JPH11341345A - Image correcting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image correcting device capable of obtaining a uniform image in the case of using an area sensor. SOLUTION: This device is provided with an illuminating device 1, which a two-dimensional image into an analog signal by using plural elements arranged two-dimensionally, a CCD sensor 4, an EEPROM 11 which stores a correction quantity that is for compensating the non-uniformity of illumination of the device 1, an A/D converter 6 which converts an analog signal outputted from the sensor 4 into a digital signal and a RISC(reduced instruction set computer) 14, which corrects the value of a digital signal outputted from the converter 6 based on correction quantity stored in the EEPROM 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image correction apparatus for compensating for non-uniformity of an image read by an image pickup device such as a two-dimensionally arranged CCD.

[0002]

2. Description of the Related Art In recent years, with the spread of personal computers and image processing software, devices for reading images, such as digital cameras and film scanners, have been rapidly spreading. Among them, a digital camera uses an area sensor (CCD sensor) having a large number of elements arranged on a plane, and forms an image of a subject on the area sensor using an optical lens. The formed subject image is output as an analog electric signal by the area sensor, then converted into a digital signal, and the subject image is recorded as digital image data.

On the other hand, in a film scanner, for example, a developed silver halide film is fed, and a line sensor (CCD) in which a number of elements are arranged in a direction perpendicular to the film feeding direction.
An image is captured by line-scanning this film using a sensor. By such a line scan, image data which originally has a spread of a plane is decomposed into several hundred or 1000 or more one-dimensional images and taken in.

[0004]

To reduce the size of a digital camera, it is desirable to use a bright and small-diameter lens. However, a so-called bright optical lens having a small F-number has a problem that the peripheral light amount on the screen is lower than that at the center. Has optical properties. In order to reduce the size of the camera, it is necessary to reduce the size of the lens. However, due to the existence of such optical characteristics, there is a limit in reducing the size of the lens. It is difficult to plan.

On the other hand, when an image formed on a film is to be taken in, if a line sensor such as the above-described film scanner is used, the illuminance of the illuminating device for illuminating the film is determined by the line sensor. Only the extending direction of the element needs to be taken into consideration, and uniform illuminance can be easily ensured as compared with the area sensor. Therefore, there is a possibility that a uniform image can be ensured.

[0006] However, film feeding is required for capturing an image by the line sensor, and the image cannot be captured in a short time. Therefore, when it is necessary to capture an image in a short time, it is advantageous to use an area sensor. In this case, unless the illuminance of the illuminating device is made uniform within a plane corresponding to the entire screen, the image is not required. Cannot ensure the uniformity. However, it is practically extremely difficult to ensure two-dimensional uniformity of the illuminance of the lighting device. The light quantity of the illumination device decreases as approaching the four corners of the image formed on the film. Such a decrease in the amount of light in the peripheral portion of the image always occurs to some extent, and the image in the peripheral portion becomes dark. For this reason, when an area sensor is used, the speed of capturing an image is improved due to the unevenness of the amount of illumination light, but there is a problem that the uniformity of the image is deteriorated.

An object of the present invention is to provide an image correction device which can obtain a uniform image when an area sensor is used.

[0008]

FIG. 1 shows an embodiment of the present invention.
Explained in connection with FIG. 10, the invention according to claim 1 includes imaging means 1, 3, and 4 for converting a two-dimensional image into an analog signal by using a plurality of two-dimensionally arranged elements. A storage unit for storing a correction amount for compensating for non-uniformity of a conversion rate between pixels in the units, and converting an analog signal output from the imaging unit to a digital signal; The above-mentioned object is achieved by providing the A / D conversion means 6 and the correction means 14 for correcting the value of the digital signal output from the A / D conversion means 6 based on the correction amount stored in the storage means 11. Is done. According to a second aspect of the present invention, in the image correction device according to the first aspect, the imaging units 1, 3, and 4 are illuminated by the illuminating unit 1 that illuminates the film F on which the image is formed and the illuminating unit 1. Conversion means 4 for converting the image of the film F into an analog value by means of a plurality of elements arranged two-dimensionally, and the storage means 11 stores a correction amount for compensating for the illuminance non-uniformity of the illumination means 1. Is what is being done. According to a third aspect of the present invention, in the image correction apparatus according to the first or second aspect,
The storage unit 11 stores the one-dimensional correction data in the X direction and the one-dimensional correction data in the Y direction of the two-dimensional image as the correction amount, and the correction unit 14 stores the correction data based on the corresponding correction data of the X coordinate and the Y coordinate. This is to correct the value of the digital signal of the pixel at an arbitrary XY coordinate output from the A / D converter 6. According to a fourth aspect of the present invention, in the image correction apparatus according to the third aspect, the correcting means 14 converts a value obtained by integrating or dividing the corresponding correction data of the X coordinate and the Y coordinate into an A / D conversion means. The correction is performed by multiplying by the value of the digital signal of the pixel at an arbitrary XY coordinate output from 6. According to a fifth aspect of the present invention, in the image correction apparatus according to any one of the first to fourth aspects, the nonuniformity of the conversion rates of the image reading units 1, 3, and 4 is set symmetrically, The storage unit 11 stores a correction amount for a part of the reading area of the image reading units 1, 3, and 4, and the correction unit 14 stores the image reading units 1, 3, and 4.
The same correction amount is used for three and four symmetry points. According to a sixth aspect of the present invention, in the image correction apparatus of the first aspect, the image reading units 1, 3, and 4 include an optical lens 3 for forming a subject image on a light receiving surface of the element. In the table, a correction amount for compensating for a decrease in the amount of light around the image based on the optical lens 3 is stored. According to a seventh aspect of the present invention, in the image correction apparatus according to the sixth aspect, the storage unit 11 stores a correction amount using a distance from the optical axis as a parameter, and the correction unit 14 performs processing from the optical axis to each pixel. Is calculated and the correction is performed using a correction amount corresponding to the calculated distance.

In the meantime, in the section of the means for solving the above-mentioned problem which explains the constitution of the present invention, the drawings of the embodiments of the present invention are used in order to make the present invention easy to understand. However, the present invention is not limited to this.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment Hereinafter, a first embodiment of an image correction apparatus according to the present invention will be described with reference to FIGS. The first embodiment is an example of application to an image reading device that reads an image of a silver halide film.

In FIG. 1, F is a silver halide film on which an image has been fixed through a development process, and can be stored in a film cartridge FC shown in FIG. The film F has a film perforation FP corresponding to each image area. The image correction device of the first embodiment is provided with a film feeding device (not shown), and by driving the film feeding device, an arbitrary frame formed on the film F is opposed to a CCD sensor 4 described later. be able to.

In FIG. 1, reference numeral 1 denotes an illumination device for illuminating a film F. As shown in FIG. 3, the lighting device 1 includes a fluorescent lamp 1a, a reflecting mirror 1b for emitting light from the fluorescent lamp 1a in the direction of the film F, and a fluorescent lamp 1a attached to an opening of the reflecting mirror 1b. Direct light from the mirror and reflector 1
and a diffuser plate 1c for diffusing the reflected light from b. As shown in FIG. 3, the length of the fluorescent lamp 1a is
(The width in the horizontal direction in FIG. 3) is set in consideration of uniformity of illumination on the film F and availability of fluorescent lamps.

In FIG. 1, reference numeral 3 denotes an imaging lens for forming an image formed on the film F. In FIG. 1, reference numeral 4 denotes a CCD sensor (area sensor) having a light receiving surface in which a large number of elements are arranged in a matrix, and a subject image projected via an imaging lens 3 is a CCD sensor 4.
Are arranged so that an image is formed on the light receiving surface of the light emitting element. On the light receiving surface of the CCD sensor 4, a filter which is partitioned into regions corresponding to the respective elements and in which each of the partitioned regions is regularly colored in one of RGB (red, green, blue) is attached. With such a configuration, each element selectively extracts any one of RGB color components corresponding to the color of the filter.

In FIG. 1, reference numeral 5 denotes a method called CDS (correlation double sampling), which samples and holds the output from the CCD sensor 4 at a high S / N ratio, amplifies the output with an appropriate gain, and outputs it. amplifier,
Reference numeral 6 denotes an A / D converter for converting an analog output of the amplifier 5 into a digital signal. In FIG. 1, reference numeral 7 denotes an image signal processing unit 7a for performing image signal processing, a timing clock unit 7b for outputting a timing clock, a white balance unit 7c for detecting white balance, a Y signal (luminance signal) and a C signal ( Signal output unit 7 for outputting a color difference signal)
d) is an image processing DSP (Digital Signal Processor) that incorporates d. The image processing DSP 7 converts RGB pixel signals output from each pixel of the CCD sensor 4 into standardized digital image signals, or an amplifier 5.
It performs data processing and white balance adjustment necessary for automatically adjusting the gain of the image.

The timing generator 8 shown in FIG. 1 receives a signal from the timing clock 7b, and outputs a scanning signal to the CCD sensor 4 at a predetermined interval obtained by counting the signal. As shown in FIG. 1, the CPU 9 includes an amplifier 5, an image processing DSP 7, and a RISC
(Reduced Instruction Set Computer) 14 and controls the operation of each section of the image correction apparatus.

As shown in FIG. 1, the output of the signal output section 7d is connected to a bus SB of the system, and further includes an EEPROM 11 in which correction data for compensating for non-uniformity of illumination of the film F is stored in advance. An image memory 12 for temporarily storing an image during image data compression processing;
A JPEG IC 13 for compressing image data according to the JPEG standard and a RISC 14 for correcting an image according to a correction table are connected to each other via a bus SB.

In the first embodiment, with respect to the illumination of the film F, the illuminance distribution in the X direction is similar regardless of the position in the Y direction, and the illuminance distribution in the Y direction is similar regardless of the position in the X direction. Thus, the shape of the reflecting mirror 1b of the lighting device 1, the characteristics of the diffuser plate 2, and the like are optimized. Therefore, if the illuminance at the center (0, 0) of the image is 1, the relative illuminance at the position (X, 0) is a, and the relative illuminance at the position (0, Y) is b, then (a, b) The illuminance at the position is approximated by a × b. FIG. 4 shows the illuminance distribution of the film F by contour lines.

In order to cancel the influence of the illuminance distribution of the film F, it suffices to multiply each pixel position by a value of 1 / (a × b). The image data output W of

## EQU1 ## It is calculated as W = V / (a × b).

In the first embodiment, the values of 1 / a and 1 / b for each pixel are stored in the EEPROM 11 as a correction table, and the image data output V of each pixel is sequentially stored as 1 / a and 1 / b. Is multiplied. Rather than storing the values of a and b and executing division, multiplication is executed in consideration of the fact that multiplication is generally more convenient for hardware operations than division. is there. Of course, if the operation speed does not matter, division may be executed. FIG. 5 shows an example of a correction table storing 1 / a and 1 / b. Here, as shown in FIG. 4, the illuminance distribution is assumed to have vertical and horizontal symmetry with X = 0 and Y = 0 as symmetry axes, and X> 0 and Y> 0 corresponding to １ ／ of the entire image. Is provided.
The correction table stored in the EEPROM 11 can be created, for example, based on the measurement result obtained by measuring the illuminance distribution on the film F in advance.

Next, the operation of the image correction apparatus according to the first embodiment will be described. When a predetermined frame of the film F is opposed to the CCD sensor 4 by the film feeding device, the image of the frame is converted into an analog signal by the CCD sensor 4 and amplified by the amplifier 5. Amplifier 5
Are converted into digital signals by the A / D converter 6 and input to the image processing DSP 7.

The image processing DSP 7 converts image data input as a digital signal into a standardized digital image signal. As a format of the digital still image, a format including two components of a luminance signal Y and a color difference signal C (Cb, Cr) is used, and is converted into image data of this format by the image processing DSP 7. The color difference signal C is composed of Cb and Cr, but the sampling density is reduced to Ｃ or あ る い は compared to the luminance signal Y. The former is called YUV422 and the latter is called YUV411. Both the luminance signal Y and the color signal C are signals quantified in the same scanning order as the television image scanning from upper left to lower right shown in FIG.

The Y signal and the C signal output from the image processing DSP 7 are transferred to the memory 12 via the system bus SB.
Is output and stored.

Next, image correction is performed on the image data stored in the memory 12 to compensate for the influence of the illuminance distribution of the film F. In the image correction processing, the correction table stored in the EEPROM 11 is stored in the RAM or the cache memory of the RISC 14 in advance, so that the correction table can be read at a high speed at the time of calculation. The operation of multiplying the compressed image data by the values of 1 / a and 1 / b is RISC
14 is performed. As described above, since the luminance signal Y and the color signal C constituting the image data are both signals quantified in the same scanning direction as the television image scanning from upper left to lower right shown in FIG. It is clear which position (pixel) on the screen the luminance signal Y and the color signal C correspond to, so that the correction table of each pixel necessary for compensating for illumination non-uniformity can be easily referred to. There is an advantage that can be. Although FIG. 7 shows non-interlaced scanning, even when interlaced scanning in which odd-numbered lines and even-numbered lines are temporally separated like a television scanning line is adopted, Since it is clear which position on the screen the data corresponds to, reference to the correction table is as easy as in the case of non-interlace scanning.

FIG. 6 is a diagram showing an example of RI for executing image correction processing and the like.
9 shows an operation sequence of SC14. The image correction process is performed by A / D conversion or image processing DS according to a command from the CPU 9.
This is performed in synchronization with the processing in P7. In step S1 of FIG. 6, it is determined whether the storage of the image data in the memory 12 has been completed. If it is determined in step S1 that the storage of the image data has been completed, the process proceeds to step S2. If it is determined that the storage has not been completed, the process proceeds to step S1.
Is repeated. In a succeeding step S2, a pointer for reading the Y signal is set to an initial value (upper left in FIG. 7), and the process proceeds to a step S3. In step S3, the Y signal at the position (pixel) where the pointer is set is read, and the corresponding XY coordinates are obtained, and the process proceeds to step S4. In step S4, an operation of multiplying the correction parameter 1 / a of the X coordinate obtained in step S3 by the parameter 1 / b of the Y coordinate is performed, and the correction amount for the pixel is calculated. Next, in step S5, an operation of multiplying the Y signal component read in step S3 by the correction amount calculated in step S4 is performed.
The component is obtained, and the Y component before correction written in the memory 12 is rewritten to the Y component after correction.

Next, at step S6, the position of the pointer for reading the Y signal is advanced by one according to the scanning order of FIG. Next, in step S7, it is determined whether or not the correction processing has been completed for all the Y signals by reading the pointer. If it is determined that the correction processing has been completed, step S8 is performed.
Then, if it is determined that the correction process has not been completed, the process returns to step S3.

In step S8, the pointer for reading the C signal is set to an initial value (upper left in FIG. 7).
Go to 9. In step S9, the C signal at the position (pixel) where the pointer is set is read, and the corresponding XY coordinates are obtained. Then, the process proceeds to step S10. In step S10, the correction parameter 1 / a of the X coordinate obtained in step S9 and Y
An operation of multiplying by the coordinate parameter 1 / b is performed to calculate a correction amount for the pixel. Then, step S1
In step 1, the Y signal component read in step S9 is multiplied by the correction amount calculated in step S10 to obtain a corrected Y component, and the uncorrected Y component written in the memory 12 is corrected. Rewrite to Y component.

Next, at step S12, the position of the pointer for reading the Y signal is advanced by one according to the scanning order of FIG. Next, in step S13, it is determined whether or not the correction processing has been completed for all the Y signals by reading the pointer. If it is determined that the correction processing has been completed, the process proceeds to step S14, and it is determined that the correction processing has not been completed. If so, the process returns to step S9.

In step S14, operations such as image compression processing in the JPEGIC 13 and recording of compressed data on a recording medium are executed, and the process returns. Since the image signal output from the image processing DSP 7 is a data file having a considerable capacity, it is recorded on a recording medium such as a flash memory or a floppy disk with this capacity unless a very high image quality is required. Never. In the normal case, the image signal output from the image processing DSP 7 is a JPEG I
The capacity is compressed to about 1/10 or less by the high-speed data compression processing in C13 and recorded in the memory 12.

In the first embodiment, since the image correction operation is performed using the RISC 14, flexible data processing is possible and the correction table can be easily changed.
In order to digitally process the output of the CCD sensor 4 in real time and simultaneously perform image correction, it is conceivable to incorporate a calculation function for image correction into the image processing DSP 7.
However, adding such dedicated logic to a DSP already used as a general-purpose product requires a large development cost, and has problems such as an increase in logic and the number of pins.

In the first embodiment, a dedicated JPEGIC
13 using the dedicated IC
Alternatively, image compression may be performed via software using RICS without using. When RISC is used, the arithmetic processing for image correction and the subsequent image compression processing can be executed as a series of operations. Further, in this case, since two processes can be performed by RISC, there is also an effect that hardware cost can be reduced. Although it takes a long processing time, it is also possible to perform image correction using a CPU for operation control (a CPU corresponding to the CPU 9) without using the RISC.

As shown in FIG. 8, the image processing DSP 7,
CPU 9, timing generator 8, EEPROM 1
1. The functions of the JPEG IC 13 and the RISC 14 may be replaced by a dedicated IC 7A that is integrated into one chip.

Second Embodiment Hereinafter, a second embodiment of the image correction device according to the present invention will be described with reference to FIGS. 9 and 10. The second embodiment is an example of application to an electronic still camera. The second embodiment basically has a configuration in which the lighting device 1 and the film F are removed from the second embodiment in FIG.
Hereinafter, description will be made using the reference numerals in FIG. However, in the second embodiment, an imaging lens (photographing lens group) 3 is provided so that a subject image is formed on the light receiving surface of the CCD sensor 4.

In the case of an electronic still camera, since an illumination device such as an image reading device is not used, non-uniformity of an image due to the illumination device does not occur. However, in a so-called bright lens having a small F-number, the peripheral light amount of the screen is lower than that of the center due to the optical property of the lens called the cosine fourth law. As shown in FIG. 9, the amount of light gradually decreases concentrically around the optical axis (0, 0) of the lens toward the periphery.

In the second embodiment, the image is corrected so as to cancel the decrease in the amount of light, thereby ensuring the uniformity of the entire image. In this case, the distribution of the light amount shows a concentric pattern as shown in FIG.
As in the first embodiment, the correction amount cannot be resolved in the X-axis and Y-axis directions. In the second embodiment, since the reduction rate of the light amount is the same on concentric circles having the same distance r from the optical axis, when the center of the image is (X, Y) = (0, 0), (X ² + Y ² ) A correction table using ^1/2 (= r) as a parameter is created and stored in the EEPROM 11. RI
If SC14 is used, it does not matter because it does not take much time to calculate (X ² + Y ² ) ^1/2 . Therefore, image correction can be performed in the same manner as in the first embodiment.

Next, the operation of the second embodiment will be described with reference to FIG. Steps S21 to S34 in FIG. 10 correspond to steps S1 to S14 in FIG. 6 in the first embodiment, respectively.

In step S21 of FIG. 10, it is determined whether the storage of the image data in the memory 12 has been completed. If it is determined in step S21 that the storage of the image data has been completed, the process proceeds to step S22, and if it is determined that the storage has not been completed, step S21 is repeated. In a succeeding step S22, a pointer for reading the Y signal is set to an initial value (upper left of FIG. 7), and the process proceeds to a step S23.
In step S23, the position (pixel) where the pointer is set
Is read and the corresponding XY coordinates (x,
y), and the process proceeds to step S24. In step S24, based on the XY coordinates obtained in step S23, r = (x
² + y ² ) ^1/2 is calculated, and a correction amount using the calculated r as a parameter is read from the correction table. Next, in step S25, an operation of multiplying the Y signal component read in step S23 by the correction amount read in step S24 is performed to obtain the corrected Y component, and the uncorrected Y component written in the memory 12 is calculated. Rewrite with the corrected Y component.

Next, at step S26, the position of the pointer for reading the Y signal is advanced by one according to the scanning order of FIG. Next, in step S27, it is determined whether or not the correction processing has been completed for all the Y signals by reading the pointer. If it is determined that the correction processing has been completed, the process proceeds to step S28, and it is determined that the correction processing has not been completed. If so, the process returns to step S23.

In step S28, the pointer for reading the C signal is set to an initial value (upper left in FIG. 7), and the flow advances to step S29. In step S29, the C signal at the position (pixel) where the pointer is set is read, and the corresponding X signal is read.
The Y coordinate (x, y) is obtained, and the process proceeds to step S30. In step S30, r = (x ² + y ² ) ^1/2 is calculated based on the XY coordinates obtained in step S29, and a correction amount using the calculated r as a parameter is read from the correction table. Next, in step S31, an operation of multiplying the Y signal component read in step S29 by the correction amount read in step S30 is performed to obtain a corrected C component.
The C component before correction written in the memory 12 is rewritten to the C component after correction.

Next, in step S32, the position of the pointer for reading the Y signal is advanced by one according to the scanning order of FIG. Next, in step S33, it is determined whether or not the correction processing has been completed for all the Y signals by reading the pointer. If it is determined that the correction processing has been completed, the process proceeds to step S34, and it is determined that the correction processing has not been completed. If so, the process returns to step S29.

In step S34, operations such as image compression processing in the JPEGIC 13 and recording of compressed data on a recording medium are executed, and the process returns.

In the second embodiment, image correction is performed so as to compensate for the decrease in the amount of light around the lens. Therefore, a smaller and brighter lens can be adopted by tolerating the amount of decrease in the amount of light around the lens. it can. Therefore, the size of the camera can be reduced without sacrificing performance.

The amount of decrease in the amount of light at the peripheral portion is the F of the lens.
It depends on the value. For this reason, in a lens-exchangeable camera, for example, the parameters of the lens may be read by the camera through communication between the lens and the camera, and an optimal correction table may be selected based on the read parameters.

[0043]

According to the first aspect of the present invention, the storage means for storing the correction amount for compensating for the non-uniformity of the conversion ratio between pixels in the imaging means, and the correction amount stored in the storage means And a correction unit for correcting the value of the digital signal output from the A / D conversion unit based on the above. Therefore, the uniformity of the image can be ensured. According to the second aspect of the present invention, the correction amount for compensating the non-uniformity of the illuminance of the illumination means is stored in the storage means, so that the influence of the non-uniformity of the illumination means can be canceled. According to the third aspect of the present invention, the storage means stores one of the two-dimensional images in the X direction.
The dimensional correction data and the one-dimensional correction data in the Y direction are stored as a correction amount, and the correction unit outputs an arbitrary XY coordinate output from the A / D conversion unit based on the corresponding X coordinate and Y coordinate correction data. Is corrected, the correction process can be simplified. According to the fourth aspect of the present invention, the correction means integrates or divides the correction data of the corresponding X coordinate and Y coordinate with each other to obtain a pixel at an arbitrary XY coordinate output from the A / D conversion means. Since the correction is performed by multiplying the value of the digital signal, the correction process can be simplified. According to the fifth aspect of the present invention, the non-uniformity of the conversion rate of the image reading unit is set symmetrically, and the correction amount is stored in the storage unit for a part of the reading area of the image reading unit. Since the means uses the same correction amount for the symmetry point of the image reading means, the capacity of the storage means can be reduced. According to the sixth aspect of the present invention, since the storage unit stores the correction amount for compensating the decrease in the amount of light near the image based on the optical lens, a bright and small optical lens can be used. According to the seventh aspect of the present invention, the correction means calculates the distance from the optical axis to each pixel and performs correction using the correction amount corresponding to the calculated distance. The drop can be compensated.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a first embodiment of an image correction device according to the present invention.

FIG. 2 is a perspective view showing a film and a film cartridge.

FIG. 3 is a perspective view showing an illumination device used in the image correction device of FIG. 1;

FIG. 4 is a diagram showing an illuminance distribution of the lighting device.

FIG. 5 is a diagram illustrating a correction table.

FIG. 6 is a flowchart showing the operation of the first embodiment.

FIG. 7 is a diagram showing a digital image signal standardized by an image processing DSP.

FIG. 8 is a block diagram showing an image correction device when a one-chip IC is used.

FIG. 9 is a diagram illustrating a decrease in the amount of light around an optical lens in the image correction apparatus according to the second embodiment.

FIG. 10 is a flowchart showing the operation of the second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Illumination device 3 Lens 4 CCD sensor 6 A / D converter 11 EEPROM 14 RISC F Silver halide film

Claims (7)

[Claims] An imaging unit for converting a two-dimensional image into an analog signal using a plurality of two-dimensionally arranged elements, and a correction for compensating for non-uniformity of a conversion ratio between pixels in the imaging unit. Storage means for storing an amount; A / D conversion means for converting an analog signal output from the imaging means to a digital signal; and A / D conversion based on the correction amount stored in the storage means.
An image correction apparatus comprising: a correction unit that corrects a value of a digital signal output from a / D conversion unit. 2. The image pickup means converts the image of the film illuminated by the illuminating means into an analog value by a plurality of two-dimensionally arranged elements, the illuminating means illuminating the film on which the image is formed. And a correction unit that compensates for non-uniformity of illuminance of the illumination unit.
An image correction device according to claim 1. 3. The storage means stores one-dimensional correction data in the X direction of the two-dimensional image and one-dimensional correction data in the Y direction as the correction amount.
3. The method according to claim 1, wherein a value of a digital signal of a pixel at an arbitrary XY coordinate output from the A / D converter is corrected based on the coordinate and Y coordinate correction data. Image correction device. 4. The correction means according to claim 1, wherein said correction means includes a corresponding X coordinate and a Y coordinate.
The correction is performed by multiplying a value obtained by integrating or dividing coordinate correction data with a value of a digital signal of a pixel at an arbitrary XY coordinate output from the A / D conversion means. Item 4. The image correction device according to Item 3. 5. The method according to claim 1, wherein the non-uniformity of the conversion rate of the image reading unit is set symmetrically, and the storage unit stores a correction amount for a part of a reading area of the image reading unit. 5. The method according to claim 1, wherein the same correction amount is used for a symmetric point of said image reading means.
The image correction device according to any one of the preceding claims. 6. The image reading means has an optical lens for forming a subject image on a light receiving surface of the element, and the storage means has a correction amount for compensating a decrease in light amount around an image based on the optical lens. The image correction device according to claim 1, wherein the image is stored. 7. The storage unit stores a correction amount using a distance from the optical axis as a parameter, and the correction unit calculates a distance from the optical axis to each pixel and corresponds to the calculated distance. The image correction apparatus according to claim 6, wherein the correction is performed using the correction amount.