JP2003250092A - Image reader - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an image with high quality wherein a density difference and a border line or the like are not conspicuous even when an image is read while an imaging area is split. <P>SOLUTION: A correction means of the image reader wherein an imaging area of a photoelectric conversion element for storing electric charges in response to a transmission or reflection luminous quantity of an original image and outputting a signal to a prescribed transfer section is divided into a plurality of areas and a signal is outputted independently by each of a plurality of the imaging division areas, corrects each imaging area on the basis of a mean value of signal outputs at a dark state of the respective imaging areas. Correction of each imaging area to eliminate an output difference on the basis of the mean value of the signal outputs at the dark state by each imaging area can obtain an image with high quality wherein no difference takes place between the imaging areas and no border line is recognized in the case of composing output signals obtained from a plurality of the imaging areas to obtain one image. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading apparatus having an image pickup area composed of a plurality of areas and capable of outputting a signal for each image pickup area.

[0002]

2. Description of the Related Art Conventionally, in an image reading apparatus, an image recorded on an original such as a photographic film is recorded by a CCD (Charge Coupl).
ed device) is used to read the digital image data photoelectrically, the read digital image data is subjected to image processing such as enlargement / reduction and various corrections, and the laser light modulated based on the image processed digital image data. A technique for forming an image on a recording material is known.

In such a technique for digitally reading an image with an image reading sensor such as a CCD, the image pickup region of the image is divided into a plurality of regions in order to improve the reading speed, and each of these divided regions is divided. The imaging signal is being output. Then, each of the obtained signals is subjected to respective processes such as A / D conversion, shading correction, and gamma conversion, and then the signals are combined to obtain an image.

Specifically, as shown in FIG. 4, the image pickup area 90 of the image reading apparatus is divided into two parts, an image pickup area 90A on the left side and an image pickup area 90B on the right side in FIG. In each of the regions 90A and 90B, a plurality of photosensors 81 that are two-dimensionally arranged in pixel units and accumulate signal charges according to the amount of incident light, and photosensors 81 are arranged in each vertical column. Vertical transfer CC for vertically transferring the signal charges read instantaneously through the read gate unit 82
It is equipped with D83.

In these image pickup areas 90A and 90B, the signal charges transferred to the vertical transfer CCDs 83 are sequentially transferred to the horizontal transfer CCDs 84A and 84B, respectively, in units corresponding to one scanning line in each of the image pickup areas 90A and 90B. It Output amplifiers 85A and 85B are respectively arranged at the final ends of the horizontal transfer CCDs 84A and 84B, and the image pickup signals of the image pickup areas 90A and 90B are output by the output amplifiers 85A and 85B.

[0006]

However, in the above-mentioned conventional image reading apparatus, each of the divided image pickup areas 90 is divided.
Horizontal output CCDs 84A and 84B are used to output the image pickup signals of A and 90B, respectively, and independent output amplifiers 85A and 85B are used.
Due to the difference in transfer efficiency between the CDs 84A and 84B and the difference in output characteristics between the output amplifiers 85A and 85B (see FIG. 5), there is a problem that density differences and density unevenness occur in the images in the respective imaging regions. Further, due to the density difference between the image pickup areas, when the image pickup signals are combined to obtain an image, the boundary portion between the image pickup areas is recognized as a boundary line, which causes a problem of image quality deterioration.

In consideration of the above facts, the present invention is capable of obtaining an image of high quality inconspicuous in terms of density difference, boundary line, etc. even when the image pickup area of the image is divided and read. An object is to provide a reading device.

[0008]

According to a first aspect of the present invention, there is provided an image reading apparatus in which a photoelectric conversion element for accumulating charges according to an amount of transmitted light or an amount of reflected light of an original image and outputting a signal to a predetermined transfer unit. An image reading device in which an image pickup region of the photoelectric conversion element is divided into a plurality of portions, and a signal output can be independently performed for each of the divided plurality of image pickup regions, and an average value of signal outputs of the respective image pickup regions. On the basis of the above, it is characterized in that a correction means for correcting so as to eliminate the output difference between the plurality of imaging regions is provided.

According to another aspect of the image reading apparatus of the present invention, in the photoelectric conversion element that accumulates charges according to the amount of transmitted light or the amount of reflected light of an original image and outputs a signal to a predetermined transfer path, an image pickup area of the photoelectric conversion element is provided. Is applied to an image reading apparatus capable of independently outputting a signal for each of the divided imaging areas. Then, the correction means of the image reading apparatus corrects each image pickup area based on the average value of the signal output of each image pickup area. The output signals obtained from the respective image pickup regions have output differences depending on the image pickup regions due to the difference in the characteristics of the transfer paths for transferring the signals and the difference in the characteristics of the output amplifiers. Therefore, the average value of the signal output for each imaging region is obtained, and based on this average value, for example, the average value is subtracted or added, and the output difference is corrected so as to be eliminated. This makes it possible to obtain a high-quality image in which there is no difference between the image pickup regions and the boundary line is not recognized when one image is obtained by combining output signals obtained from a plurality of image pickup regions.

In the image reading apparatus according to the first aspect, the correction means eliminates the output difference between the plurality of image pickup areas based on the average value of the signal output when the respective image pickup areas are dark. The correction can be made as follows.

With this configuration, the correction means according to claim 1 eliminates the output difference between the plurality of image pickup regions, particularly on the basis of the average value of the signal output when the respective image pickup regions are dark. To correct. Here, when the signal is output in a dark state, for example, the light source of the light irradiated on the original image is turned off, or all or predetermined photoelectric conversion elements are shielded by attaching a shutter or a thin plate. Say. The image obtained from the signal output in the dark is black because there is no light supplied to the photoelectric conversion element, but due to the difference in the characteristics of the transfer path that transfers the signal and the difference in the characteristics of the output amplifier, An output difference occurs depending on the imaging area. Therefore, the average value of the signal output in darkness is calculated for each imaging region, and based on the average value in darkness, for example, the average value in darkness is subtracted or added to eliminate the output difference. Can be corrected as follows.

An image reading apparatus according to a second aspect of the invention is a photoelectric conversion element that accumulates charges according to the amount of transmitted light or the amount of reflected light of an original image and outputs a signal to a predetermined transfer path.
An image reading device in which an image pickup region of the photoelectric conversion element is divided into a plurality of portions, and a signal can be independently output for each of the divided plurality of image pickup regions. In an image reading system that outputs a signal, an idle transfer time is provided for the transfer path, and correction is performed based on the value of the signal output obtained by the idle transfer so as to eliminate an output difference between the plurality of imaging regions. It is characterized in that a correction means is provided.

According to a second aspect of the present invention, there is provided an image reading apparatus in which a photoelectric conversion element which accumulates electric charges according to an amount of transmitted light or an amount of reflected light of an original image and outputs a signal to a predetermined transfer path is provided.
The photoelectric conversion element is applied to an image reading apparatus in which an image pickup area is divided into a plurality of areas, and signals can be independently output for each of the divided plurality of image pickup areas. An idle transfer time is provided in the image reading system of the image reading apparatus that reads an image, that is, outputs a signal to the transfer path at the same time when electric charges are accumulated. Here, the idle transfer means performing a transfer operation in which the number of pixels is greater than the number of pixels in the transfer path, and outputting a signal that is not involved in image reading. And the correction means
Correction is performed based on the value of the signal output obtained by the idle transfer so as to eliminate the output difference between the plurality of imaging regions. As a result, in parallel with image reading, it is possible to obtain a value serving as a reference for correction for eliminating an output difference between a plurality of image pickup areas.

An image reading apparatus according to a third aspect of the present invention is the image reading apparatus according to the first or second aspect, in which the predetermined transfer path is a vertical transfer path and a horizontal transfer path. A CCD image sensor configured, wherein the correction means is based on an average value of signals from optical black pixels or dummy pixels set at at least one of an end of the horizontal transfer path and an end of the vertical transfer path. The correction is performed so as to eliminate the output difference between the plurality of imaging regions.

According to another aspect of the image reading apparatus of the present invention, the predetermined transfer path includes a vertical transfer path and a horizontal transfer path. The vertical transfer path is provided for each vertical column of the imaging area and vertically transfers the signal from the photoelectric conversion element, and the horizontal transfer path is provided for each imaging area from the vertical transfer section. The transferred signal is transferred horizontally. The signal from the photoelectric conversion element is output via the vertical transfer unit and the horizontal transfer unit. Image reader, C
Since the CD image pickup device is provided with an optical black pixel or a dummy pixel on at least one of the end portion of the vertical transfer portion and the end portion of the horizontal transfer portion, the output difference between the plurality of image pickup areas simultaneously with the reading of the original image. It is possible to read a value that serves as a reference for correction for eliminating the noise. Then, the correction means corrects the output difference between the plurality of imaging regions based on the average value of the signals from the dummy pixels. The optical black pixel is a pixel that is shielded in advance, and the dummy pixel is a pixel that does not have a photoelectric conversion element such as a photodiode.

It can be said that optical shading (shading) is substantially the same at the boundary between a plurality of image pickup areas. Therefore, in the image reading apparatus according to claim 1 or 2, the correction unit is configured to output differences between the plurality of image pickup areas based on an average value of signal outputs at boundaries of the plurality of image pickup areas. It is also possible to adopt a configuration in which correction is performed so as to eliminate.

With this structure, the signal output from the boundary of each image pickup area is used as a reference, and the output difference between the plurality of image pickup areas can be corrected based on this average value. By correcting the output difference based on the output signal of the boundary portion, when the output signals of the respective imaging regions are combined to obtain one image, the boundary line becomes less noticeable.

An image reading device according to a fourth aspect of the present invention is the image reading device according to any one of the first or third aspects, for detecting a defect portion such as a scratch or dust in the original image. A light source for irradiating the invisible light is provided side by side, and the correction means eliminates an output difference between the plurality of imaging regions based on an average value of output signals when the invisible light is emitted from the light source. It is characterized by correction.

In the image reading apparatus according to the fourth aspect, a light source for irradiating invisible light for detecting a defective portion such as a scratch or dust is provided. Infrared light is an invisible light generally used for detecting a defective portion. Since the invisible light passes through the original image, a uniform output can be obtained regardless of the original image, but there is a difference in the output for each imaging region due to the output characteristics and the like. A high-quality image can be obtained by correcting the average value of the output signals obtained when non-visible light is used as a reference for correction so as to eliminate the output difference between the respective imaging regions. If errors due to defects such as scratches and dust cannot be ignored, it is possible to perform higher-precision correction by determining whether to use pixels after a certain level after correction, or not.

An image reading apparatus according to a fifth aspect of the present invention is the image reading apparatus according to the fourth aspect, wherein the light sources are capable of irradiating different amounts of invisible light.
It is characterized in that correction is performed so as to eliminate an output difference between the plurality of imaging regions based on an average value of output signals when the invisible light of different light amounts is emitted.

In the image reading apparatus according to the fifth aspect, the amount of invisible light is appropriately changed and the light is emitted. Since the output difference differs depending on the difference in the light amount, the correction unit corrects the output difference between the image pickup regions based on the average value of the output signals from the invisible light having the different light amount for each image pickup region. Thereby, the output difference can be corrected with higher accuracy.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

[First Embodiment] FIG. 1 shows a first embodiment of the present invention.
The block diagram showing the schematic configuration of the image reading apparatus according to the embodiment is shown.

The image reading apparatus 10 has an image pickup region in which a plurality of photosensors 31 for converting incident light into pixel-by-pixel conversion into signal charges according to the amount of the incident light and accumulating the signal charges are two-dimensionally arranged. 40 is provided. The image pickup area 40 is composed of two image pickup areas 40A and 40B whose light receiving surface is divided in the left-right direction (horizontal transfer direction) of FIG.

The vertical transfer unit 12 transfers the signal charges read from the plurality of photosensors 31 to the imaging regions 40A and 40B through the gate unit 33, and transfers the transferred signal charges in the vertical direction. Are arranged in each vertical column of pixels. As the photo sensor 31, for example, a photodiode can be applied.
Further, vertical so-called dummy pixels 32A (imaging region 40A side) and 32B (imaging region 40B side) having no photo sensor are provided at the uppermost stage and the lowermost stage of the vertical transfer unit 12 of the respective imaging regions 40A and 40B. ing. Then, these vertical transfer units 12 perform vertical transfer so that the signal charges read from the photosensor 31 are transferred to horizontal transfer units 14A and 14B (described later) provided in the lower part of the drawing for each area. It is driven by a partial drive driver (not shown).

Below the image pickup areas 40A and 40B, horizontal transfer sections 14A and 14B for receiving the signal charges transferred from the vertical transfer section 12 and transferring them in the horizontal direction are provided. Horizontal dummy pixels 34A and 34B having no photo sensor are provided at the ends of the horizontal transfer portions 14A and 14B, respectively. The horizontal transfer units 14A and 14B are
It is divided into two in the horizontal transfer direction corresponding to the divided image pickup areas 40A and 40B. The signal charge from the image pickup area 40A is transferred to the left in the figure by the horizontal transfer unit 14A, and the signal charge from the image pickup area 40B is transferred. Is a horizontal transfer unit driver (not shown) so that the horizontal transfer unit 14B transfers to the right in the figure.
Is driven by.

The vertical transfer unit 12 and the horizontal transfer unit 14
The vertical transfer unit drive driver and the horizontal transfer unit drive driver are connected to a timing generator (not shown) for timing control of the transfer drive of A and 14B.

Output amplifiers 16A and 16B for detecting the transferred signal charges, converting the signal charges into voltage signals, and outputting the voltage charges to the output terminals of the horizontal transfer units 14A and 14B provided corresponding to the imaging regions 40A and 40B. Is provided. Further, the output amplifiers 16A and 16B include average value calculation circuits 20A and 2B via A / D converters 18A and 18B that convert the analog signals from the output amplifiers 16A and 16B into digital signals.
0B and subtraction units 23A and 23B, respectively. In the average value calculation circuits 20A and 20B, each imaging area 4
The average value of the image pickup signals transferred from the dummy pixels 32 in 0A and 40B is calculated.

The A / D converters 18A and 18B and the average value calculation circuits 20A and 20B are the same as the A / D converters 18A and 18B.
The average value calculation circuit 20A, 2 from the image pickup signal supplied from
It is connected to subtraction units 23A and 23B that subtract a predetermined average value (described later) calculated by 0B. In addition, the subtraction unit 23
A and 23B are output synthesizing circuits 2 for synthesizing and generating one image based on the image pickup signals of the image pickup areas 40A and 40B.
It is connected to the image recording unit 24 via the line 2.

Next, the image reading and image pickup signal transfer operations in the image reading apparatus 10 according to the above-described embodiment of the present invention will be described.

When the light receiving surface of the image pickup area is irradiated with predetermined light, the photosensor 31 generates an electric charge according to the brightness (amount of incident light) of the target image and accumulates it as a signal electric charge. After that, these signal charges are transferred by the gate unit 33 to the corresponding vertical transfer units 12 at once. The vertical transfer unit 12 transfers the transferred signal charges to the horizontal transfer units 14A and 14B for each of the imaging regions 40A and 40B.

The signal charges transferred to the horizontal transfer sections 14A and 14B are detected by the output amplifiers 16A and 16B,
It is converted into a voltage signal and supplied to the A / D converters 18A and 18B, respectively. The A / D converter converts the transferred voltage signal into a digital signal and sends the converted digital signal to the average value calculation circuits 20A and 20B.

In the average value calculation circuits 20A and 20B, the vertical dummy pixels 32A in the image pickup areas 40A and 40B,
The image pickup signals of the portions 32B and the horizontal dummy pixels 34A and 34B are sampled, and the average value of the outputs of the vertical dummy pixels 32A and the average value of the outputs of the horizontal dummy pixels 34A are calculated for each image pickup area. Similarly, the average value of the outputs of the vertical dummy pixels 32B and the average value of the outputs of the horizontal dummy pixels 34B are calculated.

Here, the dummy pixels 32A, 32B, 34
The images obtained from the output signals obtained by reading the portions A and 34B should be completely black. However, the output amplifier 16
The images obtained from all the output signals are not black due to the difference in the output characteristics of A and 16B, and the dummy pixels 32A, 32B, 34A, and 34 are caused due to the difference in the output characteristics.
A density difference occurs in the output of B. Therefore, the dummy pixel 32
The output signals obtained by reading the portions A, 32B, 34A, and 34B are sampled, and the average value of their outputs (density) is obtained.

Each of the calculated average values is subtracted by the subtraction units 23A and 23A.
B is transmitted to the A / D conversion unit 18A in the subtraction unit 23A.
The average value of the outputs of the dummy pixels 32A and 34A is subtracted from the output of the entire image pickup area 40A converted in. Similarly, the subtraction unit 23B subtracts the average value of the dummy pixels 32B and 34B from the output of the entire imaging region 40B converted by the A / D conversion unit 18B. As a result, the output amplifiers 16A, 1
The density difference due to the difference in the output characteristics of 6B and the difference in the characteristics of the horizontal transfer units 14A and 14B can be corrected.

The subtracted signal is supplied to the output combining circuit 22, and the image pickup signals of the image pickup areas 40A and 40B are combined,
One piece of image data is generated. The generated image data is supplied to the image recording unit 24 and recorded in the image recording unit 24.

As described above, in the present embodiment, the light-receiving surface of the image pickup area is divided into two, and each area is read out separately to transfer the signal charge, so that the signal charge can be transferred at high speed. At the same time, dummy pixels 32A and 32B are provided at the ends of the vertical transfer unit 12 and the horizontal transfer units 14A and 14B.
By providing 34A and 34B, the imaging regions 40A and 40
Along with the transfer of the signal charge of the effective pixel portion of B, the imaging area 4
The density difference of the read image due to the difference in the output characteristics of the 0A and 40B output amplifiers can be grasped. This makes it possible to correct the image pickup signals from the image pickup areas 40A and 40B based on the density difference to reduce the density difference between the two images, and to combine the image pickup signals to obtain one image. However, the density difference is not recognized as a boundary line,
A high quality image can be obtained.

Although the dummy pixels are provided in both the vertical transfer section and the horizontal transfer section in the above-described embodiment, they need not be provided in both of them and may be provided in either one. Further, in the present embodiment, the dummy pixels are provided at both ends of all the vertical transfer units. However, as shown in FIG. 2, the dummy pixels are provided only at the boundary of the divided image pickup regions, and the dummy pixels at the boundary are removed. It is also possible to adopt a configuration in which correction is performed based on the obtained signal.

Further, although the dummy pixel is configured not to have a photo sensor, it is not limited to this, and the photo sensor is provided with a so-called optical black pixel which is a pixel shielded by a light emitting member such as a metal thin film. May be. The average value of the output of the dummy pixels is calculated by the average value calculation circuit, and the subtraction is performed by the independent subtraction unit. However, the present invention is not limited to this, and a CPU such as a DSP (Digital Signal Processor) not shown. (Cen
It can also be configured by a tral Processing Unit).

[Second Embodiment] FIG. 3 shows a second embodiment of the present invention.
The block diagram showing the schematic configuration of the image reading apparatus according to the embodiment is shown.

In this embodiment, the same parts as those in the above-mentioned first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

In the image reading device 60, a plurality of photosensors 31 are two-dimensionally arranged, and image pickup areas 40A and 40B are provided.
The image pickup area 40 is composed of two areas. The imaging regions 40A and 40B include a plurality of vertical transfer units 12 that vertically transfer the signal charges read from the plurality of photosensors 31 for each vertical column of pixels, and transfer from the vertical transfer units 12. It includes horizontal transfer units 14A and 14B that receive the generated signal charges and transfer them in the horizontal direction.

The output terminals of the horizontal transfer sections 14A and 14B provided corresponding to the image pickup areas 40A and 40B are
Output amplifiers 16A and 16B are provided for detecting the transferred signal charges, converting them into voltage signals, and outputting them. Further, the output amplifiers 16A and 16B are connected to the A / D converter 18
The offset correction units 26A and 26B are connected to the offset correction units 26A and 26B via A and 18B.
It is connected to LUTs 28A and 28B (look-up table). Here, the LUTs 28A and 28B are A / D
It is a table in which correction data for correcting the converted signal (input data) to generate output data is stored in advance. For example, the amount of light and the density can be adjusted.

The LUTs 28A and 28B are provided in the respective imaging areas 40.
It is connected to the image recording unit 24 via an output synthesizing circuit 22 that synthesizes and generates one image based on the image pickup signals of A and 40B.

Next, the image reading operation and the image pickup signal transfer operation in the image reading apparatus 60 according to the above-described embodiment of the present invention will be described.

When the light receiving surface of the image pickup area is irradiated with a predetermined light, the photosensor 31 generates an electric charge according to the brightness (amount of incident light) of the target image and accumulates it as a signal electric charge. After that, these signal charges are transferred by the gate unit 33 to the corresponding vertical transfer units 12 at once. The vertical transfer unit 12 distributes and transfers the transferred signal charges to the horizontal transfer units 14A and 14B for each of the imaging regions 40A and 40B.

The signal charges transferred to the horizontal transfer sections 14A and 14B are detected by the output amplifiers 16A and 16B,
It is converted into a voltage signal and supplied to the A / D converters 18A and 18B, respectively. The A / D converter converts the transferred voltage signal into a digital signal, and transmits the converted digital signal to the offset correction units 26A and 26B. The offset correction units 26A and 26B perform predetermined offset correction on the digital signal and transmit the corrected image pickup signal to the LUTs 28A and 28B.

Before reading, scratches on the target image,
Infrared light for detecting dust is emitted from a light source (not shown). At this time, the light amount of the infrared light is appropriately changed, and an output signal corresponding to the light amount is detected. As a result, the imaging region 4 caused by the difference in the output characteristics of the output amplifiers 16A and 16B
The density difference according to the light amount of the image pickup signal obtained by 0A and 40B can be grasped, and the data to be corrected can be grasped. Therefore, the data to be corrected obtained by irradiating the infrared light is written in the LUTs 28A and 28B, respectively.

By using the correction data obtained by using the infrared light described above, the LUT 28A,
In 28B, the input image pickup signals of the image pickup areas 40A and 40B are corrected based on the written correction data.

The corrected signal is supplied to the output synthesizing circuit 22, and the image pickup signals of the image pickup areas 40A and 40B are synthesized,
One piece of image data is generated. The generated image data is supplied to the image recording unit 24 and recorded in the image recording unit 24.

In the above-described embodiment, the density difference of the image pickup area is grasped by irradiating the infrared ray. However, the image pickup area is read in blank and the correction is made based on the output signal obtained from this. It can also be configured to perform. Also,
The effective pixel portion of the imaging area is shielded by a shutter,
It is also possible to adopt a configuration in which the light source is optically turned off by, for example, turning off the light source, the average output in the darkness of the image pickup area is sampled, and the image data is corrected based on this.

Furthermore, the shading (shading) of the pixels at the boundary between the image pickup areas of the film to be read is almost unchanged. Therefore, it is possible to adopt a configuration in which the correction is performed based on the image pickup signal of the pixel at the boundary portion. In this case, the image pickup signal of one pixel or a plurality of pixels at the boundary can be used.

Further, since infrared rays (invisible light) for detecting scratches and dust on the film to be read are transmitted through the film and the transmittance is constant, the pixels at the boundaries of the divided image pickup areas are detected. Shading (shading) is almost unchanged. Therefore, it is also possible to irradiate infrared rays on the boundary of each of the divided image pickup areas and correct the image pickup signal obtained from the effective pixel with the output signal obtained thereby as a reference.

Furthermore, more detailed correction can be performed by combining the above configurations.

In the above-described embodiment, the light receiving surface of the image pickup area is divided into two, but it may be divided into four, for example, and two more horizontal transfer sections may be provided. The transfer path from the pixel to the output section becomes 1/4, and the transfer rate of the signal charge becomes 1/4.

[0056]

As described above, since the image reading apparatus of the present invention has the above-mentioned configuration, even when the image pickup area of the image is divided and the reading is performed, the density difference and the boundary line are not noticeable. It has an excellent effect that a high quality image can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an image reading apparatus according to a first embodiment of the present invention.

FIG. 2 is a schematic explanatory diagram illustrating another example of an image pickup area of the image reading apparatus according to the first embodiment of the present invention.

FIG. 3 is a schematic configuration diagram of an image reading apparatus according to a second embodiment of the present invention.

FIG. 4 is an explanatory diagram showing an outline of an image pickup area in a conventional image reading apparatus.

FIG. 5 is a diagram showing a difference in light amount and output due to a difference in output characteristic of an output amplifier.

[Explanation of symbols] 10 Image reading device 12A, 12B Vertical transfer unit 14A, 14B Horizontal transfer unit 16A, 16B output amplifier 20A, 20B average value calculation circuit 22A, 22B output synthesis circuit 23A, 23B Subtraction unit 24 Image recording section 26A offset correction unit 31 photo sensor 32A, 32B vertical dummy pixels 34A, 34B horizontal dummy pixels 40A, 40B imaging area 60 image reading device

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) H04N 5/253 H04N 1/40 101A 5C077 F term (reference) 5B047 AA05 BA02 BB04 CB22 DA06 DC09 5C022 BA16 BA19 CA07 5C024 AX07 CX39 CY47 GY01 GZ36 GZ41 GZ48 HX21 HX23 5C051 AA01 DA06 DE02 DE13 EA08 FA04 5C072 AA01 BA07 EA05 FA03 FA08 FB03 FB04 VA03 WA07 5C077 LL01 LL04 MM03 PP12 PP23 PP46 PP47 PQ03 PQ23 RR01 SS01 SS03 SS03

Claims (5)

[Claims] 1. A photoelectric conversion element for accumulating charges according to an amount of transmitted light or an amount of reflected light of an original image and outputting a signal to a predetermined transfer path, wherein an imaging region of the photoelectric conversion element is divided into a plurality of areas. An image reading apparatus capable of independently outputting a signal for each of a plurality of divided image pickup areas, wherein an output difference between the plurality of image pickup areas is eliminated based on an average value of signal outputs of the respective image pickup areas. An image reading apparatus comprising a correction unit that corrects in this manner. 2. In a photoelectric conversion element for accumulating charges according to an amount of transmitted light or an amount of reflected light of an original image and outputting a signal to a predetermined transfer path, an image pickup area of the photoelectric conversion element is divided into a plurality of areas. An image reading apparatus capable of independently outputting a signal for each of a plurality of divided image pickup areas, wherein an image reading system that outputs a signal to the transfer path at the same time as the charge accumulation The image reading apparatus is characterized in that an idle transfer timing is provided, and a correction unit is provided to correct the output difference between the plurality of imaging regions based on the value of the signal output obtained by the idle transfer. . 3. The image reading device is a CCD image sensor in which the predetermined transfer path is composed of a vertical transfer path and a horizontal transfer path, and the correction means is an end portion of the horizontal transfer path and the vertical transfer path. The correction is performed so as to eliminate the output difference between the plurality of imaging regions based on an average value of signals from optical black pixels or dummy pixels set at at least one of the end portions of the road. The image reading apparatus according to claim 2. 4. A light source for irradiating invisible light for detecting defects such as scratches and dust on the original image is provided together, and the correction means outputs when invisible light is emitted from the light source. The image reading apparatus according to claim 1 or 2, wherein correction is performed so as to eliminate an output difference between the plurality of imaging regions based on an average value of signals. 5. The light source is capable of irradiating different amounts of invisible light, and the correction means is configured to perform the plurality of imaging based on an average value of output signals when the different amounts of invisible light are irradiated. The image reading apparatus according to claim 4, wherein correction is performed so as to eliminate an output difference between areas.