JPH08242373A - Method and device for shading correction of one-dimensional sensor - Google Patents

Abstract

PURPOSE: To provide an inexpensive and compact device and to output appropriate image data as performing shading correction in real time. CONSTITUTION: Standard white paper with uniform density is placed on the object of a line camera, and a video signal in which the object is scanned with a CCD is inputted to a storage circuit 23 by switching a switch 22. In such a case, a shading correction value of one line is generated by inverting the density distribution of an inputted video signal. The shading correction value of one line is written on frame memory 24 by repeating scan on the standard white paper by moving the line camera at every line. When the shading correction is applied to the video signal image-picked up with the line camera, it is corrected to an appropriate video signal by switching the switch 22 and adding the shading correction value from the frame memory 24 by a correction circuit 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shading correction method for a one-dimensional sensor and a shading correction device for correcting the distortion of image data taken in from the one-dimensional sensor.

[0002]

2. Description of the Related Art Conventionally, there are one-dimensional and two-dimensional image sensors, and recently, the number of pixels is large,
The applications of two-dimensional CCD image sensors that can capture image data at high speed are expanding.

On the other hand, a one-dimensional image sensor (also referred to as a line camera), which is well known, is used for a facsimile because it can obtain a high resolution at a low cost. It is used for an automatic focusing mechanism that reads characters, figures, and pictures to transmit information, and an auto focus camera detects the phase difference.

Thus, the one-dimensional image sensor is
Use a high-speed response for places that require high-speed reading, and use a device with a large number of pixels for places that require high reading accuracy, such as automatic production equipment. Therefore, it is expected to be used in various fields.

For example, a one-dimensional image sensor has a CC
D (Charge Coupled Device) is used, and there are 2048 photodiodes in the photosensitive section in one row.
4096, or 1 for high precision
About ten thousand are arrayed, and the charge proportional to the amount of incident light is accumulated in the photodiode, and the accumulated charge is stored in the CCD.
It was taken out as an electric signal while being sequentially transferred by the shift register. However, if the sensitivities of the photodiodes, which are the photosensitive parts, are different, if the optical system (lens) that focuses the captured image is distorted, or if the light amount of the light source is uneven, then it is appropriate Sometimes, it was not possible to obtain accurate image data.

For example, FIG. 7 is a diagram showing the density distribution of image data with respect to time in the scanning direction for one line using a conventional one-dimensional image sensor. As shown in FIG. 7, it can be seen that, in the central portion and the peripheral portion of the lens, the density decreases from the center of the lens to the peripheral portion due to the influence of the lens aberration.

Therefore, conventionally, since the image data output from the one-dimensional image sensor is used as the true data, the distortion due to the lens aberration is corrected by using a general theoretical value, or the general experimental value is used. The shading correction has been performed by correcting variations in the light receiving sensitivity of the CCD.

Further, in the case of performing the shading correction based on the theoretical value or the experimental value as described above, after the image data is once fetched from the one-dimensional image sensor, the batch processing by software is performed.

[0009]

However, in such a conventional shading correction device for a one-dimensional sensor, the lens distortion is corrected by using a general theoretical value as described above, or the light receiving sensitivity of the CCD is used. The shading correction was performed by using a general experimental value for the variation of. For this reason, the distortion peculiar to each lens cannot be corrected, and the variation in the light receiving sensitivity of the CCD is different for each one-dimensional sensor. Therefore, a general theoretical value or an experimental value is used. There is a problem that proper shading correction cannot be achieved by using the correction. In addition, even if the above-mentioned shading correction is properly performed, there is a problem in that even the nonuniformity of the light amount of the light source cannot be corrected.

Further, in the conventional shading correction of the one-dimensional sensor, since the image data is once fetched from the one-dimensional sensor and the batch processing is performed by software, there is a problem that the shading correction cannot be performed in real time.

Therefore, the present invention has been made in view of the above problems, and by using the existing hardware configuration, the apparatus can be made inexpensive and compact, and proper image data can be obtained while performing shading correction in real time. An object of the present invention is to provide a shading correction method and a shading correction device for a one-dimensional sensor that can be obtained.

[0012]

According to a first aspect of the present invention, there is provided a shading correction method for a one-dimensional sensor, wherein a one-dimensional sensor having a plurality of optical sensors arranged in a line is scanned on an image pickup object.
A shading correction method for a one-dimensional sensor, which corrects distortion of image data taken in from the one-dimensional sensor, comprising obtaining a reference image data by scanning the one-dimensional sensor on a reference paper of uniform density. Step, a correction image data generating step of inverting the density distribution of the reference image data to generate corrected image data, and sequentially correcting the captured image data obtained by scanning the image of the imaging target with the one-dimensional sensor. The above object is achieved by including an image data correction step of adding image data to correct the image data.

A shading correction method for a one-dimensional sensor according to a first aspect of the present invention is, for example, as described in a second aspect, wherein the reference image data for one frame is captured in the reference image data capturing step and the corrected image is obtained. 1 in the data generation process
Corrected image data in which the density distribution of each frame of reference image data is inverted is generated, and the captured image data sequentially captured from the one-dimensional sensor in the image data correction step corresponds to the position of the captured image data. The image data may be corrected while adding the corrected image data.

According to a third aspect of the present invention, in a shading correction apparatus, a one-dimensional sensor in which a plurality of photosensors are arranged in a line is scanned on an object to be imaged, and a distortion of image data captured by the one-dimensional sensor is corrected. A shading correction device for an original sensor, comprising: corrected image data generation means for generating corrected image data by inverting the density distribution of reference image data obtained by scanning a reference paper of uniform density by the one-dimensional sensor. Correcting image data storage means for storing the corrected image data, and adding the corrected image data stored in the corrected image data storage means to the captured image data obtained by scanning the image of the imaging target with the one-dimensional sensor. The above object can be achieved by including the image data correcting means for correcting the image data.

A shading correction device for a one-dimensional sensor according to a third aspect of the present invention is, for example, as described in a fourth aspect, the shading correction device for the one-dimensional sensor is a primary image stored in the corrected image data storage means. Frame correction data storage means for storing at least one frame of correction data for one line of the original sensor, and captured image data taken from the one-dimensional sensor when the image data is corrected by the image data correction means. The image data may be corrected by adding the corrected image data read from the frame correction data storage unit corresponding to the position of the captured image data.

In the shading correction device for a one-dimensional sensor according to claim 3 or 4, for example, as described in claim 5, the image data correction means adds the corrected image data to the captured image data. A level-up means for raising the entire captured image data by a predetermined level before correcting the image data, and a level-down means for lowering the level of the image data by the level increased by the level-up means after correcting the image data. It may be further equipped.

[0017]

In the shading correction method for a one-dimensional sensor according to claim 1, the one-dimensional sensor is scanned with respect to a reference paper having a uniform density to obtain reference image data, and the density distribution of the reference image data is inverted. Then, the corrected image data is generated, and the corrected image data is added to the captured image data obtained by scanning the image of the imaging target with the one-dimensional sensor to correct the image data.

Therefore, the image data obtained by using the reference paper of uniform density is the image data in which the variation of the light receiving sensitivity of the CCD, the lens distortion, and the nonuniformity of the light amount of the light source are combined. A shading correction value corresponding to each one-dimensional sensor can be easily obtained only by reversing the density distribution of the image data. Then, by using this corrected image data and adding it to the captured image data, accurate shading correction can be performed in real time.

In the shading correction method for a one-dimensional sensor according to a second aspect, the reference image data for one frame is captured in the reference image data capturing step according to the first aspect, and one frame is captured in the corrected image data generating step. The corrected image data in which the density distribution of each reference image data is inverted is generated, and the captured image data sequentially captured from the one-dimensional sensor in the image data correction process is added to the captured image data from one frame of the corrected image data. The corrected image data corresponding to the data position is added to correct the image data.

In this way, when the image pickup object is fixed and the image is read by scanning while moving the one-dimensional sensor side, the shading correction value may change depending on the position of the one-dimensional sensor. The image data of the imaging area for one screen (one frame) is taken in, and the corrected image data for one frame is generated by inverting the data. Therefore, when performing shading correction, it is possible to perform appropriate shading correction according to each position simply by adding the captured image data to be corrected and the corrected image data at the position corresponding to the captured image data.

In the shading correction apparatus according to the third aspect, the corrected image data is generated by reversing the density distribution of the reference image data obtained by scanning the one-dimensional sensor on the reference paper of uniform density by the corrected image data generation means. The corrected image stored in the corrected image data storage means is generated, the corrected image data is stored in the corrected image data storage means, and the captured image data obtained by scanning the image of the imaging target with the one-dimensional sensor by the image data correction means Correct the image data by adding the data.

Therefore, the image data obtained by using the reference paper of uniform density is the image data including the variation of the light receiving sensitivity of the CCD, the lens distortion, and the nonuniformity of the light amount of the light source. A shading correction value corresponding to each one-dimensional sensor can be easily obtained only by reversing the density distribution of. Then, by using this corrected image data and adding it to the captured image data, accurate shading correction can be performed in real time.

The shading correction device for a one-dimensional sensor according to claim 4 further comprises frame correction data storage means for storing at least one frame of correction data for one line of the one-dimensional sensor stored in the corrected image data storage means. Provided, the captured image data taken in from the one-dimensional sensor when the image data is corrected by the image data correction means,
The image data is corrected by adding the corrected image data from the frame correction data storage unit corresponding to the position of the captured image data.

As described above, when the image pickup object is fixed and the image is read by scanning while moving the one-dimensional sensor side, the shading correction value may change depending on the position of the one-dimensional sensor. The image data of the image pickup area for one minute (one frame) is taken in, and the corrected image data for one frame is generated by reversing the data. Therefore, when performing shading correction, it is possible to perform appropriate shading correction according to each position simply by adding the captured image data to be corrected and the corrected image data at the position corresponding to the captured image data.

In the shading correction device for a one-dimensional sensor according to claim 5, the image data correction means adds the corrected image data to the picked-up image data to correct the image data. The image data is raised by a predetermined level, and the level of the image data is lowered by the level down unit by the level up by the level up unit after the correction of the image data.

This is to prevent the difference between the input image data and the corrected image data from reaching the zero level when performing the shading correction using the corrected image data obtained by inverting the reference image data. By returning to the original signal level later, proper shading correction can be performed.

[0027]

Embodiments of the present invention will be described below in detail with reference to the drawings. 1 to 6 are views for explaining a shading correction device for a one-dimensional sensor according to the present invention. In the present embodiment, shading correction in a line camera of an automatic production facility or the like that needs to recognize an image with high accuracy is performed. An example will be explained.

First, the structure will be described. FIG. 1 is a diagram showing an imaging state of a subject using the line camera 1 of the present embodiment, (a) is a side view showing a positional relationship between the line camera 1 and the subject 4, and (b) is a subject. 4 is a plan view showing a scanning state when the line camera 1 captures an image of the image of FIG.

In FIG. 1A, the line camera 1 is
Image sensor 2 composed of a photodiode and a CCD in which a shift register is connected to these photodiodes
And an optical system 3 including a lens unit that focuses an image of a subject on the light receiving surface of the CCD described above. The line camera 1 captures an image of a product 4 produced in automatic production equipment or the like, or a subject 4 such as reference paper having uniform density for capturing reference image data for shading correction, and captures those image data. Is.

The image pickup device 2 is a high-precision one-dimensional CCD in which photodiodes of about 10,000 pixels are arranged in one column, and is arranged in the horizontal scanning direction shown by an arrow in FIG. By sequentially scanning, the image data of each line is read. Then, as shown in FIG. 1B, here, the line camera 1 is horizontally scanned and is sequentially moved line by line in a direction orthogonal to the horizontal scanning direction. That is, the line camera 1 performs horizontal scanning, and the line camera 1 is moved to the “A position, ..., B position, ...
., C position ", the image data for one screen (one frame) of the subject 4 can be captured.

FIG. 2 is a schematic block diagram of the signal processing unit 11 which corrects image data taken in from the line camera of this embodiment and performs signal processing. In FIG. 2, the signal processing unit 11 includes a line camera 12 and an image signal correction unit 1.
3 and the image signal processing unit 14. The configuration of the line camera 12 is the same as that of the line camera 1 shown in FIG.

The image signal correction unit 13 is a characteristic component of this embodiment, and is for performing shading correction of the video signal input from the line camera 12. For example, in the line camera 12, there are variations in the light detection sensitivity of the photodiodes arranged in a row, or a density difference occurs due to the influence of lens aberration of the optical system 3, or the like.
If the light amount of the light source is non-uniform due to external light or illumination, the image data output from the CCD will not be true data and cannot be used as it is as image data, so shading correction is necessary.

The image signal processing section 14 includes the image signal correction section 1
The signal processing according to the application is performed by using the appropriate image data which has been subjected to the shading correction in 3. For example, performing image signal processing for displaying an image on a display, etc., emphasizing the outline part to grasp the shape and size,
Image processing is performed such as rotating the image of the subject or moving the image in the x-axis and y-axis directions by a predetermined amount.

FIG. 3 is a block diagram showing the configuration of the image signal correction section 13 of FIG. In FIG. 3, the image signal correction unit 13 includes a correction circuit 21, a switch 22, and a storage circuit 2.
3, a frame memory 24, a control circuit (CPU) 25, and the like.

The correction circuit 21 is used for the line camera 12 of FIG.
The shading correction value prepared in advance is added to the video signal input from the device to perform appropriate shading correction according to each line camera 12, and the corrected video signal is output.

The switch 22 switches a video signal input from the line camera 12 between a case where a shading correction value is created in advance and a case where a shading correction of a video signal of a subject is performed.

When the switch 22 is switched to create a shading correction value, the storage circuit 23 places a reference blank sheet of uniform density as the subject of the line camera 12, and the density distribution of the video signal input when the image is picked up is displayed on the line. The corrected image data inverted in units is stored.

The frame memory 24 is used by the line camera 1 to create a shading correction value for one frame.
When a reference blank sheet is placed as the subject of No. 2 and the image is taken, the line camera 12 performs scanning while shifting each line position, and the corrected image data for each line stored in the storage circuit 23 is sequentially captured. The shading correction value for the frame is created.

The control circuit 25 controls the overall operation of the image signal correction section 13 based on a basic program in a ROM (not shown). The control circuit 25 creates a shading correction value in accordance with an operator's command, or when the power is turned on. The shading correction value is automatically created, and the switch 22 is switched after the shading correction value is created to perform shading correction on the input video signal through the correction circuit 21.
Also, depending on the situation, it is possible to use one line of shading correction values for correction, or one frame of shading correction values to perform shading correction according to the position of each captured image data. To do.

FIG. 4 is a diagram showing the configuration of the correction circuit 21 of FIG. In FIG. 4, the correction circuit 21 includes a level shifter 31, an adder 32, a D / A converter 33, a level shifter 34, and the like.

The level shifter 31 and the level shifter 34 are
The signal level of the input video signal is changed to the level shifter 31.
The signal level is prevented from becoming zero when the shading correction value is added by the adder 32 at the next stage by increasing the level by a predetermined level at. After the shading correction of the video signal, the level shifter 34 lowers the level up by the level shifter 31 to obtain the shading-corrected video signal having an appropriate signal level.

The D / A converter 33 D / A converts the shading correction value input from the frame memory 24 and outputs it to the adder 32 in the next stage. The adder 32 adjusts the signal level at each pixel position by adding the image pickup video signal input from the level shifter 31 and the shading correction value stored in the frame memory 24 to perform an appropriate shading correction. It is something to do.

FIG. 5 is a diagram showing the configuration of the storage circuit 23 of FIG. In FIG. 5, the storage circuit 23 includes an A / D converter 41, an inverter 42, a line memory 43 and the like.

When the shading correction value is created, the A / D converter 41, when the switch 22 is switched and the analog video signal obtained by scanning the reference blank paper is input from the line camera 12, is A / D converted. Digital video signal.

The inverter 42 is the A / D converter 41.
The digital video signal is generated by inverting the density distribution of the digital video signal input from. A video signal input obtained by scanning a reference blank paper of uniform density should have uniform density if it is true image data.
When the density distribution is non-uniform as shown in FIG. 7, it can be considered that the influence is caused by the lens aberration, the non-uniformity of the light source, or the variation of the light receiving sensitivity of the CCD. Therefore, when the density of the video signal is significantly low, it is necessary to greatly increase the signal level at that position, and conversely, when the density is high, it is necessary to lower the signal level at that position. Therefore, as the correction value for performing the shading correction, an appropriate shading correction value according to each line camera can be obtained by inverting the density distribution of the video signal obtained by scanning the reference blank paper of uniform density. .

The line memory 43 stores the shading correction value for one line by inverting the video signal obtained by horizontally scanning one line of the reference blank sheet by the CCD of the line camera 12 by the inverter 42.

Next, the operation will be described. First, image data is read with a reference blank sheet as a subject of the line camera, and shading correction values created based on this image data are stored in the frame memory 24.

That is, the line camera 1 shown in FIG. 1A is used to horizontally scan a reference blank photographic subject 4 with the CCD of the image sensor 2 to capture image data. In this embodiment, FIG.
As shown in (b), the subject 4 which is a reference blank sheet is fixed, horizontal scanning is performed using the CCD, and the line camera is moved line by line in the direction orthogonal to the horizontal scanning direction to sequentially scan to the C position. By doing so, the reference blank image data can be read for one frame. This reference blank image data is output to the storage circuit 23 by switching the switch 22 of the image signal correction unit 13 shown in FIG.

In the storage circuit 23, as shown in FIG.
The video signal input for the line is D by the D / A converter 41.
A / A conversion is performed, the result is inverted by the inverter 42, and the result is written in the line memory 43 as a shading correction value.
The shading correction value is written in the line memory 43 every time the line camera scans line by line. The shading correction value for each line stored in the line memory 43 is sequentially output to and written in the frame memory 24 shown in FIG. In this way, the shading correction value creation operation ends with the shading correction value for one frame written in the frame memory 24.

In the present embodiment, the above-described shading correction value creating operation is programmed so as to be automatically carried out at power-on, but it may also be carried out at the instruction of the operator, at predetermined time intervals. It can also be done on a regular basis.

Next, the switch 22 shown in FIG. 3 is switched to the correction circuit 21 side. Then, as a subject 4 shown in FIG. 1A, when a product produced by an automatic production facility is imaged by the CCD, the image data is output from the CCD as a video signal to the correction circuit 21.

FIG. 6 is a diagram showing a video signal waveform in each part of the correction circuit 21 of FIG. When the image pickup video signal as shown in FIG. 6A is input to the correction circuit 21 shown in FIG. 4, the level shifter 31 shown in FIG. 4 shifts up the level of the video signal from a1 to b1. This shifted up video signal waveform is shown in FIG.
(B).

When the shading correction value stored in the frame memory 24 is converted into analog data by the D / A converter 33 of the correction circuit 21 of FIG. 4, for example, as shown in FIG. 6C. In addition, the shading correction signal “c” is obtained in which the density of the peripheral portion is higher than that of the central portion.

In the adder 32 shown in FIG. 4, the video signal "b" whose signal level is shifted up by a predetermined level and the shading correction signal "c" are added.
Shading correction is performed so as to obtain an appropriate signal level. FIG. 6D shows a video signal waveform after shading correction, in which a high density portion and a low density portion cancel each other out to obtain a flat video signal having a signal level of approximately d1. Since this video signal has been shifted up by a predetermined level by the level shifter 31 of FIG. 4, the level shifter 34 of FIG.
As shown in (e), the signal level is downshifted from d1 to e1. As a result, true image data that has been subjected to shading correction is obtained.

The shading correction value added by the adder 32 shown in FIG. 4 is read from the frame memory 24, but the shading correction value corresponding to the scanning line position of the video signal input from the line camera is sequentially read from the frame memory 24. It is read and used. When the shading correction of the line camera is performed as described above, proper shading correction can be performed even when the illuminance distribution of the light source or the like varies depending on the imaging position of the line camera.

As described above, the shading correction device for a one-dimensional sensor according to the present embodiment creates a shading correction value on a line-by-line basis or on a frame-by-frame basis according to each line camera and stores it in a memory for correction. When a video signal to be input is input, the shading correction value corresponding to the input video signal is read out, and correction is performed so as to obtain an appropriate video signal. Therefore, by using the existing hardware configuration, it is possible to provide an inexpensive and compact shading correction device and to perform correction processing in real time.

In the above embodiment, the example in which the shading correction is performed by using the line camera for the automatic production equipment is shown, but of course the invention is not limited to this, and the shading correction of various one-dimensional sensors can be performed. It can be applied.

In the above embodiment, the shading correction value for one frame is stored in the frame memory and the shading correction value corresponding to the scanning position of the input video signal is used for correction. If the image data is captured by moving the subject side while performing horizontal scanning while fixing the same, the non-uniformity of the light source does not change at the position of the scanning line in one frame, so the same shading correction value can be obtained from the line memory. It is also possible to repeatedly read and correct.

Further, in the above embodiment, the video signal is level-shifted by using the level shifters 31 and 34 in the correction circuit 21 shown in FIG. 4, but the darkness of the color of the reference paper when the shading correction value is created. If it is possible to prevent the video signal level after shading correction from becoming zero by controlling the signal level difference between the video signal for shading correction and the shading correction value by changing the height, the level shifter 31 And 34 can be omitted.

[0060]

According to the shading correction method for a one-dimensional sensor of claim 1, the density distribution of the reference image data obtained by scanning the reference paper with the one-dimensional sensor is inverted to generate the corrected image data. Then, since the corrected image data is added to the captured image data to correct the image data, a shading correction value corresponding to each one-dimensional sensor can be obtained, and accurate shading correction can be performed in real time.

According to the shading correction method of the one-dimensional sensor of claim 2, when the reference image data is taken in,
The reference image data for one frame is fetched, the correction image data in which the density distribution of the reference image data for one frame is inverted is generated, and the correction image data corresponding to the position of the captured image data to be corrected is generated. Since the image data is corrected by adding, the corrected image that changes according to the position of the one-dimensional sensor even when scanning the image while moving the one-dimensional sensor side while fixing the imaging target Since the captured image data is corrected using the data, proper shading correction can always be performed.

According to the shading correction apparatus of the third aspect, the corrected image data is generated by inverting the density distribution of the reference image data obtained by scanning the one-dimensional sensor on the reference paper of uniform density. The corrected image data is stored, and the corrected image data is added to the captured image data obtained by scanning the one-dimensional sensor to correct the image data. Therefore, the shading correction value corresponding to each one-dimensional sensor can be easily obtained. By adding the corrected image data to the captured image data, accurate shading correction can be performed in real time.

According to the shading correction device for a one-dimensional sensor of claim 4, at least one corrected image data is obtained.
Since the image data is corrected by storing the frame data and adding the captured image data captured from the one-dimensional sensor when correcting the image data and the corrected image data corresponding to the position of the captured image data, When fixing the imaging target and moving the one-dimensional sensor side to read the image,
Even if the shading correction value changes depending on the position of the sensor, proper shading correction can always be performed simply by adding the captured image data to be corrected and the corrected image data at the position corresponding to the captured image data. .

According to the shading correction device for a one-dimensional sensor of claim 5, the signal level is increased by a predetermined level before the correction of the image data by adding the correction image data to the captured image data to correct the image data. Since the amount of down is reduced by a predetermined level later, it is possible to prevent the difference between the input image data and the corrected image data from reaching the zero level when shading correction is performed using the corrected image data, and it is always possible to obtain an appropriate value. Shading correction can be performed.

[Brief description of drawings]

FIG. 1 is a diagram showing an imaging state of a subject using a line camera according to an embodiment.

FIG. 2 is a schematic block diagram of a signal processing unit that processes a signal of image data captured from the line camera of the present embodiment.

FIG. 3 is a block diagram showing a configuration of an image signal correction unit in FIG.

FIG. 4 is a diagram showing a configuration of a correction circuit in FIG.

5 is a diagram showing a configuration of a storage circuit of FIG.

FIG. 6 is a diagram showing a video signal waveform in each part of the correction circuit of FIG.

FIG. 7 is a diagram showing a density distribution of image data with respect to time in a scanning direction for one line using a conventional one-dimensional image sensor.

[Explanation of symbols]

 1, 12 Line camera 2 Image sensor 3 Optical system 4 Subject 13 Image signal correction unit 14 Image signal processing unit 21 Correction circuit 22 Switch 23 Storage circuit 24 Frame memory 25 Control circuit (CPU) 31, 34 Level shifter 32 Adder 33 A / D converter 41 D / A converter 42 Inverter 43 Line memory

Claims (5)

[Claims] 1. A shading correction method for a one-dimensional sensor, wherein a one-dimensional sensor having a plurality of optical sensors arranged in a line is scanned on an object to be imaged to correct the distortion of image data captured from the one-dimensional sensor. A reference image data capturing step of obtaining the reference image data by scanning the one-dimensional sensor with respect to a reference paper of uniform density; and a corrected image for inverting the density distribution of the reference image data to generate corrected image data. A data generation step, and an image data correction step of correcting the image data by sequentially adding the correction image data to the captured image data obtained by scanning the image of the imaging target with the one-dimensional sensor. Shading correction method for one-dimensional sensor. 2. Corrected image data obtained by taking in one frame of reference image data in the reference image data taking step and inverting the density distribution of each frame of reference image data in the corrected image data generating step. The image data is corrected by adding the corrected image data corresponding to the position of the captured image data generated and sequentially captured from the one-dimensional sensor in the image data correction step. Item 1. A shading correction method for a one-dimensional sensor according to item 1. 3. A shading correction device for a one-dimensional sensor, wherein a one-dimensional sensor having a plurality of optical sensors arranged in a line is scanned on an object to be imaged to correct distortion of image data taken in from the one-dimensional sensor. And a corrected image data generation unit for generating corrected image data by inverting the density distribution of reference image data obtained by scanning the reference paper of uniform density with the one-dimensional sensor, and storing the corrected image data. Corrected image data storage means and image data for correcting the image data by adding the corrected image data stored in the corrected image data storage means to the captured image data obtained by scanning the image of the imaging target with the one-dimensional sensor A shading correction device for a one-dimensional sensor, comprising: a correction unit. 4. The shading correction device for a one-dimensional sensor further comprises frame correction data storage means for storing at least one frame of correction data for one line of the one-dimensional sensor stored in the corrected image data storage means. When correcting the image data with the image data correction means,
Captured image data captured from the one-dimensional sensor,
4. The shading correction device for a one-dimensional sensor according to claim 3, wherein the image data is corrected by adding the correction image data read from the frame correction data storage unit corresponding to the position of the captured image data. 5. The image data correction means adds level correction image data to the captured image data to raise the entire captured image data by a predetermined level before correcting the image data, and after correcting the image data. The level down means for lowering the level of the image data by the level up by the level up means is further provided.
The shading correction device for a one-dimensional sensor according to claim 1.