JP2018159600A - Printed image inspection device, printed image inspection method, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect the poor density of a printed image with high accuracy in a printing process for printing a plurality of the same pattern.SOLUTION: Provided is a printed image inspection device, comprising: an inspection image acquisition unit for acquiring, from an imaged image obtained by imaging a printing medium with imaging means on which the same pattern is printed, a plurality of inspection images, imaged images included in each of which constituting the same pattern; an average information generation unit for averaging, for each pixel, the feature information per pixel of the plurality of inspection images and generating average information; and a density determination unit for determining whether the printing medium includes a defect pertaining to density, on the basis of the average information and predefined determination information.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a print image inspection apparatus, a print image inspection method, and a program.

  In the printing process that prints a large amount of identical designs such as newspaper manuscripts, billboards, posters, etc., it is necessary to inspect defects such as density defects, smudges, missing prints, etc. in the printed matter. Techniques related to inspection devices are known. For example, Patent Document 1 discloses an area of a printed matter printed by a newspaper offset rotary press, a non-image area where the density of each color element is zero, and an image line where the density of at least one color element is not zero. A technique for performing quality inspection separately for each part is disclosed. In this technology, by dividing into a non-image portion and an image portion, quality inspection can be performed on the basis of each region, thereby improving the detection accuracy of the non-image portion scumming, It is intended to improve the detection accuracy of the density fluctuation in the image area.

JP 2006-88562 A

  In the technique described in Patent Document 1, the presence / absence of density fluctuation is determined by dividing an image line portion of a printed material to be inspected into unit blocks and calculating an integrated value obtained by integrating the light amounts in the unit blocks. Compare the calculated integrated value of the print object to be inspected with the integrated value of the light quantity in the unit block at the corresponding position in the non-defective print object to determine whether density fluctuation has occurred in the unit block of the inspected print object doing.

  However, the density defect in the printed matter has a smaller difference between the non-defective product and the defective product as compared with dirt, omission, and the like. Therefore, in order to detect it accurately, the inspection standard must be made very strict. On the other hand, if the inspection standard is too strict, the number of false detections increases, resulting in a problem that the yield deteriorates. This problem is presumed to occur also in the technique described in Patent Document 1 in which a determination is made for each print object to be inspected based on a good print.

  Further, in the technique described in Patent Document 1, an image line portion of a printed material to be inspected is divided into unit blocks, an integrated value obtained by integrating the light quantity in the unit block is calculated, and the integrated value is calculated as a corresponding unit in a non-defective printed material. This is a method for comparing with the integrated value of the amount of light in the block. However, with this method, there is also a problem that even if the density is not defective, such as dirt or omission, the integrated value of the light amount is different from the integrated value of the non-defective printed matter, so that it is detected as a defective density.

  The present invention provides a print image inspection apparatus, a print image inspection method, and a program that solve the above problems.

  According to the first aspect of the present invention, the print image inspection apparatus is an average information of feature information of a plurality of inspection images each including the same pattern obtained from a captured image of a print medium on which the same pattern is printed. And a density determination unit that determines whether or not the print medium includes a density defect based on predetermined determination information.

  According to the second aspect of the present invention, in the printed image inspection method, the average information of the feature information of the plurality of inspection images each including the same pattern obtained from the captured image of the print medium on which the same pattern is printed. And determining whether or not the print medium includes a defect related to density based on predetermined determination information.

  According to the third aspect of the present invention, the program causes the computer of the print image inspection apparatus to obtain a plurality of inspection images each including the same design obtained from a captured image of a print medium on which the same design is printed. It is characterized by functioning as density determination means for determining whether or not the print medium includes a density defect based on average information of characteristic information and predetermined determination information.

  According to the present invention, it is possible to accurately detect a density defect in a printed image in a printing process in which a plurality of the same symbols are printed.

1 is a block diagram illustrating a configuration of a printing system including a print image inspection apparatus according to a first embodiment. FIG. 3 is a diagram illustrating a positional relationship between a print sheet and an imaging device in the embodiment. It is a figure which shows the internal structure of the printing image inspection apparatus of the embodiment, and the connection relation of an imaging device and a discharge device. It is a figure (the 1) which shows the flow of a process by the print image inspection apparatus of the embodiment. It is FIG. (2) which shows the flow of a process by the print image inspection apparatus of the embodiment. It is FIG. (1) explaining the effect by the process of the printing image inspection apparatus of the embodiment. It is FIG. (2) explaining the effect by the process of the printing image inspection apparatus of the embodiment. It is a figure (the 1) which shows an example of the weighting by the average information generation part in the embodiment. It is a figure (the 2) which shows an example of the weighting by the average information generation part in the embodiment. It is a figure (the 3) which shows an example of the weighting by the average information generation part in the embodiment. It is a figure (the 4) which shows an example of the weighting by the average information generation part in the embodiment. It is a figure explaining the weighting by the average information generation part in the embodiment. It is a figure (the 5) which shows an example of the weighting by the average information generation part in the embodiment. It is a figure (the 6) which shows an example of the weighting by the average information generation part in the embodiment. It is a figure which shows the internal structure of the printing image inspection apparatus of 2nd Embodiment, and the connection relation of an imaging device and a discharge device. It is a figure which shows the flow of a process of the printing image inspection apparatus of the embodiment. It is a figure which shows the internal structure of the printed image inspection apparatus of 3rd Embodiment, and the connection relation of an imaging device and a discharge device. It is a figure which shows the flow of a process of the printing image inspection apparatus of the embodiment. It is a figure which shows the other example of the printing paper in embodiment of this invention. It is a figure which shows the minimum structure of a printing image inspection apparatus.

(First embodiment)
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic block diagram showing the configuration of a printing system 200 having a print image inspection apparatus 1 according to the first embodiment of the present invention. The printing system 200 includes a print image inspection device 1, an imaging device 20, a printing device 30, inspection cylinders 40-1, 40-2, 40-3, and a discharge device 50.

  The printing apparatus 30 prints the same predetermined pattern on the printing paper 60 by, for example, intaglio printing or offset printing. Here, the printing apparatus 30 will be described as an apparatus that prints a plurality of bill designs on a printing paper 60, as shown in FIG.

  The inspection cylinders 40-1, 40-2, and 40-3 are rollers that feed the printing paper 60 in the rotation direction. In FIG. 1, the printing paper 60 is sent in the order of the printing device 30, the imaging device 20, and the discharge device 50 as shown as printing papers 60-a, 60-b, and 60-c.

  The imaging device 20 is an imaging unit that captures a print image printed on the print paper 60 sent by the inspection cylinder 40-2, and outputs captured image information obtained by the imaging to the print image inspection device 1. The imaging device 20 is arranged so that the imaging range 25 includes a plurality of symbols printed on the printing paper 60.

  The print image inspection device 1 determines whether or not the print image printed on the print paper 60 includes a defect related to density, based on the captured image information captured by the imaging device 20. Here, the state where there is a defect related to density means, for example, a state where a pattern to be originally printed is printed but the density exceeds a predetermined range. For example, the ink pigment is excessively attached during printing, and although the pattern can be visually recognized, it is printed darkly, resulting in poor density. On the other hand, the adhesion of the ink pigment is insufficient, and the pattern can be visually recognized, but it is printed lightly, so that the density is poor.

  On the other hand, a stain or missing state that is a defect other than a density defect is, for example, a state in which something other than the pattern to be printed (ink, machine oil, etc.) is attached to the printed matter. That means. The term “missing” refers to a state in which a pattern that should originally be printed has not been printed.

  Further, the print image inspection apparatus 1 instructs the discharge device 50 to discharge the non-defective print paper 60 to the non-defective pile for the print paper 60 determined that the print image does not include the density defect. Output a signal. Further, the print image inspection apparatus 1 causes the discharge device 50 to discharge the defective print paper 60 to a defective pile in which the print paper 60 determined to contain a density defect is discharged. An instruction signal is output.

  The discharge device 50 discharges the printing paper 60 sent by the inspection cylinder 40-3 to a good product pile or a defective product pile in accordance with an instruction signal from the print image inspection device 1.

  In the printing system 200, a plurality of printing sheets 60 are sequentially inserted into the printing apparatus 30 and printed by the printing apparatus 30. The printing paper 60 is sent by the inspection cylinders 40-1, 40-2, and 40-3, and is discharged by the discharge device 50 to a good pile or a defective pile. That is, the print image inspection apparatus 1 uses the image pickup image information captured by the image pickup apparatus 20 while the print sheet 60 is being sent by the inspection cylinder 40-2, and then the print sheet 60 is transferred to the inspection cylinder 40-. No. 2 and the inspection cylinder 40-3 are sent to the discharge device 50 to determine the discharge destination.

  FIG. 3 is a block diagram illustrating an internal configuration of the print image inspection apparatus 1 and a connection relationship between the imaging device 20 and the discharge device 50. The print image inspection apparatus 1 includes an inspection image information acquisition unit 11, an average information generation unit 12, a density determination unit 13, a determination information storage unit 14, and a discharge destination designation unit 15.

  The inspection image information acquisition unit 11 acquires the captured image information of the printing paper 60 output from the imaging device 20, and generates the inspection image information by dividing the acquired captured image information for each print image of the pattern to be inspected. . The average information generation unit 12 generates average information obtained by averaging the feature information of each pixel of the plurality of inspection image information included in the printing paper 60 for each pixel. The determination information storage unit 14 stores determination information used for density determination. As the determination information, for example, reference image information 140 obtained by capturing a printed image for one sheet without defects such as defective density, dirt, and missing, and a density determination threshold 141 are applied.

  Based on the average information generated by the average information generation unit 12 and the determination information stored in the determination information storage unit 14, the density determination unit 13 includes a density-related defect in the print image printed on the printing paper 60. It is determined whether or not.

  The discharge destination designation unit 15 instructs the discharge device 50 to discharge the print paper 60 that the density determination unit 13 has determined that the printed image printed on the print paper 60 does not include a density-related defect to a good pile. Is output. In addition, the discharge destination designation unit 15 causes the discharge device 50 to discharge the print sheet 60 that the density determination unit 13 has determined that the print image printed on the print sheet 60 includes a defect related to the density to the defective product pile. An instruction signal is output.

(Processing by the print image inspection apparatus of the first embodiment)
Next, processing by the print image inspection apparatus 1 according to the first embodiment will be described with reference to FIGS. 4 to 7. The printing device 30 prints a print image including a plurality of bill patterns on the printing paper 60, and the printing paper 60 is sent to the imaging range 25 of the imaging device 20 by the inspection cylinders 40-1 and 40-2. The imaging device 20 captures a print image printed on the printing paper 60. The imaging device 20 outputs the captured image information 70-1, 70-2, 70-3, and 70-4 shown in FIG. 4 to the inspection image information acquisition unit 11 of the print image inspection device 1 (step Sa1).

  The inspection image information acquisition unit 11 acquires the captured image information 70-1, 70-2, 70-3, and 70-4 output from the imaging device 20, and prints the design of one sheet of paper on one inspection image information. Division is performed so that an image is included (FIG. 4: Step Sa2). For example, the inspection image information acquisition unit 11 divides the captured image information 70-1 into four pieces of inspection image information 80-1, 80-2, 80-3, and 80-4 as shown in FIG. The division processing is also applied to the captured image information 70-2, 70-3, and 70-4, and the inspection image information acquisition unit 11 generates a plurality of inspection image information 80-1 to 80-16 (FIG. 5: Step Sa2).

  The average information generation unit 12 generates average information obtained by averaging the feature information of each pixel of the plurality of inspection image information 80-1 to 80-16 included in the printing paper 60 for each pixel. As the feature information, for example, the pixel value included in each pixel of the inspection image information 80-1 to 80-16 may be used as the feature information as it is. Further, the difference between the pixel value of each pixel of the inspection image information 80-1 to 80-16 and the pixel value of each pixel of the reference image information 140 may be calculated, and the calculated difference value may be used as the feature information. Further, the pixel value of each pixel obtained by performing some kind of image processing on the inspection image information 80-1 to 80-16 may be used as the feature information. Here, the feature information will be described as pixel values included in each pixel of the inspection image information 80-1 to 80-16.

  The average information generation unit 12 averages the pixel values of the inspection image information 80-1 to 80-16 for each pixel to generate average information (step Sa3). Since this average information uses the pixel value included in each pixel of the inspection image information 80-1 to 80-16 as characteristic information as it is, it will be described as average image information 90 in the following description.

  For example, each of the inspection image information 80-1 to 80-16 is image information including X pixels vertically and Y pixels horizontally, and the position of each pixel is represented as (X, Y). The average information generation unit 12 sums the pixel values at the (1, 1) positions of the inspection image information 80-1 to 80-16, and sets the number of inspection image information 80-1 to 80-16 as “16”. The average value of the pixel values is calculated by dividing by “,” and the calculated average value is set as the pixel value of (1, 1) in the average image information 90. The average information generation unit 12 repeats this calculation for all the pixels to generate average image information 90.

  The density determination unit 13 is based on the average image information 90 generated by the average information generation unit 12, the reference image information 140 that is determination information stored in the determination information storage unit 14, and the density determination threshold 141. It is determined whether or not the print image printed on the printing paper 60 includes a density defect (step Sa4).

  For example, the density determination unit 13 calculates the difference between the pixel value of each pixel in the average image information 90 and the pixel value of each pixel in the reference image information 140. For example, the density determination unit 13 determines whether the calculated difference value is equal to or greater than the value of the density determination threshold 141 and determines that the calculated difference value is equal to or greater than the value of the density determination threshold 141. In this case, it is determined that the print image printed on the printing paper 60 includes a density defect. On the other hand, when the density determination unit 13 determines that the calculated difference value is not equal to or greater than the value of the density determination threshold 141, that is, less than the value of the density determination threshold 141, it is printed on the printing paper 60. It is determined that the printed image does not include a density defect.

  If there is no defect in the print image printed on the printing paper 60, the pixel value of each pixel in the average image information 90 is the same as the pixel value of each pixel in the reference image information 140. The value of the difference is “0”. Actually, since there are variations in printing by the printing apparatus 30 and noise mixed in the captured image information at the time of shooting by the imaging apparatus 20, even if there are no defects such as density defects, stains, omissions, etc. The value is not “0”. Therefore, a difference value within a range acceptable as a non-defective product is determined in advance, and the value is stored in advance as determination information in the determination information storage unit 14 as a concentration determination threshold value 141.

  When the density determination unit 13 determines that the print image printed on the printing paper 60 does not include a density-related defect (step Sa4, less than the threshold), the discharge destination designation unit 15 discharges the printing paper 60 to a non-defective pile. Thus, an instruction signal is output to the discharging device 50 (step Sa5). On the other hand, when the density determination unit 13 determines that the print image printed on the printing paper 60 includes a density-related defect (step Sa4, greater than or equal to the threshold value), the discharge destination designation unit 15 turns the printing paper 60 into a defective product pile. An instruction signal is output to the discharging device 50 so as to be discharged (step Sa6). Thereafter, the print image inspection apparatus 1 repeats the processing from step Sa1 for the next printing paper 60 (step Sa7).

(Effects of processing of the print image inspection apparatus of the first embodiment)
Next, the effects of the processing of the print image inspection apparatus 1 according to the first embodiment will be described with reference to FIGS. Defects that occur in the printed image printed on the printing paper 60 include sudden wrinkles such as smudges and omissions and density defects that occur in a certain area depending on the state of ink.

  FIG. 6 shows an example in which a stain wrinkle region 100 is generated only in the inspection image information 80-1, and the other inspection image information 80-2 to 80-16 is in a normal state with no contamination. ing. The difference between the pixel value of each pixel of the inspection image information 80-1 and the pixel value of each pixel of the reference image information 140 is obtained, and the difference value at the pixel on the line indicated by the broken line A of the inspection image information 80-1 is calculated. The distribution is represented as distribution 85-1. Similarly, in the inspection image information 80-2 to 80-16, distributions of difference values in pixels on the line indicated by the broken line A are distributions 85-2 to 85-16. From these distributions 85-1 to 85-16, in the distribution 85-1, the value in the vicinity where the wrinkle region 100 exists is very large compared to other values.

  The average image information 90 is generated by the average information generator 12, and the difference between the pixel value of each pixel of the average image information 90 and the pixel value of each pixel of the reference image information 140 is obtained. When the distribution is shown, a distribution 95 is obtained. In the distribution 95, the size of the value in the vicinity where the wrinkle region 100 exists in the inspection image information 80-1 is compressed to about 1/16.

  On the other hand, in FIG. 7, a density defective area 110 is generated in the central area of the inspection image information 80-1 to 80-4 that is continuous in the vertical direction on the printing paper 60. -5 to 80-16 show an example of a normal state with no dirt. Similar to the example of FIG. 6, in the example of FIG. 7, the difference between the pixel value of each pixel of the inspection image information 80-1 to 80-16 and the pixel value of each pixel of the reference image information 140 is obtained, The distribution of difference values in pixels on the line indicated by the broken line A is represented. The distribution for the inspection image information 80-1 to 80-4 including the density defective area 110 is the distribution 86-1 to 86-4, and the distribution for the inspection image information 80-6 to 80-16 is the distribution 86-. 5 to 86-16.

  The average image information 90 is generated by the average information generator 12, and the difference between the pixel value of each pixel of the average image information 90 and the pixel value of each pixel of the reference image information 140 is obtained. When the distribution is shown, the distribution 96 is obtained. The distribution 96 includes inspection image information 80-1 to 80-4 having four density defects, and the value of the density defect area 110 is compressed to about one-fourth. Will appear.

  That is, the value indicating sudden wrinkles such as dirt and omission becomes about 1/16 by the average value calculation by the average information generation unit 12. On the other hand, the density defect often occurs over a plurality of pieces of inspection image information 80-1 to 80-4. Therefore, even if the average value is calculated by the average information generation unit 12, it may occur suddenly such as dirt or missing. It appears as a value larger than the value indicating the wrinkles that occur in. This makes it easy to set a density determination threshold 141 that separates defects such as stains and omissions that occur suddenly and defects of density defects, and does not require strict inspection standards, and also prevents false detection. It becomes difficult to happen.

  In addition, regarding the variation in printing by the printing apparatus 30 and the noise mixed in the captured image information at the time of shooting by the imaging apparatus 20, such an unnecessary information element that is randomly generated is generated by the average information generation unit 12. In the average calculation, it is removed to a negligible level. Therefore, the accuracy of the determination process based on the concentration determination threshold 141 in the concentration determination unit 13 is improved.

  With the configuration of the first embodiment described above, in the print image inspection apparatus 1, the inspection image information acquisition unit 11 captures a plurality of print images of the same design printed on the print paper 60 by the imaging apparatus 20. Captured image information 70-1 to 70-4 obtained by dividing the image into column-by-column images in the dividing process is acquired. The inspection image information acquisition unit 11 divides the acquired captured image information 70-1 to 70-4 into images of ticket units in the second division process, thereby inspecting image information 80-corresponding to each of the plurality of print images. Generate 1-80-16. The average information generation unit 12 generates the average image information 90 by averaging the feature information for each pixel of the inspection image information 80-1 to 80-16 for each pixel. Based on the average image information 90 and predetermined determination information, the density determination unit 13 determines whether the print image printed on the printing paper 60 includes a defect related to density. The discharge destination designation unit 15 outputs an instruction signal to the discharge device 50 for discharging the non-defective pile for the printing paper 60 that the density determination unit 13 has determined not to contain a density defect, and the density determination unit 13 relates to the density. An instruction signal for discharging the determined printing paper 60 including a defect to a pile of defective products is output to the discharging device 50. This makes it possible to accurately detect density defects in a printed image in a printing process in which a plurality of the same symbols are printed.

  In the configuration of the first embodiment described above, the average image information 90 is calculated using all the print images of a plurality of symbols printed on one print sheet 60. However, the configuration of the present invention is as follows. It is not limited to the embodiment. Depending on the state of the printing apparatus 30, an area in which a density defect appears may be specified in advance. In such a case, the average information generation unit 12 performs an operation that emphasizes the size of the pixel value included in the region, so that the density determination unit 13 can more accurately determine the presence or absence of a density-related defect. be able to.

  For example, as shown in FIG. 8, when the density defect area 111 is concentrated on the left end of the printing paper 60, the test image information 80-1 to 80-4 including the density defect area 111 is weighted and weighted. An average may be calculated. As the weighting, for example, as shown in FIG. 9, the weight of the density defective area 111 is set to “1”, and the weight of the other areas is set to “0”. There is a method in which the weight of the area 111 is “1” and the weight of the other areas is “0.5”. In addition, as shown in FIG. 11, when there is a tendency that a density defect appears slightly weakly in the area 112 on the right side of the density defective area 111, the weight of the area 111 is set to “1”, and the weight of the area 112 is set. “0.5” may be set, and the weights of other regions may be set to “0”.

  Differences in the value of the average image information 90 generated by the average information generation unit 12 by these weightings will be described using the example of FIG. In FIG. 12, pixel values of one pixel having the same coordinate position in each of the inspection image information 80-1 to 80-16 are shown in each frame of the inspection image information 80-1 to 80-16. As shown in FIG. 12, the pixel values of the inspection image information 80-1 to 80-4 at the left end are “90”, and a strong density defect appears. As the process proceeds to the right, the density defect is reduced and the pixel values are also reduced to “60”, “50”, and “40”.

  When there is no weighting, the average information generation unit 12 averages the pixel values of all the pixels. Therefore, the pixel value of the pixel at the same position in the average image information 90 is calculated by the following equation. That is, (90 × 4 + 60 × 4 + 50 × 4 + 40 × 4) / 16 = (360 + 240 + 200 + 160) / 16 = 960/16 = 60.

  Weighting pattern 1 shown in FIG. 9, that is, inspection image information 80-1 to 80-4 is weighted 1 time, and other inspection image information 80-5 to 80-16 is weighted 0 times. When performing, the pixel value of the pixel of the same position in the average image information 90 calculated by the average information generation part 12 is calculated by the following formula by calculating a weighted average. That is, (90 × 4) / 4 = 90. Since the denominator is a weighted average, the denominator is “4” corresponding to the number of inspection image information 80-1 to 80-4 on which weighting of 1 is performed.

  Weighting pattern 2 shown in FIG. 10, that is, inspection image information 80-1 to 80-4 is weighted 1 time, and other inspection image information 80-5 to 80-16 is multiplied by 0.5 times. When weighting is performed, the pixel value of the pixel at the same position in the average image information 90 calculated by the average information generation unit 12 is calculated by the following equation by calculating the weighted average. That is, (90 × 4 + 60 × 4 × 0.5 + 50 × 4 × 0.5 + 40 × 4 × 0.5) / (4 + 12 × 0.5) = (360 + 120 + 100 + 80) / 10 = 660/10 = 66. Since the denominator is a weighted average, “4” for the number of inspection image information 80-1 to 80-4 that has been weighted by 1 is weighted by 0.5. The value is “10” obtained by adding “12” corresponding to the number of pieces of the inspection image information 80-5 to 80-16 and a value obtained by multiplying the weight “0.5”.

  Weighting pattern 3 shown in FIG. 11, that is, inspection image information 80-1 to 80-4 is weighted 1 time, and inspection image information 80-5 to 80-8 is weighted 0.5 times. In addition, when 0-times weighting is applied to the other inspection image information 80-9 to 80-16, the pixel value of the pixel at the same position in the average image information 90 calculated by the average information generation unit 12 is weighted. By calculating the average, the following formula is used. That is, (90 × 4 + 60 × 4 × 0.5) / (4 + 4 × 0.5) = (360 + 120) / 6 = 80. Since the denominator is a weighted average, “4” for the number of inspection image information 80-1 to 80-4 that has been weighted by 1 is weighted by 0.5. The result is “6” obtained by adding “4” corresponding to the number of inspection image information 80-5 to 80-8 and a value obtained by multiplying the weight “0.5”.

  To summarize, when there is no weighting, the pixel value of the average image information 90 is “60”. When the weighting pattern is 1, the pixel value of the average image information 90 is “90”. The pixel value of “66” is “66”, and in the case of the weighting pattern 3, the pixel value of the average image information 90 is “80”. Therefore, when the area where the density defect appears strongly is known in advance, the value of the pixel value of the average image information 90 is increased by increasing the weighting value in the area. The accuracy of the determination process based on 141 can be improved.

  For example, as shown in FIG. 13, when an area 113 with poor density appears in the horizontal direction, the inspection image information 80-1, 80-5, 80-9, 80-13 in the top row is weighted by one. The other inspection image information 80-2 to 80-4, 80-6 to 80-8, 80-10 to 80-2, and 80-14 to 80-16 are weighted 0 times. It may be.

  In addition, as shown in FIG. 14, when defective density regions 111 and 114 appear at both ends, the inspection image information 80-1 to 80-4 and 80-13 to 80-16 are weighted by 1 time. The other inspection image information 80-5 to 80-12 may be weighted 0 times.

  However, if the weighting of a certain area is set to 0 times as in the weighting pattern 1, it is impossible to detect a density defect that appears in the area where the weighting is 0 times. Therefore, even when the area where density defects appear is known to some extent, if it is desirable to detect density defects that appear in unexpected areas, it is preferable to select a balanced weight such as weighting pattern 2. There is also.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. FIG. 15 is a block diagram illustrating an internal configuration of the print image inspection apparatus 1a according to the second embodiment and a connection relationship between the imaging apparatus 20 and the discharge apparatus 50. The same components as those in the first embodiment are denoted by the same reference numerals, and different components will be described below. The print image inspection apparatus 1a includes an inspection image information acquisition unit 11, an average information generation unit 12a, a density determination unit 13, a reference image information storage unit 14-1, a density determination threshold storage unit 14-2, a discharge destination designation unit 15a, A difference calculation unit 16, a wrinkle determination unit 17, a wrinkle determination threshold storage unit 18, and an inspection image information storage unit 10 are provided.

  The inspection image information storage unit 10 stores inspection image information 80-1 to 80-16 generated by the inspection image information acquisition unit 11. Based on the determination result of the eyelid determination unit 17, the average information generation unit 12a generates average information obtained by averaging the feature information of each pixel of the inspection image information 80-1 to 80-16 for each pixel. In the second embodiment, the feature information is the pixel value of each pixel of the inspection image information 80-1 to 80-16 as in the first embodiment, and the average information generated by the average information generation unit 12a is Average image information 90 is obtained.

  The reference image information storage unit 14-1 and the density determination threshold storage unit 14-2 have a configuration corresponding to the determination information storage unit 14 of the first embodiment, and the reference image information storage unit 14-1 is the first implementation. The reference image information 140 of the form is stored in advance. The density determination threshold storage unit 14-2 stores the density determination threshold 141 of the first embodiment in advance.

  The difference calculation unit 16 includes the pixel values of the pixels of the inspection image information 80-1 to 80-16 generated by the inspection image information acquisition unit 11, and the reference image information 140 stored in the reference image information storage unit 14-1. The difference between each pixel and the pixel value is calculated, and difference image information using the difference value as the pixel value is generated. The wrinkle determination unit 17 determines whether or not the print image printed on the printing paper 60 includes a defect other than a density defect based on the value of each pixel of the difference image information and the value of the wrinkle determination threshold value 180. judge. Here, the defect other than the defect related to the density is a defect that appears suddenly as typified by, for example, the above-described dirt or omission. The wrinkle determination threshold value storage unit 18 stores a wrinkle determination threshold value 180 in advance.

  In addition to the configuration provided in the discharge destination designating unit 15, the discharge destination designating unit 15 a converts the print sheet 60, which has been determined that the print image printed on the print sheet 60 does not contain wrinkles, into a non-defective pile. An instruction signal is output to the discharging device 50 so as to discharge. Further, the discharge destination designating unit 15a instructs the discharge device 50 to discharge the print paper 60 that the print determining unit 17 has determined that the print image printed on the print paper 60 includes the wrinkle to the defective pile. Is output.

(Processing by the print image inspection apparatus of the second embodiment)
Next, processing by the print image inspection apparatus 1a of the second embodiment will be described with reference to FIG. A printing image including a plurality of designs is printed on the printing paper 60 by the printing device 30, and the printing paper 60 is sent to the imaging range of the imaging device 20 by the inspection cylinders 40-1 and 40-2. The imaging device 20 included in the imaging device 20 captures a print image printed on the printing paper 60. The inspection image information acquisition unit 11 acquires the captured image information 70-1, 70-2, 70-3, and 70-4 shown in FIG. 4 output from the imaging device 20 and then divided (step Sb1).

  The inspection image information acquisition unit 11 divides the captured image information 70-1, 70-2, 70-3, and 70-4 to generate inspection image information 80-1 to 80-16. The inspection image information acquisition unit 11 outputs the generated inspection image information 80-1 to 80-16 to the difference calculation unit 16. The inspection image information acquisition unit 11 writes and stores the generated inspection image information 80-1 to 80-16 in the inspection image information storage unit 10 (step Sb2).

  The difference calculation unit 16 includes any one of the inspection image information 80-1 to 80-1 that is not determined by the eyelid determination unit 17 among the inspection image information 80-1 to 80-16 output by the inspection image information acquisition unit 11. Select 80-16. The difference calculation unit 16 selects the pixel value of each pixel of the selected inspection image information 80-1 to 80-16 and the pixel value of each pixel of the reference image information 140 stored in the reference image information storage unit 14-1. The difference image information is generated using the difference value as a pixel value. The difference calculation unit 16 outputs the generated difference image information to the wrinkle determination unit 17 (step Sb3).

  The wrinkle determination unit 17 determines whether the pixel value of any pixel in the difference image information generated by the difference calculation unit 16 is equal to or greater than the value of the wrinkle determination threshold value 180 stored in the wrinkle determination threshold value storage unit 18. Is determined (step Sb4). When the heel determination unit 17 determines that the pixel value of any pixel in the difference image information is equal to or greater than the value of the threshold value for heel determination 180 (step Sb4, Yes), the discharge destination designation unit 15a displays the difference image information. An instruction signal is output to the discharge device 50 so as to discharge the print paper 60 on which the print image corresponding to is discharged to the defective product pile (step Sb5).

  On the other hand, when it is determined that the pixel value of any pixel of the difference image information is not equal to or greater than the value of the threshold value for wrinkle 180 (No in step Sb4), the wrinkle determination unit 17 performs all the inspection image information 80-1 to 80. It is determined whether or not −16 has been determined (step Sb6). When it is determined that the eyelid determining unit 17 has not determined all the inspection image information 80-1 to 80-16 (No in Step Sb6), the process returns to Step Sb3.

  On the other hand, when the wrinkle determination unit 17 determines that all the inspection image information 80-1 to 80-16 has been determined (step Sb6, Yes), the average information generation unit 12a has no wrinkles by the wrinkle determination unit 17. The determined inspection image information 80-1 to 80-16 is read from the inspection image information storage unit 10, and the pixel values of the read inspection image information 80-1 to 80-16 are averaged for each pixel to obtain average image information 90. Generate (step Sb7).

  The density determination unit 13 includes the pixel value of each pixel of the average image information 90 generated by the average information generation unit 12a and the pixel value of each pixel of the reference image information 140 stored in the reference image information storage unit 14-1. Is calculated (step Sb8). The density determination unit 13 determines whether or not the calculated difference value is greater than or equal to the value of the density determination threshold 141 stored in the density determination threshold storage unit 14-2 (step Sb9).

  When the density determination unit 13 determines that the calculated difference value is equal to or greater than the value of the density determination threshold 141 (Yes in step Sb9), the discharge destination designation unit 15a prints the printing paper corresponding to the average image information 90 Since the print image printed on the image 60 includes a density defect, an instruction signal is output to the discharge device 50 so that the print paper 60 is discharged to a defective pile (step Sb5).

  On the other hand, when the density determination unit 13 determines that the calculated difference value is not greater than or equal to the value of the density determination threshold 141 (No in step Sb9), the discharge destination designation unit 15a prints corresponding to the average image information 90. Since the printed image printed on the paper 60 does not include a density-related defect, an instruction signal is output to the discharge device 50 so that the print paper 60 is discharged to a non-defective pile (step Sb10).

  With the configuration of the second embodiment, the difference calculation unit 16 calculates the difference between the pixel value of each pixel of the inspection image information 80-1 to 80-16 and the pixel value of each pixel of the reference image information 140. . The wrinkle determination unit 17 determines whether or not the print image printed on the printing paper 60 includes a wrinkle that appears suddenly, such as dirt or missing, based on the difference value and the value of the wrinkle determination threshold value 180. Determine. The average information generation unit 12a generates the average image information 90 based on the inspection image information 80-1 to 80-16 determined to have no wrinkles in the wrinkle determination unit 17. As a result, in addition to the effects exhibited by the print image inspection apparatus 1 of the first embodiment, the printing paper 60 including the suddenly appearing wrinkles such as dirt and omissions includes a density-related defect by the density determination unit 13. It is not necessary to make such a determination, so the processing load is reduced.

(Third embodiment)
Next, a third embodiment of the present invention will be described. FIG. 17 is a block diagram illustrating an internal configuration of the print image inspection apparatus 1b according to the third embodiment and a connection relationship between the imaging apparatus 20 and the discharge apparatus 50. The same components as those in the first and second embodiments are denoted by the same reference numerals, and different configurations will be described below. The print image inspection apparatus 1b includes an inspection image information acquisition unit 11, an average information generation unit 12b, a density determination unit 13b, a reference image information storage unit 14-1, a density determination threshold storage unit 14-2, a discharge destination designation unit 15a, A difference calculation unit 16b, a wrinkle determination unit 17, a wrinkle determination threshold storage unit 18, and a difference image information storage unit 19 are provided.

  In addition to the configuration of the difference calculation unit 16 of the first embodiment, the difference calculation unit 16b writes and stores the generated difference image information in the difference image information storage unit 19. In the difference image information storage unit 19, the difference image information generated by the difference calculation unit 16b is written by the difference calculation unit 16b. Based on the determination result of the eyelid determination unit 17, the average information generation unit 12b reads the difference image information corresponding to each of the inspection image information 80-1 to 80-16 from the difference image information storage unit 19, and reads the plurality of read image information Average information is generated by averaging the pixel values of each pixel of the difference image information for each pixel.

  That is, in the third embodiment, the difference value between the pixel value of each pixel of the inspection image information 80-1 to 80-16 and the pixel value of each pixel of the reference image information 140 is used as the feature information, Based on this, the average information generation unit 12b generates average information. Since the average information is different from the average image information 90 obtained by averaging the pixel values of the pixels of the inspection image information 80-1 to 80-16 described above, the average information is hereinafter described as difference average image information.

  The density determination unit 13b is printed on the printing paper 60 based on the difference average image information generated by the average information generation unit 12 and the density determination threshold value 141 stored in the density determination threshold storage unit 14-2. It is determined whether the printed image contains a density defect.

(Processing by the print image inspection apparatus of the third embodiment)
Next, processing by the print image inspection apparatus 1b according to the third embodiment will be described with reference to FIG. A printing image including a plurality of designs is printed on the printing paper 60 by the printing device 30, and the printing paper 60 is sent to the imaging range of the imaging device 20 by the inspection cylinders 40-1 and 40-2. The imaging device 20 included in the imaging device 20 captures a print image printed on the printing paper 60. The inspection image information acquisition unit 11 acquires the captured image information 70-1, 70-2, 70-3, and 70-4 shown in FIG. 4 output by the imaging device 20 and then divided (step Sc1).

  The inspection image information acquisition unit 11 divides the captured image information 70-1, 70-2, 70-3, and 70-4 to generate inspection image information 80-1 to 80-16. The inspection image information acquisition unit 11 outputs the generated inspection image information 80-1 to 80-16 to the difference calculation unit 16b (Step Sc2).

  The difference calculation unit 16b is one of the inspection image information 80-1 to 80-1 that is not determined by the eyelid determination unit 17 among the inspection image information 80-1 to 80-16 output by the inspection image information acquisition unit 11. Select 80-16. The difference calculation unit 16b includes the pixel value of each pixel of the selected inspection image information 80-1 to 80-16 and the pixel value of each pixel of the reference image information 140 stored in the reference image information storage unit 14-1. The difference image information is generated using the difference value as a pixel value. The difference calculation unit 16 b outputs the generated difference image information to the wrinkle determination unit 17. The difference calculation unit 16b writes and stores the generated difference image information in the difference image information storage unit 19 (step Sc3).

  The wrinkle determination unit 17 determines whether the pixel value of any pixel in the difference image information generated by the difference calculation unit 16b is equal to or greater than the value of the wrinkle determination threshold value 180 stored in the wrinkle determination threshold storage unit 18. Is determined (step Sc4). If the heel determination unit 17 determines that the pixel value of any pixel in the difference image information is equal to or greater than the value of the threshold value for heel determination 180 (step Sc4, Yes), the discharge destination designation unit 15a displays the difference image information. An instruction signal is output to the discharge device 50 so as to discharge the print paper 60 on which the print image corresponding to is discharged to the defective pile (step Sc5).

  On the other hand, if it is determined that the pixel value of any pixel in the difference image information is not equal to or greater than the value of the threshold value for wrinkle 180 (No in step Sc4), the wrinkle determination unit 17 sets all pieces of inspection image information 80-1 to 80. It is determined whether or not −16 has been determined (step Sc6). When it is determined that the eyelid determining unit 17 has not determined all the inspection image information 80-1 to 80-16 (No in Step Sc6), the process returns to Step Sc3.

  On the other hand, when it is determined that the eyelid determination unit 17 has determined all the inspection image information 80-1 to 80-16 (Yes in Step Sc6), the average information generation unit 12a reads the inspection image from the difference image information storage unit 19. Difference image information corresponding to each of the information 80-1 to 80-16 is read, and the pixel value of the read difference image information is averaged for each pixel to generate difference average image information (step Sc7).

  In the density determination unit 13b, the pixel value of any pixel of the difference average image information generated by the average information generation unit 12a is equal to or greater than the value of the density determination threshold 141 stored in the density determination threshold storage unit 14-2. Is determined (step Sc8). When the density determination unit 13b determines that the pixel value of any pixel in the difference average image information is greater than or equal to the value of the density determination threshold 141 (step Sc8, Yes), the discharge destination designation unit 15a Since the print image printed on the print image 60 includes a density defect, an instruction signal is output to the discharge device 50 so as to discharge the print paper 60 to a defective pile (step Sc5).

  On the other hand, when the density determination unit 13b determines that the pixel value of any pixel in the difference average image information is not greater than or equal to the value of the density determination threshold 141 (No in Step Sc9), the discharge destination designation unit 15a Since the print image printed on 60 does not include a density defect, an instruction signal is output to the discharge device 50 so that the print paper 60 is discharged to a non-defective pile (step Sc9).

  With the configuration of the third embodiment, the difference calculation unit 16b calculates the difference between the pixel value of each pixel of the inspection image information 80-1 to 80-16 and the pixel value of each pixel of the reference image information 140. . The wrinkle determination unit 17 determines whether or not the print image printed on the printing paper 60 includes a wrinkle that appears suddenly, such as dirt or missing, based on the difference value and the value of the wrinkle determination threshold value 180. Determine. The average information generation unit 12a generates difference average image information based on the difference image information corresponding to the inspection image information 80-1 to 80-16 determined to have no wrinkles in the wrinkle determination unit 17. The density determination unit 13b determines whether or not the print image printed on the printing paper 60 includes a defect related to density based on the pixel value of each pixel of the difference average image information and the threshold for density determination. . Thereby, in addition to the effect which the printing image inspection apparatus 1 of 1st Embodiment has, about the printing paper 60 containing the wrinkles which appear suddenly, such as a stain | pollution | contamination and omission, similarly to the printing image inspection apparatus 1b of 2nd Embodiment. Since it is not necessary to determine whether or not the density determination unit 13b includes a density defect, the processing load is reduced. Further, in the print image inspection apparatus 1b according to the third embodiment, since the difference average image information is obtained based on the difference image information generated by the difference calculation unit 16b, the density determination unit 13b performs the inspection image information 80-1 to 80-1. It is not necessary to calculate the difference between the pixel value of each pixel 80-16 and the pixel value of each pixel of the reference image information 140. Therefore, in the print image inspection apparatus 1b of the third embodiment, the amount of calculation is reduced compared to the print image inspection apparatus 1a of the second embodiment, and further, the processing load is reduced.

  In the first, second, and third embodiments described above, a plurality of designs on the same ticket surface are printed as print images to be printed on the printing paper 60. It is not limited to the embodiment. For example, like a poster as shown in FIG. 19, there is only one symbol printed on each of a plurality of printing papers 60-α, 60-β,..., But the same symbol is printed on a plurality of sheets. Even in such a case, the print image inspection apparatus 1 of the first embodiment may be applied. In this case, when the printing paper 60-α is sent to the imaging range 25d, the single imaging device 20d captures an image and outputs captured image information.

  The inspection image information acquisition unit 11 acquires a plurality of captured image information corresponding to a predetermined number of print sheets 60-α, 60-β,..., And each of the acquired captured image information is directly used as inspection image information. . The average information generation unit 12 calculates the average of the pixel values of each pixel of the plurality of inspection image information acquired by the inspection image information acquisition unit 11 and generates average information. The density determination unit 13 calculates the difference between the pixel value of each pixel in the average information and the pixel value of each pixel in the reference image information 140. Here, the reference image information 140 is a print image having the same size as the print image included in each of the print sheets 60-α, 60-β,. Can be obtained.

  Whether the density determination unit 13 includes a density-related defect in any of the plurality of printing sheets 60-α, 60-β,... Based on the calculated difference value and the density determination threshold value 141. Determine whether or not. When the density determination unit 13 determines that the calculated difference value is equal to or greater than the value of the density determination threshold 141, any one of the printing sheets 60-α, 60-β,. Therefore, the discharge destination designating unit 15 outputs an instruction signal for discharging all of the plurality of print sheets 60-α, 60-β,... Corresponding to the average information to the defective product pile to the discharge device 50. On the other hand, when the density determination unit 13 determines that the calculated difference value is not greater than or equal to the value of the threshold value 141 for density determination, the discharge destination designation unit 15 includes a plurality of print sheets 60-α, corresponding to the average information. An instruction signal for discharging all of 60-β,... To the non-defective pile is output to the discharging device 50.

  When the same design is printed on each of a plurality of printing sheets 60-α, 60-β,... Like a poster as shown in FIG. Similarly to the application of the image inspection apparatus 1, the configurations of the print image inspection apparatuses 1a and 1b of the second and third embodiments may be applied.

  In the first, second, and third embodiments, the inspection image information acquisition unit 11 generates inspection image information 80-1 to 80-16 by performing division for each of the symbols on the plurality of bills. However, the configuration of the present invention is not limited to the embodiment. Since it is sufficient that the symbols included in each of the plurality of pieces of examination image information 80-1 to 80-16 are the same, for example, the captured image information 70-1 and 70- including five symbols on the card surface illustrated in FIG. Each of 2, 70-3 and 70-4 may be used as the inspection image information, or the inspection image information may be generated by being divided into or combined with a plurality of predetermined symbol patterns.

  For example, the captured image information 70-1, 70-2, 70-3, 70-4 may be combined to make one print image of the print paper 60 as one inspection image information. In this case, as in the poster shown in FIG. 19, the density determination is performed for each of the plurality of printing papers 60. Further, when one or more of the symbols on the ticket surface is used as the inspection image information, average information may be calculated for each of the plurality of printing papers 60 and the density may be determined for each of the plurality of printing papers 60.

  In the first, second, and third embodiments, the printing paper 60 that is a paper medium is described as an example of the medium that is printed on the printing apparatus 30. However, the configuration of the present invention is not limited to this embodiment. As long as it is a print medium, it is not limited to this form.

  In the first, second, and third embodiments described above, in the determination based on threshold values such as the density determination threshold 141 and the wrinkle determination threshold 180 and the comparison target value, the comparison target value is However, the present invention is not limited to this embodiment. The determination as to whether or not the comparison target value is equal to or greater than the threshold value is merely an example, and the determination may be made based on whether or not the comparison target value exceeds the threshold value.

FIG. 20 is a diagram showing the minimum configuration of the print image inspection apparatus.
The print image inspection apparatuses 1, 1a, 1b of the above-described embodiments may have at least the function of the density determination unit 13 (13b). The density determination unit 13 (13b) generates average information of feature information of a plurality of inspection images each including the same design obtained from a captured image of a print medium on which the same design is printed. The density determination unit 13 (13b) determines whether or not the print medium includes a density defect based on the average information and predetermined determination information.

  The print image inspection apparatuses 1, 1a, and 1b in the above-described embodiments may be realized by a computer. In that case, a program for realizing this function may be recorded on a computer-readable recording medium, and the program recorded on this recording medium may be read into a computer system and executed. Here, the “computer system” includes an OS and hardware such as peripheral devices. The “computer-readable recording medium” refers to a storage device such as a flexible medium, a magneto-optical disk, a portable medium such as a ROM and a CD-ROM, and a hard disk incorporated in a computer system. Furthermore, the “computer-readable recording medium” dynamically holds a program for a short time like a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line. In this case, a volatile memory inside a computer system serving as a server or a client in that case may be included and a program held for a certain period of time. Further, the program may be a program for realizing a part of the above-described functions, and may be a program capable of realizing the functions described above in combination with a program already recorded in a computer system. You may implement | achieve using programmable logic devices, such as FPGA (Field Programmable Gate Array).

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes designs and the like that do not depart from the gist of the present invention.

DESCRIPTION OF SYMBOLS 1 Print image inspection apparatus 11 Inspection image information acquisition part 12 Average information generation part 13 Density determination part 14 Determination information storage part 15 Ejection destination designation | designated part

Claims (11)

The print medium has a density based on average information of feature information of a plurality of inspection images each including the same pattern obtained from a captured image of the print medium on which the same pattern is printed, and predetermined determination information. A concentration determination unit for determining whether or not a defect is included, and
A printed image inspection apparatus comprising: An inspection image acquisition unit for acquiring the inspection image;
An average information generating unit that generates average information by averaging feature information for each pixel of the plurality of inspection images;
A density determination unit that determines whether or not the print medium includes a density defect based on the average information and predetermined determination information;
The print image inspection apparatus according to claim 1, further comprising: A reference image information storage unit that stores reference image information obtained by imaging a print medium on which the same design that does not include a defect is printed;
The predetermined determination information is a pixel value of each pixel of the reference image information and a predetermined density determination threshold,
The average information generator is
As the feature information, the pixel value of each pixel of the plurality of inspection images is read, the read pixel value is averaged for each pixel, and the average information is generated,
The concentration determination unit
A difference between the pixel value of each pixel of the average information and the pixel value of each pixel of the reference image information is calculated, and based on the calculated pixel value difference of each pixel and the density determination threshold value The print image inspection apparatus according to claim 2, wherein it is determined whether or not the print medium includes a density defect. A reference image information storage unit that stores reference image information obtained by imaging a print medium on which the same design that does not include a defect is printed;
A difference calculation unit that generates difference image information including a difference between a pixel value of each pixel of the inspection image and each pixel value of the reference image information in each pixel;
The predetermined determination information is a predetermined concentration determination threshold value,
The average information generator is
As the feature information, the pixel value of each pixel of the difference image information generated by the difference calculation unit is read, and the average value is generated by averaging the read pixel value for each pixel.
The concentration determination unit
The print image according to claim 2, wherein it is determined whether or not the print medium includes a density defect based on the pixel value of each pixel of the average information and the threshold value for density determination. Inspection device. It is determined whether or not a defect other than the defect related to the density is included based on difference image information including a difference between a pixel value of each pixel of the inspection image and each pixel value of the reference image information. It has a judgment part,
The defect other than the defect related to the density is a defect in which an information amount related to the defect in the inspection image including the defect is reduced in the average information generated by the average information generation unit. Or the printed image inspection apparatus of 4. The average information generator is
The print image inspection apparatus according to claim 5, wherein the wrinkle determination unit does not generate the average information for the inspection image determined as including a defect other than the defect related to the density. A plurality of the same symbols are printed for each one of the print media,
The inspection image acquisition unit
The imaging unit divides the captured image obtained by imaging the print medium, and generates the inspection image in which each captured image has the same design,
The average information generator is
For each print medium, the feature information of a plurality of the inspection images corresponding to the print medium is averaged for each pixel to generate average information,
The concentration determination unit
Based on the average information and predetermined determination information, it is determined for each of the print media whether any of the inspection images corresponding to the print medium includes a density defect. The print image inspection apparatus according to any one of claims 2 to 6. The average information generator is
The weighted average is used to generate the average information by weighting the inspection image existing at a predetermined position on the print medium when generating the average information. Print image inspection device. One of the same symbols is printed for each one of the print media,
The inspection image acquisition unit
The captured image obtained by the imaging means imaging the print medium is the inspection image,
The average information generator is
Averaging the feature information of the plurality of inspection images corresponding to each of a predetermined number of the plurality of print media for each pixel to generate average information;
The concentration determination unit
Based on the average information and predetermined determination information, for each of the predetermined number of the plurality of print media, it is determined whether any of the print media includes a density defect. The printed image inspection apparatus according to claim 2.   The print medium has a density based on average information of feature information of a plurality of inspection images each including the same pattern obtained from a captured image of the print medium on which the same pattern is printed, and predetermined determination information. Print image inspection method for determining whether or not a defect is included. The computer of the print image inspection device,
The print medium has a density based on average information of feature information of a plurality of inspection images each including the same pattern obtained from a captured image of the print medium on which the same pattern is printed, and predetermined determination information. Density determination means for determining whether or not it contains a defect,
Program to function as.

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