JP5540595B2 - Printed matter inspection apparatus, printed matter inspection system, printed matter inspection method, and printed matter inspection program - Google Patents

Description

  The present invention relates to a printed matter inspection system, a printed matter inspection method, and a printed matter inspection apparatus that perform defect inspection on a printed matter that includes a plurality of printing units on a single sheet and the same pattern is printed on each printing unit.

In a printed matter in which a plurality of the same patterns (hereinafter referred to as “printing units”) are printed on a single sheet of paper (hereinafter referred to as “large format”) such as banknotes or stamps, the printed unit images are compared with each other. Inspecting for defects has been done.
For example, Patent Document 1 discloses a method of comparing print unit images having the same positional relationship between different large formats, and a method of comparing print unit images having vertical or horizontal positional relationships within the same large format. ing.

Japanese Patent No. 3031286 JP 09-015168 A Japanese Patent No. 3965189

However, the printed matter inspection method disclosed in Patent Document 1 has the following problems.
The first problem is that the printing unit image to be inspected is subject to various fluctuations (imaging errors) at the time of imaging, and the inspection accuracy is lowered.
That is, the printing unit is the same pattern, but has undergone various fluctuations on the optical image due to the influence of the transport system and the optical system. In the existing inspection technique, the reason why the print unit images having the same positional relationship or the vertical or horizontal positional relationship are compared is to cancel such a variation on the optical image as much as possible.
However, the fluctuation on the optical image is dynamically generated, and even if the optical images in a fixed positional relationship are compared with each other, the fluctuation may remain without being canceled. The influence of fluctuation cannot be eliminated, and the inspection accuracy may be significantly reduced.

The second problem is that the number of printing units that can be compared with respect to one printing unit is limited, and the inspection accuracy cannot be improved by increasing the number of comparison partners.
That is, the number of comparison partners leads to suppression of variation due to averaging, so it is preferable to increase the number of comparison partners. However, in the existing inspection technology, in order to cancel the fluctuation, only with a partner having a limited fixed positional relationship. We were comparing and could not increase the number of comparison partners. For example, when comparing printing units that are in the same vertical size or vertical and horizontal positional relationship, there are a maximum of four comparison partners for one printing unit, and it was difficult to increase the number of comparison partners further. .

In order to reduce the influence of fluctuations during imaging, it has also been proposed to correct the optical image of the printing unit in the previous stage of comparing the printing units (see, for example, Patent Documents 2 and 3).
However, the correction of the optical image has led to the deterioration of the image, which may reduce the inspection accuracy. In particular, when a plurality of types of correction are sequentially performed on one optical image, there is a possibility that the image is significantly deteriorated due to an accumulated error.

  An object of the present invention is a printed matter inspection that can eliminate the influence of fluctuations during imaging as much as possible and perform highly accurate defect detection without correcting the print unit image to be inspected. An object is to provide an apparatus, a printed matter inspection system, a printed matter inspection method, and a printed matter inspection program.

  In order to achieve the above object, the printed matter inspection apparatus of the present invention inputs a predetermined print unit image to be inspected, and retrieves and extracts a predetermined contrast print unit image similar to the print unit image to be inspected from the storage means. Comparing partner search means, and defect detection means for comparing the print unit image to be inspected with the contrast print unit image to detect defects in the print unit image to be inspected.

  Further, the printed matter inspection system of the present invention includes an input device that captures a predetermined print unit image to be inspected, and a printed matter inspection that performs a predetermined defect detection inspection by inputting the print unit image to be inspected from the input device. An output device that outputs an inspection result in the printed matter inspection apparatus, wherein the printed matter inspection device inputs a print unit image to be inspected from the input device, and is similar to a predetermined print unit image to be inspected. A comparison partner search unit that searches and extracts a comparison print unit image from a storage unit, and a defect detection that detects a defect in the print unit image to be inspected by comparing the print unit image to be inspected with the comparison print unit image. Means.

  Further, the printed matter inspection method of the present invention includes an input step for inputting a predetermined print unit image to be inspected, and a comparison for retrieving / extracting a predetermined contrast print unit image similar to the print unit image to be inspected from the storage means. The method includes a partner search step and a defect detection step of comparing the print unit image to be inspected with the contrast print unit image to detect a defect in the print unit image to be inspected.

  Furthermore, the printed matter inspection program of the present invention inputs a predetermined print unit image to be inspected and inputs a predetermined print unit image to be inspected to a computer constituting a printed matter inspection apparatus that performs inspection for predetermined defect detection. Input, a comparison partner search means for searching and extracting a predetermined contrast print unit image similar to the print unit image to be inspected from the storage means, comparing the print unit image to be inspected with the contrast print unit image, and This is a program that functions as defect detection means for detecting defects in the print unit image to be inspected.

  According to the present invention, it is possible to eliminate defects as much as possible at the time of imaging as much as possible without correcting a print unit image to be inspected, and to perform highly accurate defect detection.

It is a block diagram showing a schematic structure of a printed matter inspection system concerning a first embodiment of the present invention. It is a block diagram which shows the specific structure of the printed matter inspection system which concerns on 1st embodiment of this invention. It is a flowchart which shows the operation | movement procedure of the printed matter inspection system which concerns on 1st embodiment of this invention. It is explanatory drawing for showing the specific example of the printed matter inspection method which concerns on 1st embodiment of this invention. It is a block diagram which shows the specific structure of the printed matter inspection system which concerns on 2nd embodiment of this invention. It is a flowchart which shows the operation | movement procedure of the printed matter inspection system which concerns on 2nd embodiment of this invention.

Hereinafter, embodiments of a printed matter inspection apparatus, a printed matter inspection system, a printed matter inspection method, and a printed matter inspection program of the present invention will be described with reference to the drawings.
The processing operation (printed material inspection method) executed by the printed material inspection apparatus and the printed material inspection system of the present invention described below is realized by processes, means, and functions executed by a computer according to instructions of a program (software).
The program sends a command to each component of the computer, and is similar to a predetermined process of the present invention as described below, for example, a process of inputting a predetermined print unit image to be inspected, a print unit image to be inspected Each process / procedure such as a process for retrieving / extracting a predetermined comparison print unit image from the storage means, a process for comparing the print unit image to be inspected with the comparison print unit image, and detecting a defect in the print unit image to be inspected To do.

Thus, each process and means in the present invention are realized by specific means in which the program and the computer cooperate.
Note that all or part of the program is provided by, for example, a magnetic disk, optical disk, semiconductor memory, or any other computer-readable recording medium, and the program read from the recording medium is installed in the computer and executed. The The program can also be loaded and executed directly on a computer through a communication line without using a recording medium.

[First embodiment]
FIG. 1 is a block diagram showing a schematic configuration of a printed matter inspection system according to the first embodiment of the present invention.
As shown in this figure, the printed matter inspection system according to the first embodiment of the present invention is configured to include an input device 1, a printed matter inspection device 2, and an output device 3.
The input device 1 includes an apparatus having an imaging unit such as a CCD camera, and includes a plurality of printing units on a single sheet, and is included in the printed material for a printed material on which the same pattern is printed on each printing unit. A plurality of print units are imaged.
The printed matter inspection apparatus 2 is an inspection apparatus that inspects defects of a printed matter in print units based on a captured image input from the input device 1, that is, a print unit image to be inspected.
The output device 3 is a device for outputting / notifying the inspection result of the printed matter inspection device 2 to the outside, and is configured by, for example, a monitor or a printer that outputs the inspection result.

As shown in FIG. 1, the printed matter inspection apparatus 2 includes a comparison partner search unit 22 and a defect detection unit 23.
The comparison partner search unit 22 inputs a predetermined print unit image to be inspected from the input device 1. Then, a predetermined contrast print unit image similar to the print unit image to be inspected is retrieved and extracted from storage means (not shown in FIG. 1) (see the print unit image / correction parameter storage unit 25 shown in FIG. 2).
In the present embodiment, a print unit image having a defect similar to a defect due to a variation at the time of imaging included in a print unit image to be inspected is retrieved and extracted as a comparative print unit image. In this way, past inspection results can be fed back to the current inspection processing, and appropriate and quick inspection processing can be performed.
The defect detection means 23 compares the print unit image to be inspected input from the input device 1 with the contrast print unit image searched and extracted by the comparison partner search means 22 to detect defects in the print unit image to be inspected. To detect.
Then, the inspection result in the defect detection means 23 is input to the output device 3, and the inspection result is output to the outside (display / printing etc.) via the output device 3.

In the printed matter inspection system according to the present embodiment having the above-described configuration, a defect in a print unit image is detected based on a comparison between print unit images that have undergone similar fluctuations during imaging. Without correcting the print unit image, it is possible to eliminate the influence of fluctuation at the time of imaging as much as possible, and to perform highly accurate defect detection.
In addition, since the image to be compared with the print unit image to be inspected can be selected and extracted regardless of the positional relationship in the printed matter, the comparison image is arbitrarily selected, and the number thereof is also set arbitrarily. It can be increased or decreased. Therefore, by using an arbitrary plurality of contrast images, it is possible to increase the number of contrast images and promote suppression of variation due to averaging, thereby improving inspection accuracy.

Hereinafter, the detailed configuration of the printed matter inspection apparatus provided in the printed matter inspection system of the present embodiment having the above-described configuration will be described with reference to FIG.
FIG. 2 is a block diagram illustrating a specific configuration of the printed matter inspection apparatus according to the present embodiment.
As shown in this figure, the printed matter inspection apparatus 2 according to the first embodiment of the present invention includes the comparison partner search means 22 and the defect detection means 23 shown in FIG. Each unit includes a model image storage unit 24 and a printing unit image / correction parameter storage unit 25.

The printing unit model image storage unit 24 stores in advance a single image serving as a printing unit model (reference), that is, a model image. This model image is an image having no defect corresponding to the printing unit to be inspected, and is an image serving as a reference for defect detection. The correction parameter for the print unit image to be inspected is calculated with this model image as a reference.
The print unit image / correction parameter storage unit 25 stores a set of the print unit image and the correction parameter given from the comparison partner search unit 22. That is, the print unit image / correction parameter storage unit 25 stores one or two or more predetermined correction parameters in association with the print unit image corresponding to each correction parameter.

  The correction parameter calculation unit 21 calculates a correction parameter between the print unit image to be inspected given from the input device 1 and the model image of the print unit stored in the print unit model image storage unit 24. That is, the correction parameter calculation unit 21 inputs a print unit image to be inspected and also inputs a print unit model image to be a defect detection reference, thereby obtaining a print unit image to be inspected with the model image as a reference. A predetermined correction parameter for correction is calculated.

Specifically, the correction parameter calculation unit 21 virtually performs a process of correcting the print unit image to be inspected with the model image of the print unit as a reference, and obtains a correction parameter between the two images.
Here, an existing parameter calculation method can be used as a correction parameter calculation / generation method in the correction parameter calculation means 21. For example, a coefficient of a linear filter that minimizes an error between two images is used as a correction parameter. There is a method to ask for.
For example, as shown in Japanese Patent No. 3965189, two correction parameters are used when a 5 × 5 pixel area is used for two images of a model image as a reference and a print unit image to be inspected. 5 × 5 = 25 parameters of the variation model between the images.
This correction parameter can be obtained by solving a predetermined relational expression (simultaneous linear equations). In other words, in the above example, the correction parameter can represent the variation between images with 25 real values.

Then, the correction parameter calculation unit 21 sends the print unit image to be inspected to the comparison partner search unit 22 and the defect detection unit 23 (see FIG. 1), and sends the calculated correction parameter to the comparison partner search unit 22.
The comparison partner search unit 22 compares the correction parameter given from the correction parameter calculation unit 21 with the correction parameter stored in the print unit image / correction parameter storage unit 25. Then, a print unit image having similar correction parameters is retrieved from the print unit image / correction parameter storage unit 25 and sent to the defect detection means 23 as comparison data.

Here, the comparison determination of the correction parameter to be compared in the comparison partner search means 22 is, for example, in the case of 5 × 5 = 25 parameters described above, the variation between images can be expressed by 25 real values. In this case, the analogy determination of the correction parameters can be realized as follows, for example.
That is, if 25 real values are regarded as 25-dimensional real vectors and the L2 norm between the real vectors falls below a predetermined threshold value, it can be determined as a similar correction parameter.

  Further, as described above, the comparison partner search unit 22 stores the correction parameter given from the correction parameter calculation unit 21 and the print unit image as a set in the print unit image / correction parameter storage unit 25.

The defect detection means 23 compares the print unit image to be inspected given from the correction parameter calculation means 21 with the print unit image that is comparison data given from the comparison partner search means 22, and prints the print unit image to be inspected. It is determined whether or not a defect exists above, and the determination result is sent to the output device 3.
Here, the defect determination performed by the defect detection means 23 can use an existing defect determination method, and can be realized as follows using a known technique, for example.
First, a difference image between the print unit image given from the correction parameter calculation means 21 and the print unit image given from the comparison partner inspection means 22 is taken. The difference image is obtained by taking an absolute value of a difference between gradation values in each pixel.
Here, if there are a plurality of print unit images provided from the comparison partner inspection means 22, a plurality of difference images can be formed. In that case, an average of a plurality of difference images is taken and converted into one difference image.
If the gradation value of the difference image is larger than a predetermined threshold value, it is determined that the pixel has a defect.
In addition, as another example of the defect determination method, for example, a method disclosed in Japanese Patent No. 3031286 can be used.

Next, the operation (printed matter inspection method) of the printed matter inspection apparatus and printed matter inspection system according to the present embodiment configured as described above will be described with reference to FIGS.
FIG. 3 is a flowchart showing an operation procedure (printed matter inspection method) of the printed matter inspection system according to the present embodiment.
First, as shown in FIG. 2, a printed matter to be inspected is imaged by the input device 1 in print units, and the print unit image is given to the printed matter inspection device 2.
The print unit image given from the input device 1 is supplied to the correction parameter calculation means 21 of the printed matter inspection device 2.
The correction parameter calculation unit 21 calculates a correction parameter between the print unit image to be inspected and the model image of the print unit stored in the print unit model image storage unit 24 (step A1 in FIG. 3).
Then, the print unit image to be inspected is sent to the comparison partner search unit 22 and the defect detection unit 23, and the correction parameter is sent to the comparison partner search unit 22.

The comparison partner search unit 22 searches the print unit image / correction parameter storage unit 25 for a correction parameter similar to the correction parameter sent from the correction parameter calculation unit 21, and print unit images paired with the searched correction parameter. Are read from the print unit image / correction parameter storage unit 25.
Then, the comparison partner search unit 22 sends the print unit image read from the print unit image / correction parameter storage unit 25 to the defect detection unit 23 as comparison data (contrast print unit image) (step A2 in FIG. 3).
Further, the comparison partner search unit 22 additionally stores the print unit image and the correction parameter sent from the correction parameter calculation unit 21 in the print unit image / correction parameter storage unit 25 (step A3 in FIG. 3).

The defect detection unit 23 compares the print unit image to be inspected sent from the correction parameter calculation unit 21 with the print unit image that is comparison data sent from the comparison partner search unit 22, and prints the print unit to be inspected. It is determined whether or not a defect exists on the image, and the determination result is sent to the output device 3 (step A4 in FIG. 3).
The output device 3 outputs the determination result to a monitor or a printer (step A5 in FIG. 3).
After the determination result is output, if the inspection is not completed, the process returns to step A1 to repeat the series of processes. If the inspection is completed, the process is terminated (step A6 in FIG. 3).

Next, a specific example of the operation (printed matter inspection method) of the printed matter inspection apparatus and the printed matter inspection system according to the present embodiment as described above will be described with reference to FIG.
FIG. 4 is an explanatory diagram for illustrating a specific example of the printed matter inspection method according to the present embodiment.

As shown in this figure, the printing unit model image storage unit 24 stores a model image B3 as a printing unit model image. The model image is, for example, an image obtained by capturing a normal printing unit having no defect.
As shown in FIG. 4, the print unit image / correction parameter storage unit 25 stores a plurality of sets of correction parameters and print unit images, for example, in the storage area B4. The correction parameter and the print unit image are stored in association with the print unit image generated and accumulated by the past defect inspection and the correction parameter.
In the example shown in FIG. 4, the correction parameter 1 is a correction parameter between the model image B3 and the printing unit image B5, and the correction parameter 2 is a correction parameter between the model image B3 and the printing unit image B6. .

The correction parameter calculation means 21 obtains a correction parameter between the print unit image B1 to be inspected and the model image B3 of the print unit sent from the input device 1 using the above-described existing method (FIG. 3). Step A1).
Here, the obtained correction parameter is referred to as correction parameter A.

The comparison partner search unit 22 searches for a correction parameter similar to the correction parameter A among the correction parameters stored in the printing unit image / correction parameter storage unit 25. Here, it is assumed that the correction parameter 1 is searched as a similar parameter.
In this case, the comparison partner search means 22 sends the print unit image B5 stored in a set with the correction parameter 1 to the defect detection means 23 (step A2 in FIG. 3).
Further, the comparison partner search unit 22 additionally records the correction parameter A and the print unit image B1 as a set in the print unit image / correction parameter storage unit 25 (step A3 in FIG. 3).

The defect detection unit 23 compares the print unit image B1 to be inspected sent from the correction parameter calculation unit 21 with the print unit image B5 which is comparison data sent from the comparison partner search unit 22, and print unit image B1. It is determined whether or not B1 has a defect (step A4 in FIG. 3).
As a method for determining a defect by comparing two images, an existing method can be used as described above.
Then, the defect detection means 23 sends the determination result to the output device 3.
In the example shown in FIG. 4, information indicating that the defect B2 exists in the print unit image B1 to be inspected is sent to the output device 3.
The output device 3 outputs a predetermined inspection result to the outside based on the sent defect inspection information. Thereby, the inspection result of the printed matter to be inspected is notified / output to the outside.

  As described above, according to the printed matter inspection apparatus and the printed matter inspection system of the present embodiment, for a printed matter that includes a plurality of printing units on one sheet and the same pattern is printed on each printing unit, An input device 1 that captures images of a plurality of print units included in a printed material, a printed material inspection device 2 that inspects defects of the printed material in print units, and an output device 3 that outputs an inspection result. For comparison between the comparison partner search means 22 for searching for a print unit image that has undergone similar variations to the variation that the target print unit image has undergone during imaging, and the print unit images that have undergone similar variation during imaging. Based on the configuration, the defect detection means 23 for detecting a defect in the print unit image eliminates the influence of fluctuation at the time of imaging as much as possible without correcting the print unit image to be inspected, and has high accuracy. Recessed detection can be performed.

Further, since the comparison partner can be selected ignoring the positional relationship, by increasing the number of comparison partners as necessary, it is possible to promote the suppression of variation due to averaging, and to further improve the inspection accuracy.
The printed matter inspection apparatus 2 further includes a correction parameter calculation unit 21 that calculates a correction parameter when correcting the print unit image to be inspected with reference to the model image of the print unit. Since the printing unit image that is the comparison partner is searched based on the similarity, it is possible to search for the printing unit image subjected to the similar variation with a simple configuration. The reason is that if an existing image correction program is used, a correction parameter between the model image of the print unit and the print unit image to be inspected can be easily obtained.

  Furthermore, the printed matter inspection apparatus 2 includes a print unit image / correction parameter storage unit 25 that stores print unit images that have been inspected in the past in combination with the correction parameters. Since a print unit image having a correction parameter similar to the print unit image is retrieved from the print unit image / correction parameter storage unit 25 and used as comparison data, an operation of separately storing the comparison data in advance is performed. It can be unnecessary.

[Second Embodiment]
Next, a printed matter inspection system according to a second embodiment of the present invention will be described with reference to FIGS. However, about the part which is common with the said embodiment, the same code | symbol as the said embodiment is attached | subjected and the description of the said embodiment is used.
FIG. 5 is a block diagram showing a specific configuration of the printed matter inspection system according to the second embodiment of the present invention, and FIG. 6 is a flowchart showing an operation procedure of the printed matter inspection system according to the second embodiment of the present invention. .

As shown in these drawings, the printed matter inspection apparatus 2 according to the second embodiment includes a comparison data exclusion unit 26 (step A11 in FIG. 6) that excludes past print unit images in which defects are detected from comparison data. The point provided is different from the first embodiment.
Specifically, the comparison data excluding means 26 excludes the past print unit image in which the defect is detected and / or its correction parameter from the print unit image / correction parameter storage unit 25 to thereby exclude it from the comparison data. It is supposed to be.

According to the printed matter inspection system of this embodiment provided with such a comparison data exclusion unit 26, the printed matter inspection apparatus 2 excludes past print unit images in which defects are detected from the comparison data. 26, it is possible to avoid the problem that the inspection accuracy is lowered by the defect detection using the past print unit image in which the defect is detected as the comparison data.
Further, the comparison data excluding means 26 deletes the past print unit image in which the defect is detected and / or its correction parameter from the print unit image / correction parameter storage unit 25, so that the past print unit in which the defect has been detected. Images can be easily and reliably excluded from comparison data.

As described above, the printed matter inspection apparatus, the printed matter inspection system, the printed matter inspection method, and the printed matter inspection program according to the present invention have been described with reference to the embodiments. However, the present invention is not limited to the above-described embodiments, and is claimed. It goes without saying that various modifications can be made within the range described above.
For example, in each of the above-described embodiments, as a printed material to be inspected according to the present invention, a printed material (for example, banknotes, stamps, etc.) on which a single sheet includes a plurality of printing units and the same pattern is printed. Although shown in the example, the present invention is not limited to such a printed material, but can be applied to various printed materials that require defect inspection.

  The present invention is applied to a printed matter inspection system, a printed matter inspection method, and a printed matter inspection apparatus that perform defect inspection on a printed matter that includes a plurality of printing units on a single sheet and the same pattern is printed on each printing unit. Specifically, it can be suitably used for inspection of printed matter on which banknotes and stamps are stamped.

DESCRIPTION OF SYMBOLS 1 Input device 2 Printed material inspection apparatus 3 Output device 21 Correction parameter calculation means 22 Comparison partner search means 23 Defect detection means 24 Print unit model image storage part 25 Print unit image / correction parameter storage part 26 Comparison data exclusion means

Claims (7)

For capturing and inputting a print target image to be inspected, inputting a model image of a predetermined printing unit as a reference for defect detection, and correcting the print target image to be inspected based on the model image Correction parameter calculating means for calculating a predetermined correction parameter;
A print unit image / correction parameter storage means for storing the correction parameter calculated by the correction parameter calculation means as a past correction parameter and storing the print target image to be inspected in association with each other;
The print unit image / correction parameter storage unit is searched, the past correction parameter similar to the correction parameter calculated by the correction parameter calculation unit is extracted, and the print unit image corresponding to the extracted correction parameter is extracted. A comparison partner search means for extracting as a comparative print unit image whose variation at the time of imaging is similar to the print unit image to be examined;
A printed matter inspection apparatus comprising: a defect detection unit configured to compare the print unit image to be inspected with the contrast print unit image to detect a defect in the print unit image to be inspected. The print unit image to be inspected is
The printed matter inspection apparatus according to claim 1, comprising a print unit image obtained by imaging each print unit of a printed matter including a plurality of print units on a single sheet and the same pattern printed on each print unit.   The printed matter inspection apparatus according to claim 1, further comprising a comparison data excluding unit that excludes past print unit images in which defects are detected from the comparison data.   The printed matter inspection apparatus according to claim 3, wherein the comparison data excluding unit deletes a past print unit image in which a defect is detected and / or a past correction parameter corresponding thereto from the print unit image / correction parameter storage unit. An input device that captures a predetermined print unit image to be inspected;
  A printed matter inspection device that inputs a print unit image to be inspected from the input device and inspects a predetermined defect detection; and
  An output device for outputting the inspection result in the printed matter inspection device,
  The printed matter inspection apparatus comprises:
For a print target image to be inspected input from the input device, a predetermined correction parameter for correcting the print target image to be inspected is calculated based on a model image of a predetermined print unit serving as a reference for defect detection. Correction parameter calculation means;
  A print unit image / correction parameter storage means for storing the correction parameter calculated by the correction parameter calculation means as a past correction parameter and storing the print target image to be inspected in association with each other;
  The print unit image / correction parameter storage unit is searched, the past correction parameter similar to the correction parameter calculated by the correction parameter calculation unit is extracted, and the print unit image corresponding to the extracted correction parameter is extracted. A comparison partner search means for extracting as a comparative print unit image whose variation at the time of imaging is similar to the print unit image to be inspected;
A defect detection unit that compares the print unit image to be inspected with the comparative print unit image to detect defects in the print unit image to be inspected.
  A printed matter inspection system characterized by that. Capturing and inputting a print target image to be inspected;
  A correction parameter calculating step for calculating a predetermined correction parameter for correcting the print target image to be inspected with a predetermined model image serving as a reference for defect detection;
  A printing unit image / correction parameter storage step for storing the correction parameter calculated in the correction parameter calculation step as a past correction parameter and storing the print target image to be inspected in association with each other;
  A correction parameter similar to the correction parameter calculated in the correction parameter calculation step is extracted from past correction parameters stored in the printing unit image / correction parameter storage step, and printing corresponding to the extracted correction parameter is performed. A comparison partner search step for extracting a unit image as a comparative printing unit image having a variation similar to that of a printing unit image to be inspected and a variation at the time of imaging;
A defect detection step of comparing the printing unit image to be inspected with the comparative printing unit image to detect a defect in the printing unit image to be inspected.
  The printed matter inspection method characterized by the above-mentioned. A computer constituting a printed matter inspection apparatus that inputs a predetermined print unit image to be inspected and performs a predetermined defect detection inspection,
For capturing and inputting a print target image to be inspected, inputting a model image of a predetermined printing unit as a reference for defect detection, and correcting the print target image to be inspected based on the model image Correction parameter calculation means for calculating a predetermined correction parameter;
  A print unit image / correction parameter storage unit that stores the correction parameter calculated by the correction parameter calculation unit as a past correction parameter and stores the print target image to be inspected in association with each other,
  The print unit image / correction parameter storage unit is searched, the past correction parameter similar to the correction parameter calculated by the correction parameter calculation unit is extracted, and the print unit image corresponding to the extracted correction parameter is extracted. A comparison partner search means for extracting as a comparative print unit image having a similar variation at the time of imaging with the print unit image to be inspected, and
Comparing the printing unit image to be inspected with the comparative printing unit image to function as a defect detecting means for detecting defects in the printing unit image to be inspected
  A printed matter inspection program characterized by that.

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