Document scanning device

Abstract

This helps to prevent the FCOT (Frequency Continuity Time) from becoming too long. [Solution] The document scanning device comprises a scanning means for scanning an image of a document, a reference member, and a control means that determines one of a plurality of scanning modes based on the input of a scanning start instruction, causes the scanning means to scan an image of the document according to the selected scanning mode while transporting the document placed on the tray, and corrects the image data of the document scanned by the scanning means based on correction data. Before the scanning means scans an image of the document, the control means performs a generation process in which the scanning means scans the reference member in one of a plurality of candidate scanning modes, generates a plurality of correction data corresponding to each candidate scanning mode as correction candidate data, and when it determines one of the plurality of scanning modes based on the input of a scanning start instruction, it determines the correction candidate data corresponding to the selected scanning mode as correction data.

Description

Technical Field

[0001] The present invention relates to a document reading apparatus that reads an image of a document.

Background Art

[0002] A document reading apparatus includes a reading unit that optically reads an image of a conveyed document (hereinafter referred to as a document image). As an example, the reading unit includes a line sensor that reads an image of one line in the main scanning direction. The document reading apparatus reads a document image by repeatedly reading an image of one line of a document placed on a document table glass by the reading unit while moving the reading unit in a sub-scanning direction orthogonal to the main scanning direction. Also, a document reading apparatus equipped with an automatic document feeder (ADF: Auto Document Feeder) reads a document image by repeatedly reading an image of one line of a document conveyed in the sub-scanning direction (conveying direction) by the reading unit. In the following description, reading a document image while conveying the document is also referred to as "continuous reading". In a document reading apparatus, it may be important to shorten the time (referred to as FCOT: First Copy Output Time) from when an instruction to start reading is input until image data of the document image is output.

[0003] In reading a document image, the document reading apparatus performs shading correction for correcting a difference in light amount at each position of the document in the main scanning direction and a difference in sensitivity for each pixel of the line sensor. Correction data used for shading correction is generated by reading a white reference plate provided in the document reading apparatus. In the following description, correction data used for shading correction is also simply referred to as "correction data", and a process for generating correction data is also simply referred to as "generation process". Patent Document 1 discloses executing the generation process when the power of the apparatus is turned on.

[0004] The document scanner is configured to read document images at various resolutions. Here, the correction data used by the document scanner when reading a document at a certain resolution must be generated by reading a reference plate at that resolution. In other words, the correction data is associated with the document reading resolution, and the document scanner uses the correction data for that reading resolution (the correction data associated with that resolution) for shading correction during document reading.

[0005] Therefore, if the resolution associated with the correction data generated when the power is turned on differs from the resolution specified during scanning, the document scanner needs to perform a generation process to generate correction data for the specified resolution before scanning the document. In this case, the FCT (Field Correction Time) becomes longer. For this reason, Patent Document 2 discloses a configuration in which the generation process is executed as a trigger when the user changes the resolution setting. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2011-023990 [Patent Document 2] Patent No. 7455559 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] A document scanner can be configured to perform both the process of reading a document image in color and outputting color image data, and the process of reading a document image in monochrome and outputting monochrome image data. In the following description, the operation of reading a document image in color will also be referred to as "color scanning operation," and the operation of reading a document image in monochrome will also be referred to as "monochrome scanning operation." Furthermore, both color scanning and monochrome scanning operations will be collectively referred to as "scanning operation." Here, for shading correction during document scanning, it is necessary to use correction data generated by scanning a reference plate during that scanning operation. For example, the correction data used when scanning a document in color scanning operation must be generated by scanning a reference plate in color scanning operation. Therefore, correction data needs to be generated for each scanning operation in addition to the scanning resolution. In the following description, the combination of resolution and scanning operation will be referred to as "scanning mode."

[0008] For example, in a configuration where the user pre-selects (sets) the resolution and scanning operation on the settings screen, and then presses a "button" to indicate the start of scanning, the system can perform the correction data generation process each time the user changes the scanning mode setting. However, there are also document scanners where only the resolution can be pre-selected (set), and whether to perform color scanning or monochrome scanning is specified by the button indicating the start of scanning. In such document scanners, the scanning mode of the pre-generated correction data may differ from the scanning mode specified when the start of scanning is indicated, which can lead to a longer FCOT (Field Correction Time).

[0009] This invention provides a technology to suppress the lengthening of the FCOT (Frequency Control Unit). [Means for solving the problem]

[0010] According to one aspect of the present invention, a document reading device includes a tray on which a document is placed, a reading means for reading an image of the document, a reference member, and a control means for determining one of a plurality of reading modes based on an input of an instruction to start reading, causing the reading means to read an image of the document according to the chosen reading mode while transporting the document placed on the tray, and correcting the image data of the document read by the reading means based on correction data. The control means performs a generation process before the reading means reads an image of the document, causing the reading means to read the reference member in a plurality of candidate reading modes, and generating a plurality of correction data corresponding to each candidate reading mode as correction candidate data. When the control means determines one of the plurality of reading modes based on an input of an instruction to start reading, it determines the correction candidate data corresponding to the determined reading mode as the correction data. [Effects of the Invention]

[0011] According to the present invention, it is possible to suppress the lengthening of the FCOT. [Brief explanation of the drawing]

[0012] [Figure 1] A schematic cross-sectional view of a document scanning device. [Figure 2] A block diagram showing the control configuration of the document scanning device. [Figure 3] A diagram showing an example of the light emission sequence of a light source. [Figure 4] Diagram explaining the correction data. [Figure 5] A diagram showing an example of a screen displayed on the control panel. [Figure 6] A diagram illustrating an example of the relationship between processing content and reading mode. [Figure 7] A flowchart of the processes performed by the read control unit. [Figure 8] Flowchart of the generation process. [Figure 9] A more detailed flowchart of the generation process. [Figure 10]Flowchart of the process performed by the reading control unit in parallel with the generation process.

Embodiments for Carrying Out the Invention

[0013] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the invention according to the claims. Although a plurality of features are described in the embodiments, not all of these plurality of features are essential for the invention, and the plurality of features may be arbitrarily combined. Further, in the accompanying drawings, the same or similar configurations are denoted by the same reference numerals, and redundant descriptions are omitted.

[0014] <First Embodiment> FIG. 1 is a schematic cross-sectional view of a document reading apparatus 10 according to the present embodiment. The document reading apparatus 10 includes a reader 100 that generates image data of a document image by reading a document, and an ADF 200 that feeds the document to the reader 100. The document reading apparatus 10 can transmit the generated image data to a personal computer (PC) via a network (scanning process). The document reading apparatus 10 of the present embodiment is further configured to be able to perform facsimile transmission by outputting the generated image data to a facsimile (FAX) function unit (not shown) (FAX process). Further, the document reading apparatus 10 of the present embodiment is configured to be able to form a document image on a sheet by outputting the generated image data to an image forming unit (not shown) (copy process).

[0015] A document to be read is stacked on the document tray 201. The detection sensor 204 detects whether or not a document is stacked on the document tray 201. The guide plate 203 regulates the position in the width direction of the document stacked on the document tray 201. Note that the width direction is a direction orthogonal to the document conveyance direction and corresponds to the main scanning direction. Also, the conveyance direction corresponds to the sub-scanning direction.

[0016] The pickup roller 205 feeds the topmost original among one or more originals placed on the original tray 201 into the conveyance path of the original reading device 10. The separation roller pair 206 is provided to prevent double feeding of originals. The original reading device 10 has a plurality of rollers for conveying an original along the conveyance path. The reading unit 104 optically reads the original image on the first side of the original being conveyed through the glass 102. The reading unit 216 optically reads the original image on the second side of the original being conveyed through the glass 217. Each of the reading unit 104 and the reading unit 216 has a light source capable of emitting light of red (R), green (G), and blue (B), for example, a light-emitting diode (LED). Also, each of the reading unit 104 and the reading unit 216 has a line sensor that receives the light emitted by the light source and reflected by the original. The line sensor has a plurality of light-receiving elements (pixels) provided along the main scanning direction.

[0017] The original whose second-side original image has been read by the reading unit 216 is discharged to the discharge tray 220. The lead sensor 212 detects the conveyed original. The detection timing of the original by the lead sensor 212 is used to determine the reading timing of the original by the reading unit 104 and the reading unit 216. The white reference plate 110 is a reference member used to generate correction data for shading correction during reading by the reading unit 104. The white reference plate 215 is a reference member used to generate correction data for shading correction during reading by the reading unit 216.

[0018] The reading unit 104 is configured to be movable in the left-right direction in the figure along the movement guide 109 in order to read the image of the original placed on the original table glass 101. The position where the reading unit 104 reads the conveyed original and the position where the reading unit 104 reads the reference plate 110 can be different. When the position where the reading unit 104 reads the conveyed original and the position where the reading unit 104 reads the reference plate 110 are different, the reading unit 104 is moved to the position where the reference plate 110 is read when reading the reference plate 110.

[0019] Figure 2 is a block diagram showing the control configuration of the document scanning device 10. The controller 310 controls the entire document scanning device 10, including a fax function unit and an image forming unit (not shown). The scanning control unit 300 controls the ADF 200 and the reader 100 under the control of the controller 310.

[0020] The CPU 301 of the reading control unit 300 controls the ADF 200 and reader 100 by executing a program stored in the memory device 302. The memory device 302 includes both volatile and non-volatile memory devices. The memory device 302 stores the program executed by the CPU 301 and various information used to control the ADF 200 and reader 100. The image memory 305 is used to temporarily store image data read by the reading unit 104 and the reading unit 216. The image processing unit 306 performs various image processing, including shading correction, on the image data stored in the image memory 305. The image processing unit 306 performs shading correction using correction data stored in the shading memory 307. The image transfer unit 304 transmits the image data processed by the image processing unit 306 to the image transfer unit 314 of the controller 310.

[0021] The CPU 311 of the controller 310 controls the entire document scanner 10 by executing a program stored in the memory device 312. The memory device 312 includes volatile and non-volatile memory devices. The memory device 312 stores the program executed by the CPU 311 and various information used to control the document scanner 10. The image transfer unit 314 stores image data received from the image transfer unit 304 in the image memory 315. The operation unit 90 provides a user interface for the user to operate the document scanner 10. The CPU 311 sends and receives various control commands and control data with the CPU 301 to control the reading control unit 300.

[0022] For example, when a user inputs a command to start scanning a document via the control unit 90, the CPU 311 sends a scan start request to the CPU 301. The CPU 301 responds to the scan start request from the CPU 311 and controls the scanning of the document. The CPU 301 notifies the CPU 311 of the progress of the document scanning control, and the CPU 311 displays the progress on the control unit 90.

[0023] The CPU 301 generates correction data for use in shading correction on image data read by the reading unit 104, i.e., correction data for the reading unit 104, by having the reading unit 104 read the reference plate 110. The CPU 301 also generates correction data for use in shading correction on image data read by the reading unit 216, i.e., correction data for the reading unit 216, by having the reading unit 216 read the reference plate 215. Since the method for generating the correction data for the reading unit 104 and the method for generating the correction data for the reading unit 216 are the same, the method for generating the correction data for the reading unit 104 will be described as an example below, and the description regarding the reading unit 216 will be omitted.

[0024] In this embodiment, the document scanner 10 has four scanning modes. Scanning mode #C1 is a mode in which color scanning is performed with resolutions of 300 DPI and 600 DPI in the main scanning direction and sub-scanning direction. Scanning mode #C2 is a mode in which color scanning is performed with resolutions of 300 DPI and 300 DPI in the main scanning direction and sub-scanning direction. Scanning mode #M1 is a mode in which monochrome scanning is performed with resolutions of 600 DPI and 600 DPI in the main scanning direction and sub-scanning direction. Scanning mode #M2 is a mode in which monochrome scanning is performed with resolutions of 300 DPI and 600 DPI in the main scanning direction and sub-scanning direction. In the following description, scanning modes #C1 and #C2 will be collectively referred to as scanning mode #C. Also, scanning modes #M1 and #M2 will be collectively referred to as scanning mode #M. Reading mode #C is the mode for performing color reading operations, and reading mode #M is the mode for performing monochrome reading operations.

[0025] Figure 3(A) shows the illumination timing of the light source of the reading unit 104 in reading mode #C1. Figure 3(B) shows the illumination timing of the light source of the reading unit 104 in reading mode #C2. Figure 3(C) shows the illumination timing of the light source of the reading unit 104 in reading mode #M1. Figure 3(D) shows the illumination timing of the light source of the reading unit 104 in reading mode #M2.

[0026] In color reading operation, the light source of the reading unit 104 is illuminated in the order of red, blue, and green in order to acquire the brightness levels of red, green, and blue respectively. On the other hand, in monochrome reading operation, the light source is illuminated simultaneously in red, blue, and green. In other words, in monochrome reading operation, the light source emits white light. Furthermore, in both color and monochrome reading operation, the illumination period of the light source is changed if the resolution is different.

[0027] Figure 4(A) shows the reading results when the reference plate 110 is read in reading mode #M1, or more specifically, the brightness level detected by each pixel arranged along the main scanning direction of the line sensor. Ideally, the brightness level detected by each pixel of the line sensor should be the same when the reference plate 110 is read, but in reality, this is not the case due to differences in the amount of irradiated light at the position in the main scanning direction and differences in the sensitivity of each pixel of the line sensor. The correction data is data that shows the correction coefficient for each pixel in order to bring the brightness level detected by each pixel of the line sensor when the reference plate 110 is read to the target level. In Figure 4(A), each arrow corresponds to the correction coefficient. The correction data consists of data for each color of light emitted by the light source, corresponding to the number of pixels in the main scanning direction.

[0028] Figure 4(B) shows the reading result when the reference plate 110 is read in reading mode #M2. In reading mode #M2, the number of pixels in the main scanning direction is half that of reading mode #M1. As shown in Figures 4(A) and 4(B), the relationship between each pixel and the correction coefficient differs depending on the resolution in the main scanning direction, so correction data needs to be generated for each resolution. Figure 4(C) shows the reading result when the reference plate 110 is read in reading mode #C2. As shown in Figure 4(C), in the case of color reading operation, it is necessary to calculate the correction coefficient for R, G, and B separately. Therefore, even if the resolution is the same, the correction data used in color reading operation and the correction data used in monochrome reading operation will be different. In summary, correction data needs to be generated for each combination of resolution and reading operation, that is, for each reading mode.

[0029] Figure 5 shows an example of a screen displayed on the control unit 90. Figure 5(A) is, for example, the top screen displayed after the document scanner 10 is started up. When the copy button 601 is pressed, the CPU 311 displays a setting screen for the copy process on the control unit 90, which sends the image data of the document image to an image forming unit (not shown) to form the document image on a sheet. When the fax button 603 is pressed, the CPU 311 displays a setting screen for the fax process on the control unit 90, which sends the image data of the document image by fax. When the scan transmission button 602 is pressed, the CPU 311 displays a setting screen for the scan process on the control unit 90, which sends the image data of the document image to a PC.

[0030] Figure 5(B) shows an example of a screen displayed on the control unit 90 when the scan transmission button 602 is pressed. When the address book button 611 is pressed, the CPU 311 displays a screen on the control unit 90 for selecting the PC to which the image data will be sent. When the new input button 612 is pressed, the CPU 311 displays a screen on the control unit 90 for registering the PC to which the image data will be sent. When the size button 615 is pressed, the CPU 311 displays a screen on the control unit 90 for specifying the size of the document. When the image quality button 614 is pressed, the CPU 311 displays a screen on the control unit 90 for selecting the image quality of the document.

[0031] When the color scan button 93 is pressed, CPU 311 sends a request to CPU 301 to start scanning the document in scanning mode #C. Note that whether scanning mode #C1 or #C2 is used depends on the image quality setting described later. When the monochrome scan button 94 is pressed, CPU 311 sends a request to CPU 301 to start scanning the document in scanning mode #M. Note that whether scanning mode #M1 or #M2 is used depends on the image quality setting described later.

[0032] Figure 5(C) shows an example of the screen displayed on the control unit 90 when the image quality button 614 is pressed. The image quality priority button 641 and the speed priority button 642 are configured so that only one of them can be selected at a time. In the following description, the image quality priority button 641 and the speed priority button 642 will be collectively referred to as the "priority button". When the image quality priority button 641 is selected, the CPU 311 uses the reading mode with the higher resolution of the two reading modes for the same reading operation. On the other hand, when the speed priority button 642 is selected, the CPU 311 uses the reading mode with the lower resolution of the two reading modes for the same reading operation.

[0033] Therefore, when the color scan button 93 is pressed after the image quality priority button 641 is selected, CPU 311 sends a request to CPU 301 to start scanning the document in scanning mode #C1. Also, when the monochrome scan button 94 is pressed after the image quality priority button 641 is selected, CPU 311 sends a request to CPU 301 to start scanning the document in scanning mode #M1. Furthermore, when the color scan button 93 is pressed after the speed priority button 642 is selected, CPU 311 sends a request to CPU 301 to start scanning the document in scanning mode #C2. Furthermore, when the monochrome scan button 94 is pressed after the speed priority button 642 is selected, CPU 311 sends a request to CPU 301 to start scanning the document in scanning mode #M2.

[0034] When the OK button 644 is pressed, the CPU 311 confirms the selection result of the priority button and displays the screen shown in Figure 5(B) on the control unit 90. When the Cancel button 643 is pressed, the CPU 311 cancels the selection result of the priority button and displays the screen shown in Figure 5(B) on the control unit 90. In this case, the previous selection result is maintained.

[0035] As described above, and as shown in Figure 6, when image quality priority is selected during scanning, the document reader 10 reads the document in high quality, i.e., scanning mode #C1 or scanning mode #M1. When speed priority is selected during scanning, the document reader 10 reads the document in low quality, i.e., scanning mode #C2 or scanning mode #M2. Furthermore, as shown in Figure 6, when copying in color, the document reader 10 reads the document in scanning mode #C1, and when copying in monochrome, it reads the document in scanning mode #M2. In addition, as shown in Figure 6, when faxing in color, the document reader 10 reads the document in scanning mode #C2, and when faxing in monochrome, it reads the document in scanning mode #M2.

[0036] In the following explanation, "Scan (Image Quality Priority)", "Scan (Speed ​​Priority)", "Copy", and "FAX", as shown in Figure 6, will be referred to as the "processing options" of the document reader 10. As shown in Figure 6, one reading mode for color scanning and one reading mode for monochrome scanning are determined according to the selected processing option. Below, the one reading mode for color scanning and the one reading mode for monochrome scanning determined according to the selected processing option will be referred to as the "first mode" and the "second mode". For example, if "Scan (Image Quality Priority)" is selected as the processing option, the first mode is reading mode #C1, and the second mode is reading mode #M1. The first and second modes are the reading modes that are most likely to be used to actually read the document in the subsequent instruction to start scanning, and are also referred to as "candidate reading modes".

[0037] The CPU 311 is configured to notify the CPU 301 of the first and second modes determined by the changed processing content when the processing content is changed. The CPU 311 may also be configured to notify the CPU 301 of the first and second modes determined by the default processing content when the document reader 10 is started up. In the case of scanning, whether or not the processing content has been changed is determined when the user presses the OK button 644 on the screen shown in Figure 5(C). Specifically, if the user selects a different priority button than previously selected and presses the OK button 644, the CPU 311 determines that the processing content has been changed. On the other hand, if the user selects the same priority button as previously selected and presses the OK button 644, the CPU 311 determines that the processing content has not been changed. Although not shown, similarly for copy and fax processing, the CPU 311 determines whether or not the processing content has been changed when the user performs a predetermined operation on the operation unit 90. When the button indicating the start of document scanning is pressed, CPU 311 sends a request to CPU 301 to start scanning the document with the specified scanning mode. In the case of scanning, the buttons indicating the start of document scanning are the monochrome scan button 94 and the color scan button 93 shown in Figure 5(B). Although not shown, buttons indicating the start of document scanning are similarly displayed on the operation unit 90 for copy and fax processing.

[0038] Figure 7 is a flowchart of the process executed by the reading control unit 300. In S10, the CPU 301 sets both flags CF and MF to 0. A flag CF of 0 indicates that no correction data for the first mode has been generated. A flag MF of 0 indicates that no correction data for the second mode has been generated. In S11, the CPU 301 determines whether it has received a read start request from the CPU 311. If a read start request has been received in S11, the CPU 301 performs the process of generating correction data for the operation mode specified in the read start request in S19. Then, in S18, the CPU 301 reads the document. At this time, shading correction is performed using the correction data generated in S19. If a read start request is received when no document is placed in the document tray 201, the CPU 301 notifies the CPU 311 that no document is placed, and the determination in S11 is set to "No". After scanning the document in S18, CPU301 repeats the process from S10.

[0039] If no read start request has been received in S11, CPU 301 determines in S12 whether it has been notified of the first mode and the second mode by CPU 311. If CPU 311 has not notified it of the first mode and the second mode, CPU 301 repeats the process from S11. If CPU 311 has notified it of the first mode and the second mode, CPU 301 starts the correction data generation process in S13. Alternatively, the correction data generation process can be started in S13 only if a document is placed in the document tray 201, and if no document is placed in the document tray 201, the determination in S12 can be treated as "No".

[0040] Figure 8 is a flowchart of the correction data generation process in S13. In S20, the CPU 301 determines whether CF is 0. If CF is 0, in S21, the CPU 301 generates correction data for the first mode (hereinafter referred to as the first correction data) by reading the reference plate 110 in the first mode. The generated first correction data is stored in the shading memory 307, but the CPU 301 stores this first correction data in the memory device 302. Subsequently, in S22, the CPU 301 sets CF to a value other than 0, which in this example is 1. If CF is not 0 in S20, the CPU 301 skips the processes in S21 and S22.

[0041] Subsequently, in S23, the CPU 301 determines whether MF is 0. If MF is 0, in S24, the CPU 301 generates correction data for the second mode (hereinafter referred to as second correction data) by reading the reference plate 110 in second mode. The generated second correction data is stored in the shading memory 307. Subsequently, in S25, the CPU 301 sets MF to a value other than 0, which in this example is 1. If MF is not 0 in S23, the CPU 301 skips the processing in S24 and S25.

[0042] In S10, since both CF and MF are set to 0, both the first correction data and the second correction data are generated in S13. In the explanation of Figure 8, the second correction data was not stored in the memory device 302, but it is also possible to configure the system so that the second correction data is also stored in the memory device 302. Furthermore, in this embodiment, since both the first correction data and the second correction data cannot be stored in the shading memory 307, one of the correction data is stored in the memory device 302. However, if both the first correction data and the second correction data can be stored in the shading memory 307, both correction data can be stored in the shading memory 307. Moreover, in this embodiment, the first correction data was generated first, but it is also possible to configure the system so that the second correction data is generated first.

[0043] Returning to Figure 7, in S14, CPU 301 transitions to a state of waiting to receive a read start request from CPU 311. If CPU 301 does not receive a read start request from CPU 311 after a certain period of time has elapsed, it discards the first and second correction data generated in S13 and repeats the process from S10. In S14, if the certain period of time has not elapsed, CPU 301 determines in S15 whether it has received notification from CPU 311 of a change in at least one of the first and second modes. If neither the first nor the second mode has changed, CPU 301 determines in S16 whether it has received a read start request from CPU 311. If it has not received a read start request in S16, CPU 301 repeats the process from S14.

[0044] If a read start request is received in S16, the CPU 301 selects correction data in S17. Specifically, if a color read operation is specified by the CPU 311, the CPU 301 selects the first correction data generated in S13, and if a monochrome read operation is specified, the CPU 301 selects the second correction data generated in S13. If the selected correction data is not stored in the shading memory 307, the CPU 301 reads the selected correction data from the memory device 302 and stores it in the shading memory 307. Then, in S18, the CPU 301 reads the document. At this time, the image processing unit 306 performs shading correction using the correction data stored in the shading memory 307. After reading the document in S18, the CPU 301 repeats the process from S10.

[0045] On the other hand, if in S15 the CPU 301 receives notification from the CPU 311 of a change in at least one of the first and second modes, the CPU 301 sets the flag of the changed mode to 0 and repeats the process from S13. In other words, the CPU 301 sets CF to 0 if the first mode is changed, sets MF to 0 if the second mode is changed, and sets both CF and MF to 0 if both the first and second modes are changed. Therefore, in the generation process in S13 performed due to a change in the first and / or second mode, only correction data for the changed mode, i.e., correction data that has not been generated, is generated.

[0046] As described above, for both color and monochrome scanning operations, correction data for the selected resolution is generated as correction candidate data before the instruction to start scanning is input. Then, once the input to start scanning determines whether to perform color or monochrome scanning, the correction candidate data for the determined scanning operation is used as the correction data to perform shading correction. This configuration allows for a shorter FCOT (Full Countout Time).

[0047] In the sequence shown in Figure 7, if a read start request is not received after a certain period of time following the generation process (S13), the CPU 301 discards the first and second correction data and repeats the process from S10. However, it is also possible to configure the system so that the first correction data generated in the generation process is maintained unless the first mode is changed, and the second correction data generated in the generation process is maintained unless the second mode is changed.

[0048] <Second Embodiment> Next, the second embodiment will be described, focusing on the differences from the first embodiment. In the generation process executed in S13 of Figure 7, if both CF and MF are 0, the CPU 301 was required to generate both the first correction data and the second correction data. Here, the details of the generation process for one correction data will be explained using Figure 9.

[0049] First, in S30, the CPU 301 activates the line sensor of the reading unit 104, that is, sets it to be operational. In S31, the CPU 301 moves the reading unit 104 to a reference position for reading the reference plate 110. In S32, the CPU 301 performs black level adjustment by measuring with the line sensor without emitting light from the light source. In S33, the CPU 301 emits light from the light source of the reading unit 104. In S34, the CPU 301 obtains the first measurement value (first measurement value) by measuring the reference plate 110. Based on the first measurement value, the CPU 301 determines a threshold for extracting singularities indicating contamination of the reference plate 110. In S35, the CPU 301 obtains the second measurement value (second measurement value) by measuring the reference plate 110 while moving the reading unit 104 within the range in which the reference plate 110 can be measured. Based on the second measurement value, the CPU 301 extracts singularities and determines a correction coefficient. In S36, the CPU 301 moves the reading unit 104 back to the reference position. In S37, the CPU 301 obtains a third measurement (third measurement) by measuring the reference plate 110 at the reference position. The third measurement is used to generate correction data. In S38, the CPU 301 generates correction data by performing singularity correction using a correction coefficient determined based on the second measurement.

[0050] For example, if the color scan button 93 is pressed during the generation of the second correction data in the generation process S13 in Figure 7 (while S24 in Figure 8 is being executed), the generation process can be terminated without waiting for the second correction data generation to be completed, and the document scanning in S18 can be started, thereby shortening the FCOT. Similarly, if the monochrome scan button 94 is pressed during the generation of the first correction data (while S21 in Figure 8 is being executed), the FCOT can be shortened by starting the generation of the second correction data without completing the generation of the first correction data.

[0051] In this embodiment, at S13 in Figure 7, the generation process shown in Figure 8 is executed while the process described in Figure 10 is performed. At S40, the CPU 301 determines whether the generation process has finished. If the generation process has finished, the CPU 301 terminates the process in Figure 10. If the generation process has not finished, at S41, the CPU 301 determines whether it has received a read start request from the CPU 311. For example, the timing of the determination at S41 can be configured to be performed each time S30 to S38 in Figure 9 is executed. If a read start request has not been received, the CPU 301 repeats the process from S40. If a read start request has been received, at S42, the CPU 301 determines whether to perform a color read operation or a monochrome read operation.

[0052] In color scanning operation, CPU 301 determines in S43 whether the first correction data has been generated and therefore the process in S24 of Figure 8 is being executed. If the first correction data has been generated, CPU 301 terminates the generation process in S44 without waiting for the completion of the process in S24 and starts the process in S18 of Figure 8, i.e., scanning the original document. On the other hand, if the first correction data has not been generated in S43, it means that the process in S21 of Figure 8 is being executed. If the first correction data has not been generated in S43, CPU 301 waits until the generation of the first correction data is completed, and once the generation of the first correction data is completed, it terminates the generation process without performing the process for generating the second correction data and performs the process in S44.

[0053] In S42, if monochrome reading is in operation, the CPU 301 determines in S45 whether it has already started generating the second correction data, that is, whether it is currently executing the process in S24 of Figure 8. Not having started generating the second correction data means that it is currently executing the process in S21 of Figure 8. If it has not started generating the second correction data, the CPU 301, in S46, cancels the process in S21 without waiting for its completion and starts the process for generating the second correction data. In S47, the CPU 301 waits until the generation of the second correction data is complete, and once the generation of the second correction data is complete, it proceeds to S44.

[0054] As described above, according to this embodiment, if a user inputs a request to start reading during the generation process, the FCOT can be shortened by not generating unnecessary correction data among the first and second correction data.

[0055] <Third Embodiment> Next, the third embodiment will be described, focusing on the differences from the first and second embodiments. In this embodiment, the shading memory 307 can store only one of the correction data, either the first or second correction data. Therefore, the CPU 301 stores only one of the pre-generated first and second correction data in the shading memory 307, and stores the other in the memory device 302. For example, when the second correction data is stored in the shading memory 307, if a read start request for color reading is received, the CPU 301 had to read the first correction data stored in the memory device 302 and store it in the shading memory 307. This embodiment shortens the FCOT by reducing the frequency of processing to store the correction data stored in the memory device 302 in the shading memory 307 when a read start request is received.

[0056] In this embodiment, the CPU 301 determines which correction data, the first correction data or the second correction data, to store in the shading memory 307 based on the history of the reading modes used to read the document. As an example, the CPU 301 records the reading mode used in the previous document reading in the memory device 302. In the following description, the reading mode used in the last document reading will be referred to as the "reference reading mode". If the reference reading mode is the same as either the first mode or the second mode notified by the CPU 311, the CPU 301 stores the one of the first and second modes that matches the reference reading mode in the shading memory 307 and the other in the memory device 302. For example, if the first mode is reading mode #C1, the second mode is reading mode #M1, and the reference reading mode is reading mode #C1, the CPU 301 stores the first correction data in the shading memory 307 and the other in the memory device 302.

[0057] If a user continues to scan documents in the same scanning mode, the FCOT can be shortened by storing correction data for the same scanning mode as the reference scanning mode in the shading memory 307.

[0058] Furthermore, if both the first mode and the second mode notified by the CPU 311 are different from the reference read mode, the CPU 301 stores one of the first correction data and the second correction data in the shading memory 307 and the other in the memory device 302. For example, if the first correction data is generated first and then the second correction data is generated, the first correction data generated first is stored in the memory device 302, and the second correction data generated later is stored in the shading memory 307.

[0059] Furthermore, if the reference reading mode is a color reading mode, the first correction data can be stored in the shading memory 307, and if the reference reading mode is a monochrome reading mode, the second correction data can be stored in the shading memory 307. For example, for users who perform continuous color reading operations at different resolutions, or continuous monochrome reading operations, this configuration can shorten the FCOT (Full Countout Time).

[0060] Furthermore, as another example, the CPU 301 can record the reading modes used in document scanning over a predetermined period, determine the number of times each reading mode was used, and designate the reading mode with the most occurrences as the reference reading mode.

[0061] As described above, according to this embodiment, the frequency of processing to store the correction data stored in the memory device 302 in the shading memory 307 when a read start request is received can be reduced. Therefore, the FCOT can be shortened.

[0062] In the above embodiments, the reading mode was classified by a combination of two parameters: reading resolution and reading operation (color or monochrome). However, it is also possible to classify the reading mode by a combination of three or more parameters. Furthermore, in the above embodiments, two reading modes were selected as candidate reading modes, and correction data for each candidate reading mode was generated in advance. However, it is also possible to configure the system to select three or more reading modes as candidate reading modes.

[0063] [Other embodiments] The present invention can also be realized by supplying a program that implements one or more of the functions of the above-described embodiments to a system or device via a network or storage medium, and by having one or more processors in the computer of that system or device read and execute the program. It can also be realized by a circuit (e.g., an ASIC) that implements one or more functions.

[0064] The invention is not limited to the embodiments described above, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, claims are attached to disclose the scope of the invention. [Explanation of symbols]

[0065] 201: Document tray, 104, 216: Scanning unit, 300: Scanning control unit, 310: Controller

Claims

1. A tray on which the manuscript is placed, A reading means for reading the image of the aforementioned document, Reference member and A control means that determines one of several reading modes based on the input of an instruction to start reading, causes the reading means to read the image of the document according to the chosen reading mode while transporting the document placed on the tray, and corrects the image data of the document read by the reading means based on correction data, Equipped with, The control means, before the reading means reads the image of the document, causes the reading means to read the reference member in a plurality of candidate reading modes, generates a plurality of correction data corresponding to each candidate reading mode as correction candidate data, and determines one of the plurality of reading modes based on the input of an instruction to start reading, and then determines the correction candidate data corresponding to the determined one reading mode as the correction data, in a document reading device.

2. The system further includes setting means for setting the multiple candidate reading modes selected from the multiple reading modes as candidates for one reading mode, The document reading apparatus according to claim 1, wherein the control means starts the generation process that generates correction data for each of the plurality of candidate reading modes when the setting means sets the plurality of candidate reading modes.

3. The document reading apparatus according to claim 2, wherein the control means generates correction data for each of the plurality of candidate reading modes, and then, when the setting means changes the plurality of candidate reading modes, the control means starts generating correction data for the candidate reading modes among the changed plurality of candidate reading modes for which correction data has not yet been generated.

4. The document reading apparatus according to claim 2, wherein the control means starts the process of generating correction data for each of the multiple candidate reading modes when the setting means sets the multiple candidate reading modes while the document is placed on the tray.

5. The document reading device according to claim 1, wherein the control means sequentially generates correction data for each of the plurality of candidate reading modes in the generation process, and terminates the generation process if the generation process is not completed at the time the instruction to start reading is input but the generation of correction data for one of the reading modes is completed.

6. The document reading device according to claim 1, wherein the control means sequentially generates correction data for each of the plurality of candidate reading modes in the generation process, and if the generation of correction data for one reading mode is in progress at the time the instruction to start reading is input, the generation process is terminated when the correction data for the one reading mode is generated.

7. The document reading device according to claim 1, wherein the control means sequentially generates correction data for each of the plurality of candidate reading modes in the generation process, and at the timing when the instruction to start reading is input, it is generating correction data for a reading mode other than one of the plurality of candidate reading modes and has not started generating correction data for the one reading mode, it stops generating correction data for the other reading mode and starts generating correction data for the one reading mode, and when it has generated correction data for the one reading mode, it terminates the generation process.

8. The system further includes a first storage means for storing correction data used by the control means when correcting the image data of the original document read by the reading means, The document reading device according to claim 1, wherein the control means determines, based on the history of one of the reading modes, which of the correction data for each of the plurality of candidate reading modes generated in the generation process is to be stored in the first storage means.

9. The document reading device according to claim 8, wherein the control means determines a candidate reading mode for storing correction data in the first storage means based on the one reading mode determined based on the input of the previous instruction to start reading.

10. The document reading device according to claim 8, wherein the control means determines a candidate reading mode for which correction data is stored in the first storage means based on the number of times each of the plurality of candidate reading modes has been determined as one reading mode.

11. The aforementioned plurality of reading modes include a plurality of first reading modes and a plurality of second reading modes, The aforementioned plurality of first reading modes are modes in which the reading means reads the image of the document in color. The aforementioned plurality of second reading modes are modes in which the reading means reads the image of the document in monochrome. The document reading device according to any one of claims 1 to 10, wherein the plurality of candidate reading modes includes one first reading mode from the plurality of first reading modes and one second reading mode from the plurality of second reading modes.

12. The instruction to start reading is either a first instruction indicating color reading or a second instruction indicating monochrome reading. The document reading device according to claim 11, wherein the control means determines the one first reading mode to the one reading mode when the first instruction is input, and determines the one second reading mode to the one reading mode when the second instruction is input.

13. Each of the above-mentioned plurality of first reading modes has a different resolution for reading the document by the reading means. The document reading device according to claim 11, wherein each of the plurality of second reading modes has a different resolution for reading the document by the reading means.

14. The document reading device according to claim 11, wherein the one first reading mode and the one second reading mode are set in accordance with the input of the setting for the resolution of the document reading.

15. The document reading device according to any one of claims 1 to 10, wherein the correction is shading correction.

Images