected by the mirror 130 downward in FIG.

On the laser beam emitting side of the mirror 130,
The scanning lens 138 and the mirror 140 are arranged in order. The laser beam reflected by the mirror 130 passes through the scanning lens 138 and is reflected by the mirror 140. On the laser beam emitting side of the mirror 140, the photographic paper 112 is arranged such that the longitudinal direction thereof coincides with the vertical direction of FIG. 4, and the laser beam reflected by the mirror 140 is photographic paper 1
12 is illuminated. Further, below the laser beam irradiation position on the conveyance path of the photographic paper 112, a conveyance roller pair 142 for nipping and conveying the photographic paper 112 is arranged. A pulse motor 144 is connected to the conveying roller pair 142.
The pulse motor 144 is connected to the control circuit 122 via a driver 146. The control circuit 122 is the driver 1
By driving the pulse motor 144 via 46, the printing paper 112 is conveyed downward in FIG.

As shown in FIG. 2, the photographic printing paper 112 that has passed through the printer section 110 is sent to the reservoir section 150. The reservoir unit 150 has a pair of rollers 1 spaced apart by a predetermined distance.
52 is provided, and the photographic printing paper 112 forms a loop between the pair of rollers 152. This loop absorbs the difference in transport speed between the printer unit 110 and the downstream processor unit 154. The processor unit 154 includes
Color developing tank 156, bleach-fixing tank 158, washing tank 160,
162, 164 are arranged in order. A predetermined processing liquid is stored in each of these processing tanks. Photographic paper 11
2 is sent into each processing tank in order and immersed in each processing solution for processing.

The drying unit 1 is provided downstream of the processor unit 154.
66 is provided. The drying unit 166 supplies hot air generated by a fan and a heater (not shown) to the printing paper 112. As a result, the moisture adhering to the surface of the printing paper 112 is dried. The printing paper 112 that has passed through the drying unit 166.
Is cut by the cutter unit 168 for each print and then discharged to the outside of the printer processor 18.

Next, the operation of this embodiment will be described. The negative film 12 set in the film processor 14 is sent to each processing tank and then to the drying unit 32,
Color development, bleaching, bleach-fixing, washing with water, stabilization and drying are performed. As a result, the latent image recorded by the camera is visualized. The negative film 12 processed by the film processor 14 is set in the film image reading device 16.

Next, referring to the flow charts of FIGS. 5 and 6, the prescan unit 36 of the film image reading device 16 is described.
The action of will be explained. In step 200, it is determined whether or not the negative film 12 is inserted into the film image reading device 16 based on a signal input from the insertion detection sensor 40. Negative film 1 on the film image reading device 16
If it is determined that No. 2 has been inserted, the determination in step 200 is affirmative, and in step 202, the negative film 12 starts to be conveyed.

In the next step 204, the negative film 12
It is determined whether or not it is possible to read information such as the frame number of the image recorded in (3). For example, when the information is optically recorded (for example, a bar code or the like) on the edge portion of the negative film 12, the determination in step 204 is affirmed when the recorded portion corresponds to the frame number detection sensor 48. If the information is magnetically recorded on the transparent magnetic layer formed on the back side of the negative film, the determination at step 204 is affirmative when the magnetically recorded portion of the information corresponds to the read head 46. To be done.

When the determination in step 204 is negative, the routine proceeds to step 206, and it is determined whether or not the image corresponds to the screen detection position corresponding to the installation site of the screen detection sensor 50. When the determination in step 206 is also negative, the process proceeds to step 208, and it is determined whether or not the image has reached the image reading position, more specifically, whether or not the leading pixel row of the image has reached the reading position. If the determination in step 208 is also negative, the process returns to step 202 and the negative film 1
Steps 204, 206, 20 while continuing to carry 2
Each judgment of 8 is repeated.

If the determination at step 204 is affirmative, the routine proceeds to step 210, where the frame number detection sensor 48
Alternatively, information such as a frame number is read by the reading head 46 and the read frame number is stored. If the determination in step 206 is affirmative, step 212
Then, the screen position and the screen size are detected based on the output signal from the screen detection sensor 50, and in the next step 214, the screen position and the size are stored in association with the frame number. If the determination in step 208 is affirmative, in step 216 image scanning and reading processing (described later) is performed, and in step 218, it is determined whether the negative film 12 is finished. When the determination in step 218 is negative, the process returns to step 202 and the above process is repeated.

As described above, the prescan unit 36 sequentially performs the process of reading the frame number, detecting the screen position and size, and scanning and reading the image for a single image frame.
In addition, the above processes for each image frame are performed in parallel.

Next, the details of the scanning reading process in the prescan unit 36 will be described with reference to the flowchart of FIG. When this process is executed, the pixel row at the beginning of the image is located at the reading position, and of the light emitted from the lamp 52 and transmitted through the CC filter group 56, the light diffusion box 58, and the negative film 12, The light transmitted through the pixel array is imaged on the light receiving surface of the CCD line sensor 62 by the imaging lens 60, the signal output from the CCD line sensor 62 is amplified by the amplifier 64, and the density is converted by the LOG converter 66. It is converted into a level corresponding to the value, converted into digital data by the A / D converter 68, and held.

In step 250, the density value data for one pixel column is fetched from the A / D converter 68. Step 25
In step 2, the captured density value data is corrected in accordance with variations in the sensitivity of each of a number of sensor units arranged along the width direction of the negative film 12 and stored in the image buffer 70. In step 254, the pulse motor 80 is driven via the driver 82, and the negative film 12 is conveyed by a predetermined amount corresponding to the distance between the image rows.

At the next step 256, it is determined whether or not the reading of the image for one screen is completed. Step 256
If the determination is negative, the process returns to step 250, and the processes of steps 250 to 256 are repeated until the determination of step 256 is positive. As a result, when the determination in step 256 is affirmative and the process proceeds to step 258, the entire image surface is scanned, and a single image is colored in three colors (R,
Data representing the density of each pixel of the image decomposed into G and B (hereinafter referred to as R image data, G image data, and B image data) is stored in the image buffer 70.

In step 258, the density of the base portion (see FIG. 11) of the negative film 12 is measured for each color of R, G, B and stored. In step 260, the pixel data with the lowest density is extracted from the image data of each color stored in the image buffer 70. In step 262, the optimum light amount of the lamp 84 of the fine scan unit 38 for the read image is calculated and stored based on the extracted data. This is because when the minimum value of the density value data is very small, the fine scan unit 3
This is because there is a possibility that the level of the output signal from the CCD line sensor 94 may be saturated when the image is read in 8.

In step 264, correction is performed by subtracting the base density of the negative film 12 measured in step 258 from the density value of each pixel of each image data stored in the image buffer 70. In the next step 266, each image data stored in the image buffer 70 is averaged. In this averaging process, for example, for each of the R, G, and B image data, the density value of a predetermined pixel is compared with the density values of surrounding pixels, and if the density values differ greatly, This can be realized by performing the process of replacing the average value with the density value of the pixel for all the pixels. As a result, even if dust is attached to the surface of the negative film 12 or is scratched, the influence of these can be reduced.

At step 268, the R, G, and B image data are converted into C (cyan), M (magenta), and Y (yellow) dye densities to correspond to C image data and M image corresponding to the C image. M image data and Y image data corresponding to the Y image are obtained. In the next step 270,
As shown in FIG. 11, the data surrounded by the imaginary line in FIG. 11 is cut out by removing the data of the pixels corresponding to the vicinity of the edge portion of the image from the C, M, and Y image data. In step 272, the screen is divided into a predetermined number n of areas, for example, n = 5 × 5 = 25 areas as shown by a broken line in FIG.

In step 274, for each divided area
Is the maximum value C of the density values of a plurality of pixels belonging to the same area.
_max(i), M_max(i), Y_max(i) and minimum density value C
_min(i), M _min(i), Y_min(i) (However, i identifies each area
Is a code for differentiating and has a value of 1 to n)
It In step 276, according to the following equation (2), the C concentration
Maximum reference value C_maxAs the maximum value of C concentration in each area C
_maxWhile calculating the weighted average value of (i),
Minimum reference value C_minIs the minimum value C of C concentration for each area.
_minCalculate the weighted average of (i).

[0062]

[Equation 1]

However, K (i): weight of area i In addition, in the same manner as described above, the maximum value M of M concentration for each area M
_max(i) and minimum value M _minMaximum of M concentration based on (i)
Reference value M_maxAnd minimum reference value M_minIs calculated for each area
Y concentration maximum value Y_max(i) and minimum value Y_minBased on (i)
Based on the Y density maximum reference value Y_maxAnd minimum reference value Y_min
To calculate. The weight of each area is, for example,
The area corresponding to the central part of the screen where there is a high probability that
The weight of the region can be set to be high. Also,
The amount of light emitted from the lamp 52 peaks at the optical axis position.
As a result, the distribution gradually diminishes toward the periphery.
However, the weight is determined considering the influence of this distribution.
You may do it.

In step 278, the maximum reference values C _max , M _max , Y of each color obtained above are calculated according to the following equation (3).
average value D _max, the minimum reference value C _min of _max, M _min, Y
It calculates an average value D _min of _min.

D _max = (C _max + M _max + Y _max ) / 3 D _min = (C _min + M _min + Y _min ) / 3 (3) In the next step 280, the following simultaneous equations (4) are satisfied. The C image conversion coefficient A _C and the constant B _C are calculated.

D _max = A _C · C _max + B _C D _min = A _C · C _min + B _C (4) Similarly, the M image conversion coefficient A _M , the constant B _M, and the Y image conversion coefficient A _Y , And the constant B _Y , the following (5),
It is obtained according to the simultaneous equations shown in equation (6).

D _max = A _M · M _max + B _M D _min = A _M · M _min + B _M (5) D _max = A _Y · Y _max + B _Y D _min = A _Y · Y _min + B _Y (6) ) In the next step 282, the coefficient _{C C} and the constant B _C of the C image conversion obtained above are used to sequentially substitute a value in the range of 0.0 to 2.0 as the C density into the conversion formula shown in the following formula (7). The lookup table LUTc for converting the C density into the C ′ density to obtain the C ′ image is created and stored.

C ′ = A _C · C + B _C (7) Further, as for M and Y, as shown in the equations (8) and (9), the coefficient A _M , the constant B _{M, the} coefficient A _Y , and the constant B _Y By sequentially substituting values in the same range into the conversion formula using
A lookup table LUTm for converting density to M'density to obtain an M'image and a LUTy for converting Y density to Y'to obtain an Y'image are created and stored.

M ′ = A_M・ M + B_M (8) Y '= A_Y・ Y + B_Y (9) In addition, referring to this lookup table,
C'concentration, M concentration to M'concentration, Y concentration to Y'concentration
The conversion is performed using the equations (7) to (9) above.
Is equivalent to that. Coefficient A of each equation above_C, A_M, A_YOver
And constant B_C, B _M, B_Y(4) to (6) for obtaining
As described above, the expressions have the same value on the left side (D_maxOr
D_min). Therefore, use equations (7) to (9)
12A to 12C as an example of the conversion.
As shown in C_max, M_max, Y _maxValue of and C_min,
M_min, Y_minEven if the values of fluctuate, C
_{ma x}, M_max, Y_maxC'concentration, M'concentration after conversion of
Y'concentration is average value D_maxMatches C_min, M_min, Y
_minThe converted C ′ density, M ′ density, and Y ′ density are average values D
_minTo convert (correct the density value) so that
equal.

In step 284, C image data, M image data, Y image data to C ′ image data, M ′ image data, Y ′ image data are calculated according to each lookup table as an operation for displaying an image on the display 72. Ask for. In step 286, the positive image data (R ′ image, R ′ image, based on the C ′, M ′, and Y ′ image data).
Data representing an image obtained by superimposing the G ′ image and the B ′ image) is obtained, and a positive image is displayed on the display 72 using this data. By referring to this display image, for example, the operator can instruct the correction of the color, the density and the like with respect to the exposure amount.

Next, with reference to the flow chart of FIG. 7, the image reading process in the fine scan section 38 will be described. In step 300, the negative film 12 is conveyed. In step 302, it is determined whether or not the leading pixel row of the image has reached the reading position. If the determination in step 302 is negative, the process returns to step 300, and steps 300 and 30 are performed until the determination in step 302 is positive.
The process of 2 is repeated to continue the transportation of the negative film 12.

If the determination at step 302 is affirmative, the routine proceeds to step 304, where the prescan section 36 takes in the optimum light quantity of the lamp 84, and the voltage supplied to the lamp 84 becomes a value according to the light quantity. Control to be. After performing the process of step 304, wait a little until the light quantity of the lamp stabilizes, and then move to step 306.
Image reading processing is performed in steps 306 to 312.

That is, in step 306, the density value data for one pixel column is fetched from the A / D converter 100. In step 308, the captured density value data is corrected according to the variations in the sensitivity of each of the many sensor units of the CCD line sensor 94, and the corrected data is corrected in the image buffer 70.
Remember. In step 310, the pulse motor 104 is driven via the driver 106, and the negative film 12 is conveyed by a predetermined amount corresponding to the interval between image rows. It should be noted that this carry amount corresponds to the interval between the sensor units and is smaller than the carry amount in the prescan unit 36. Therefore, the fine scan unit 38 finely divides the image into a large number of pixels and measures the transmitted light amount of each pixel.

At the next step 312, it is determined whether or not the reading of the image for one screen is completed. Step 312
If the determination is negative, the process returns to step 306, and the processes of steps 306 to 312 are repeated until the determination of step 312 is positive. As a result, the R image data, G image data, and B image data of a single image are stored in the image buffer 70. Next step 3
At 14, shading correction is performed. This is lamp 8
This is because the light amount of the light emitted from No. 4 also has a distribution in which the optical axis position has a peak and gradually attenuates toward the periphery. In this step 314, the image data stored in the image buffer 70 is corrected according to the distribution of the light amount measured in advance.

In step 316, the base density of the negative film 12 measured by the prescan section 36 is subtracted from the density value of each pixel of the image data stored in the image buffer 70 for correction. In step 318, R, G, B
C image density data is converted to C, M, and Y to obtain C image data, M image data, and Y image data, respectively.

By the way, various conditions for image reading are different between the pre-scan section 36 and the fine scan section 38. For example, as described above, the distance between the sensor units of the CCD line sensor is different between the pre-scan unit 36 and the fine scan unit 38, and the conveyance pitch during image reading is also different. Therefore, the image data obtained by the prescan unit 36 and the image data obtained by the fine scan unit 38 have different pixel areas. There may be differences in the sensitivity of CCD line sensors. Therefore, in the next step 320, the image data obtained in step 318 is corrected according to the difference in various conditions such as the pixel area difference.

In the next step 322, gray balance correction processing is performed. Details of this gray balance correction processing will be described with reference to the flowchart in FIG. First, in step 370, the lookup tables LUTc, LUTm, and LUTy created by the prescan unit 36.
Take in. In the next step 372, the C image data, M image data, and Y image data obtained by the fine scan unit 38 are referred to as C ′ image data, M ′ image data, and Y ′ image data by referring to the fetched lookup tables. Convert to.

The lookup table is C,
This is for obtaining C ′, M ′, Y ′ image data at high speed from M, Y image data, and the present invention is not limited to using a lookup table. For example, by substituting the data for each pixel forming the image data of C, M, and Y into any of the above equations (7), (8), and (9), the image of C ', M', and Y ' Data may be obtained.

At the next step 374, the above-obtained value is obtained.
Image data of C ', M', and Y'is displayed on the color coordinates for each pixel.
To lot. In the following, the horizontal axis represents M ′ concentration and the vertical axis represents
An explanation will be given by taking the color coordinates of the C ′ density and the Y ′ density as an example.
The present invention is not limited to this, and various color coordinates can be set.
It is possible to use, for example, based on a color other than M
Different color coordinates may be used. Thus, as an example, FIG.
A color coordinate diagram as shown in (A) is obtained. Step 37
6 shows, as an example, as shown in FIG. _max
And D_minA predetermined area S including a straight line L connecting with is set.
In the present embodiment, the boundary of the predetermined area S is defined by the straight line L described above.
Straight line L moved by a fixed amount₁, L₂I am trying.

The setting of the predetermined area S is not limited to the above. For example, as the predetermined color coordinates,
When the color coordinates in which the horizontal axis is M'density and the vertical axis is C '/ M' and Y '/ M' are used, C '/ M' and Y '/ M' at D _max and D _min The value becomes 1.0, and the above-mentioned straight line L becomes a straight line parallel to the horizontal axis. In this case, the predetermined area S may be defined such that the straight line L is included and the values of C ′ / M ′ and Y ′ / M ′ are within a range of 1.0 ± the predetermined value α.

As described above, the C ′, M ′, and Y ′ image data have the same C ′, M ′, and Y ′ densities at D _max and D _min . Further, a straight line L connecting these two points represents an appropriate gray balance standard assumed at the time of conversion into C ′ image data, M ′ image data, and Y ′ image data, and the plotted points in a general image are It is distributed on the straight line L or in the vicinity of the straight line L. However, for example, in an image in which color ferria is generated, the distribution is generated even in a portion greatly separated from the straight line L. This distribution corresponds to the high-saturation portion of the image and can be determined to be the distribution that represents the background portion. When the distribution of points in the region corresponding to the intermediate density is slightly deviated from the straight line L, C ′, M ′,
It can be determined that the gray balance in the intermediate density of each image of Y ′ is slightly deviated.

In step 378, the data of the points plotted at positions outside the predetermined area S on the color coordinate diagram are not used, but only the data located in the predetermined area S is used to obtain C ′ for M ′. The average value of the points and the average value of the points of Y ′ with respect to M ′ are calculated, and the corresponding points are plotted on the color coordinate diagram as shown in FIG. 13C as an example. In this way, by calculating the average value without using the data at the position outside the predetermined region S, the influence of the color ferria can be eliminated, and these average values can be used as the appropriate gray level at the intermediate density in the image. It can be used as a balance criterion.

Therefore, in step 380, as an example,
As shown in 13 (C), D_maxAnd D_minPass through
Quadratic curve P passing through the mean value of the points of C'to M '
_CAnd D _maxAnd D_minAnd of Y'to M '
Quadratic curve P passing through the average value of points_YAnd, respectively. This
Like D_max, D_minAnd the point of C'to M '
Between the average value or the average value of the points of Y'relative to M ',
Quadratic curve P_C, P_YSince it connects smoothly with, the quadratic curve P
_C, P_YIs D_max, D_minA proper greyber between
The probability of representing Lance is very high. Note that the above two
Derivation of the next curve is a process of estimating and interpolating changes between three points.
This is an example, and the present invention is not limited to this.

At step 382, the _C relationship with respect to the conversion relationship of the M concentration (see FIG. 12B) is calculated based on the quadratic curve P C.
The density conversion relationship (see FIG. 12A) is the quadratic curve P _C.
Lookup table LU so that the relation expressed by
Correct T _C. As a result, the C concentration is taken as an example in FIG.
A lookup table LUT _C for converting to C ″ density by the conversion relationship shown in (A) is obtained. Further, based on the quadratic curve P _Y , the conversion relationship of Y density with respect to the conversion relationship of M density (see FIG. ) reference) is to modify the look-up table LUT _Y such that the relationship represented by a quadratic curve P _Y. Thus, the Y "concentration conversion relationship shown in FIG. 14 (C) the concentration of Y as an example Lookup table L to convert
UT _Y is obtained. Look-up table LUT _M
No correction is made as shown in FIG. 14 (B).

In step 384, FIG.
Look-up table LU showing the conversion relationship shown in (C)
Referring to T _C , LUT _M , and LUT _Y , C "image data, M" image data, Y "is selected from each of C, M, Y image data.
Obtain image data. By using the above-mentioned lookup table, the maximum reference value and the minimum reference value of each color are converted so as to match, and the balance of C and Y with respect to M at the intermediate density is based on the quadratic curves P _C and P _Y. Will be corrected as.

Note that this processing is not limited to using the lookup table, and C,
By substituting the data for each pixel forming the M and Y image data into the relational expressions representing the quadratic curves P _C and P _Y , the image data of C ″, M ″, and Y ″ are obtained. After performing the process of step 384, the process proceeds to step 324 of the flowchart of FIG.

In step 324, the image data of C ", M", and Y "representing the C" image, M "image, and Y" image are converted into positive image R "image, G" image, and B "image. It is converted into each image data of R ", G", and B ". In addition,
This conversion is performed so that the difference between the maximum value and the minimum value of the converted positive image (density width) corresponds to the sensitivity width of the printing paper 112.

As described above, the C "image data, the M" image data, and the Y "image data have the same maximum reference value and minimum reference value for each color, that is, the maximum and minimum density values substantially match. The color balance has been corrected.
Therefore, in the image in which the R "image, the G" image, and the B "image are superposed, a gray balance can be obtained in the region corresponding to the white or near white portion of the subject and the region corresponding to the black or near black portion of the subject. ing.

Further, even in an image in which a density ferria or a color ferria has occurred, the maximum reference value, the minimum reference value, the average value of the points of C ′ with respect to M ′ and the value of Y ′ with respect to M ′. Since the average value of the points rarely changes, each image of C ″, M ″, Y ″ and R ″,
The influence of ferria is eliminated from each of the G "and B" images.
In addition, since the gray balance reference of the intermediate density portion is corrected by the quadratic curves P _C and P _Y based on the distribution of the image data of C ′, M ′, and Y ′ on the color coordinates, the light source of the intermediate density portion of the light source is corrected. Even if the image has a color different from the color of the light source in the maximum density portion, it is possible to prevent the gray balance from being lost in the intermediate density portion.

Further, in step 324, R ",
The density value of each pixel of each image data of G "and B" is subjected to index conversion to obtain exposure amount data representing the exposure amount of R, G, B for each pixel. From the above, it is assumed that the distribution of the light amount represented by the exposure amount data is uniform on the negative film 12 by recording an ideal image in which the images of C ″, M ″, and Y ″ are superimposed. It becomes equal to the distribution of the light that has passed through the image when irradiated with a different amount of light.

At step 326, the exposure amount data calculated above is transferred to the control circuit 122 of the printer section 110. In step 328, it is determined whether or not the exposure amount has been calculated for all the images recorded on the negative film 12. If the determination in step 328 is negative, the process returns to step 300, and the processes of steps 300 to 328 are repeated. If the determination in step 328 is affirmative, the process ends.

Next, referring to the flowchart of FIG.
The exposure control process in the printer unit 110 will be described. In step 350, rotation of the polygon mirror 126 is started. In step 352, the pulse motor 144
The photographic printing paper 112 is conveyed through the, and the unexposed portion of the photographic printing paper 112 is positioned at the exposure position. In step 354,
The exposure amount data corresponding to the image to be exposed is fetched. In the next step 356 and thereafter, the image is exposed on the printing paper. That is, in step 356, the exposure amount control signal corresponding to the exposure amount data of R corresponding to the first one line of the captured exposure amount data is set to the AOM driver 120R.
To the AOM for the exposure amount control signal according to the G exposure amount data.
An exposure amount control signal corresponding to the exposure amount data of B is output to the driver 120G to the AOM driver 120B.

The AOM drivers 120R, G, B output high frequency signals to the AOMs 133R, G, B, respectively, when the level of the input exposure amount control signal is high. As a result, the AOM 133R, G, B emits a recording laser beam for each pulse period t ₀ of the exposure amount control signal for a time corresponding to the pulse width d, and is combined by the dichroic mirrors 134G, 134B. It is incident on the polygon mirror 126.

The irradiation position of the laser beam on the printing paper 112 is sequentially moved by the rotation of the polygon mirror 126. The pulse period t ₀ of the exposure amount control signal is the irradiation position of the laser beam at the pulse period t ₀ . The amount of movement is determined so as to correspond to the pixel interval of the image recorded on the photographic printing paper 112. Therefore, since the irradiation time of the laser beam for each pixel varies depending on the pulse width d, the exposure amount is changed for each pixel according to the exposure amount data. The laser beam reflected by the polygon mirror 126 is reflected by the mirrors 130 and 140 and is applied to the photographic printing paper 112. One scanning of the laser beam by the polygon mirror 126 causes one pixel row (one line) on the photographic printing paper 112. Exposure is performed.

When exposure for one line is performed, step 3
Moving to 58, until the rotation angle of the polygon mirror 126 reaches the rotation angle at which the incident laser beam is reflected to the scanning start position, the pulse motor 144 causes the photographic paper 112 to have a predetermined amount corresponding to the interval of one line. To transport. At the next step 360, it is determined whether or not the exposure for one image is completed. If the determination in step 360 is negative, the process returns to step 356, and the AOM driver 120 outputs the exposure amount control signal corresponding to the exposure amount data corresponding to the next one line.
The signals are output to R, G, and B, respectively, and the next one line is exposed in the same manner as above.

By repeating the processing of steps 356 to 360 a predetermined number of times, the image is exposed according to the exposure amount data. When the exposure process for one image is completed, the determination in step 360 is affirmative, and step 36
Move to 2. In step 362, it is determined whether or not the exposure has been completed for all the transferred exposure data. If the determination in step 362 is negative, step 352
Then, the process goes back to the same as above, and the exposure process for the next image is performed. If the determination in step 362 is affirmative, the rotation of the polygon mirror 126 is stopped in step 364, and the main exposure control processing ends.

The printing paper 112 for which the exposure control processing has been completed
The unexposed portion is cut by the cutter unit 116 and rewound into the magazine 114, and the exposed portion of the image is sent into each processing tank of the processor unit 154 and then sent to the drying unit 166 for color development, Each of the processes of bleach-fixing, washing with water and drying is performed, and the image exposed by the printer unit 110 is visualized. Printing paper 112 that has been dried
Is cut for each image frame and ejected outside the printer processor 18.

[Explanation of Experimental Results] Next, an example of the results of an experiment for comparing the conventional integral neutral method and the gray balance correction method according to the present invention will be described. FIG. 16 shows the result of scanning and reading a negative image in which an R ferria occurs, with the G density of each pixel on the horizontal axis, and the R density with respect to the G density,
It is the figure which plotted the B density with respect to G density on the vertical axis for every pixel. In FIG. 16, the group of points “*” representing the R density with respect to the G density, which is largely deviated to the vertical axis, represents the red background pixels that occupy a large area in the image.

FIG. 17 shows the printing result when the integral neutral method is applied to the above negative image, the exposure amount is determined based on the integrated transmission density, and the image is printed on photographic paper. In FIG. 17, the group of points “*”, which is largely deviated to the vertical axis side in FIG. 16, has moved to a position near the straight line of inclination “1” that passes through the origin, and along with this movement, A large number of points “*” are distributed at positions deviated to the horizontal axis. From this, it can be understood that the color balance of the main subject is lost due to the influence of the color (red) of the background portion.

On the other hand, in FIG. 18, which shows the print result when the same negative image is printed on photographic paper by determining the exposure amount by applying the gray balance correction method of the present invention, the inclination of "1" is passed through the origin. It is divided into a gray-balanced group that is close to a straight line and a group that is composed of "*" points and the color ratio is greatly deviated to R, and the color balance of the main subject is not disturbed, and It can be seen that the red color in the background is also reproduced at the time of shooting. As described above, when the gray balance correction method of the present invention is applied, even for an image (for example, an image in which a feria is generated) for which an appropriate print result cannot be conventionally obtained,
It is possible to obtain a proper print result.

In the above description, D _max is the average value of the maximum reference values C _max , M _max and Y _max of each color, and D _min is the average value of the minimum reference values C _min , M _min and Y _min of each color. , D _max and D _min are merely references for matching the density values of the respective colors, and are not limited to the above.
For example, the value may not be changed for each image and may be a predetermined constant value, or any one of C _max , M _max , and Y _max and any one of C _min , M _min , and Y _min may be used. May be.

Further, in the above-mentioned embodiment, in each of the scanning units 36 and 38 of the film image reading device 16, CCs are respectively set.
Although the image was scanned and read using the D line sensor, the present invention is not limited to this, and as shown in FIG. 15 as an example, the photometric sensors are arranged in a matrix. The CCD area sensor 170 may be used to detect the amount of light transmitted through each pixel of the image at once.

The prescan unit 36 shown in FIG.
The photometric sensor of the D area sensor 170 has sensitivity to each wavelength of R, G, B, and the imaging lens 60 and CCD
A spectral filter group 172 composed of three spectral filters that transmits only light of R, G, or B wavelengths is arranged between the area sensor 170 and one of the spectral filters by a filter driving device 174. Is inserted in the optical path to sequentially measure the amount of transmitted light of each color.

It should be noted that, like the CCD line sensors 62 and 94, a sensor unit including a sensor for detecting the amount of R light, a sensor for detecting the amount of G light, and a sensor for detecting the amount of B light is If the area sensors are arranged in a matrix, the spectral filter group 172 and the filter driving device 174 can be omitted.

Further, in the above, the exposure amount is determined for each pixel,
The case where the printer unit 110 scans and exposes each pixel has been described as an example, but the present invention is not limited to this, and when an image is exposed by surface exposure as is commonly used in general printers. It is also possible to apply to.

[0106]

As described above, according to the present invention, the image is divided into a large number of areas, and the maximum reference for each color is based on the density values of the three colors corresponding to the dye density of the film measured for each area. The value and the minimum reference value are calculated, the conversion relationship for matching the converted values of the maximum reference value of each color with each other and the converted value of the minimum reference value are matched, and using the calculated conversion relationship, 3 Based on the distribution of the density data obtained by converting the measured color values on the color coordinates, the average of the density data in the specified area including the line passing through the maximum reference value after conversion and the minimum reference value after conversion. Obtain the value, maximum density value after conversion,
The conversion relationship of each color is corrected according to the curve passing through the minimum density value and the average value after conversion, and the conversion is performed again using the corrected conversion relationship. The excellent effect that the correction ability is not deteriorated and the influence of the ferria can be eliminated is obtained.

[Brief description of drawings]

1A and 1B are diagrams showing, as an operation of the present invention, a density change characteristic of each color before correction and a density change characteristic corrected so that a maximum reference value and a minimum reference value match.

FIG. 2 is a schematic configuration diagram of a photographic processing system according to the present embodiment.

FIG. 3 is a schematic configuration diagram of a film image reading apparatus.

FIG. 4 is a perspective view showing a schematic configuration of a printer unit.

FIG. 5 is a flowchart illustrating a main routine of a prescan unit of the film image reading apparatus.

FIG. 6 is a flowchart illustrating a scan reading process of a prescan unit.

FIG. 7 is a flowchart illustrating a reading process in a fine scan unit.

FIG. 8 is a flowchart illustrating details of gray balance correction processing in a fine scan unit.

FIG. 9 is a flowchart illustrating an exposure process in the printer unit.

FIG. 10 is a diagram showing a waveform of an exposure amount control signal output to an AOM driver.

FIG. 11 is a plan view of the negative film for explaining the screen cutting and the area dividing processing of the negative film and showing the base density measurement area.

12A to 12C are diagrams showing conversion relations when converting C density, M density, Y density to C ′ density, M ′ density, Y ′ density.

13A is a diagram showing data plotted on color coordinates, FIG. 13B is a diagram showing a predetermined region S, and FIG. 13C is a diagram showing quadratic curves P _C and P _Y passing through average values. is there.

14A to 14C are diagrams for explaining a process of converting C density, M density, and Y density into C ″ density, M ″ density, and Y ″ density.

FIG. 15 is a schematic configuration diagram showing another example of the configuration of the scanning unit.

FIG. 16 is a color coordinate diagram showing the color balance of each pixel of a negative image in which an R ferria occurs, as an explanation of the experimental results.

FIG. 17 is a color coordinate diagram showing a result of printing by applying the integral neutral method to the negative image of FIG. 15 as a description of the experimental result.

FIG. 18 is a color coordinate diagram showing a result of printing by applying the present invention to the negative image of FIG. 15 as a description of experimental results.

19A and 19B are diagrams for explaining a conventional problem, where FIG. 19A is an ideal density change characteristic of each color of a negative image, FIG. 19B is an actual density change characteristic, and FIG. FIG. 7 is a diagram showing the respective density change characteristics corrected in this way.

[Explanation of symbols]

 16 film image reading device 36 pre-scan unit 38 fine scan unit 42 control circuit 62 CCD line sensor 94 CCD line sensor

Claims (1)

[Claims] 1. An image recorded on a negative film is divided into a plurality of areas, and the density values of three colors corresponding to the dye density of the film are measured for each area, and based on the measured density values. Obtaining the maximum reference value and the minimum reference value for each color, determining the conversion relationship for matching the converted values of the maximum reference value of each color and matching the converted values of the minimum reference value, the determination Based on the distribution on the color coordinates of the density data obtained by the conversion, the measured values of the three colors are converted using the conversion relationship described above, and a predetermined line including the maximum reference value after conversion and the minimum reference value after conversion is included. Obtain the average value of the density data in the area, modify the conversion relationship of each color according to the maximum density value after conversion, the minimum density value after conversion, and the curve that passes through the average value, and convert again using the modified conversion relationship. To correct the gray balance, Gray balance correction method.