JP5287442B2 - Image reading device - Google Patents

Description

  The present invention relates to an image reading apparatus used for reading a form or the like written by a user on a manuscript printed in a predetermined format such as a voting ticket or a mark sheet.

  A lottery ticket to be voted by selecting a voting ticket issued by various stadiums, such as horse races, bicycle races and boat races, and a lottery ticket to be voted by selecting the number of the lottery to vote, discriminates the entered numbers and symbols, and records the voting ticket Reading devices and image processing devices that notify and return reading results to users are widely used.

  In general, a voting ticket is printed as a guide for filling in a portion where a numerical value or a symbol is entered for convenience of a user, a numerical value of a reading device, and simplification of a process for specifying a symbol position. Since this guide print section becomes unnecessary information when extracting numerical values and symbols written in various colors and types of writing instruments from the form, this guide print section is read out from the scanned image and the numerical values and symbols entered An image processing apparatus and a drop processing apparatus provided with means for reading only the image have been proposed.

For example, in FIG. 1 of JP 2006-339875 A (see Patent Document 1), image data in a predetermined area of image information is extracted, and a specific color is replaced with predetermined pixel data based on the extracted pixel data. Thus, an image processing apparatus that performs dropout processing is disclosed. The specific color is obtained by dividing the recognizable color space into color space areas, displaying the representative colors in the color space area as a color palette on the display device of the image processing apparatus, and selecting the color for which the user designates dropout. Is called. An image in which the specific color is replaced is displayed on a display device so that the user can check the processing result.

In FIG. 1 (see Patent Document 2), the histogram creation unit 14 performs SVH conversion on the RGB of the partial region image to generate S, V, and H histograms, and the color information setting unit 15. Obtains color information to be dropped out from the histogram, sets the value in the color table and stores it, and the binarization unit 16 determines that the pixel of the color image of the form 3 corresponds to the color information of the color table. A method for performing a dropout process for binarizing the image as a background pixel is disclosed.

JP 2006-339875 A (FIG. 1) JP 2003-216894 A (FIG. 1)

  However, in the one described in Patent Document 1, it is necessary to make a selection while looking at the specific color display to be dropped out, and it is necessary to ensure that the color of the displayed color palette is the same as the actual form color. . Further, there is a problem that correction input is required every time for fluctuations in the read images of R, G, and B, and an environment in which the operator manages the read results is required.

  In the one described in Patent Document 2, in order to perform dropout determination based on the histogram result of each color in the form image, the read image result of the entire form is required. A dedicated circuit for calculating the recorded image at high speed is required.

  Also, when processing forms that are input continuously, the processing capability of the subsequent dropout processing unit must be capable of completing the processing within the maximum number of sheets that can be read continuously. There was a problem that it was difficult to perform out-color processing.

  In the case of such a conventional technique, the data acquired by the image reading unit of the form is visually recognized in order to determine the pixel to be dropped out using the color (independent data of R, G, B) of the form image data and the histogram thereof. Will be processed as a collection of colors. In general, color information visually recognized by humans has a plurality of combinations of the same color and a visually recognized color, and the spectral wavelength configuration differs between a color displayed on a display or the like and a color printed on a printed matter.

  Therefore, the accurate reflected color reflected by the form document is not reflected between the color displayed on the display device and the color information to be dropped out in the actual form.

  In addition, when specifying the dropout color using the histogram information, although the actual document reflection data is used at the time of color specification, the final color judgment is performed only on the specific color plane after the dropout plane is determined. This is an image determination, leaving uncertainty in the color determination for intermediate colors.

  The present invention collects image data by irradiating a plurality of illumination wavelengths for illuminating the form at the time of image reading by spectral reflectance with respect to the wavelength of the light of the printed form and numbers, characters and symbols entered by the user, The feature of the read image data from the form depending on the wavelength of the illumination light of the printing section to be dropped out is extracted, and the pixel to be dropped out is replaced with the data that is determined to be white at the time of binarization. An object of the present invention is to provide an image reading apparatus that can separate a user entry part and a user entry part in real time with a small circuit.

An image reading apparatus according to a first aspect of the present invention includes a light source that irradiates light to a document by sequentially controlling lighting colors of a plurality of wavelengths, a lens that converges light reflected from the document, and the lens that is converged by the lens. A light receiving unit having a large number of pixels for receiving and photoelectrically converting light, an analog / digital conversion unit for analog / digital conversion of an analog signal photoelectrically converted by the light receiving unit, and a digital conversion by the analog / digital conversion unit The photoelectric conversion output is generated for each pixel of the light receiving unit by generating dark output data and uniformed and corrected, and the light emitted from the light source is received by the light receiving unit, and each pixel has a light output at the time of light. A white correction unit that generates and uniformizes output data, and the image data obtained for each emission color calculated by the white correction unit and the black correction unit are synchronized for each emission color of the same pixel of the light receiving unit. Across all line pixels An output color image position synchronization circuit unit; a multiplier that outputs one of the signals branched from the output of the color image position synchronization circuit unit for each emission color; and an output signal of the multiplier. When the data for each emission color at the same pixel position in the part is all within the range in which the upper limit value and the lower limit value corresponding to each emission color are specified in advance, the color that outputs the pixel position information as dropout data A determination unit; an image monochromeization gain unit that outputs the other signal branched from the output of the color image position synchronization circuit unit by multiplying the constant data determined for each emission color; and the image monochromeization gain unit An image monochromating circuit unit that adds the same pixel position data of the light receiving unit to the signal of the image and outputs it as monochromatic data, and an output signal of the image monochromating circuit unit A data replacement unit that outputs after replacing the pixel corresponding to the position information to a level that is not output as image data, a binarization unit that binarizes and outputs the data of the data replacement unit, and the data replacement unit A selector unit that receives an output signal and an output signal of the binarization unit and outputs the data of the data replacement unit as binarized dropout color processed image data; and The difference between the gain of the image data input to the color determination unit output from the multiplier and the gain of the image data input to the monochrome circuit unit output from the image monochromeization gain unit is adjusted. Further, the constant data is determined.

According to the image reading apparatus of claim 1 , the image data obtained sequentially for each emission color is aligned as color information for each pixel in the color image position synchronization circuit unit and branched from the color image position synchronization circuit unit. One output is amplified by a multiplier in units of emission color, and then the data for each emission color at the same pixel position in the color determination unit falls within the range in which an upper limit value and a lower limit value are specified in advance, and is used as dropout data. Monochromatic data corresponding to the pixel position information of the color determination unit in the data replacement unit by determining the pixel position, adding the same pixel position data multiplied by the constant data determined for each emission color in the image monochrome circuit part and adding it to the single color data Dropout pixels are replaced with dropout data, so if the output data for each luminescent color is low, the dropout pixel expands the dynamic range between the upper and lower limit values specified in the color judgment section. The position of the pixel to be dropped out can be specified with high accuracy by selecting the position, and the accuracy of the dropout process due to the difference between the relatively large gain applied to the color determination image and the gain of the monochrome image Decline can be prevented.

1 is a functional block diagram of an image reading apparatus according to Embodiment 1 of the present invention. It is a figure explaining the example of the spectral reflection spectrum of a form. It is a figure explaining the color range specification of a light source wavelength. It is a functional block diagram of the dropout processing part of the image reading apparatus by Embodiment 2 of this invention. It is a functional block diagram of the dropout processing part of the image reading apparatus by Embodiment 3 of this invention. It is a functional block diagram of the image reading apparatus by Embodiment 4 of this invention. It is a figure explaining the gain setting method by the multiplier of the image reading apparatus by Embodiment 4 of this invention. It is a functional block diagram of the dropout processing part of the image reading apparatus by Embodiment 5 of this invention.

Embodiment 1 FIG.
Embodiment 1 of the present invention will be described below with reference to FIG. FIG. 1 is a block diagram of the image reading apparatus according to the first embodiment. In FIG. 1, 1 is a document (form) printed in a predetermined format such as a voting ticket or a mark sheet, 2 is a light source such as an LED chip, 2a is a red light source (R light source), and 2b is a green light source (G). A light source 2c is a blue light source (B light source). 3 is a light guide that propagates the light irradiated by the light source 2 in the reading direction of the document 1 and uniformly irradiates the document 1 with light, and 4 is a rod that converges the reflected light of the light irradiated on the document 1. A lens array (lens) 5 includes a light receiving unit (sensor chip) including a driving unit in which a large number of photoelectric conversion elements are linearly arranged in the reading direction, and 5a is a part of the light receiving unit 5 and is referred to as a pixel. Reference numeral 6 denotes a sensor substrate on which the sensor chip 5 is mounted.

  7 is a glass plate (transmitter) that is interposed between the document 1 and the light guide 3 and allows light from the light source 2 to pass therethrough, and 8 is an analog / digital converter that digitally converts the analog signal photoelectrically converted by the sensor chip 5. A conversion unit (ADC) 9 is a black correction unit for correcting black level variation, 9a is a black correction memory, 10 is a white correction unit for correcting white level variation, and 10a is for white correction. A memory 11 is a PGA (Programmable Gain Amp) that adjusts the gain of each signal for each emission color, and 12 is a control unit that supplies power and control signals to the light source 2, the sensor chip 5, and the ADC 8.

  Reference numeral 13 denotes a synchronization line memory and the like, and an image position synchronization circuit unit that aligns image data read out in time series sequentially for each emission color with color information read in line pixel units, and 14 denotes light emission at the same pixel position. A color determination unit that determines a pixel position as dropout data when the data for each color is within a range in which an upper limit value and a lower limit value are designated in advance, and 15 is the same after being multiplied by constant data determined for each emission color An image monochromator circuit unit for adding pixel position data to monochromatic data, 16 is a data substituting unit for substituting monochromatic data pixels corresponding to the pixel position information of the color determining unit with data to be dropped out, and 17 is an image monochromator circuit. A background detection unit that detects the maximum value of the monochromatic data in the unit 15 and outputs the reference reflection density of the background of the document 1 to the data replacement unit 16; Binarization unit containing data is binarized by the value previously specified image data which is substituted by the designation of the color determining portion 14, 19 denotes a selector for outputting the image data processed dropout color to the outside. In the drawings, the same reference numerals indicate the same or corresponding parts.

  Next, the operation will be described. In FIG. 1, the light sources 2a, 2b, and 2c are sequentially turned on and off in accordance with the speed at which the document (form) 1 is conveyed, and lighting is controlled to be turned on. By individual lighting control, photoelectric conversion is performed by the sensor chip 5, and image data corresponding to the illumination color is sequentially digitized as an analog signal by the analog / digital conversion unit 8. The black correction unit 9 performs black correction when the light source 2 is turned off, so that there are cases where the fixed pattern noise of the light receiving unit 5 is corrected over all pixels (all pixel correction) and correction is performed in units of a certain pixel. . In any case, correction is performed by a known means so as to align with a constant value (for example, “0h” with 10-bit accuracy). These correction data are stored in the correction memory 9a for use.

Further, in the white correction unit 10, there is a variation in illumination intensity and a variation in sensitivity of the sensor chip 5 in the main scanning direction (the arrangement direction of the sensor chips 5) of each color light source 2. The white correction is performed to correct the variation in the dynamic range of the image data caused by the above. These correction data are stored in the correction memory 10a and used. In the PGA 11, image data output from each color light source 2 is amplified for each color.

  Next, the dropout color process will be described. In order to perform color determination, all color image line data read from the same line on the form 1 are synchronized so that data input as image line data for each color can be determined as color information in units of pixels. For this reason, the color determination unit 14 precedes the color (RGB) image position synchronization circuit unit 13 performs image position synchronization processing so that RGB three-color data is simultaneously output to the subsequent circuit for each pixel. The synchronized image data is sent to the color determination unit 14 to determine the color to be dropped out for each pixel.

  The color determination unit 14 determines whether or not the photoelectrically converted data of each color data exists in a predetermined range based on the color image information synchronized in pixel units in the color image position synchronization circuit unit 13, When all the color data exists in a predesignated range in pixel units, the data read by the photoelectric conversion element is determined as data to be dropped out. This dropout determination is performed in synchronism with the pixel processed by the image monochrome circuit 15 and the value of the pixel determined to be a dropout pixel is changed to a preset pixel value in the data replacement unit 16 in real time. Replace. By this processing, the image to be dropped out is erased, and when it is binarized by the binarization unit 18 at the subsequent stage, it is surely skipped as a background.

  This determination is based on the spectral reflectance of the form 1 shown in the spectral reflectance spectrum example of the form 1 shown in FIG. 2 and the measurement result of the spectral reflectance of the writing instrument used for marking, and the determination of orange as shown in FIG. This is done using a color light source.

  The spectral reflectance shown in FIG. 2 is determined by, for example, the composition and combination of printing inks used in the case of a printing pattern. In FIG. 2, the reflectance of the paper to be printed is shown as the background, and the background shows a low-density printing of the portion corresponding to the printed background such as characters and symbols. In this form 1, the color to be skipped (dropped out) is a reflection pattern described as “print to be dropped out”, and the reflectivity changes abruptly when the optical wavelength is around 550 nm. The other reflectance data shows the reflectance of the writing instrument that is considered to be used when the user marks, and it can be seen that it has spectral characteristics with large reflection intensities in red and blue.

  As a result, as shown in FIG. 3, in order to extract orange, which is a color to be skipped (dropped out), it is only necessary to make a determination by considering a green image as a main determination parameter and red and blue information. I understand.

  For example, the output estimated value of the form guide printing unit when the background color of the back side of the form 1 is converted to 100% and the RGB light source and color sequential reading are shown below.

These outputs are converted into digital values of the image, and the pixels in the dropout portion of the form 1 are determined. Specifically, in consideration of variations such as printing unevenness and density, the color determination unit 14 designates a color range centered on this value, and a pixel having a color to be dropped out has a reflectance such as a background color. By replacing the data with a high white color, for example, white by the data replacement unit 16, the pixel to be dropped out is omitted from the image data before binarization.

  As an example of the first embodiment of the present embodiment, 200 to 255 digits for red data and 120 to 255 digits for green data are used as determination values for designating dropout pixels of RGB colors for read RGB image data. For the blue data, a pixel in which each color data exists in the range of 0 to 200 digits was specified, and the reading test of the form 1 was performed. As a result, it was confirmed from the test results that almost 100% of the guide print portion is designated as a dropout pixel by this processing.

    Next, the image data sent from the image position synchronization circuit unit 13 to the color determination unit 14 is also sent to the image monochrome circuit 15 at the same time, and the image is monochromeized at a predetermined blending ratio. The image monochromator circuit unit 15 calculates the monochrome image output data by calculating each color data by the following formula based on the color image information synchronized by the pixel unit in the color image position synchronizing circuit unit 13 at a predetermined ratio. Generate based on the following formula.

I (n) = {Ir (n) * Cr} + {Ig (n) * Cg} + {Ib (n) * Cb} where
Ir (n): n-th pixel data with a red light source, Ig (n): n-th pixel data with a green light source, Ib (n): n-th pixel data with a blue light source, Cr: Red light source coefficient, Cg: Green light source coefficient, Cb: Blue light source coefficient, I (n): Monochrome output value of the nth pixel.

  This monochrome processing is performed for preprocessing for image binarization in the subsequent stage and for specifying the color-determined pixels. The pixel position information determined by the color determination unit 14 is used for a monochrome image, and the pixel to be dropped out is subjected to a replacement process with a preset value that is surely determined as white when binarizing. Then, a monochrome image from which a portion to be dropped out is deleted is generated.

  The image reading apparatus may output this monochrome information. However, since the mark information only needs to be able to determine the presence or absence of a mark, the monochrome image data is sent to the binarization unit 18 at the subsequent stage, and 2 at a predetermined slice level. The data is converted into black and white binary data. In this process, the information of the pixel to be skipped (dropped out) is replaced with a value that is surely determined as white at the time of binarization in advance, so that only the contrast of the form 1 background and the mark entered is considered. It ’s fine.

  As described above, it is possible to obtain an image reading apparatus that can perform image data to be subjected to dropout color processing in real time with a small circuit and can surely skip a printing ground such as a form or a guide printing unit. it can.

  In addition, data peak detection of a monochrome image is performed, and the peak value is used as the background density of the monochrome image, so that the replacement data of the dropout designated pixel can be created by the data replacement unit, and the pixel data is the background of the document. Therefore, the quality of the original image is improved, and there is an effect that it is surely recognized as a white background in binarization.

Embodiment 2. FIG.
In the first embodiment, the basic configuration of the image reading apparatus according to the present invention has been shown. However, in general, the difference between the dropout color in the read image of the form and the color of the writing tool for marking is small, and the read image is If the color determination is performed as it is, there may be a problem in the accuracy of color separation. In the second embodiment, a configuration for determining the color by expanding the dynamic range will be described with reference to FIG.

FIG. 4 is a functional block diagram of a dropout processing unit of the image reading apparatus according to the second embodiment of the present invention. In FIG. 4, reference numeral 20 denotes a multiplier that branches from the output of the color image position synchronization circuit unit 13 and that multiplies and inputs it to the color determination unit 14. In the figure, the same reference numerals as those in FIG. 1 denote the same or corresponding parts. The multiplier 20 concentrates on the halftone area necessary for color determination by multiplying the image data by a numerical value corresponding to each color set in advance to multiply each color data by a predetermined gain before the color determination unit 14. It plays a role of enlarging (enlarging) a portion necessary for color determination, for example, a low output value portion. Therefore, there is an effect that a setting range of a determination area necessary for color determination can be secured and reliable color determination and separation can be performed.

Embodiment 3 FIG.
In the second embodiment, the method for determining the color by expanding the dynamic range has been described. In the third embodiment, a configuration for determining the color by providing a plurality of color determination units will be described with reference to FIG.

  FIG. 5 is a functional block diagram of a dropout processing unit of the image reading apparatus according to Embodiment 3 of the present invention. In FIG. 5, reference numeral 140 denotes a color determination unit that performs parallel signal processing on a signal branched from the output of the color image position synchronization circuit unit 13. 140 a is a first color determination unit, 140 b is a second color determination unit, and 140 n is An nth color determination unit. Reference numeral 150 denotes a logical comparison unit that performs a logical operation on the output from each color determination unit 140 and sends the data selected or verified by the control signal to the data replacement unit 16. In the figure, the same reference numerals as those in FIG. 1 denote the same or corresponding parts.

In the third embodiment, a plurality of determination conditions can be combined because the determination is performed by a plurality of color determination units. That is, an output selected in combination by interposing a logic circuit such as an OR circuit, an AND circuit, an XOR circuit, etc., in which the determination result is designated in advance is sent to the data replacement unit. For example, when there are a plurality of colors to be read (dropped out), the determination result is selected by an OR circuit using the plurality of color determination units 140, and all the dropout colors are selected. Dropout can be specified. In addition, data defect due to digital noise can be improved by performing data collation of the color determination unit 140 itself using an AND circuit and outputting the data from the logic collation unit.

Also, for the entry mark that is read as a color close to the dropout color, the color determination unit 140 specifies the color of the entry mark, and the result of the determination is combined with XOR, so that the dropout specification pixel specified in the color determination Thus, pixels determined to be significant in the color determination result of the entry mark are excluded. That is, it is possible to detect mark colors that are difficult to discriminate by using some of the color determination units 140 as color detection circuits and using them as color detections for the output from the color determination unit 140 for other dropout colors. It becomes.

Embodiment 4 FIG.
In the first to third embodiments, the basic operation and configuration of the image reading apparatus are mainly described. However, in the fourth embodiment, it is caused by an environmental change caused by an environmental temperature, a supplied power supply voltage fluctuation, an illumination fluctuation of a light source to be used, and the like. An image reading apparatus capable of stably ensuring the accuracy of a read image even when there is a reading fluctuation will be described with reference to FIG. FIG. 6 is a functional block diagram of an image reading apparatus according to Embodiment 4 of the present invention. In FIG. 6, reference numeral 200 denotes a reference plate provided outside the reading width of the document, and 201 denotes a digital variable unit provided in front of the color image position synchronization circuit unit 13. In the figure, the same reference numerals as those in FIG. 1 denote the same or corresponding parts.

  In FIG. 6, the reference plate 200 is installed on the transmissive body 7 or outside the reading area of the document 1 and is configured by a reflective member having a high reflectance. In the fourth embodiment, a structure in which a sheet made of white is attached to the transmissive body 7 is adopted. During the image reading operation, the output value from the reference plate (reference white original) is always monitored, the initial reading result is stored in a non-volatile memory (not shown), etc., and the reference white portion with respect to fluctuations in the read image data The digital variable unit 201 multiplies the image signal by a gain so that the value of 常 に always becomes a constant value asymptotic to the initial data. That is, the light that is illuminated from the light source 2 and reflected by the reference plate 200 is photoelectrically converted as a reference signal by the pixels 5a around the edge, and the output of each line is read during the reading operation.

  By arranging the reference plate 200 in this way, the output from the reference plate 200 is always constant when the light amount of the initial light source does not fluctuate. When there is a change in the light source 2, there is a change in the amount of light in the reference plate 200, and the image data passing through the black correction unit and the white correction unit also changes, but from the pixel 5a corresponding to the position of the reference plate 200 from the PGA. Is adjusted by the digital variable device 201, the image data input and the image data output are subjected to feedback processing using a multiplier or the like as in the example shown in FIG. 7, and the gain is automatically set. That is, the reference pixels are averaged, the correction numerical value is calculated using the system clock signal (XSYNC) and the register signal, the correction coefficient (Pcor) is determined, and the gain is varied by the multiplier.

As described above, the reflected light from the reference plate 200 is always read by using a part of the pixel 5a and compared with the RGB reference value set in advance in the PGA 11 or the digital variable device 201 or the like. Since the digital variable device is provided so as to send out the output, stable color determination is possible by always inputting a certain range of image data to the color determination unit 14. The reference value is set for each of red, green, and blue (RGB). However, any of RGB may be used.

In Embodiments 1 to 4, an RGB three-color light source capable of reading a color image is used. However, when reading of a color image is not necessary, a combination of light sources that is optimal for the spectral reflection spectrum of the object to be read is used. This makes it possible to perform more effective reading processing of forms and the like. That is, by using an infrared light source other than RGB, a yellow-green color light source, a blue-green color light source, or the like, the determination accuracy is improved by collecting a characteristic color image in the spectral reflection spectrum. Further, if the emission wavelength used for the determination is two or more wavelengths, an appropriate effect can be obtained.

Embodiment 5 FIG.
FIG. 8 is a functional block diagram of a dropout processing unit of an image reading apparatus according to Embodiment 5 of the present invention. In FIG. 8, reference numeral 310 denotes an image monochromating gain unit that branches from the output of the color image position synchronizing circuit unit 13 and that multiplies and inputs to the image monochromating circuit unit 15. The image monochromeization gain unit 310 plays a role of multiplying the image data by a numerical value corresponding to each color set in advance in order to multiply each color data by a predetermined gain before the image monochromeization circuit unit 15. In the figure, the same reference numerals as those in FIG. 4 denote the same or corresponding parts.

The image monochromeization gain unit 310 multiplies constant data determined for each emission color, adds the same pixel position data of the light receiving unit 5 to the signal of the image monochromeization gain unit 310, and outputs the result as single color data. For example, when a relatively large gain (for example, 1.25 times or more) is applied to the multiplier 20 in the preceding stage of the color determination unit 14 in the second embodiment, the gain of the output of the image monochrome circuit 15 and the output at the time of color determination When the data is replaced based on the color determination due to the difference between the dropout color and the dropout color boundary part may not be completely removed, the dropout process accuracy may be lowered.

In the fifth embodiment, even when a relatively large gain is applied to the multiplier 20 in the previous stage of the color determination unit 14, the image monochromeization is performed by the image monochromeization gain unit 310 provided in the previous stage of the image monochromeization circuit unit 15. By adjusting the difference in gain between the output of the circuit unit 15 and the output at the time of color determination, the boundary portion of the dropout color can be completely removed, and the accuracy of the dropout process is improved.

In this way, when the portion (mostly low output value portion) necessary for color determination concentrated in the halftone area necessary for color determination is stretched (enlarged), it is not limited by the gain of the color determination section 14. A setting range of a determination area necessary for color determination is ensured, and reliable color determination and separation can be performed.

Other configurations and functions other than those described in the fifth embodiment are the same as those described in the first to fourth embodiments. Further, the logic collating unit 150 shown in FIG. 5 described in the third embodiment and the digital variable device 201 shown in FIG. 6 described in the fourth embodiment may be added to those described in the fifth embodiment. This has a corresponding effect on the accuracy of dropout processing such as judgment and separation.

From the above, when the read image is monochromeized, before the data is input to the image monochrome circuit 15, the image data is multiplied independently by the gain designated in advance for each color, so that a relatively large image is applied to the color determination image. Prevents dropout processing accuracy from being reduced due to the difference between the gain and the monochrome image gain, and it is possible to set a large gain for color reflection data that has a subtle difference in reflectance. As a result, it is possible to secure a large specified threshold width of the color.

1..Original (form) 2..Light source 2a..Red color light source 2b..Green color light source 2c..Blue color light source 3..Light guide 4..Rod lens array (lens)
5. ・ Sensor IC (light receiving part) 5a ・ ・ Pixel 6 ・ ・ Sensor substrate 7 ・ ・ Glass plate (Transmitter)
8 .. Analog / digital conversion unit (ADC) 9 .. Black correction unit 9 a .. Correction memory 10 .. White correction unit 10 a .. Correction memory 11.
12. Control unit 13. Color image position synchronization circuit unit 13a Line memory 14 Color determination unit 15. Monochrome circuit unit 16. Data replacement unit 17. Background detection unit 18. Binary ... Selector 20 .. Multiplier 140... Color determination unit 140 a... First color determination unit 140 b... Second color determination unit 140 n .. nth color determination unit 150. Reference plate (white reference document)
201 .. Digital variable device 310 Image monochromeization gain section

Claims (1)

A light source that irradiates light on a document by sequentially controlling lighting colors of a plurality of wavelengths, a lens that converges light reflected from the document, and a large number of pixels that receive the light converged by this lens and perform photoelectric conversion A light receiving unit, an analog / digital conversion unit that performs analog / digital conversion of an analog signal photoelectrically converted by the light receiving unit, and a photoelectric conversion output digitally converted by the analog / digital conversion unit for each pixel of the light receiving unit. A black correction unit that generates dark output data and makes uniform correction, and a white correction unit that receives light emitted from the light source by the light receiving unit and generates light output data for each pixel to make uniform correction And a color image position for outputting image data obtained for each emission color calculated by the white correction unit and the black correction unit over all line pixels in synchronization with each emission color of the same pixel of the light receiving unit. Synchronous circuit section and this A multiplier for outputting from the multiplying one signal branched from the output of the color image position synchronizing circuit for each emission color, a signal of the multiplier, the data of each emission color at the same pixel position of the light receiving portion Are all within a range in which an upper limit value and a lower limit value corresponding to each emission color are specified in advance, a color determination unit that outputs the pixel position information as dropout data, and the color image position synchronization circuit unit An image monochromeization gain unit that outputs the other signal branched from the output of the output by multiplying by constant data determined for each emission color, and the same pixel of the light receiving unit with respect to the signal of this image monochromeization gain unit An image monochromating circuit unit that adds position data and outputs it as monochromatic data, and an output signal from the image monochromating circuit unit is converted into pixel data corresponding to the pixel position information of the color determining unit. The data replacement unit that outputs the data after replacing the data to a level that is not output, the binarization unit that binarizes and outputs the data of the data replacement unit, the output signal of the data replacement unit, and the binarization unit And a selector unit that outputs the data of the data replacement unit as image data obtained by performing binarized dropout color processing, and the image monochromeization gain unit is output from the multiplier The constant data is determined so as to adjust the difference between the gain of the image data input to the color determination unit and the gain of the image data input to the monochrome circuit unit output from the image monochromeization gain unit. Image reading apparatus.

Images