Information processing apparatus, information processing method, and program

Abstract

To accurately detect a foreign matter that is attached to a print sheet, and to appropriately perform quality management of a printed matter.SOLUTION: An image data acquisition unit acquires sheet image data and reference sheet image data to store in a storage unit. A foreign matter detection unit compares between the reference sheet image data acquired from the storage unit and the sheet image data acquired from the image data acquisition unit, and detects a pixel indicating a foreign matter from a difference between them. An identification unit acquires a coordinate of the pixel that is detected as the foreign matter from the foreign matter detection unit, and calculates size of the foreign matter. A inspecting data generation unit calculates a threshold value of the size of the foreign matter which value is detected as abnormality in inspecting a printed matter, on the basis of the size of the foreign matter calculated by the identification unit.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to an inspection processing technique for printed matter considering foreign matter adhering to printing paper.

Background Art

[0002] There are cases where unintended dirt or the like adheres to printed matter output by a printing device. Such abnormalities in the printed matter deteriorate the quality of the printed matter. Therefore, in order to guarantee the quality of the printed matter, inspection processing of the printed matter is performed. Since visual inspection by an inspector requires a lot of time and cost, in recent years, automation techniques for inspection processing have been developed.

[0003] In order to improve the quality of printed matter, it is necessary to determine whether the abnormality of the printed matter detected by the inspection process is due to foreign matter adhering to the printing paper or due to the printing device, and appropriately determine whether to discard the printing paper with foreign matter attached or adjust the printing device. Therefore, in Patent Document 1, spectral information of a toner image for creating printed matter is stored in advance, a reference spectrum for inspection is selected from among them, and the selected reference spectrum is compared with the spectrum of the printed matter to disclose a method for determining the cause of the abnormality.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the technique according to Patent Document 1, when the reference spectrum and the spectrum of the printed matter containing foreign matter are similar, there is a problem that the accuracy of detecting foreign matter adhering to the printing paper is reduced and the quality control of the printed matter cannot be appropriately performed.

Means for Solving the Problems

[0006] The technology of the present disclosure is an information processing apparatus, comprising: image data acquisition means for acquiring paper image data obtained by reading printing paper before printing and print image data obtained by reading a printed matter obtained by printing on the printing paper; foreign matter detection means for detecting an image area indicating a foreign matter attached to the printing paper in the paper image data; inspection data generation means for generating, as inspection data to be used for inspection of a printed matter obtained by printing on the printing paper, reference print image data obtained by synthesizing the color indicated by the pixel value of the image area indicating the foreign matter in the paper image data with the color indicated by the pixel value of the area in the print image data corresponding to the image area indicating the foreign matter. Inspection means for inspecting a printed matter obtained by printing on the printing paper based on the reference printed image data as the inspection data, wherein the inspection means generates difference image data between the reference printed image data and the printed image data, and when a predetermined inspection parameter in the difference image data is not within a predetermined range, determines that the printed matter obtained by printing on the printing paper is abnormal It is characterized by the above.

Advantages of the Invention

[0007] According to the present invention, foreign matters attached to printing paper can be detected with high precision, and quality control of printed matters can be appropriately performed.

Brief Description of the Drawings

[0008]

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Embodiments for Carrying Out the Invention

[0009] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the following embodiments do not limit the present invention, and not all combinations of the features described in this embodiment are essential for the solution means of the present invention. For the same configuration, the same reference numerals will be used for description.

Examples

[0010] In Example 1, image data of the printing paper before printing is acquired, foreign matter adhering to it is detected from the image data, the size of the foreign matter is specified, and a threshold value for the size of the foreign matter is calculated so as not to be detected as an abnormality in the printed matter.

[0011] FIG. 1 is a configuration example of the entire inspection system including the information processing apparatus 103 in the present embodiment. The inspection system in this example includes an image inspection apparatus 100 and a printing apparatus 190. The printing apparatus 190 includes a paper feeding apparatus 191. The user sets printing paper in the paper feeding apparatus 191 in advance, and the printing paper is conveyed to the image inspection apparatus 100 by a paper conveyance apparatus 101. The image inspection apparatus 100 includes an image reading apparatus 102, an information processing apparatus 103, and a UI panel 104. The image reading apparatus 102 reads one or both sides of the printing paper conveyed on the paper conveyance apparatus 101 and acquires image data. The information processing apparatus 103 processes the image data and generates data and the like used for inspection. The UI panel 104 functions as a user interface of the image inspection apparatus 100 and displays the current status and settings to the user. The UI panel 104 also includes an input device such as a touch panel and buttons, and functions as a user input acquisition unit. An output tray 105 outputs the printing paper conveyed by the paper conveyance apparatus 101 to the tray.

[0012] FIG. 2 is a functional block diagram of the information processing apparatus 103 in this example. An image data acquisition unit 201 acquires the image data read by the image reading apparatus 102. A storage unit 202 stores reference paper image data prepared by the user in advance. A foreign object detection unit 203 compares the paper image data with the reference paper image data and detects the coordinates and pixel values of the image area indicating the foreign object. An identification unit 204 identifies the size of the image area indicating the foreign object (hereinafter referred to as the size of the foreign object) using the coordinates of the image area indicating the foreign object detected by the foreign object detection unit 203. An inspection data generation unit 205 generates, as inspection data, a threshold value of the size of the foreign object to be detected as an abnormality so that the detection rate of the abnormality caused by the foreign object falls within a predetermined range based on the size of the image area indicating the foreign object identified by the identification unit 204. The inspection data generated by the inspection data generation unit 205 may be displayed on the UI panel 104.

[0013] FIG. 3 is a flowchart of the process of generating inspection data in the information processing apparatus 103 of this example.

[0014] In S301, the image data acquisition unit 201 acquires reference sheet image data. The user selects a printed sheet determined to have no foreign matter attached from among the printed sheets, and the image data obtained by the image data acquisition unit 201 is stored in the storage unit 202 as the reference sheet image data. Note that the reference sheet image data may be one selected from among the sheet image data acquired by the image data acquisition unit 201, may be obtained by synthesizing a plurality of sheet image data, or may be image data acquired from another external device. Alternatively, data acquired in advance may be held and acquired by reading it out.

[0015] The processes of S302 to S306 repeat the processes of S303 to S305 until the number of printed sheets reaches a predetermined number.

[0016] In S303, the image data acquisition unit 201 acquires image data (sheet image data) of a printed sheet to be inspected for foreign matter read by the image reading device 102.

[0017] In S304, the foreign matter detection unit 203 compares the reference sheet image data acquired from the storage unit 202 with the sheet image data acquired from the image data acquisition unit 201. Then, a pixel in which the difference between them is equal to or greater than a predetermined value and there are also pixels in the adjacent surrounding 8 pixels whose difference is equal to or greater than the predetermined value is detected as a pixel indicating a foreign matter.

[0018] In S305, the specifying unit 204 acquires the coordinates of the pixels detected as foreign matter from the foreign matter detection unit 203 and calculates the size of the foreign matter. As will be described later, in this embodiment, the size of the foreign matter is calculated by calculating the total number of pixels detected as foreign matter. Alternatively, as another size of the foreign matter, the distance between the most distant pixels among the consecutive pixels detected as foreign matter may be used.

[0019] In S307, the inspection data generation unit 205 calculates a threshold value for the size of the foreign matter so as not to be detected as an abnormality during inspection of the printed matter based on the size of the foreign matter calculated by the specifying unit 204 in S305, and displays it on the UI panel 104.

[0020] <Foreign Object Detection Method by Image Comparison> Here, a foreign object detection method by image comparison performed in S304 will be described.

[0021] FIG. 4 illustrates the image comparison method in this embodiment. The foreign object detection unit 203 compares the reference paper image data 401 and the paper image data 402, and calculates the difference in RGB values for each pixel. The foreign object detection unit 203 generates difference image data 403, which is a binary image in which the pixel value of each pixel is set to evaluation value 1 when the difference in RGB values is equal to or greater than a preset threshold, and evaluation value 0 when it is less than the threshold. Then, the foreign object detection unit 203 detects the coordinates of the pixels with a pixel value of 1 in the difference image data 403 as the coordinates of the foreign objects, and calculates the total number of pixels having a pixel value of 1 among the eight surrounding adjacent pixels of the pixels detected as foreign objects.

[0022] Note that instead of using the difference in RGB values for the comparison between the reference paper image data and the paper image data, the difference in luminance values for each pixel may be used. That is, the difference image data 403 may be generated with an evaluation value of 1 when the difference in luminance values is equal to or greater than a preset threshold, and an evaluation value of 0 when it is less than the threshold.

[0023] As a result, for each piece of acquired paper image data, it is possible to obtain the coordinates of the pixels detected as foreign objects and the total number of pixels having a pixel value of 1 among the eight surrounding adjacent pixels.

[0024] <Method for Obtaining the Size of the Detected Foreign Object> Here, a method for measuring the size of a foreign object performed in S305 will be described. By obtaining the size of the foreign object, it is possible to observe the degree of dispersion of the pixels detected as foreign objects in the foreign object detection method. FIG. 5 is a diagram for explaining a method for obtaining the size of a foreign object. However, for a target pixel a as in the image data 501, it is determined that the eight neighboring pixels (b to i) surrounding the target pixel a are continuous pixels with respect to the target pixel a.

[0025] (A) Method for obtaining the area of the detected foreign object In S304, when the foreign object detection unit 203 detects the coordinates of a foreign object, the following processing is performed.

[0026] In S305, based on the coordinates of the pixels detected as foreign objects for each sheet image data, the specific unit 204 extracts the pixels that can be determined to be continuous among the pixels detected as foreign objects, and obtains the coordinates of the continuous pixel group detected as the foreign object. The total number of pixels corresponding to the foreign object is tabulated, and the area of the foreign object for each print sheet image data is calculated. The processes of S302 to 306 are repeated, the maximum area is calculated among those that fall within the lower x% of the distribution of the areas of the foreign objects in each sheet image data, and this is used as the threshold for the size of the foreign object so as not to be detected as an abnormality during the inspection of the printed matter. Here, x is the allowable false detection rate of foreign objects set in advance during the inspection of the printed matter.

[0027] (B) Method for obtaining the width of the detected foreign object In S304, when the foreign object detection unit 203 detects the coordinates of the pixels corresponding to the foreign object, the following processing is performed.

[0028] In S305, the specific unit 204 obtains the coordinates of the pixel group that can be determined to be continuous among the pixels detected as foreign objects for each sheet image data obtained from the foreign object detection unit 203. The distance between the two most distant pixels among the pixel groups corresponding to each foreign object is calculated, and the width of the foreign object for each sheet image data is calculated. The processes of S302 to 306 are repeated, the maximum width is calculated among those that fall within the lower x% of the distribution of the widths of the foreign objects in each sheet image data, and this is used as the threshold for the size of the foreign object to be detected as an abnormality during the inspection of the printed matter. Here, x is the allowable false detection rate of foreign objects set in advance during the inspection of the printed matter.

[0029] Thus, in this embodiment, information about the size of foreign matter present on the printing paper is acquired in advance before printing, and based on the distribution of the acquired sizes of the foreign matter, a threshold value for the size of the foreign matter to be detected as an abnormality is set. As a result, it becomes possible to keep within an allowable range the ratio of detection of abnormalities in the printed matter due to foreign matter adhering to the printing paper before printing. For example, the information processing apparatus 103 may further include an inspection unit (not shown) that performs an inspection process on the printed matter based on the difference image data between the printed image data obtained by reading the printed matter with a reading device and the reference printed image data including the image printed on the printed matter. In such a case, the size of the image area determined to be abnormal in the difference image data, which is an inspection parameter of the inspection unit, may be adjusted based on the threshold value of the size of the foreign matter.

[0030] The present invention described in Example 1 may be modified and applied as follows.

[0031] (Modification Example 1 of Example 1) In the above-described Example 1, the threshold value for the size of the foreign matter was calculated from the detected area and width of the foreign matter so as not to be detected as an abnormality during the inspection of the printed matter. However, instead of the area and width, information about the shape of the foreign matter, such as whether the foreign matter is rectangular or round, is stored.

[0032] <Method for acquiring the shape of the detected foreign matter> When the foreign matter detection unit 203 detects the coordinates of the pixels corresponding to the foreign matter in S304, the following processing is performed.

[0033] In S305, the specifying unit 204 acquires the coordinates of a pixel group that can be determined to be continuous among the pixels detected as foreign matter for each sheet image data acquired from the foreign matter detection unit 203. Among the pixel groups corresponding to each foreign matter, the distance d1 between the two most distant pixels and the distance d2 between the two closest pixels are acquired, and the aspect ratio of each foreign matter is calculated. If the difference between the long side and the short side of the foreign matter is large and the calculated aspect ratio is equal to or greater than a predetermined threshold value, it is determined that the shape of the foreign matter is rectangular, and the shape evaluation value is stored as 1. If it is not determined to be rectangular, it is determined that the shape of the foreign matter is round, and the shape evaluation value is stored as 2.

[0034] According to Modification Example 1 of Example 1, by memorizing information about the shape of the foreign matter, it becomes possible to calculate the size threshold of the foreign matter so that it is not detected during the inspection of the printed matter for each shape of the foreign matter.

[0035] (Modification Example 2 of Example 1) In the above-mentioned Example 1, information about the size of the detected foreign matter was memorized and the threshold value was calculated. However, instead of the size, information about the color is memorized.

[0036] (Method for obtaining the color of the detected foreign matter) When the foreign matter detection unit 203 detects the coordinates of the pixels corresponding to the foreign matter in S304, the following processing is performed.

[0037] The color of the foreign matter is the average value of the RGB values of each pixel detected as the foreign matter, and the user defines in advance the RGB value (r0, g0, b0) of color 0 to be distinguished.

[0038] In S305, the specifying unit 204 obtains the coordinates of the pixel group that can be determined to be continuous among the pixels detected as foreign matter for each sheet image data acquired from the foreign matter detection unit 203, and obtains the RGB value of each pixel included in the pixel group acquired from the sheet image data. The average value (r, g, b) of the obtained RGB values is calculated and memorized as the color of the detected foreign matter. The difference between the memorized RGB value (r, g, b) of the foreign matter and the predefined RGB value (r0, g0, b0) is taken, and if it is less than or equal to a predetermined threshold value, the memorized foreign matter is determined to be color 0, and the color evaluation value is memorized as 1.

[0039] Also, the color of the foreign matter may be evaluated based on the luminance value of the pixel detected as the foreign matter. At this time, the user defines in advance the luminance value 0 of color 0 to be distinguished.

[0040] In S305, among the pixels detected as foreign matter for each sheet image data obtained by the specific part 204 from the foreign matter detection part 203, the coordinates of the pixel group that can be judged to be continuous are obtained, and the luminance value of each pixel included in the pixel group obtained from the sheet image data is obtained. The average value of the obtained luminance values is calculated and stored as the color of the detected foreign matter. The difference between the luminance value of the recorded foreign matter and the predefined luminance value 0 is taken, and if it is below a predetermined threshold value, the stored foreign matter is determined to be color 0, and the color evaluation value is stored as 1.

[0041] According to Modification Example 2 of Example 1, by storing information about the color of the foreign matter, it becomes possible to calculate the threshold value of the size of the foreign matter that is not detected during the inspection of the printed matter for each color of the foreign matter.

Example

[0042] In Example 2, the detection rate of foreign matter at the threshold value related to the size of the foreign matter to be detected set in advance is calculated, and the user determines the threshold value. Regarding the same configuration as in Example 1, the description thereof is omitted.

[0043] FIG. 6 is a functional block diagram of the information processing apparatus 103 in Example 2. The difference from Example 1 is that the detection data generation part 205 generates the detection rate of foreign matter as inspection data for each threshold value of the size of the foreign matter. In the storage part 202, the threshold value of the size of the foreign matter to be detected, which is defined in advance by the user, is stored. The detection data generation part 205 calculates the detection rate of foreign matter when inspecting the sheet image data obtained by the image data acquisition part 201 using the threshold value of the size of the foreign matter stored in the storage part 202.

[0044] FIG. 7 is a flowchart showing the processing in the information processing apparatus 103 of Example 2. The same processing as the processing in Example 1 shown in FIG. 3 is denoted by the same reference numerals.

[0045] In S701, the information processing apparatus 103 obtains one or more (N threshold)Obtain and store it in the storage unit 202.

[0046] In S301 to S306, in the same manner as in the first embodiment, the size of foreign matter on the printing paper before printing of a predetermined number N paper is obtained.

[0047] S702 to S710 are repeated until the threshold values (j) (where j is an integer such that 1 ≤ j ≤ N threshold ) stored in the storage unit 202 are each used once. Also, S703 to S707 are repeated until the printing paper (i) (where i is an integer such that 1 ≤ i ≤ N paper ) reaches the predetermined number N paper .

[0048] In S704, the detection data generation unit 205 determines whether the size of the foreign matter on the printing paper (i) obtained in S305 is greater than or equal to the threshold value (j) of the size of the foreign matter stored in the storage unit 202 in S701. If it is greater than or equal to the threshold value (j), it proceeds to S705; if it is less than the threshold value (j), it proceeds to S706.

[0049] In S705, the detection data generation unit 205 adds 1 to the number of foreign matter detections N detection (j).

[0050] In S706, the detection data generation unit 205 adds 1 to i.

[0051] In S707, if i ≤ N paper , it returns to S704; if i > N paper , it proceeds to S708.

[0052] In S708, the detection data generation unit 205 calculates the detection rate (N detection (j)), which is the ratio of foreign matter detected at the threshold value (j) based on the number of foreign matter detections N detection (j) counted in S703 to S707. paper ) (N

[0053] In S709, the detection data generation unit 205 substitutes 1 for i and adds 1 to j.

[0054] In S710, if j ≦ N threshold it returns to S702, and if j > N threshold it moves to S711.

[0055] In S711, the detection data generation unit 205 displays, on the UI panel 104, a list of combinations of the detection rate calculated in S708 and the threshold values of the foreign object size. FIG. 8 is a diagram showing an example of the UI panel display that displays the combinations of the detection rate and the threshold values of the foreign object size in the second embodiment. By displaying the threshold value of the foreign object size in association with the detection rate, it becomes possible for the user to make a decision.

[0056] According to the second embodiment, among a plurality of preset threshold values of the foreign object size, the user can select a threshold value that the user himself / herself considers appropriate, and the threshold value can be adjusted by the user. For example, when the information processing apparatus 103 includes an inspection unit similar to that in the first embodiment, the size of the image area determined to be abnormal in the differential image data, which is an inspection parameter of the inspection unit, may be adjusted based on the threshold value of the foreign object size selected by the user.

Example

[0057] In the third embodiment, using the obtained coordinates of the foreign object, reference printed image data used at the time of inspecting the printed matter is generated. Note that the description of the same configuration as that in the first embodiment is omitted.

[0058] FIG. 9 is a functional block diagram of the information processing apparatus 103 in the third embodiment. The difference from the first embodiment is that there is no measurement unit 203, and the inspection reference printed image data is generated by the inspection data generation unit 205 based on the reference printed image data obtained by reading the printed matter in the image data acquisition unit 201. The image data acquisition unit 201 acquires the image data read by the image reading device 102. The inspection data generation unit 205 generates inspection reference printed image data using the coordinates and pixel values of the pixels indicating the foreign matter acquired by the foreign matter detection unit 203 and the reference printed matter image data acquired by the image data acquisition unit 201. The storage unit 202 stores the inspection reference printed image data generated by the inspection data generation unit 205.

[0059] FIG. 10 is a flowchart showing the processing in the information processing apparatus 103 of the third embodiment. The same processing as that in the first embodiment shown in FIG. 3 is denoted by the same reference numerals.

[0060] S301 to S304 and S306 are the same as those in the first embodiment, but the process of S1001 is performed instead of S305 for calculating the size of the foreign matter. In S1001, the inspection data generation unit 205 acquires the coordinates and pixel values of the image area indicating the foreign matter detected by the foreign matter detection unit 203 for each sheet image data.

[0061] The processes of S1002 to S1006 repeat the processes of S1003 to S1005 until the predetermined number of printed sheets is reached.

[0062] In S1003, the image data acquisition unit 201 acquires the printed image data obtained by reading a predetermined number of printed matters with the image reading device 102. Here, the printed matter to be read is the printed matter using the printed paper output to the output tray 105 after repeating the processes of S302 to S306. A screen prompting to set the bundle of printed papers output to the output tray 105 to the paper feeding device 191 may be displayed on the UI panel 104 so that the printed matter read in S1003 is the printed matter using the printed paper read in S303.

[0063] In S1004, the image data acquisition unit 201 displays the printed image data acquired in S1003 on the UI panel 104, and acquires, as the reference printed matter image data serving as a criterion for determining an abnormality, what the user has selected from among those printed image data. Note that the reference printed matter image data may be one selected from among the printed image data, may be obtained by synthesizing a plurality of printed image data, or may be image data acquired from another external device.

[0064] In S1005, the inspection data generation unit 205 generates inspection reference printed image data based on the coordinates and pixel values of the image area indicating a foreign object acquired in S1001 and the printed image data acquired in S1003, and stores the inspection reference printed image data in the storage unit 202.

[0065] <Method for Generating Reference Printed Image Data> Here, the method for generating reference printed image data performed in S1005 will be described.

[0066] FIG. 11 is a diagram showing a method for generating reference printed image data. The sheet image data 1101 is superimposed on the reference printed matter image data 1102 to generate the inspection reference printed image data 1103. The sheet image data 1101 is the sheet image data acquired in S303. The reference printed matter image data 1102 is the printed matter image data selected and acquired by the user in S1003. The inspection reference printed image data 1103 is generated as described later for use in place of the reference printed image data when inspecting a printed matter when a foreign object is detected from the printing paper.

[0067] Obtain the coordinates (x, y) of the foreign object stored in the information processing device 103, and obtain the RGB values (r1, g1, b1) of the pixel at the coordinates (x, y) in the paper image data 1101. Further, obtain the RGB values (r2, g2, b2) of the pixel at the coordinates (x, y) in the reference printed matter image data 1102. Synthesize the RGB values (r2, g2, b2) as the base color and the RGB values (r1, g1, b1) as the composite color, and calculate the RGB values (r3, g3, b3) of the generated resultant color as follows, and use them as the RGB values of the pixel at the coordinates (x, y) in the inspection reference printed image data 1103.

[0068] r3 = r2 × (r1 / 255) g3 = g2 × (g1 / 255) b3 = b2 × (b1 / 255) Note that r3, g3, and b3 may be used as real numbers as in the above formula, or may be integers obtained by truncating or rounding the decimal part.

[0069] In Example 3, by using the difference image data between the printed image data to be inspected and the inspection reference printed image data as the difference image data used when inspecting the printed matter, the difference in the part where the foreign object adheres becomes smaller. Therefore, it becomes possible to lower the detection rate of abnormalities due to foreign objects adhering to the printing paper. For example, when the information processing device 103 is provided with the same inspection unit as in Example 1, the inspection process of the printed matter may be performed based on the difference image data between the printed image data obtained by reading the printed matter with a reading device and the above reference printed image data.

Example

[0070] In Example 4, an inspection exclusion area map used when inspecting the printed matter is generated using the obtained coordinates of the foreign object. Note that the description of the same configuration as in Examples 1 to 3 is omitted.

[0071] FIG. 12 is a functional block diagram of the information processing apparatus 103 in the fourth embodiment. The difference from the third embodiment is that in the inspection data generation unit 205, instead of generating inspection reference print image data, an inspection exclusion region map for excluding an image region indicating a foreign object from the inspection target is generated. When a foreign object is detected on the printing paper, the inspection data generation unit 205 generates an inspection exclusion region map based on the coordinates of the foreign object detected by the foreign object detection unit 203 and the reference print image data acquired by the image data acquisition unit 201.

[0072] FIG. 13 is a flowchart showing the processing in the information processing apparatus 103 of the fourth embodiment. The same reference numerals are used for the processing similar to the processing in the first embodiment shown in FIG. 3 and the processing in the third embodiment shown in FIG. 10.

[0073] In S1301, an inspection exclusion region map is generated based on the coordinates of the image region indicating the foreign object acquired in S1001 and the print image data acquired in S1002 or the reference print image data acquired in S1003.

[0074] <Method for generating inspection exclusion region map> Here, the method for generating the inspection exclusion region map performed in S1302 will be described.

[0075] FIG. 14 is a diagram showing a method for generating an inspection exclusion area map. In S1302, the center coordinates (x, y) of a foreign object are calculated as in the case of image data 1401. The center coordinates (x, y) of the foreign object are set to the average value of the coordinates of the foreign object for each pixel stored in the information processing device 103 stored in S1301. Among the pixels that are continuous among the pixels where the foreign object and the detected pixels are located, the distance d between the two farthest pixels is calculated, and an inspection exclusion area map 1402 is generated with the range of a circle having a diameter of d centered on the center coordinates (x, y) as the exclusion area. Note that the center coordinates of the foreign object may be an average value obtained by weighting the coordinates of the foreign object for each pixel with pixel values. Further, the shape of the exclusion area may be a rectangle other than a circle, or may be an ellipse or a rectangle adjusted according to the shape of the foreign object. Further, among the image areas indicating the foreign object, all of them may be used as the inspection exclusion area, or only a part of them may be used as the inspection exclusion area.

[0076] According to Example 4, it is possible to prevent the inspection of the portion where the foreign object is attached during the inspection of the printed matter, and to reduce the ratio at which an abnormality due to the foreign object is detected. For example, when the information processing device 103 includes an inspection unit similar to that of Example 1, the printed matter may be inspected based on the differential image data between the printed image data and the reference printed image data for the area not specified in the inspection exclusion area map.

[0077] (Other Embodiments) The present invention can also be realized by supplying a program that realizes one or more functions of the above-described embodiment to a system or device via a network or a storage medium, and causing one or more processors in the computer of the system or device to read and execute the program. Further, it can also be realized by a circuit (for example, an ASIC) that realizes one or more functions.

Description of Reference Numerals

[0078] 103 Information processing device 201 Image data acquisition unit 202 Storage unit 203 Foreign object detection unit 205 Inspection data generation unit

Claims

1. Image data acquisition means for acquiring paper image data obtained by reading printing paper before printing and print image data obtained by reading a printed matter obtained by printing on the printing paper; Foreign matter detection means for detecting an image area indicating foreign matter attached to the printing paper in the paper image data; Inspection data generation means for generating, as inspection data to be used for inspection of a printed matter obtained by printing on the printing paper, reference print image data obtained by synthesizing the color indicated by the pixel value of the image area indicating the foreign matter in the paper image data with the color indicated by the pixel value of the area in the print image data corresponding to the image area indicating the foreign matter; Inspection means for inspecting a printed matter obtained by printing on the printing paper based on the reference print image data as the inspection data, comprising: The inspection means generates difference image data between the reference print image data and the print image data, and determines that the printed matter obtained by printing on the printing paper is abnormal when a predetermined inspection parameter in the difference image data is not within a predetermined range. An information processing apparatus characterized by the above.

2. The foreign matter detection means detects an image area indicating foreign matter attached to the printing paper in the paper image data based on reference paper image data not including an image area indicating foreign matter, according to the information processing apparatus according to claim 1.

3. The foreign matter detection means compares the pixel values of corresponding pixels between the reference paper image data and the paper image data, and detects, as an image area indicating the foreign matter, an image area in which pixels with a difference in the pixel values of a predetermined value or more are continuous. An information processing apparatus according to claim 2, characterized by the above.

4. The apparatus further comprises specifying means for specifying the size of the image area indicating the foreign matter for each paper image data based on the detected image area indicating the foreign matter; The inspection data generation means calculates a threshold value for the size of the image area indicating the foreign matter detected as abnormal so that the detection rate of the image area indicating the foreign matter detected as abnormal becomes a predetermined value based on the size of the image area indicating the foreign matter specified, and uses the calculated threshold value as the inspection data. An information processing apparatus according to any one of claims 1 to 3, characterized by the above.

5. The size of the image area indicating the foreign matter for each sheet image data specified by the inspection data generation means is the size of the image area indicating the largest foreign matter in the sheet image data. The information processing apparatus according to claim 4, characterized in that.

6. Further comprising user input acquisition means for acquiring a user input for specifying a threshold value of the size of the foreign matter, Based on the user input, the inspection data generation means determines a threshold value of the size of the image area indicating the foreign matter. The information processing apparatus according to claim 5, characterized in that.

7. Display control means for associating and displaying on a display device the detection rate of the image area indicating the foreign matter detected as the abnormality and the threshold value corresponding to the detection rate. The information processing apparatus according to claim 6, further comprising.

8. The inspection data generation means calculates a threshold value of the size of the image area indicating the foreign matter to be detected for each shape of the image area indicating the foreign matter. The information processing apparatus according to claim 7, characterized in that.

9. The inspection data generation means determines the shape of the image area indicating the foreign matter based on the aspect ratio of the image area indicating the foreign matter. The information processing apparatus according to claim 8, characterized in that.

10. The foreign matter detection means detects the color of the image area indicating the foreign matter. Based on the color of the image area indicating the foreign matter, the inspection data generation means calculates a threshold value of the size of the image area indicating the foreign matter to be detected. The information processing apparatus according to claim 8, characterized in that.

11. The inspection data generation means generates an inspection exclusion area map for designating the image area indicating the detected foreign matter as an inspection exclusion area. The information processing apparatus according to any one of claims 1 to 10, characterized in that.

12. The inspection means generates difference image data between the reference printed image data and the printed image data for an area not specified by the inspection exclusion area map, and when a predetermined inspection parameter in the difference image data is not within the range set based on the inspection data, determines that the printed matter obtained by printing on the printing paper is abnormal. The information processing apparatus according to claim 11, characterized in that.

13. A step of acquiring sheet image data obtained by reading a printing paper before printing and printed image data obtained by reading a printed matter obtained by printing on the printing paper. A step of detecting an image area indicating a foreign object attached to the printing paper in the paper image data; A step of generating, as inspection data to be used for inspecting a printed matter obtained by printing on the printing paper, reference printed image data obtained by synthesizing the color indicated by the pixel value of the image area indicating the foreign object in the paper image data with the color indicated by the pixel value of the area in the printed image data corresponding to the image area indicating the foreign object; A step of inspecting a printed matter obtained by printing on the printing paper based on the reference printed image data as the inspection data, and In the step of performing the inspection, generating difference image data between the reference printed image data and the printed image data, and when a predetermined inspection parameter in the difference image data is not within a predetermined range, determining that the printed matter obtained by printing on the printing paper is abnormal. An information processing method characterized by the above.

14. A program for causing a computer to function as the information processing apparatus according to any one of Claims 1 to 12.

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