JPH04875A - Film picture reader - Google Patents

Abstract

PURPOSE:To eliminate the necessity of performing auxiliary scanning for shading correction only by performing the shading correction in such a way that whether or not each section of a film stage is positioned in an optical path is detected by driving the film stage or CCD line sensor for scanning and a film picture is read. CONSTITUTION:When it is read that a light transmissive window 12a for white ground correction is positioned in an optical path from the ON signal of a sensor 18 by moving a film stage 12 and detecting a projection for detecting shading position by means of a photosensor 18, transmitted light is read by one line quantity and RGB signals are A/D-converted. The the A/D-converted signals are successively stored in a line memory as white ground correcting signals. When the sensor 18 detects a light transmissive window 12c for film positioned in the optical path and a film reading starting position, film picture reading operations are performed. Read picture signals are added to a shading circuit at every R, G, and B signals.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a photoelectric conversion type image reading device for reading film images.

[Conventional technology]

Conventionally, an image reading device is known in which a film image is projected and read by a CCD line sensor (Japanese Patent Laid-Open No. 64-24690).

FIG. 5 shows an example of such an image reading device, in which a light source 101 projects light onto a color film 104 via a condenser lens 102 and an optical filter 103 for positive film or negative film. The film is fed at a constant speed in the direction of the arrow in the figure, and an optical image of the film is formed on a CCD line sensor 106 by an imaging lens 105.
5 CCD line sensor 106 read every scanning line
The R, G, and B digital outputs of the A/D converter 107
The shading correction circuit 109 corrects the uneven sensitivity of the CCD line sensor 106 and the uneven amount of light from the light source 101.

In this correction, the light source 101 is turned on, and the difference between the CCD output (white background correction signal) when there is no film and the CCD output (black background correction signal) when the light source is turned off is stored in the shading RAM 103 for each pixel. This is done by optimizing the signals obtained by reading the film image using the stored correction values for each pixel. R, G with shading correction
, B image code is further subjected to density conversion and color conversion, and is output as appropriate by a printer or the like.

[Problem to be solved by the invention]

Incidentally, the CCD line sensor output varies over time due to temperature fluctuations. In addition, the amount of light from the light source fluctuates due to instability in the light amount at the end of the lamp's life, fluctuations due to changes in the light source power output due to temperature changes, changes in the refractive index of the optical system due to temperature changes, and fluctuations due to mechanical deformation. have. Furthermore, when using a lamp that generates high heat, a heat ray absorption filter is inserted to cut off infrared rays, but its spectral characteristics change due to temperature changes, and the amount of light changes.

In this way, the CCD line sensor output and light intensity change over time, so in order to read film images with high resolution,
Shading correction is required to correct such unevenness in light amount and CCD sensitivity. The white background correction signal for shading correction must be read with no film on the optical path of the image reading device, so the procedure is shading correction → film insertion → image reading, which results in long operator time (and poor operability). In addition, there is a possibility of an erroneous operation in which the shading correction signal is read with the film inserted in the optical path, and a mechanism to issue a warning message is required, resulting in high costs. there were.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a film image reading device that can perform shading correction by reading a shading correction signal and a film image signal after inserting a film.

[Means to solve the problem]

To this end, the present invention arranges a film stage having a transparent part for shading correction and a transparent part for film image reading on the film image reading optical path, and also detects whether each part of the film stage is located within the optical path. The present invention is characterized in that it includes a sensor for detection and a scanning drive means for moving the film stage or CCD line sensor, and a system controller controls the scanning drive, signal reading, and shading correction. Furthermore, if dark current correction of the CCD line sensor is required, a light shielding section is provided on the film stage.

Then, in one sub-scan to read the image quality, the transmitted light for white background correction (and the dark current signal for black background correction if dark current correction of the CCD line sensor is required) and the film image signal are sequentially read. shading correction is performed.

[Effect]

The present invention provides a film stage or CC having a transparent section for shading correction and a transparent aS for reading film images.
The D-line sensor is scan-driven and detects whether each part of the film stage is located in the optical path.When it first detects that the transparent part is located in the optical path, it reads one line of white background correction signals. Then, when it is detected that the film image reading transmission section is located in the optical path, the film image is read and shading is corrected using the already read white background correction signal.

In addition, if dark current correction of the CCD line sensor is required, a light shielding part is provided on the film stage, and after reading and storing one line of white background correction signals, the light source is set to 0FFL, and when the light shielding part is located in the optical path. One line of dark current is read as a black background correction signal, and when the reading of the dark current is completed, the lamp is turned on to read the film image and perform shading correction.

In this way, the shading correction signal and the film image signal can be read after the film is inserted, so that the image can be read and the shading can be corrected in one sub-scanning for reading the film image.

〔Example〕

Examples will be described below with reference to the drawings.

FIG. 1 is a diagram for explaining a film scanner used in the image reading device of the present invention, FIG. 2 is a diagram showing the overall configuration of an image reading device using the film scanner of FIG. 1, and FIG. FIG. 4, a block diagram of the image reading device, is a diagram for explaining the image reading sequence. In the figure, 1 is a film scanner, 11 is a slide table, 12 is a film stage, 13 is a ball screw, 14 is a film holder, 15 is a guide, 16 is a shading position detection projection, 17 is a film reading position detection projection, and 18 is a Photo sensor, 21 is a lamp, 22 is a condensing lens, 23
is a heat ray absorption filter, 24 is a filter, 24a is a positive filter, 24b is a negative filter, 25 is an imaging lens,
26 is a CCD line sensor.

This embodiment is an example in which white background correction and black character correction are performed. In FIG. 1, the film scanner 1 includes a film stage 12 placed on a slide table 11, and the film stage 12 is operated by a motor (not shown) or the like. and ball screw 1
By rotating 3, the guide 15 slides in the direction of the arrow in the figure. film stage 1
2 is provided with a transparent window 12a1 for white background correction, a light shielding part 12b for black background correction, and a transparent window t2c for film reading. Note that the film has a film mount part around the film hole, so the light-transmitting part 12a is connected to the light-blocking part 12.
If the transparent part 12a is provided between the transparent window 12c and the transparent window 12c, it is necessary to provide the transparent part 12a aside from the film mount part, which increases the size of the film stage. The light shielding part 12b is connected to the light transmitting part 1.
2a and the transparent window 12c, the light shielding part 12
Since b may overlap the film mount portion, the film stage can be made smaller.

A film is attached to the film reading transmission window 12c by a film holder 14. The position of the film stage is determined by detecting the protrusions 16 and 17 with the photosensor 18, and detecting whether or not the transparent window 12a for white background correction, the light shielding part 12b for black background correction, and the window 12c for film transmission are on the optical path.

Image reading using such a film scanner will be explained with reference to FIGS. 2 to 4. In addition, in FIG. 2, each element of the optical system is shown in its cross section.

In FIG. 2, light from a lamp 21 is condensed by two condensing lenses 22, and is projected onto the film scanner 1 through a filter 24. A heat ray absorption filter 23 is disposed between the two condensing lenses 22 to absorb infrared light in order to prevent the influence of the temperature of the lamp 21. Further, the filter 24 has a positive filter 24a and a negative filter 24b, and can be selected depending on whether the film used is a positive film or a negative film. The light transmitted through the film scanner is imaged by an imaging lens 25 on a CCD line sensor 26 and read.

The overall control of these light sources, filters, film scanners, CCD line sensors, etc. is performed by a sequence controller 30 as shown in FIG. That is, the sequence controller 30 controls the lamp power supply 32 via the lamp controller 31, controls the voltage supplied to the light source 21 to adjust the amount of light, and also controls the filter controller 33 to drive the motor 34. Control to select positive filter or negative filter and set either one. Further, the motor controller 35 controls the motor 36 to drive the film scanner, and at the same time reads the output of the sensor 18 to detect the scanning position of the film stage. It also controls the CCD driver 37 to drive and control the CCD 26 .

When reading, insert and set a positive or negative filter in the optical path depending on the type of film, and set the lamp 2.
1 is turned on to drive the motor controller 35 and start sub-scanning. Set the film stage 12 to the 1st v
! J is moved from the right side to the left side, and the photosensor 18 detects the shading position detection protrusion, and when it is read from the ON signal of the sensor 18 that the transparent window 12a for white background correction is located in the optical path (the fourth (Fig. 4), the sequence controller 30 drives the CCD driver 37 to read one line of transmitted light (Fig. 4). And I read R,
The G and B signals are converted to/D, switched by a switch circuit 41, and sequentially stored in line memories 42, 43, and 44 as white background correction signals. The system controller 30 is
After reading the white background correction signal, turn the lamp 21 to 0F.
FL (Figure 4), CC when the light shield is located in the optical path
The D driver 37 is driven to read the dark current. In this case, even if the lamp current is turned off, the lamp continues to emit light for a while, so it is necessary to read it with a light shielding part. The read R, G, and B signals of the dark current are similarly A/D converted, switched by the switch circuit 41, and manually inputted to the line memories 42, 43, and 44 as a black background correction signal, and then converted from the value of the white background correction signal in the memory. The dark current value of the corresponding pixel is subtracted and re-stored in the line memory. Next, turn the lamp ONL (4th
When the film transmission window 12c is positioned within the optical path and the film reading start position is detected by the sensor 18, the film image is read (Fig. 4). The read image signal is converted into R and G signals via a switch circuit 41.

Each B signal is applied to the shading circuit 45.

The shading circuit 45 reads the correction signals stored in the line memories 42 to 44, optimizes each pixel of the film image using the read values, and stores the shading-corrected R, G, and B image signals in a buffer memory. 46 and output to a printer, CRT, etc. as appropriate. The sub-scanning ends in this way, but the film stage is driven at a constant speed during the sub-scanning period.

In the above embodiment, the light-transmitting window 12a is provided inside the film stage, but the part from the left end to the light-transmitting window is cut so that the light-shielding part is at the left end, and the left-hand side of the light-shielding part, that is, the cut If the cutout is used as a light-transmitting part, there is no need to provide a light-transmitting window, and the film stage can be made narrower and more compact.

Further, in the above embodiments, the sensor fixation and film moving method was explained, but it goes without saying that a sensor moving and film fixing method may also be used.

In addition, although the above embodiment describes the case where white background correction and black character correction are performed, dark current correction may not be necessary depending on the CCD, and in that case, it is not necessary to provide a light shielding part on the film stage. After reading the white background correction signal, it is sufficient to read the film image signal and perform shading correction.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to read the white background correction signal and, if necessary, the black background correction signal in one sub-scanning of the film scanner, so that the sub-scanning is performed only for shading correction. There is no need to do this, and the shading signal and film image can be read while the film is inserted, which simplifies the operation. In particular, fluctuations in the amount of light, fluctuations in the amount of light, and fluctuations in the sensor output are likely to occur due to the influence of temperature.
Even in such cases, it is desirable to perform shading correction for each image reading scan in order to obtain high image quality.
According to the present invention, it is possible to accurately meet such demands.

[Brief explanation of the drawing]

FIG. 1 is a diagram for explaining a film scanner used in the image reading device of the present invention, FIG. 2 is a diagram showing the overall configuration of an image reading device using the film scanner of FIG. 1, and FIG. FIG. 4 is a block diagram of the image reading device. FIG. 4 is a diagram for explaining an image reading sequence, and FIG. 5 is a diagram for explaining a conventional film image reading device. 1... Film scanner, 11... Slide stand, 1
2... Film stage, 13... Pole screw, 1
4... Film holder, 15... Guide, 16...
-Protrusion for detecting shading position, 17... Protrusion for detecting film reading position, 18... Photo sensor, 21
Lamp, 22 Condensing lens, 23 Heat ray absorption filter, 24 Filter, 24a Positive filter, 24b Negative filter, 25 Imaging lens, 26...CCD line sensor. Applicant Fuji Xerox Co., Ltd. Agent Patent Attorney Masanobu Hirukawa (7 others) 1st

Claims (2)

[Claims] (1) In a film image reading device that irradiates light onto a positive or negative color film, forms an optical film image on a CCD line sensor, converts it into an electrical signal, and performs shading correction using a separately read transmitted light signal. , a film stage having a transparent part for shading correction and a transparent part for reading film images, a position detection means for detecting whether each part of the film stage is located in the optical path, and a film stage or a CCD line sensor. 1. A film image reading device comprising: a scanning drive means for moving a film stage or a CCD line sensor to scan and drive a film stage or a CCD line sensor to sequentially read a transmitted light signal and a film image signal and perform shading correction. (2) Positive or negative color film is irradiated with light, an optical image of the film is formed on a CCD line sensor, converted into an electrical signal, and shading is corrected using a separately read transmitted light signal and dark current signal. In a film image reading device, a film stage has a light-transmitting part for shading correction, a light-shielding part, and a light-transmitting part for reading film images, and a position detection means for detecting whether each part of the film stage is located within an optical path. and a scanning drive means for moving the film stage or CCD line sensor, and scan and drive the film stage or CCD line sensor to sequentially transmit transmitted light signals, dark current signals,
A film image reading device characterized in that it reads a film image signal and performs shading correction.