JP2010010839A - Image reading device, its processing method, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image reading device, its processing method, and a program, for improving an analysis capability when performing pre-scanning. <P>SOLUTION: The image reader reads image data from a recording medium by optically scanning an original table by first reading operation and second reading operation for performing reading with higher resolution than the first reading operation in succession to the first reading operation, analyzes the image data read, and updates a parameter used for analyzing the image data read in the first reading operation after the second time onward on the basis of a result of analysis of the image data read in the second reading operation. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image reading apparatus, a processing method thereof, and a program.

  In general, an image reading apparatus (for example, an image scanner) analyzes various image characteristics based on input image data. In the image reading apparatus, for example, when reading an image, first, a preliminary scan (hereinafter referred to as pre-scan) is performed. In pre-scanning, the entire surface of the document table is scanned with a coarse resolution. The read image data is stored in a memory in the apparatus or a connected computer, and the boundary between the pressure plate of the image reading apparatus and the paper document is automatically determined based on the stored image data. Is identified. The document area is specified by applying a technique such as edge extraction to the image data stored in the memory. When the image reading device specifies the document area, the image reading device calculates a relative angle with the document table and performs a predetermined rotation correction. Thus, the angle difference generated when the user sets the document is corrected.

  The image data (pre-scan image) stored in the memory by the pre-scan is subjected to various analyzes in addition to specifying the document area. For example, information necessary for image correction such as background removal processing, gradation correction processing, and color conversion processing is analyzed. In the background removal process, the background of the paper document at the time of pre-scanning is estimated, and the luminance value is corrected so that the background of the paper whose density value is high and gray is close to white. In the gradation correction process, it is determined whether the document area is a photograph or a document document, and the gradation is corrected to an appropriate gradation according to the determination result. Also, in the color conversion process, when a document is determined to be a photographic document, it is determined whether the recording method for recording the photograph is a silver salt method or an inkjet recording, and is appropriate for the recording method. The color conversion table is specified.

  After performing such a pre-scan, the image reading apparatus performs a second scan (hereinafter referred to as a main scan) on the specified document area with a predetermined resolution. Then, after performing the above-described correction processing on the high-resolution image data read by the main scan, the corrected image data is stored in the memory. In an image reading apparatus having a recording apparatus, for example, a copying machine, the read high-resolution image data is not stored in a memory, and copying is performed using a system such as an ink jet system or an electrophotographic system in an attached recording apparatus. May be performed.

  A number of techniques for specifying an area where a document is arranged based on a pre-scan image have been proposed. Patent Document 1 discloses a technique for accurately separating a document area by using a light source complementary to the pressure plate of the image reading apparatus. Patent Document 2 discloses a colored coloring member on the back side of the document table. A technique for separating a predetermined document area by installing it in a document is disclosed. Further, Patent Document 3 discloses a technique for coloring a document pressing surface with a color different from that of a document, discriminating between an open state and a closed state of the platen cover, and specifying a document region based on document edge detection in both states. Has been.

Further, a technique for estimating a document area from a slight difference in reading pixel values without coloring a special color material on a pressure plate of an image reading apparatus is also known. For example, there is a method of estimating the edge of a document by applying an edge detection filter such as Laplacian and evaluating the continuity and linearity of a plurality of detected edges. In addition, for example, there is a method of detecting each side using a straight line extraction method such as Hough transform, determining a right angle of a document by assuming a point where each side intersects as a vertex, and estimating a document position.
Japanese Patent Laid-Open No. 62-170948 Japanese Examined Patent Publication No. 56-22424 JP-A-3-54966

  However, the above-described technique has the following problems. For example, when a special color material is colored on the pressure plate of the image reading apparatus, when the document is thin, the document is seen through and the special color of the pressure plate is reflected on the document. In addition, there are problems such as an increase in cost caused by special processing, and the color of the pressure plate of a special color material is trimmed and remains around the original.

  When an edge detection filter, Hough transform, or the like is used, the versatility is high and the cost is low, but there is a problem in detection accuracy. That is, since the document area is specified based on the pre-scanned low-resolution image data, the edge of the paper edge may not be noticeable. Furthermore, since the image reading apparatus is required to reduce the time required for scanning and copying, it is necessary to perform the image analysis process quickly. However, when this process is performed, it takes time. Also, there is no particular problem when connecting a computer and an image reading apparatus and performing various complex image processing operations in the computer. However, when image processing is performed by the image reading apparatus, an increase in processing time or calculation is performed. Accuracy will deteriorate. This is because the image reading apparatus is often equipped with a low-speed CPU and a small memory capacity compared to a computer due to cost factors.

  In addition, there are a large number of paper types that can be used in the image reading apparatus, and there are some paper types in which the color difference is almost the same as that of the crimping plate. Furthermore, postcards, cards, photo-dedicated paper, etc. have a certain thickness, and shadows are likely to occur, so the accuracy of edge detection may not be preferable. For example, when the edge of the document is detected by edge detection using Laplacian, the detected edge amount is compared with a predetermined threshold value (comparison threshold value), and it is determined whether or not it is an edge. Easy to be affected.

  From the above, the device designer has to set a neutral comparison threshold value that is unbiased for all paper types regardless of the usage environment and the destination of the device, and also considers paper types that are never used. Equipment design must be done. Therefore, such a device design leads to an impediment to accuracy improvement. Actually, the type of paper used depends on the usage environment. For example, in a usage environment where only newspapers are copied, it is required to automatically cut out only newspapers, but in a different environment, settings are made so that only photo paper can be emphasized. Is required. In addition, when used in an office environment, there are many cases in which a large number of specific paper types (for example, recycled paper) are purchased in the entire office and only that paper type is used in the office. In addition, there are cases where specific paper types are used frequently in the countries and regions where they are used.

  The deviation from the optimum setting caused by the difference in the use environment applies to all image analysis, such as the above-described document type specification and gradation correction, in addition to document cutting. The parameters used at the time of image analysis by prescan had to be used with the factory default settings experimentally designed by the device designer. Therefore, it must be said that it is impossible to improve the image analysis ability adapted to the use environment.

  In recent years, products that are customized for each user by providing a learning function to the apparatus have been introduced to the market. For example, in Kanji conversion at the time of character input, such as a mobile phone, a product is provided in which a Kanji conversion example of a character input in the past is displayed at the top. However, such a change in display (setting) merely replaces the priority set by the user, and does not improve the analysis capability of the device that the user is not aware of at all.

  Accordingly, the present invention has been made in view of the above problems, and an object of the present invention is to provide an image reading apparatus, a processing method thereof, and a program for improving the analysis capability at the time of pre-scanning.

  In order to achieve the above object, an image reading apparatus according to an aspect of the present invention includes a first reading operation and a second reading operation that performs reading at a higher resolution than the first reading operation following the first reading operation. A reading means for optically scanning the document table to read image data from a recording medium, an image processing means for analyzing the image data read by the reading means, and a second reading operation. Parameter update means for updating parameters used for analysis of image data read in the first reading operation from the next time on the basis of the analysis result of the read image data, and the image processing means includes the parameter update The image data read in the first reading operation is analyzed using the parameter updated by the means.

  One embodiment of the present invention is a processing method in an image reading apparatus, which includes a first reading step of optically scanning a document table to read image data from a recording medium, and the first reading step. Based on a second reading step for performing the reading at a high resolution, an image processing step for analyzing the read image data, and an analysis result of the image data read in the second reading step, A parameter updating step for updating parameters used for analysis of image data read in the first reading step. In the image processing step, the parameters updated in the parameter updating step are used in the first reading step. The read image data is analyzed.

  According to another aspect of the present invention, a program includes a first reading operation and a second reading operation that performs reading at a higher resolution than the first reading operation following the first reading operation. A computer built in an image reading apparatus having reading means for optically scanning a table and reading image data from a recording medium, image processing means for analyzing image data read by the reading means, and the second reading Based on the analysis result of the image data read by the operation, functioning as parameter update means for updating parameters used for the analysis of the image data read by the first reading operation from the next time onward, and the image processing means The image data read in the first reading operation is analyzed using the parameter updated by the updating means.

  According to the present invention, in the analysis based on the image read by the first reading operation, the analysis result of the high-resolution image read by the second reading operation (than the image read by the first reading operation) is obtained. Use. Thereby, since the analysis capability at the time of the first reading operation can be improved, the reading performance by the second reading operation can be improved.

  Hereinafter, an image reading apparatus, a processing method thereof, and a program according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. In the following embodiments, a multifunction printer apparatus (hereinafter referred to as an MFP apparatus) to which the image reading apparatus according to the present invention is applied will be described as an example.

  FIG. 1 is a diagram illustrating an example of an overview perspective view of the MFP apparatus 100 according to the present embodiment.

  The MFP apparatus 100 includes an image reading function (an image reading unit 200 described later), an image processing function (an image processing unit 600 described later), an image recording function (an image recording unit 700 described later), and the like. As will be described in detail later, the image reading unit 200 scans an image original (hereinafter referred to as an original) to read image data, and the image processing unit 600 performs background removal processing or the like on the read image data. Image processing such as gradation correction processing and color conversion processing is performed. The image recording unit 700 records an image on a recording medium such as paper based on the image data processed by the image processing unit 600.

  For example, the MFP apparatus 100 records an image on a recording medium based on image data input from the image reading unit 200. Note that the input destination of the image data is not limited to the image reading unit 200, and may be, for example, a memory card storing the image data or a host (not shown). In the embodiment, a case where the image is input from the image reading unit 200 will be described.

  Here, FIG. 1A shows a state in which the document cover 103 is closed, and FIG. 1B shows a state in which the loading tray 101, the discharge tray 102, and the document cover 103 of the recording medium are opened. Is shown.

  The image reading unit 200 includes a contact image sensor (CIS) unit. The image reading unit 200 optically scans the document table to read the document, and the red (R), green (G), and blue (B) colors. The analog luminance signal is output. Here, the reading operation by the image reading unit 200 is roughly divided into, for example, two operations. As the first reading operation, there is a preliminary scan, that is, a pre-scan operation. In the pre-scan operation, the entire surface of the document table is read with a coarse resolution (low resolution). At this time, the read image data is used, for example, for analysis such as specifying a document area. The second reading operation includes a main scanning operation. The main scanning operation is performed after pre-scanning, and reads a document placed on a document table with high resolution.

  The card interface 9 is used, for example, for inserting a memory card or the like on which an image file photographed with a digital still camera (not shown) is recorded. When a memory card is inserted into the card interface 9, the MFP apparatus 100 reads image data from the memory card via the card interface 9 in accordance with an operation using the operation unit 4 from the user.

  In addition, a display device 110 is mounted on the MFP apparatus 100. The display device 110 is composed of, for example, an LCD (Liquid Crystal Display) or the like, and displays a screen or the like for selecting setting contents and functions from the operation unit 4.

  FIG. 2 is a cross-sectional view schematically showing an image reading unit 200 provided in the MFP apparatus 100 shown in FIG.

  The image reading unit 200 includes a main body unit 210 and a pressure plate 230 that presses a document to be read and blocks light from the outside. The pressure plate 230 is provided on the back surface of the document cover 103. The main body 210 includes an optical unit 240, a circuit board 250 electrically connected to the optical unit 240, a sliding rod 260 that serves as a rail when the optical unit 240 is scanned, and a document table glass 270. The optical unit 240 includes a contact image sensor (CIS) unit 300 that irradiates light on a document, receives the reflected light, and converts it into an electrical signal. When reading an image, the optical unit 240 scans the document placed on the platen glass 270 in the direction of the arrow B (sub-scanning direction), thereby reading the image recorded on the document.

  FIG. 3 is a cross-sectional view schematically showing the contact image sensor (CIS) unit 300 shown in FIG.

  The CIS unit 300 includes a plurality of LEDs (Light Emitting Diodes). Specifically, a red LED 303 that emits R (red) light, a green LED 304 that emits G (green) light, and a blue LED 305 that emits B (blue) light are provided. When reading a document, each color LED is turned on in a time-sharing manner for each line, and the lit light is irradiated uniformly toward the document through the light guide 302. Then, the reflected light is condensed for each pixel by the Selfoc lens 301 and imaged on a photoelectric conversion element (not shown) in the unit, thereby converting the light into an electric signal. In this way, the CIS unit 300 outputs an image signal for one line composed of color signals of RGB three color components. The CIS unit 300 is moved in the sub-scanning direction in order to read an image from the entire surface of the document. In the present embodiment, the direction of the arrow A indicating the arrangement direction of each cell of the SELFOC lens 301 is referred to as a main scanning direction. The main scanning direction and the sub scanning direction are orthogonal to each other. In FIG. 2, the main scanning direction is a direction perpendicular to the paper surface.

  FIG. 4 is a block diagram illustrating an example of a configuration of a control circuit of the image reading unit 200 illustrated in FIG. In addition, the same reference number is attached | subjected to the component demonstrated in FIGS. 1-3 mentioned above, and the description is abbreviate | omitted.

  Under the control of the LED drive circuit 403, the CIS unit 300 switches on and turns on the LEDs 303 to 305 of each color for each line, and reads a color image in a line sequential manner. The LEDs 303 to 305 are composed of light sources that can change the amount of light emitted from the document. Note that the LED drive circuit 403 can arbitrarily turn on the LEDs 303 to 305. That is, the LEDs 303 to 305 can be turned on sequentially one channel at a time, two channels can be turned on sequentially, or all three channels can be turned on in some cases.

  The amplifier (AMP) 404 amplifies the signal output from the CIS unit 300. The A / D converter 405 performs A / D conversion on the amplified electrical signal and outputs, for example, digital image data of 16 bits for each color component of each pixel.

  The image processing unit 600 processes the digital image data converted by the A / D converter 405. The interface control circuit 406 reads image data from the image processing unit 600, exchanges control data with the external device 412 or the image recording unit 700, and outputs image data. The external device 412 corresponds to, for example, a personal computer (not shown) as a host.

  Reference numeral 407 denotes a reference signal transmitter (OSC), which includes, for example, a crystal transmitter. Reference numeral 408 denotes a timing signal generation circuit that divides the output of the reference signal transmitter 407 according to the setting of the RAM 411 and generates various timing signals that are the basis of the operation. The LED 414 is an LED serving as a backlight light source of the display device 110 (for example, LCD), and lighting control is performed by a lighting signal output from the timing signal generation circuit 408.

  The image recording unit 700 is a device that converts data from the interface control circuit 406 into binary data of “recording” and “not recording” for each pixel and records the data on a recording medium using a recording material. Examples of such an apparatus include an ink jet printer, a laser beam printer using an electrophotographic system, and a sublimation printer. However, details are omitted here.

  The series of processes by the various components as described above can be explained by two types of control systems when roughly classified according to the operation contents. Here, a case where a copy or scan operation is performed as a single MFP will be described. In this case, an operation instruction is determined by the operation unit 4. Here, the operation unit 4 will be described in detail. FIG. 5 is an example of a schematic configuration of the operation unit 4. An output signal from the operation unit 4 is input to the input port of the CPU 409.

  A button 501 is a power key. A button 502 is a function selection button. Various function contents are displayed on the display device 110 according to the number of times the button 502 is pressed. When an operation is performed according to the displayed function contents and the determination button 503 is pressed, the contents are set in the RAM 411. The button 504 is a cancel button. When the button 505 is pressed, the color copy operation starts according to the setting of the RAM 411. When the button 506 is pressed, the monochrome copy operation starts according to the setting of the RAM 411. A button 507 is pressed for quantitative designation such as number designation or density designation. A button 508 is a reset button, and is pressed when canceling scanning or printing. The operation instruction from the operation unit 4 shown in FIG. 5 is controlled by a CPU 409 in the form of a microcomputer, for example. The control is realized by the CPU 409 reading a program (a control program 670 described later) stored in a ROM (Read Only Memory) 410 and executing a RAM (Random Access Memory) 411 as a work area.

  When the MFP apparatus 100 operates based on an instruction from the external apparatus 412, instructions such as copying and scanning are issued to the CPU 409 via the interface control circuit 406. Subsequent operations are the same as when copying or scanning is performed as a single MFP.

  Next, the image processing unit 600 shown in FIG. 4 will be described. FIG. 6 is a block diagram illustrating an example of the configuration of the image processing unit 600.

  Digital image data converted by the A / D converter 405 is input to the shading correction unit 610. The shading correction unit 610 performs shading correction by reading a standard white plate (not shown) attached to the back surface of an indicator plate (not shown) attached to the platen glass 270 of the image reading unit 200. Further, shading data 611 stored in the ROM 410 is used as data used for the shading correction.

  The pre-gamma conversion unit 620 receives digital image data that has undergone shading correction. The pre-gamma conversion unit 620 performs gamma correction so that the luminance distribution is visually suitable. The pre-gamma conversion unit 620 uses pre-gamma data 621 stored in the ROM 410.

  Digital image data that has undergone pre-gamma conversion is input to the color correction processing unit 630. The color correction processing unit 630 converts the digital image data that has undergone the pre-gamma conversion so as to have a suitable color. Further, the color correction data 631 stored in the ROM 410 is used as data used in the color correction processing unit 630.

  Digital image data that has passed through the color correction processing unit 630 is input to the filter processing unit 640. The filter processing unit 640 performs filter processing such as edge enhancement and noise reduction on the digital image data. Data used in this filter processing uses filter data 641 stored in the ROM 410.

  Digital image data that has passed through the filter processing unit 640 is input to the post-gamma conversion unit 650. The post-gamma conversion unit 650 finely adjusts the luminance characteristics of the input digital image data again according to the application. Data used in the post-gamma conversion unit 650 uses post-gamma data 651 stored in the ROM 410.

  Digital image data that has passed through the post-gamma conversion unit 650 is input to the analysis / correction processing unit 690. The analysis / correction processing unit 690 performs analysis for detecting the edge of the document for cutting out the document from the read image data, and the document is for a document type such as a halftone document, a silver halide photograph, a document document, and a handwritten document. Analysis and correction and processing based on the analysis result are performed.

  The corrected image data is output to the interface control circuit 406. The setting of these data from the ROM 410 to each processing unit is realized by the CPU 409 reading and executing the contents of the control program 670.

  FIG. 7 is a flowchart illustrating an example of an operation procedure at the time of a copy operation in the MFP apparatus 100. 7 to 9 and 11 are realized by the CPU 409 reading out and executing the control program 670 stored in the ROM 410. Here, the description of the operation procedure at the time of all copy operations is omitted, and the operation procedure with some settings by the user will be described.

  This process starts when a document is placed on the document table by the user and a copy command is issued from the operation unit 4. For example, when the button 505 is pressed from the operation unit 4 shown in FIG. 5, the MFP apparatus 100 accepts a copy command (for example, color copy) when the button 505 is pressed (S701).

  When receiving the copy command, the MFP apparatus 100 loads pre-scan image analysis parameters (S702). Specifically, parameters relating to prescan image analysis are loaded from a readable / writable nonvolatile memory (not shown). Note that the readable / writable nonvolatile memory preferably holds NVRAM, flash memory, and the like separately from the RAM 411 and ROM 410, but may be loaded from these memories. The prescan image analysis parameter stores a value set by the apparatus designer at the time of factory shipment.

  Subsequently, the MFP apparatus 100 performs pre-scanning (S703). In the prescan, a preliminary scan operation is performed at a predetermined resolution (for example, 75 dpi (dot per inch)), and image data (prescan image) read by the scan operation is temporarily stored in the memory.

  After the prescan, the MFP apparatus 100 analyzes the image data (prescan image) read by the prescan (S704). This analysis is performed based on the parameters loaded in S702. Although details of the prescan image analysis processing will be described later, the document area is specified and the document area is determined by this process. Note that the pre-scan image analysis processing according to the present embodiment is performed to specify the document area. Of course, other analysis may be performed.

  Subsequently, the MFP apparatus 100 determines a region to be scanned during the main scan based on the document region determined by the processing in S704 (S705), and performs the main scan on the region (S706). In the main scan, the image data in the document area is read at a predetermined resolution (for example, 600 dpi (dot per inch)) of the image reading unit 200. The read image data is transmitted to the image recording unit 700 (S707), and a recording sheet on which recording based on the image data is performed is output.

  After the main scan, the MFP apparatus 100 analyzes the image data read by the main scan (S708). That is, in the present embodiment, after the start of the recording operation, a step of performing image analysis on the main scan image data.

  After analyzing the main scan image data, the MFP apparatus 100 receives the analysis result, updates the prescan image analysis parameters (S709), and stores the updated parameters in a nonvolatile memory such as NVRAM, for example. (S710). Since the pre-scan image analysis parameters are stored in the nonvolatile memory, the updated parameters are retained regardless of whether the power is on or off. Then, at the time of the next copy or scan, the updated parameters are loaded and analyzed.

  Here, a flowchart illustrating an example of an operation procedure of the pre-scan image analysis processing in S704 illustrated in FIG. 7 will be described with reference to FIG.

  In this process, first, an edge detection filtering process is performed (S801). That is, it is a step of filtering the entire surface of the image read by the Laplacian edge detection filter. With respect to the luminance value of the entire image, a method of filtering the R, G, and B channels that are color images may be used. For example, the equation of (Expression 1) is calculated from the R, G, and B pixel values. Filtering may be performed on the luminance signal Y1 channel calculated by the above.

Y = 0.3 × R + 0.6 × G + 0.1 × B (Formula 1)
Subsequently, the MFP apparatus 100 compares the filtered edge image with a threshold value (S802). As this threshold value, the pre-scan image analysis parameter loaded in the processing of S702 shown in FIG. 7 is used. Then, the pixel position that is larger than the threshold is specified as the edge position (S803).

  When the edge position is specified, the MFP apparatus 100 determines whether or not a straight line can be formed with respect to a plurality of edge positions specified over the entire image (S804). Regarding linearity determination, various methods are conceivable, such as a method of searching for a neighborhood from a position with a high edge strength and a method of determining a distance from a straight line using a least-squares method by collecting a plurality of edges. .

  Subsequently, the MFP apparatus 100 obtains the intersection of each straight line based on the straight line determined in S804 and determines the four vertices of the rectangle (S805). As a result, the document area is specified.

  Next, a flowchart illustrating an example of an operation procedure of the main scan image analysis processing in S708 illustrated in FIG. 7 will be described with reference to FIG.

  First, the MFP apparatus 100 reads the luminance value from the main scan image (S901). That is, the luminance value for each color channel (R, G, B) read in the main scan is read. Then, a histogram is created (S902), and a base area is specified (S903). The background is specified, for example, by calculating the frequency from the luminance value of each channel and determining the high-frequency value with high frequency as the luminance value of the background. Note that a pre-scanned image may be used until the histogram creation and the background area specifying process. Further, the calculation may be simplified based on information obtained by thinning the main scan image data on average at a predetermined ratio to reduce the number of pixels.

  Subsequently, the image processing unit 600 compares the feature amount of the specified background area with the existing feature amount (S904). In other words, the device designer previously sets a feature quantity that can specify the paper type for a plurality of paper types. Although various physical quantities can be considered for the feature quantity, in the present embodiment, the difference value between the local maximum brightness value Dmax and the minimum brightness value Dmin, which is assumed to be the background, and the average brightness value are compared as the feature quantity. . This difference value depends on how the paper fiber shadows appear, and the average luminance value depends on the original paper density. These two types of values are held as a table.

  Here, the MFP apparatus 100 determines the paper type using this table value (S905). This process is performed by determining a paper type having an existing value whose distance from the TBL value (the sum of squares of the difference between the two types of values and the TBL value) is short. Then, this image analysis process ends. The method for specifying the paper type using the difference value between Dmax and the minimum value Dmin described above is disclosed in detail in Japanese Patent Application Laid-Open No. 2003-302885, but other methods are used for specifying the paper type. May be used and is not particularly limited. For example, the paper type may be specified using the fractal dimension disclosed in Japanese Patent Laid-Open No. 11-271037.

  Next, the prescan image analysis parameter update process in S709 shown in FIG. 7 will be described with reference to FIGS.

  First, the initial setting of the pre-scan image analysis parameter and the outline of the update will be described with reference to FIG.

  In specifying the document area (image clipping), the optimum pre-scan image analysis parameter (for example, edge detection parameter) differs depending on the paper type. The device designer empirically predicts the usage ratio of a plurality of paper types that the user is supposed to use, calculates the detection rate and the false detection rate, and sets the parameter with the highest performance as the initial value.

  In FIG. 10, for simplicity of explanation, an example in which settings are made for two types of paper A and paper B is represented by a one-dimensional diagram. The one-dimensional scale indicates what kind of usage ratio the parameter was optimized. The parameter used to increase the usage ratio of paper A toward the left and the usage ratio of paper B increased toward the right. The parameters are shown. For example, the designer assumes that both A paper and B paper are used at a ratio of 1: 1, and sets an optimum parameter for the ratio. If all users in the market actually use this ratio, it is optimal to keep the default value, but there is a bias in the type of paper used depending on the user's usage environment, usage region, and usage. Arise.

  Therefore, in the present embodiment, in addition to the initial setting value (ratio of 1: 1 in the figure), for example, parameters optimized only for A paper (A paper 100%), only B paper (B paper 100%) The parameters optimized in step 1 are set in advance. Furthermore, a parameter for changing the usage ratio of the paper type from A: B = 15: 1 to A: B = 1: 15 is set in advance. That is, a plurality of pre-scan image analysis parameters are provided in advance according to the ratio of the paper type used. The set values (a plurality of prescan image analysis parameters) are stored in a memory such as the ROM 410, for example.

  Although the initial setting value is a setting value of 1: 1, the MFP apparatus 100 manages information relating to the used paper type as a history in a non-volatile memory (for example, NVRAM), and how much ratio has been set in the past. To find out if A-sheet and B-sheet were used. That is, in the processing of S709 shown in FIG. 7, the past paper type usage rate is calculated, and it is determined where the scale (set ratio) in FIG. 10 is closest. For example, when the usage ratio of the past A paper and B paper is close to 1: 4, the setting value is shifted by four scales to the right from the initial setting value, and when the usage ratio is close to 1:15, B The set value is shifted to the left by one scale of the parameter optimized with paper. That is, at the beginning of use, it does not deviate significantly from the initial setting value, but if only the B paper is used, the scale gradually shifts to the left and is updated to the parameters optimized for the B paper.

  In the description of FIG. 10, the designer sets a plurality of usage ratio parameters. However, the designer sets only two types of paper A optimum parameters and B paper optimum parameters, and sets parameters between parameters. You may make it produce the optimal parameter which adapted to the usage ratio by calculation. In this case, the same effect can be obtained.

  Further, in the embodiment of FIG. 10, only two types of parameters have been described for ease of explanation, but naturally the number is not limited to two types. Further, the updating of the scale may be reflected by calculating the use ratio after exceeding the predetermined number of sheets without moving the initial setting value up to the predetermined number.

  Here, a flowchart illustrating an example of an operation procedure of the pre-scan image analysis parameter update process will be described with reference to FIG.

  First, the MFP apparatus 100 identifies the paper type of the used paper by analysis based on the main scan image analysis process, and stores the identification result in a memory (for example, NVRAM) as a paper type usage history (S1101). Then, the paper type usage rate is calculated from the paper type usage history (S1102). That is, the paper type usage rate is calculated to determine what type of paper is used frequently.

  When this calculation is completed, the MFP apparatus 100 determines one of the plurality of parameters provided corresponding to the usage rate of the paper type as an update parameter (step S1103). The update parameter is determined based on the paper type usage rate calculated in step S1102. When the update parameter is determined, the MFP apparatus 100 updates the currently set pre-scan image analysis parameter using the update parameter (S1104).

As described above, according to the present embodiment, the analysis result of the high-resolution image read by the main scan operation is used in the analysis based on the low-resolution image read by the pre-scan operation. As a result, the analysis capability at the time of pre-scanning can be improved. As a result, the reading performance (for example, document area specifying processing, background removal processing, gradation correction processing, color conversion processing, etc.) by the main scanning operation can be improved. I can plan. Also, no cost increase
The above is an example of a typical embodiment of the present invention, but the present invention is not limited to the embodiment described above and shown in the drawings, and can be appropriately modified and implemented without departing from the scope of the present invention. .

  For example, in the above description, the MFP apparatus 100 including the image reading unit 200, the image processing unit 600, and the image recording unit 700 has been described as an example, but the present invention is not limited thereto. For example, instead of the MFP apparatus 100, the above-described processing may be performed using an image reading apparatus having an image reading unit or an image processing unit.

  Further, in the above description, the case where the document area is specified (cut out of the document) by analyzing the pre-scan image has been described as an example, but the pre-scan image may of course be used for other analysis. . For example, it is assumed that the A sheet and the B sheet shown in FIG. In this case, by analyzing the pre-scan image, it is possible to identify whether the document is mainly a character or line drawing or a photograph. When such identification is performed, a plurality of pre-scan image analysis parameters that are set to change the background amount when removing the background are prepared. Then, when the document is identified as a document original, the background is largely skipped, and when the document is identified as a photographic document, the background is not skipped at all. As a result, for example, in a usage environment where only document originals are copied, the setting shifts to a setting where the background is easy to fly every time the apparatus is used. Further, even if the paper type used in the document original is biased, the background color and density value can be analyzed, so that optimum parameters can be set. If it is assumed that the A paper and the B paper shown in FIG. 10 are ink jet photographic paper and silver salt photographic paper, conversion processing can also be performed with color conversion parameters optimum for each recording method.

  Further, in the above description, the case where the paper type is specified by analyzing the main scan image and the setting of the analysis parameter at the time of pre-scan is updated based on the result is described as an example. Of course, it may be used for other analysis. For example, various analyzes such as the usage ratio of document originals and photographic originals, the number of halftone lines used, the recording method being recorded, and the recording resolution can be considered.

  Further, in the above description, the parameters used for the analysis at the time of pre-scanning are determined based solely on the usage ratio of the past used paper types, but the past used paper types are weighted on the time axis, The parameter may be updated in consideration of the time axis. That is, instead of determining parameters based on all past used paper types, only the latest used paper type may be used, or the update parameter may be determined by increasing the weight for the latest data.

  In the above description, for the sake of simplicity, the example in which the pre-scan, the main scan, and the optical system are scanned twice has been described. However, the present invention is not limited to this. For example, mechanically, high resolution information is acquired by one scan, and the first time is analysis of low resolution information thinned out from high resolution information, and the second time is analysis of stored high resolution information. Analysis may be performed. Even in this case, considering the time axis, the second analysis can accumulate data effective for image analysis at the time of the next and subsequent scans. Therefore, it is preferable for the convenience of the user to perform after the start of recording on the recording paper. .

  It should be noted that the present invention can take the form of, for example, a system, apparatus, method, program, or recording medium. Specifically, the present invention may be applied to a system composed of a plurality of devices, or may be applied to an apparatus composed of a single device.

  Further, the present invention achieves the functions of the embodiments by supplying a software program directly or remotely to a system or apparatus, and reading and executing the supplied program code by a computer incorporated in the system or apparatus. This includes cases where In this case, the supplied program is a computer program corresponding to the flowchart shown in the drawings in the embodiment.

  Accordingly, since the functions of the present invention are implemented by computer, the program code installed in the computer also implements the present invention. In other words, the present invention includes a computer program itself for realizing the functional processing of the present invention. In that case, as long as it has the function of a program, it may be in the form of object code, a program executed by an interpreter, script data supplied to an OS (Operating System), or the like.

  Examples of the computer-readable recording medium for supplying the computer program include the following. For example, floppy (registered trademark) disk, hard disk, optical disk, magneto-optical disk, MO, CD-ROM, CD-R, CD-RW, magnetic tape, nonvolatile memory card, ROM, DVD (DVD-ROM, DVD- R).

  As another program supply method, a client computer browser is used to connect to a homepage on the Internet, and the computer program of the present invention is downloaded from the homepage to a recording medium such as a hard disk. In this case, the downloaded program may be a compressed file including an automatic installation function. It can also be realized by dividing the program code constituting the program of the present invention into a plurality of files and downloading each file from a different homepage. That is, a WWW server that allows a plurality of users to download a program file for realizing the functional processing of the present invention on a computer is also included in the present invention.

  Further, the program of the present invention may be encrypted, stored in a recording medium such as a CD-ROM, and distributed to users. In this case, a user who has cleared a predetermined condition is allowed to download key information for decryption from a homepage via the Internet, execute an encrypted program using the key information, and install the program on the computer. You can also.

  In addition to the functions of the above-described embodiment being realized by the computer executing the read program, the embodiment of the embodiment is implemented in cooperation with an OS or the like running on the computer based on an instruction of the program. A function may be realized. In this case, the OS or the like performs part or all of the actual processing, and the functions of the above-described embodiments are realized by the processing.

  Furthermore, the program read from the recording medium is written in a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer, so that part or all of the functions of the above-described embodiments are realized. May be. In this case, after a program is written to the function expansion board or function expansion unit, the CPU (Central Processing Unit) provided in the function expansion board or function expansion unit is a part of the actual processing or based on the instructions of the program. Do everything.

2 is a diagram illustrating an example of an overview perspective of the MFP apparatus 100 according to the present embodiment. FIG. FIG. 2 is a cross-sectional view schematically showing an image reading unit 200 provided in the MFP apparatus 100 shown in FIG. FIG. 3 is a cross-sectional view schematically showing a contact image sensor (CIS) unit 300 shown in FIG. 2. FIG. 3 is a block diagram illustrating an example of a configuration of a control circuit of the image reading unit 200 illustrated in FIG. 2. It is a figure which shows an example of schematic structure of the operation part 4 shown in FIG. FIG. 5 is a block diagram illustrating an example of a configuration of an image processing unit 600 illustrated in FIG. 4. 3 is a flowchart illustrating an example of an operation procedure during a copy operation in the MFP apparatus 100 illustrated in FIG. 1. It is a flowchart which shows an example of the operation | movement procedure of the prescan image analysis process in S704 shown in FIG. 8 is a flowchart illustrating an example of an operation procedure of a main scan image analysis process in S708 illustrated in FIG. 7. It is a figure which shows the outline | summary of a prescan image analysis parameter. It is a flowchart which shows an example of the operation | movement procedure of the prescan image analysis parameter update process in S709 shown in FIG.

Explanation of symbols

4 Operation Unit 100 MFP Device 101 Loading Tray 102 Paper Discharge Tray 103 Document Cover 110 Display Device (LCD)
200 Image Reading Unit 600 Image Processing Unit 700 Image Recording Unit 300 CIS Unit 403 LED Drive Circuit 404 Amplifier (AMP)
405 A / D converter 406 Interface control circuit 407 Reference signal transmitter (OSC)
408 Timing signal generation circuit (TG)
409 CPU
410 ROM
411 RAM
412 External device 610 Shading correction unit 620 Pre-gamma conversion unit 630 Color correction processing unit 640 Filter processing unit 650 Post gamma conversion unit 690 Analysis / correction processing unit

Claims (8)

The document table is optically scanned from the recording medium by the first reading operation and the second reading operation for reading at a higher resolution than the first reading operation following the first reading operation. Reading means for reading image data;
Image processing means for analyzing image data read by the reading means;
Parameter updating means for updating parameters used for analysis of image data read in the first reading operation from the next time onward based on an analysis result of image data read in the second reading operation;
The image processing means includes
An image reading apparatus that analyzes the image data read by the first reading operation using the parameter updated by the parameter updating means. Further comprising a non-volatile storage means,
The image processing means includes
Identifying the paper type of the recording medium, which is a paper sheet, by analyzing the image data read in the second reading operation, and storing the identification result as a paper type use history in the storage means;
The parameter update means includes
The image reading apparatus according to claim 1, wherein the update is performed based on a paper type use history stored in the storage unit. The parameter is
Depending on the ratio of the paper type used, there are several in advance.
The parameter update means includes
The image reading apparatus according to claim 2, wherein the update is performed using any one of the plurality of parameters based on the paper type use history. The parameter update means includes
The image reading apparatus according to claim 1, wherein a parameter used when specifying an area of the recording medium placed on the document table is updated. The image processing means includes
Based on the analysis result of the image data read in the first reading operation, at least one of background removal processing, gradation correction processing, and color conversion processing of the image data read in the second reading operation is performed. The image reading apparatus according to claim 1, wherein the image reading apparatus is an image reading apparatus. The first reading operation is a pre-scan operation,
The image reading apparatus according to claim 1, wherein the second reading operation is a scanning operation after pre-scanning. A processing method in an image reading apparatus, comprising:
A first reading step of optically scanning the document table and reading image data from a recording medium;
A second reading step for performing the reading at a higher resolution than the first reading step;
An image processing step of analyzing the read image data;
A parameter updating step for updating parameters used for analysis of image data read in the first reading step after the next time based on an analysis result of the image data read in the second reading step,
In the image processing step,
A processing method in an image reading apparatus, wherein the image data read in the first reading step is analyzed using the parameter updated in the parameter updating step. The document table is optically scanned from the recording medium by the first reading operation and the second reading operation for reading at a higher resolution than the first reading operation following the first reading operation. A computer incorporated in an image reading apparatus having reading means for reading image data,
Image processing means for analyzing image data read by the reading means;
Based on the analysis result of the image data read in the second reading operation, function as parameter updating means for updating parameters used for the analysis of the image data read in the first reading operation after the next time,
The image processing means includes
A program for analyzing image data read by the first reading operation using a parameter updated by the parameter updating means.

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