JP5617502B2 - Image reading device - Google Patents

Description

  The present invention relates to an image reading apparatus that reads an image of an original, and more particularly to an image reading apparatus that can be detected when the original is a blank sheet.

  Conventionally, it has been proposed that an image reading apparatus that reads an image of a document detects that when a blank document is read. For example, when the number of pixels having a predetermined density or higher that is set in advance is less than a threshold value, the document is determined to be blank. In that case, it is necessary to appropriately set the threshold value. In view of this, it has been proposed that the user scans an original that the user does not want to detect as a blank sheet, and the image reading apparatus sets the threshold based on the read data (see, for example, Patent Document 1). .

JP 2008-22275 A

  On the other hand, in a conventional image reading apparatus, a user sets parameters related to image processing such as gamma correction so that an original can be read with appropriate brightness and contrast. However, in Patent Document 1, image processing such as gamma correction is executed only when it is determined that the document is not blank (for example, paragraph 0023), and the above settings of the user are not reflected in blank page detection.

  In view of the above, an object of the present invention is to provide an image reading apparatus capable of appropriately detecting a blank page by reflecting the setting of image processing by the user to the blank page detection.

In order to achieve the above object, the present invention includes a reading unit that reads an image of a document, a counting unit that counts the number of pixels having a predetermined density or more from the reading data read by the reading unit, and a total of the counting unit. When the numerical value is less than a threshold value for blank sheet detection stored in advance, the image reading apparatus includes a blank sheet detection unit that determines that the document is blank. An image processing unit that performs image processing related to image quality, an image processing setting unit that sets image processing by the image processing unit in response to a user's operation, and outputs read data after image processing by the image processing unit And a determination unit that determines whether or not the setting made by the image processing setting unit is to reduce the density of a pixel, and the determination unit determines that the reduction is performed If you The counting unit counts the number of pixels from the read data before image processing by the image processing unit, the blank sheet detection unit makes the determination based on the counted value, and the determination unit does not reduce the value. If it is determined that there is not, the counting unit counts the number of pixels from the read data after the image processing by the image processing unit, and the blank sheet detection unit makes the determination based on the count value. It is said.

In the image reading apparatus of the present invention configured as described above, the image processing unit performs image processing related to image quality on the read data read by the reading unit that reads the image of the document. This image processing setting is made via an image processing setting unit in accordance with a user operation. The output unit outputs the read data after the image processing. The counting unit counts the number of pixels having a predetermined density or more from the read data after the image processing when the determination unit determines that the setting made by the image processing setting unit does not reduce the image density. To do. Then, when the count value of the counting unit is less than the threshold value for blank sheet detection stored in advance, the blank sheet detection unit determines that the document is blank. Therefore, according to the present invention, it is possible to appropriately detect the blank page by reflecting the setting of the image processing by the user to the blank page detection.

  Note that the above-described output is a process of storing data in a memory or the like inside the image forming apparatus, or a process of outputting the data as data to the outside of the image forming apparatus. Even if it is a process to form, it may be other processes.

Also, if the upper Symbol decisions unit is determined to be one that reduces the, the counting unit counts the number of the pixels from the image processing before reading the data by the image processing unit.

  When image processing for reducing the image density is performed, there is a high possibility that the document is determined to be blank. In that case, there is a possibility that even a document to be read as a document on which an image is described is determined to be a blank sheet. Therefore, when the determination unit determines that the setting made by the image processing setting unit is to reduce the density of the pixel, the counting unit calculates the pixel from the read data before the image processing by the image processing unit. Count the number. Therefore, in this case, it is possible to suppress the determination that a document to be read as a document on which an image is written is blank. When the determination unit determines that the reduction is not performed, as described above, the counting unit may count the number of pixels from the read data after the image processing by the image processing unit.

  Various forms of image processing relating to the image quality can be considered. For example, it may be gamma correction for adjusting the brightness of the image, gamma correction for adjusting the contrast of the image, or processing for enlarging or reducing the image.

1 is a perspective view illustrating a configuration of a multifunction machine to which the present invention is applied. It is a block diagram showing the structure of the control system of the multifunction machine. It is explanatory drawing showing the gamma table used with the control system. It is explanatory drawing showing the scan setting screen of the said multifunctional device. It is explanatory drawing showing the effect of (gamma) correction by the said (gamma) table, and embodiment. It is a flowchart showing the image reading process of the said control system. It is a flowchart showing the image quality setting process of the image reading process in detail. It is a flowchart showing the reading γ process of the image quality setting process. It is a flowchart showing the emphasis filter / enlargement / reduction process of the image quality setting process.

[Configuration of MFP]
Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view illustrating a configuration of a multifunction machine 1 to which the present invention is applied. As shown in FIG. 1, the multifunction device 1 according to the present embodiment includes a scanner unit as an example of an image reading apparatus according to the present invention on an upper part of a printer unit 5 including a recording engine 51 (see FIG. 2) described later. 10 is loaded.

  The scanner unit 10 is provided with a flatbed unit 20 on which a document is placed when a thick document such as a book is read, and a document cover provided on the flatbed unit 20 so as to be openable and closable and incorporating an ADF (Automatic Document Feeder). 30. In addition, an operation panel 21 having a display unit 23 as a center and various buttons is provided at the front end (front side as viewed from the user) of the flat bed unit 20. The ADF of the document cover 30 is a well-known one that conveys the documents on the paper feed tray 110 provided on the document cover 30 one by one and discharges them to the paper discharge tray 130. Then, on the document transport path (not shown) inside the document cover 30, the image of the document transported as described above is read and placed along the surface of the flat bed portion 20 while moving. A CIS 140 (see FIG. 2) capable of executing an operation of reading an image of a document is provided.

  FIG. 2A is a block diagram illustrating a configuration of a control system of the multifunction machine 1. As shown in FIG. 2A, the above-described CIS 140 (an example of a reading unit) is connected to the bus 150 via the AFE 141. The bus 150 is connected to a CPU 151 (an example of a counting unit, a blank page detection unit, and a determination unit), a RAM 152, and a ROM 153. Further, the recording engine 51 forms an image on a sheet as a recording medium by electrophotography. (An example of an output unit) and the following image processing circuit 160 (an example of an image processing unit) are connected.

  FIG. 2B is a block diagram illustrating the configuration of the image processing circuit 160 in detail. The read data read by the CIS 140 is converted into digital data by the AFE 141 and sent to the CPU 151. Further, the read data is sent to the image processing circuit 160 to be subjected to the following various image processing (also referred to as image processing). That is, as shown in FIG. 2B, the image processing circuit 160 includes a reading γ processing circuit 161 that performs gamma correction for reading on the read data, and a filter processing circuit that performs various filter processes on the read data after the correction. 162, an enlargement / reduction processing circuit 163 that performs enlargement / reduction processing on the read data after the processing, and a recording γ processing circuit 164 that performs gamma correction for recording on the read data after the processing.

  3A and 3B are explanatory diagrams illustrating an example of a γ table used in the reading γ processing circuit 161. FIG. FIG. 3A shows a γ table representing the output density value with respect to the input density when the brightness value is changed from −50 to +50. As shown in FIG. 3A, when the above value is adjusted to the minus side, that is, the brightness is adjusted to be dark, the intermediate color of the input read data is changed to dark eyes and output. Conversely, when the above value is adjusted to the plus side, that is, when the brightness is adjusted to be brighter, the intermediate color of the input read data is changed to be lighter and output.

  FIG. 3B shows a γ table representing the output density value with respect to the input density when the contrast value is changed from −50 to +50. As shown in FIG. 3B, when the above value is adjusted to the plus side, the intermediate color of the input read data is output with further emphasized changes. Conversely, when the above value is adjusted to the minus side, the intermediate color of the input read data is output with the change suppressed.

  Therefore, the multifunction device 1 according to the present embodiment, when executing an image reading process of reading an image of a document via the scanner unit 10, displays a scan setting screen 230 (image processing setting unit) illustrated in FIG. Example). As shown in FIG. 4, the scan setting screen 230 includes a mode setting unit 231 for setting a color or monochrome mode, a resolution setting unit 232 for setting an output resolution, and an enlargement / reduction ratio. An enlargement / reduction ratio setting unit 233, a brightness setting unit 234 for setting the above-described brightness value, a contrast setting unit 235 for setting the above-described contrast value, “clear”, “clean”, etc. An option setting unit 236 for setting an optional filter. The scan setting screen 230 further includes a scan button 237 for instructing start of image reading processing after the various settings are made, and a cancel button 238 for invalidating the various settings. .

  Here, for example, when reading a document P on which a thin line is drawn as shown in FIG. 5A, the user sets the brightness value to a negative value. For example, when the brightness value is set to −50, the read data after correction according to the γ table in FIG. 3A is as shown in FIG. On the other hand, if the brightness value remains 0, the read data remains thin as shown in FIG. However, in the conventional image reading apparatus, blank sheet detection is performed to determine whether or not the document P is blank based on the image of the document P before such gamma correction is performed. For this reason, even if the user recognizes that the image of the document P is thin and sets the brightness value, it cannot be reflected in blank sheet detection.

[Processing in MFP]
Therefore, in the present embodiment, the following image reading process is executed. FIG. 6 is a flowchart showing the image reading process. This process is a process executed by the CPU 151 based on a program stored in the ROM 153 when the scan button 237 is pressed, and the CPU 151 executes this process for each page of the document P.

  As shown in FIG. 6, in this process, first, in S0 (S represents a step: the same applies hereinafter), the CPU 151 reads the mode set via the mode setting unit 231 and sets the reading mode of the CIS 140. . In the subsequent S1, the CPU 151 reads each setting made through the enlargement / reduction ratio setting unit 233, the brightness setting unit 234, the contrast setting unit 235, and the option setting unit 236 as settings relating to the read image quality. Perform the setting process.

  FIG. 7 is a flowchart showing the image quality setting process in detail. As shown in FIG. 7, in this process, the CPU 151 first executes a reading γ process for setting the reading γ processing circuit 161 in S11.

  FIG. 8 is a flowchart showing the details of the reading γ process. As shown in FIG. 8, in this process, first, in S111, the CPU 151 determines whether the reading γ is ON, that is, whether either the brightness value or the contrast value is set to a value other than 0. To do. If the reading γ is ON (S111: Y), the CPU 151 sets the operation of the reading γ processing circuit 161 to ON in S113. In subsequent S115, the γ table used in the reading γ processing circuit 161 is changed in accordance with the brightness value. In further S117, the γ table used in the reading γ processing circuit 161 is changed according to the contrast value, and the process proceeds to S13 in FIG.

  That is, in the reading γ processing circuit 161, by default, the above values are set to 0 and the input density and output density of the read data match, but when the above values are set to other than 0, those values are set. The gamma correction corresponding to is repeated. On the other hand, when each of the above values is set to 0 and reading γ is OFF (S111: N), the process proceeds to S119, and the CPU 151 sets the operation of the reading γ processing circuit 161 to OFF, and the process is performed. The process proceeds to S13 in FIG.

  Returning to FIG. 7, in S <b> 13, the CPU 151 executes enhancement filter / enlargement / reduction processing for setting the filter processing circuit 162 and the enlargement / reduction processing circuit 163. FIG. 9 is a flowchart showing the details of this enhancement filter / enlargement / reduction processing.

  As shown in FIG. 9, in this process, the CPU 151 first determines whether or not any setting is made in the option setting unit 236 and the filter is turned on in S131. When the filter is ON (S131: Y), the process proceeds to S132, and the CPU 151 determines whether “clear” is set in the option setting unit 236. If “clear” is not set (S132: N), the process proceeds to S133, and the CPU 151 determines whether “clean” is set in the option setting unit 236. If “clean” is not set (S133: N), the process proceeds to S134, the operation of the filter processing circuit 162 is set to OFF, and the process proceeds to S137. Even when the filter is OFF in S131 described above (S131: N), the operation of the filter processing circuit 162 is similarly set OFF in S134, and the process proceeds to S137.

  If “clear” is set in S132 (S132: Y), in S138, the CPU 151 turns on the enhancement filter built in the filter processing circuit 162, and the process proceeds to S137. If “clean” is set in S133 (S133: Y), in S139, the CPU 151 turns on the enhancement filter and smoothing filter built in the filter processing circuit 162, and the process proceeds to S137. Note that these enhancement filters and smoothing filters are well-known image processing filters and will not be described in detail here.

  In S <b> 137, the CPU 151 determines whether or not an enlargement / reduction ratio exceeding 100% is set by the enlargement / reduction ratio setting unit 233. When the enlargement / reduction ratio exceeding 100% is not set (S137: N), the CPU 151 determines whether the enlargement / reduction ratio is 100% in S141. If the enlargement / reduction ratio is 100% (S141: Y), the process proceeds to S143, the CPU 151 sets the operation of the enlargement / reduction processing circuit 163 to OFF, and the process proceeds to S15 in FIG.

  On the other hand, when the enlargement / reduction ratio is not 100% (S141: N), since the enlargement / reduction ratio is less than 100%, the process proceeds to S145, and the CPU 151 turns on the reduction operation in the enlargement / reduction processing circuit 163. The enlargement / reduction ratio set by the enlargement / reduction ratio setting unit 233 is set, and the process proceeds to S15 of FIG. When the enlargement / reduction ratio exceeds 100 (S137: Y), the process proceeds to S147, and the CPU 151 turns on the enlargement operation in the enlargement / reduction processing circuit 163 and sets the enlargement / reduction ratio set by the enlargement / reduction ratio setting unit 233. Is set, and the process proceeds to S15 of FIG.

  Returning to FIG. 7, when such enhancement filter / enlargement / reduction processing (S13) is completed, the CPU 151 determines in S15 whether the copy mode is set. That is, in such an image reading process, a mode in which read data is stored in a portable storage medium such as a removable disk, a PC scan mode in which read data is transmitted to a personal computer, or the recording engine 51 based on the read data is set. It is executed in a process such as a driving copy mode. Therefore, in S15, the CPU 151 determines whether or not the image reading process has been executed in the copy mode.

  When the copy mode is set (S15: Y), the CPU 151 sets the operation of the recording γ processing circuit 164 to ON at S17, and when the copy mode is not set (S15: N). , The operation of the recording γ processing circuit 164 is set to OFF in S19. Then, when the process of S17 or S19 ends, the process proceeds to S5 of FIG.

  Returning to FIG. 6, in S <b> 5, the CPU 151 instructs the start of a known reading operation by the CIS 140, and in S <b> 7 (processing as an example of a determination unit), the image quality setting read in S <b> 1 is set to darken the image. It is determined whether or not. That is, it is determined whether the brightness value is set to minus or 0. If the image quality setting is a setting to darken the image (S7: Y), the process proceeds to S9, and the CPU 151 sends the read data to the image processing circuit 160 to acquire the read data subjected to the image processing. Execute. Then, the image processing circuit 160 performs image processing according to the contents set in S1 on the read data input via the AFE 141 in response to the start of reading in S5.

  In the subsequent S21, the CPU 151 stores the read data for which the image processing by S9 has been completed in the RAM 152, and in the subsequent S23, the CPU 151 (an example of a counting unit) determines from the pixels that constitute the read data for which the image processing has been completed. The number of pixels in a predetermined density range (there is no upper limit and practically a predetermined density or more) is counted. In subsequent S25, the CPU 151 determines whether or not the processing of S9 to S23 has been completed for all the lines of the document P. If not completed (S25: N), the processing of S9 to S23 is performed. repeat. Note that the processing of S9 to S23 is not necessarily performed for each line, and may be performed for every several lines.

  When the processes in S9 to S23 are completed for all lines (S25: Y), the process proceeds to S27 (a process as an example of a blank sheet detection unit), and the CPU 151 counts the total number of documents P in S23. It is determined whether or not the value (count value) is greater than or equal to a preset threshold value. If it is equal to or greater than the threshold value (S27: Y), it can be estimated that the document P is not a blank sheet, so the CPU 151 outputs the read data stored in the RAM 152 as normal data and ends the process once. As a result, the read data after the image processing is sent to the personal computer in the PC scan mode, and is sent to the recording engine 51 in the copy mode. On the other hand, when the total count value is less than the threshold value (S27: N), the process proceeds to S31, and the CPU 151 erases the read data without outputting it, and ends the process once.

  On the other hand, when the image quality setting is a setting for thinning the image (S7: N), the process proceeds to S41 (a process as an example of a counting unit), and the CPU 151 determines the read data before the image process. Similar to S23, the number of pixels in the predetermined density range is counted. Subsequently, the CPU 151 executes image processing similar to S9 in S43, and further stores the read data whose image processing has been completed in the RAM 152 in S45. In subsequent S47, the CPU 151 determines whether or not the processing of S41 to S45 has been completed for all the lines. If the processing has not been completed (S47: N), the processing has been terminated to S41 described above. (S47: Y), the process proceeds to S27 described above.

[Effect of this embodiment and its modification]
As described above, in the present embodiment, in the case of image quality setting for darkening an image (S7: Y), blank page detection that counts the number of pixels in a predetermined density range and compares it with a threshold value for read data after image processing. (S23, S27) is executed. Therefore, in the present embodiment, it is possible to appropriately detect the blank page by reflecting the setting of the image processing by the user in the blank page detection process.

  For example, in the example of FIG. 5 described above, when the brightness value is set to −50, after image processing, the number of pixels in a predetermined density range (in FIG. If the (notation) is 1200, it is recognized that the threshold value 1000 is exceeded and the page is not blank. On the other hand, in the conventional image reading apparatus in which the image processing setting is not reflected, as illustrated in FIG. 5C, the brightness value setting is not reflected, and therefore the number of pixels in the predetermined density range is small. For example, 600, which is below the threshold value of 1000, is recognized as white paper.

  In addition, in this way, the setting of image processing performed in order to appropriately output the read data is an operation that is generally performed by the user, and it is unnecessary for the user to improve the accuracy of white background detection. There is no forced operation.

  Further, in the present embodiment, only when the image quality setting is a setting to darken an image (S7: Y), a setting for thinning the image by executing the blank sheet detection process on the read data after image processing. In the case of (S7: N), a blank page detection process is executed on the read data before the image process. For this reason, the following effects arise. That is, when image processing for thinning the image is performed, there is a high possibility that the total count value falls below the threshold value and the document P is determined to be blank. In that case, there is a possibility that even the original P that the user wants to read as the original P on which the image is written is determined to be blank and the read data is erased. Therefore, if blank page detection is performed on the read data after image processing only when the image is set to be dark as described above, it is determined that the original P to be read as the original P on which the image is described is blank. Can be suppressed.

  In addition, this invention is not limited to the said embodiment at all, It can implement with a various form in the range which does not deviate from the summary of this invention. For example, the read data relating to the document P for which the total count value is less than the threshold value and is determined to be blank may not necessarily be erased, may be temporarily stored in the RAM 152, and may be blank as desired. It may be output (printed or the like) in the same manner as the read data determined not to be. Furthermore, it goes without saying that the present invention can also be applied to a scanner-dedicated machine that does not have the printer unit 5 or the like.

DESCRIPTION OF SYMBOLS 1 ... Multifunction machine 5 ... Printer part 10 ... Scanner part 21 ... Operation panel 23 ... Display part 51 ... Recording engine 130 ... Paper discharge tray 141 ... AFE 140 ... CIS
151 ... CPU 152 ... RAM 153 ... ROM
160 ... Image processing circuit 230 ... Scan setting screen P ... Original

Claims (4)

A reading unit for reading an image of a document;
A counting unit that counts the number of pixels having a predetermined density or more from read data read by the reading unit;
A blank sheet detection unit that determines that the document is blank when the count value of the counting unit is less than a threshold value for blank sheet detection stored in advance;
An image reading apparatus comprising:
An image processing unit that performs image processing related to image quality on the read data read by the reading unit;
An image processing setting unit for setting image processing by the image processing unit in accordance with a user operation;
An output unit for outputting read data after image processing by the image processing unit;
A determination unit that determines whether the setting made by the image processing setting unit is to reduce the density of a pixel;
With
When the determination unit determines that the decrease is made, the counting unit counts the number of pixels from the read data before image processing by the image processing unit, and the blank sheet detection unit calculates the count value. If the determination unit determines that the decrease is not to be reduced, the counting unit counts the number of pixels from the read data after image processing by the image processing unit, and detects the blank page detection. The image reading apparatus, wherein the unit makes the above determination based on the count value. The image reading apparatus according to claim 1, wherein the image processing relating to the image quality is gamma correction for adjusting brightness of the image. The image reading apparatus according to claim 1, wherein the image processing relating to the image quality is gamma correction for adjusting an image contrast. The image reading apparatus according to claim 1, wherein the image processing related to the image quality is a process of enlarging or reducing the image.

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