JPH0761120B2 - Positive / negative conversion image signal processing method - Google Patents

Description

The present invention converts a positive image equivalent density signal into a negative image equivalent density signal when a negative image is reproduced on an output photosensitive material in an image output device such as a color scanner, a laser color printer and an ink jet. The present invention relates to a method for processing an image signal.

Conventionally, for example, in a color scanner, image processing for outputting a three-color separated monochrome negative image signal after photoelectrically scanning an input positive original is generally performed.However, when outputting this image signal, the scanner operator himself / herself In order to achieve this negative image equivalent density after determining the negative image equivalent density for use in internegatives by back-calculating from the target density on the final print photosensitive material,
A conversion curve serving as a standard for converting an input density signal corresponding to a positive image into a density signal corresponding to a negative image is operated.

Therefore, a certain degree of skill is required of the operator,
Also, there is a problem that reproduced images inevitably vary among operators and work efficiency is poor.

Also, for example, when a reproduced image is obtained by photoelectrically scanning an image original with a high-precision scanner such as a layout scanner or a laser color printer, a signal processing unit is provided in the middle of the process to correct the color of the input density signal. In some cases, signal processing such as sharpness enhancement (Japanese Patent Application No. 57-66053) or gradation setting (Japanese Patent Application No. 57-72781) may be performed. However, there are two types of image originals, a positive original and a negative original, and two types of desired reproduced images, a positive image and a negative image, which are different for each combination of the positive and negative types of the original and the reproduced image. The provision of the signal processing unit of 1 has a disadvantage that the system scale becomes large.

In such a case, for example, by one signal processing unit,
It would be very convenient if signal processing for all the above combinations could be performed. However, for that purpose, it is necessary to be able to reproduce either the positive image or the negative image by the density signal subjected to the signal processing in the same signal processing unit. But,
When the signal processing in this processing unit is easier to handle the density signal corresponding to the positive image, the density signal corresponding to the positive image is used in this processing unit, and when the positive image is desired as the reproduced image. In this case, the positive density signal from this processing unit is output as it is, and when a negative image is desired as a reproduced image, the positive density signal from this processing unit is regarded as the density to be realized on the final print photosensitive material. It is desirable to output this density signal after converting it to a density signal corresponding to a negative image.

The present invention has been made in order to solve the above-mentioned problems, and also to provide the above-mentioned applications.
It is a first object of the present invention to provide a method for smoothly and easily converting a density signal output from a reading means into a negative density signal corresponding to an internegative for accurately realizing the density.

A second object of the present invention is to provide a positive / negative conversion processing method that can be used for various purposes. As various applications, for example, in order to print on a color print sensitive material such as photographic paper and color positive film, a color negative image is printed on a color negative film (inter negative) or a color transmission film (reversal film, dupe film, etc.) other than the color negative film. To output,
Alternatively, a three-color separated monochrome negative image may be output to a monochrome film. When outputting a negative image to the above-mentioned color transmission film, it is also necessary to calculate the density of the orange mask as seen in the negative film in order to remove the improper absorption of the output photosensitive material dye.

A positive negative conversion image signal processing method according to the present invention is a positive negative conversion image signal processing method in an apparatus for generating a positive negative from a positive original for generating a positive image from an inter negative. The negative on the inter-negative photosensitive material is passed through a memory table in which the characteristics for correcting the positive density signal on the final positive print photosensitive material are selectively stored so that the positive density signal on the material is desired. It is characterized in that an internegative is generated by converting into a density signal corresponding to an image. The positive density may be given as an image signal that has been subjected to some signal processing after photoelectrically scanning the image original with a high-precision scanner such as a color scanner or a laser color printer to read the image signal. It is also conceivable that the frame memory of a scene photographed by a TV camera may be given as a thing converted into a density signal form.

The conversion means to which the method of the present invention is applied is preferably formed by two conversion units as described below.
That is, a first conversion unit (using a memory table) for converting an output signal from the reading unit into a printing density signal for the final print sensitive material, and a printing density signal output from the first conversion unit It is a second conversion unit that converts a negative image equivalent signal that realizes density. The density signal is not limited to a logarithmic signal such as density, but may be a linear signal such as brightness.

According to the method of the present invention, when a density signal corresponding to a positive image desired to be realized on the final print light-sensitive material is given, an output feeling that can realize a positive image whose density is the final target on the final print light-sensitive material is realized. Since the negative density signal corresponding to the density on the material (inter negative sensitive material; the same applies below) is automatically converted, the color processing conditions (gradation setting, gradation setting, which the scan operator must set)
The sharpness enhancement level, color correction amount, etc.) need only be the conditions on the final printed light-sensitive material. That is, conventionally, the operator needs some experience to inversely calculate the color processing condition on the output photosensitive material from the desired color processing condition on the final printed photosensitive material. If you don't need it. In addition, it is possible to improve the work efficiency because it is possible to save the labor of artificially inversely calculating the color processing conditions.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an example of the flow of a density signal when the present invention is applied to a color scanner.

An input signal obtained by photoelectrically scanning a negative document loaded on the input drum 1 is converted into a density signal by the logarithmic conversion circuit 2 and then passed through an AD converter 3 to be converted into a digital signal. After that, the input signal processing unit 4 (a process of converting the input density signal corresponding to the integrated density into an analysis density, and a negative / positive conversion process when the input original is a negative (applicant: FUJIFILM Corporation July 1983) 4 patent application (2)), etc.), and further, is input to the color processing unit 5 which should be called the heart of this system to be subjected to color processing, gradation processing, sharpness processing, etc. It Thereafter, the density signal output from the color processing unit 5 is input to the output signal processing unit 6 and converted into an output photosensitive material negative image equivalent signal for achieving a target density on the print photosensitive material, Further, the laser beam that is input to the modulator 8 via the DA converter 7 and output from the light source 9 is modulated, and a desired image is reproduced on the output drum 10. In the apparatus as shown in this embodiment, the density signal after photoelectrically scanning the original document is subjected to processing such as color processing and gradation conversion processing to obtain the density desired on the output photosensitive material. Converted to the corresponding density signal.

FIG. 2 is a block diagram showing in more detail the portion of FIG. 1 related to the present invention.

In FIG. 2, a density signal that has passed through the color processing unit 5 (a density signal corresponding to the density desired to be realized on the print material).
Is converted into a printing density for the printing material by the printing density conversion table 11. Next, this print signal is sent to a positive / negative operating circuit 12 (multiply accumulator) and converted into an output photosensitive material negative image equivalent density signal for realizing the density desired to be realized on the print photosensitive material. The arithmetic circuit 12 performs the following arithmetic operation.

D _i = a _0i ＋ a _1i P _Y ＋ a _2i P _M ＋ a _3i P _C ＋ a _4i P _Y P _M ＋ a _5i P _M P _C ＋ a _6i P _C P _Y ＋ a _7i P _Y ² ＋ a _8i P _M ² ＋ a _9i P _C ² ...... 1) (i = Y, M, C) where Di is the signal corresponding to the negative image on the output photosensitive material, a _0i , a _1i … a _9i
Is a coefficient.

Thereafter, the density signal output from the arithmetic circuit 12 is converted by the light amount control signal conversion table 13 into a light amount control signal for controlling the laser light amount.

Next, the coefficients (a _0i , a _1i ...) Of the first equation used for the setting of the memory table in the above-mentioned printing density conversion table 11 and the calculation performed in the positive / negative operation circuit 12 are performed.
a _9i ) setting is detailed.

First, in setting the memory table, it suffices to set the inverse function of the characteristic curve of the final print sensitive material in the conversion table 11 in the form of digital memory. Here, the characteristic curve is a curve representing the characteristic of the photographic light-sensitive material with the horizontal axis representing the common logarithm of the exposure amount E and the vertical axis representing the photographic density D.

Next, in the setting of the coefficient (a _0i , a _1i ... a _9i ) of the first equation, when the print condition for printing on the print sensitive material is known, the density on the output sensitive material under the condition is changed to the print sensitive material. Integral calculation for calculating the image sticking density is performed in advance (for example, using a mini computer) for several hundred sets of the density on the output sensitive material (D _Y , D _M , D _C ). From the hundreds of data thus obtained, the coefficients (a _0i , a _1i ... A _9i ) that satisfy the first expression can be determined by the least squares method.

The integral formula used for the above-mentioned integral calculation is shown below.

λ: Wavelength Sλ: Spectral sensitivity of print sensitive material Jλ: Spectral intensity of printer light source Tλ: Spectral transmittance of output sensitive material (where output spectral density of sensitive material is Dλ, Tλ = 10
_-Dλ T _B , λ: Output Sensitive Material Base Spectral Transmittance With the above, the present embodiment can be executed.

A supplementary description will be given below regarding the case of outputting a color negative image and the case of outputting a three-color separated negative to a black and white photosensitive material. For a detailed explanation of baking density, see The Theory of the Ph.
otographic Process (James, Macmillan, 1977), P51
Since it is clear by referring to 9 to 523, it is omitted.

In the case of I color negative image output, in the second formula, when the output photosensitive material is a negative photosensitive material, T _B ,
λ is the spectral transmittance of the negative sensitive material orange mask. on the other hand,
If the output light-sensitive material is not a negative light-sensitive material (for example, dupe film, etc.), the density corresponding to the orange mask should be developed using the three primary colors (Y, M, C). To do so, give T _B , λ the spectral transmittance when the orange mask is expressed using the three primary colors (Y, M, C) (which is almost equal to the base spectral transmittance of the negative photosensitive material). For example, the density on the output sensitive material calculated from the coefficients a _ij (i = 0,1 ... 9, j = Y, M, C) obtained from those sample data corrects the improper absorption of the output sensitive material. The concentration will take into account the orange mask.
That is, an image of an orange mask is obtained as if it were a negative sensitive material.

II When outputting a three-color separation negative on a black and white light-sensitive material It is not necessary to generate an orange mask as in the case of outputting a color negative image. That is, the spectral transmittance in the state where no color is developed may be given to T _B , λ in the second equation.

As described above, in this embodiment, the density on the output photosensitive material is automatically calculated including the correction of the improper absorption of the output photosensitive material dye, so that the number of elements that can be artificially determined is further reduced. Therefore, the work efficiency can be improved.
Furthermore, the conversion in the present embodiment may be performed only by using a memory table, a multiplication accumulator, etc., and does not require a large-capacity image memory or a circuit that executes integral calculation, and can perform calculation at high speed and in real time. it can.

Further, the operation performed by the positive / negative operation circuit 12 may be modified as follows according to the required accuracy.

That is, when high accuracy is not required, the correction is made as D _i ′ = a _0i + a _1i D _Y + a _2i D _M + a _3i D _C ... 3) ( _i = Y, M, C).

Also, if higher accuracy is _{required, D i '= a 0i +} a 1i D Y + a 2i D M + a 3i D C + a 4i D Y D M + a 5i D M D C + a 6i D C D Y + a _7i D _Y ² + a _8i D _M ² + a _9i D _C ² + a _10i D _Y D _M D _C + a _11i D _Y D _M ² + a _10i D _Y ² D _M + ... 4) (i = Y, M, C) Fix it.

Although all the above-described embodiments are premised on the processing by the digital circuit, it goes without saying that the processing may be carried out by the analog circuit.

[Brief description of drawings]

FIG. 1 is a block diagram showing an example of the flow of a density signal when the present invention is applied to a color scanner, and FIG. 2 is a block diagram showing a part of FIG. 1 in more detail. 1 ... Input drum, 2 ... Logarithmic conversion circuit 3 ... AD converter, 4 ... Input signal processing unit 5 ... Color processing unit, 6 ... Output signal processing unit 7 ... DA converter, 8 ... Modulator 9 …… Laser light source, 10 …… Output drum 11 …… Baking density conversion table, 12 …… Positive negative operation circuit 13 …… Light intensity control signal conversion table

Front page continued (72) Inventor Osamu Shimazaki 798, Fujidai Photo Film Co., Ltd., Kaisei-cho, Ashigarashie-gun, Kanagawa Prefecture Photo (72) Inventor Hitoshi Urabe, 798, Miyadai, Kaisei-cho, Ashigagami-gun, Kanagawa Pref., Fuji Photo Film Co., Ltd. (56) References JP-A-55-4071 (JP, A) JP-A-56-113138 (JP, A)

Claims (3)

[Claims] 1. A positive-negative conversion image signal processing method in an apparatus for producing an internegative from a positive original for producing a positive image from the internegative, wherein an input positive density signal is a positive density signal on a final positive print photosensitive material. So that the desired positive image density signal on the inter-negative photosensitive material is stored in the final positive print photosensitive material through a memory table in which the characteristics for correcting the positive density signal are selectively stored. A positive / negative conversion image signal processing method, characterized by converting to generate an internegative. 2. A negative image on an inter-negative photosensitive material, which is necessary to realize the printing density, by converting the input positive density signal into a printing density signal for the printing photosensitive material. The positive / negative conversion image signal processing method according to claim 1, wherein the method is performed by converting to a corresponding density signal. 3. The input positive density signal is converted into the printing density signal by passing through a memory table,
Then, a matrix operation is performed on the burned density signal so as to convert it into a density signal corresponding to a negative image on the inter-negative photosensitive material. The positive-negative conversion image signal processing method described.