JPH05330024A - Method and device for correcting deviation of position of image and image inspection device - Google Patents

Abstract

PURPOSE:To reduce the processing amount during the inspection by dividing one image into partial zones and correcting the deviation of positions in respective partial zones in the position deviation correction method for images for inspecting an image to be inspected and a reference image while comparing both. CONSTITUTION:The difference between a digital image of an inspection image memory updatedly successively and a reference image memory is computed for every renewed frame, every partial zone and every pixel while the digital image is divided into a plurality of given partial zones. When the difference is computed, the position deviation is corrected or the completion of conformity of partial zones corresponding reference image sections is carried out in the laminating range of reference zones, not comparing and referring all the pixels constituting the partial zones. The reference zones are determined preliminarily for respective partial zones and should be set up to include the sections forming the features of patterns in the partial zones. For correcting the position deviation, the digital image stored in the inspection image memory is divided into four successively to form 0-7 hierarchies, and the correction of position deviation in a rough manner is carried out for the topmost hierarchy, and as the hierarchies go down from top to bottom, the correction is applied in a more and more fine manner.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image for performing positional deviation correction between one image and the other image in order to inspect the image to be inspected while comparing the image to be inspected with a reference image. The present invention relates to a positional deviation correction method, an image positional deviation correction apparatus using the method, or an image inspection apparatus using the method, and in particular, it is possible to reduce the influence of distortion or the like of an image to be inspected. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image position shift correction method, an apparatus thereof, and an image inspection apparatus capable of reducing the amount of processing therein.

[0002]

2. Description of the Related Art Defects in printed matter include stains on printing paper,
There are various things such as printing defects. Even if the defective portion is minute, it may cause a problem in the quality of the printed matter. Furthermore, when printed matter such as a rotary printing machine is continuously running at high speed, it is necessary to inspect each printed matter at high speed.

Conventionally, printed matter inspection has been performed manually by various methods. For example, depending on the printing machine and the type of printed matter, the printed matter after printing has been appropriately extracted and visually inspected. Alternatively, in the case of a printed matter that continuously travels at a constant speed, a strobe emits light in synchronization with the traveling speed to perform a visual inspection of the printed matter.

In recent years, various techniques for automatically inspecting printed matter have been disclosed.

For example, Japanese Examined Patent Publication No. 1-47823 includes a memory capable of storing image data read from a design of a traveling printed matter at a predetermined time, and the image data read from the memory is used as reference data, and the remaining portion of the traveling printed matter. There is disclosed a technique relating to a printed matter inspection apparatus of a system in which image data read from a pattern is used as inspection data and whether the printing is good or bad is determined based on a comparison between the reference data and the inspection data. This technique uses a first feature extraction / comparison / determination unit for performing a print quality determination by extracting and comparing the features of the reference data and the features of the inspection data for each corresponding pixel unit, and A second characteristic extraction / comparison / determination means for determining the quality of printing by extracting and comparing the characteristic and the characteristic of the inspection data as the total sum of pixels in a predetermined range within the same pattern is further used. Third characteristic extraction / comparison / determination means for performing a quality judgment of printing by extracting and comparing the characteristics and the characteristics of the inspection data as the total sum of the pixels arranged on the same straight line along the traveling direction of the printed matter in the same pattern. Is also used to make a comprehensive determination of the determination results of the first to third feature extraction comparison determination means to make a final quality determination of the printed material. Further, in this technique, the comparison means for comparing the difference between the traveling speed of the traveling printed material at a predetermined time point and the traveling speed of the traveling printed material at the time of reading the inspection data with a predetermined value is used, and based on the result of the comparison, There is also provided means for newly rewriting the inspection data read from the pattern of the running printed matter at this time as the reference data. According to the technique disclosed in Japanese Patent Publication No. 1-47823, the accuracy of the quality judgment in the case where the density change such as the pattern of the printed matter is wide is improved, and the masking function is provided to change the state of the printed matter. It is possible to always obtain a stable operation.

In Japanese Patent Publication No. 1-20477, sample data detected by decomposing a sample pattern of a printed matter into a pixel matrix is compared with sampled data preliminarily extracted from a sampled printed matter and recorded in a memory, pixel by pixel. A technique relating to a pattern inspection method for a printed matter, which determines whether the pattern is good or bad, is disclosed. In this technique, one of the sample data and the sample data is displaced by one pixel in the lateral direction of the printed matter and compared with the other of the two data, and when the two data are closest to each other This is a technique in which the sample data or the sample data is corrected in position in the lateral direction of the printed matter according to the amount of position deviation and then compared with the sample data. According to the technique disclosed in Japanese Patent Publication No. 1-20477, the pattern inspection can be performed with high accuracy by a relatively inexpensive device even if the printed material conveying system is misaligned.

Further, in Japanese Patent Laid-Open No. 62-11152, the detection means for extracting the pixel data in a state where the fields of view overlap each other in the direction perpendicular to the running direction of the printed matter and the images overlap each other, first, the non-defective product data is acquired and the reference data is acquired. Then, the data to be inspected is taken in and compared with the reference data. In this comparison, each pixel is compared and then the addition data are compared. According to the technique disclosed in Japanese Patent Application Laid-Open No. 62-11152, accurate inspection can be performed without being affected by misalignment that is inevitable in running printed matter.

As described above, in the technique for automatically inspecting the printed matter, when inspecting the image to be inspected while comparing the image to be inspected with the reference image, the image between one image and the other image is Measures have been taken against the misalignment. For example, in Japanese Patent Publication No. 1-20477, one of the sample data and the sample data is displaced pixel by pixel in the lateral direction to perform the displacement correction.

[0009]

However, in the conventional techniques such as these techniques, if the inspection image is distorted, the positional deviation between the inspection image and the reference image cannot be correctly corrected. It was In the portion of the pattern of the image to be inspected or the reference image in which the density changes drastically, even if the displacement is in units of one pixel, the influence thereof is extremely large. In this case, the related art has determined that the relevant portion is defective. Alternatively, such a portion where the concentration changes drastically is excluded from the inspection target. That is, the uninspected part had occurred.

Further, in the conventional techniques such as these techniques, when the image position deviation is corrected, each time one of the inspected image and the reference image is shifted by, for example, one pixel, the inspected image and the reference image. There is a problem that a huge amount of processing time is required because it is to compare and.

The present invention has been made to solve the above-mentioned conventional problems. First, as a first problem, it is possible to reduce the influence of distortion or the like of the image to be inspected, and the process during the inspection. An object of the present invention is to provide an image position shift correction method, an apparatus therefor, and an image inspection apparatus capable of reducing the amount.

A second object of the present invention is to provide an image positional deviation correcting device which can perform positional deviation correction more closely.

[0013]

According to a first aspect of the present invention, there is provided a method for correcting a positional deviation of an image, in order to inspect the image to be inspected while comparing the image to be inspected with a reference image, one image and another image are inspected. In the image position shift correction method for correcting the position shift between the two images, at least one of the two images is divided into partial regions, and the position shift correction is performed for each partial region. That is, the first object is achieved.

Further, the image position shift correcting apparatus according to the second aspect of the present invention is arranged so that the image between the one image and the other image is inspected in order to inspect the image to be inspected while comparing the image to be inspected with the reference image. In an image position shift correcting apparatus that performs position shift correction, at least a part of one of the two images is divided into partial regions, and the position shift is performed for each partial region. The first problem is achieved by including the correction unit for each area for correction.

In the image position shift correcting apparatus according to the second aspect of the present invention, the area correction means is a means for correcting the position shift with a predetermined accuracy K, and the area correction means further corrects the position shift. A defect candidate partial area is extracted due to a defect, the defect candidate partial area is used as an image to be divided by the area dividing unit, and the predetermined accuracy K is further increased,
By providing the area dividing means and the judging means for re-executing the processing performed by the area correcting means, the first
This is a more fulfilling task.

In the image position shift correcting apparatus of the second invention, the two images are pixel images, and
The region-by-region correction unit obtains the density at the position between pixels by interpolation from the densities of neighboring pixels at the time of the positional deviation correction, and is capable of performing positional deviation correction finer than the distance of one pixel. Thus, the second problem is achieved in addition to the first problem.

The image inspection apparatus of the third invention of the present application is an image inspection apparatus for detecting a defect in an image to be inspected while comparing the image to be inspected with a reference image, and one of the two images is detected. A region dividing unit that divides at least a part of the image into partial regions, a region correcting unit that performs the positional deviation correction for each partial region, and a determining unit that detects a correction defect in the region correcting unit. And detecting the defect in the image to be inspected by detecting the correction defect, thereby achieving the first object.

[0018]

When the image to be inspected is a printed matter, for example, the image to be inspected may be distorted due to expansion and contraction or distortion of the print medium such as paper or film. Further, when the printed matter is printed by a rotary printing machine, the printed pattern may be distorted due to meandering of the printed matter during printing. Alternatively, the photographing means used when capturing the image to be inspected or the reference image also has distortion, and for example, the photographing lens has aberration such as curvature distortion. Even if the image to be inspected and the reference image are photographed by the same photographing lens, if the relative position in the field of view is different between these images to be inspected and the reference image, there is a bending distortion between these images. A difference occurs in the way of occurrence, and as a result, the image to be inspected is distorted. The present invention has been made by paying attention to the influence of such distortion of the image to be inspected in order to better perform the positional deviation correction performed in the image inspection.

FIG. 1 is a flowchart showing the gist of the first invention.

In step 500 of FIG. 1, first, at least one of the inspection image and the reference image is divided into partial areas. Then, in step 502, the positional deviation is corrected for each of the partial areas. Thus, the first
According to the invention, instead of correcting the positional deviation of the entire inspection image and the entire reference image at once, first, the image is divided into a plurality of partial areas and the positional deviation is corrected for each of the partial areas. The image inspection is performed for each area. This reduces the influence of distortion of the image to be inspected.

Although the present invention is not limited to this, when the accuracy (fineness) of the positional deviation correction or the image inspection is different for each partial area, the processing of the positional deviation correction processing is performed. It is possible to reduce the total amount of the image processing and the processing amount of the image inspection processing, and it is possible to improve the processing speed.

Although the present invention is not limited to this, when the positional deviation is corrected, the density at the position between the pixels is obtained by interpolation from the neighboring pixels, and the density is smaller than the distance of one pixel. It has also been found that positional deviation correction is performed. By performing the interpolation from the densities of the neighboring pixels as described above, it is possible to perform a finer positional deviation correction and a more precise positional deviation correction.

In the present invention, the predetermined accuracy K is
It is a shift movement step amount, a shift movement range, or the like in an embodiment described later, and is not particularly limited.

[0024]

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 2 is a block diagram showing the construction of a printing machine and a printed matter concentrated inspection apparatus to which the present invention is applied.

FIG. 2 shows a printed matter centralized inspection apparatus body 80 for inspecting a plurality of printing machines including a printing machine (not shown) at one location. In the printing machine 10 shown in FIG. 1, the strip-shaped printed matter 1 sent from the final printing unit 12 is wound into a roll shape by the feed roll 14 and the winding portion 16. Also, the printing machine 10
From the above, a printing state signal indicating whether or not the printing machine is in operation and the like, and a pulse signal according to the traveling of the printed matter 1 are output by the rotary encoder 18 attached to the printing unit 12. When the perimeter of the plate cylinder of the printing unit included in the printing machine 10 such as the printing unit 12 is longer than one pattern to be printed (hereinafter, also referred to as one surface),
Plate cylinder-Several pictures are printed by rotation. In order to detect such a surface position, the rotary encoder 18 is
A pulse signal is output every predetermined rotation. In the printing machine 10 shown in FIG. 2, a detection unit 30 that photographs the surface state of a printed material while it is running and outputs a predetermined image signal is arranged between the printing unit 12 and the feed roll 14. There is. Further, the printing state signal and the pulse signal from the rotary encoder 18 are input to the repeater 40, and the detection unit 30 is connected. Similar to the total of three repeaters 40 shown, other repeaters not shown are provided corresponding to other printing machines not shown. Each of these relays 40 is connected to the determination unit 100 in the centralized inspection apparatus body 80.

FIG. 3 is a side view of the detection section of the printed matter concentration inspection apparatus as seen from the printed matter running direction.

In FIG. 3, the printed matter 1 is running from the front side to the other side. Further, the detection unit 30 mainly includes a light source 32b housed in the lamp house 32a and an optical fiber 33 that guides light from the light source 32b to a light guide 34, and a slit provided in the light guide 34 The printed matter 1 is illuminated. A heat radiation fan (not shown) is built in the lamp house 32a to radiate heat generated by the light source 32b. A discharge light source such as a halogen lamp or a xenon lamp is used as the light source 32b. Further, the detection unit 30 has a plurality of line sensor cameras 36 arranged orthogonally to the traveling direction of the printed matter 1. The one-dimensional line-shaped imaged portion on the printed matter 1 photographed by each of the line sensor cameras 36 is also orthogonal to the traveling direction of the printed matter 1. Further, the visual fields of the plurality of line sensor cameras 36 overlap with the visual fields of other adjacent line sensor cameras 36. The electric circuit 38 obtains one one-dimensional line-shaped image signal over substantially the entire width of the printed matter 1 from the one-dimensional line-shaped image signals from the plurality of line sensor cameras 36, and Processing for transmitting this to the repeater 40 is performed.

FIG. 4 is an electric circuit diagram of a detection part electric circuit of the printed matter concentration inspection apparatus.

As shown in FIG. 4, the detection section electric circuit 38 for outputting the image signals obtained from the plurality of line sensor cameras 36 to the repeater 40 mainly includes A / D conversion. Part 38a, frame memory 38b,
The image compression circuit 38c, the optical communication unit 38d, and the driver 3
8e and.

The A / D converter 38a converts an image analog signal from each of the plurality of line sensor cameras 36 into an image digital signal by the A / D converter 38g. Further, the A / D converter 38a integrates the images of the adjacent line sensor cameras 36 to generate a continuous one-dimensional linear digital image over substantially the entire width of the printed matter 1. Further, the generated digital images are sequentially written in the frame memory 38b in synchronization with the traveling of the printed matter 1. Accordingly, it is possible to obtain an image of a two-dimensional frame scanned by the plurality of line sensor cameras 36 in synchronization with the traveling of the printed matter 1.

1 written in the frame memory 38b
The digital image for the screen (one frame) is data-compressed by the image compression circuit 38c, and the optical communication unit 38d
Is output to. The data compression performed by the image compression circuit 38c is a JPEG (joint picture expert group) that has recently been used in still image coding.
The scheme encoding is used. This image compression circuit 38
The data compression performed in step c is for improving the transmission efficiency such as shortening the transmission time of the image digital signal, and may be another data compression method. For example, conventionally known entropy coding, Huffman coding, run length coding, etc. may be used singly. The image digital signal from the image compression circuit 38c is optically modulated in the optical communication unit 38d and transmitted to the repeater 40.

On the other hand, the timing signal transmitted from the repeater 40 in synchronism with the traveling of the printed matter 1, that is, the signal of the timing of photographing the printed matter 1 in a one-dimensional line form while scanning by the traveling is the above-mentioned. The output is output to each of the line sensor cameras 36 by the driver 38e. Also, from the repeater 40, a timing signal for each surface corresponding to the pattern to be printed is also sent,
The signal is used for detecting the start of one frame when the A / D converter 38a writes a digital image in the frame memory 38b.

FIG. 5 is a block diagram showing the hardware structure of the relay of the printed matter concentration inspection apparatus.

As shown in FIG. 5, the repeater 40 installed close to each one of the printing machines is mainly
CPU (central processing unit) 40a and ROM
(Read only menory) 40b and RAM (random acces
40 c, a parallel input / output circuit 40 d, a counter 40 e, an O / E (optical to electrical) converter 40 f, a serial converter 40 g, and a serial converter 4
0h and E / O (electrical to optical) converter 40
i and a bus 40j.

The CPU 40a uses the bus 4 according to a program previously written in the ROM 40b.
The RAM 40c, the parallel input / output circuit 40d, the serial converter 40g, and the serial converter 40h are accessed via 0j to perform a predetermined process. For example, the CPU 40a is configured to generate a timing signal to the detection unit 30 mainly according to a signal from the printing machine 10 according to a program previously written in the ROM 40b, and an image digital signal from the detection unit 30. Is relayed to the determination unit 100.

The RAM 40c is used not only for temporary storage of data when the CPU 40a executes a program, but also for buffering the image digital signal when the image digital signal is relayed from the detection unit 30 to the determination unit 100. Also used as memory. The parallel input / output circuit 4
0d indicates the input / output in bit units or every predetermined number of bits to the printing machine 10 and the detection unit 30 by the CP
U40a and the bus 40j are processed in a bit number width which is a unit of processing. The counter 40e determines an absolute traveling position of the printed matter 1 from an encoder signal sent from the rotary encoder 18 and relatively corresponding to the traveling position of the printed matter 1. The O / E converter 40f demodulates the light-modulated image digital signal sent from the detector using an optical fiber, and the serial converter 4f
Output to 0g. The serial converter 40g is
The serial image digital signal output by the / E converter 40f is converted into parallel data having a predetermined number of bits width accessible by the CPU 40a. The serial converter 4
0h serially converts the image digital signal of a predetermined bit number width written by the CPU 40a and outputs it to the E / O converter 40i. The E / O converter 40i
Optically modulates the serial image digital signals sequentially sent from the serial converter 40h and sends them to the judging section 100 through an optical fiber.

FIG. 6 is a block diagram showing the functional arrangement of the repeater.

As shown in FIG. 6, the repeater 4
The main function of 0 is composed of an image timing control section 40m, an image signal relay section 40p, and a memory 40n.

The image timing control section 40m is a timing signal used by the detection section 30 according to a signal from the rotary encoder 18 of the printing press 10, for example, the A phase signal, for example, the camera start signal or the read enable signal. To generate. At this time, the image timing control unit 40m also uses the imposition information previously input by the operator from the keyboard 62 described later. This imposition information is information relating to the printing contents of the plate cylinder of the printing machine 10 and is, for example, information such as the number of pages to be printed.

The image signal relay section 40p receives the image digital signal sent from the detection section electric circuit 38 through the optical fiber and stores it in the memory 40n. Further, the image signal relay section 40p sends the digital image stored in the memory 40n to the judging section 100 as an image digital signal in response to a request from the judging section 100 of the centralized inspection apparatus body 80. Output via. A plurality of frames of digital images can be stored in the memory 40n. A plurality of repeaters 40 (40a to 40c) are connected to the determination unit 100,
In this way, the image signal relay unit 40p and the memory 40
By performing the relay process of the relay device 40 using n, it is possible to sequentially perform the printed matter inspection of each printing press corresponding to each relay device 40.

FIG. 7 is a block diagram showing the hardware configuration of the main body of the printed matter concentration inspection apparatus.

As shown in FIG. 7, the printed matter centralized inspection apparatus main body 80 mainly comprises a CPU (central pr
cessing unit) 50, main storage device 52, hard disk device 54, floppy disk device 58, input / output device 60, O / E converter 60a, and keyboard 62.
And a CRT (cathode ray tube) controller 64a, and C
The RT 64b, the network control device 66, the printer device 68, and the system bus 70.

The CPU 50 executes a program module or the like read from the hard disk device 54 into the main storage device 52, such as one relating to a printed matter inspection process. The hard disk device 54 stores program modules, data, etc. according to the present embodiment,
The data is read out to the main storage device 52 as needed. The floppy disk device 58 is used for exchanging various program modules and data with other computer systems. The input / output device 60 is used to connect to another digital processing device. For example, it is connected to the plurality of relays 40 (40a to 40c) through the plurality of O / E converters 60a, and image digital signals relating to the printed matter inspection of each printing machine are input.

The keyboard 62 is used together with the CRT control device 64a and the CRT 64b when the operator operates the centralized inspection device body 80.
The keyboard 62 is also used for various data settings and the like. Also, the CRT controller 64a and the CRT
The reference numeral 64b is used to inform the operator of the printed matter inspection result of the centralized inspection apparatus body 80 and the abnormality detection based on the result.

The network control device 66 is used to connect the centralized inspection device main body 80 online to another computer system. For example, data and printed matter inspection results that can be collected by the centralized inspection apparatus main body 80, further self-diagnosis results of the centralized inspection apparatus main body 80, devices and devices connected to the centralized inspection apparatus main body 80, for example, The repeater 40 and the detection unit 30
The results of abnormality diagnosis of the printer and the printing machine 10 can be centrally monitored by another computer system.
The printer device 68 prints a printed matter inspection result in the centralized inspection device body 80, information relating to the inspection result, and the like.

The system bus 70 is connected to the CP
U50 is the main storage device 52, the hard disk device 54, the floppy disk device 58, the input / output device 60, the keyboard 62, the CRT control device 64a, the network control device 66, the It is used when accessing the printer device 68. The system bus 70 includes an address bus used for selecting devices connected to the system bus 70 and the CPU 50.
And a data bus used for data transfer at the time of access.

FIG. 8 is a block diagram showing the functional arrangement of the main body of the printed matter concentration inspection apparatus.

As shown in FIG. 8, the printed matter concentrated inspection apparatus main body 80 mainly includes a determination unit 100, a defective image storage unit 82, a defective display unit 84, a data totaling unit 86, and a network connection unit. And 88. or,
Keyboard 62, CRT controller 64a, CRT 64b
A printer 68 and the like are used. These determination unit 1
00 and the processing and operations performed in the defective image storage unit 82, etc.
This is performed for the plurality of printing machines 10 connected to the centralized inspection apparatus body 80. The data such as the printed matter inspection result is shared among the printing machines 10.

The judging section 100 demodulates the image digital signal optically modulated and transmitted from the repeater 40 by the optical fiber, and restores the data compression performed by the image compression circuit 38c of the detection section electric circuit 38. Then, the printed matter is inspected according to the resulting digital image.

The defective image storage section 82 is connected to the judging section 1
When a defect of the printed matter is detected at 00, the digital image of the corresponding frame is data-compressed and stored in the hard disk device 54 together with the defect occurrence location information and the like. The defect occurrence location information is information indicating the frame number in which the defect of the printed matter is detected and the location of the defective portion in the frame.

The defect display section 84 is the keyboard 6
The image stored in the defective image storage unit 82 and the defect occurrence location information related to the image are displayed by an operator's operation of the CRT control device 64a or the CRT 64b, or automatically when a print defect occurs. At this time, the defective display section 84 restores the stored digital data which has been compressed and is to be displayed.

As described above, in this embodiment, when a printed matter defect occurs, the image of the frame and the defect occurrence location information related thereto are stored, so that the operator can grasp the state of the defective printed matter at any time. You can observe it. When a print defect is visually detected on a rotary printing machine, labels have been inserted and marking has been performed in the past.To observe the defective part or defective part, rewind the wound print product. There was a problem that had to be. However, according to this embodiment,
At any time, it is possible to grasp and inspect the printed matter for defects.

The data aggregating unit 86 includes the determining unit 10
The number of printed matter defects detected at 0 is totaled, and the result is stored. Further, the totalized result can be output by being displayed on the CRT 64b or being printed on the printer device 68 by an operation of the operator from the keyboard 62 or the like.

The network connection unit 88 is provided with an abnormality such as a failure of the centralized inspection apparatus main body, a device or a device connected to the centralized inspection apparatus main body 80, such as the detection unit 30, the relay 40 or the printing. An abnormality such as a failure of the machine 10 is detected, and this is transmitted online to another computer system.

FIG. 9 is a block diagram showing the functional arrangement of the determination unit of the main body of the printed matter concentration inspection apparatus.

As shown in FIG. 9, the judging unit 1
00 is mainly the light receiving unit 102 and the image restoration unit 104.
A switching unit 106, a reference image memory 108, an inspection image memory 110, a difference unit 112, and a determination circuit 116.
And a recording unit 118. These configurations are provided for each of the detectors 30 of the printing press 10. Alternatively,
One set of these configurations is provided, and the print defect determination for each of the detectors 30 is sequentially performed.

The light receiving section 102 demodulates the image digital signal optically modulated and transmitted from the repeater 40 via the optical fiber. The image decompression unit 104 decompresses the digital image data-compressed by the image compression circuit 38c in the detection unit electric circuit 38.

The switching means 106 is a data switching means for switching the output destination of the restored digital image to the reference image memory or the inspection image memory 110. When the switching means 106 turns on the contact points a and c, the restored digital image is written in the inspection image memory 110. On the other hand, when the contact b and the contact c are turned on, the restored digital image is written in the reference image memory 108. In the printed matter centralized inspection apparatus of the present embodiment, when the printed matter inspection of a predetermined printing machine is started, the switching means 106 is switched to the contact b so that a digital image of a non-defective printed matter is first written in the reference image memory 108. During the subsequent inspection of the printed matter, the switching means is switched to the contact a,
The digital images sequentially sent from the detection unit 30 and the repeater 40 and restored by the image restoration unit 104 are written in the inspection image memory 110.

The difference unit 112 divides the digital image in the inspection image memory 110, which is sequentially updated, into a plurality of predetermined partial areas for each updated frame, and the reference image for each partial area. Difference calculation is performed for each pixel with the memory 108. Specifically, the difference calculation is performed by raster-scanning each pixel of the digital image in the inspection image memory 110, and the density value of each pixel and the density value of the pixel of the reference image memory 108 corresponding to the pixel. That is, the absolute value of the difference is sequentially obtained. When performing such a difference calculation, the difference portion 112 performs a correction such as a positional deviation correction for each of the divided areas.

The determination circuit 116 is configured to include the difference unit 112.
The difference calculation result output from the above is integrated in the range of one frame (one screen), and the integration result is compared with a predetermined threshold value, whereby the surface of the printed matter corresponding to the digital image written in the inspection image memory 110 is printed. Determine pass / fail. The determination result is output to the recording unit 118. When the recording unit 118 receives a print defect from the determination circuit 116, the inspection image memory 1 corresponding to the print defect is received.
The digital image of 10 and the digital image of the reference image memory 108 are read out and temporarily stored together with various information such as a defect occurrence time and a defect occurrence location. At this time, the recording unit 1
18 also performs data compression of these digital images.
In addition, these digital images are output in response to requests from the defective image storage unit 82 and the data totaling unit 86.

FIG. 10 is a block diagram showing the functional arrangement of the difference section used in the judgment section.

As shown in FIG. 10, the difference section 112 provided in the determination section 100 mainly includes an area dividing circuit 112a and a partial area storage memory 11.
2b, template shift circuit 112c, shift range storage memory 112d, shift step storage memory 1
12e, a shift amount storage memory 112f, and a matching determination circuit 112g. In addition, the difference unit 112
Is the reference image memory 108 described above with reference to FIG.
It is connected to the inspection image memory 110 and the determination circuit 116.

The area dividing circuit 112a forms an image of a predetermined partial area from the digital image stored in the inspection image memory 110 according to the coordinate data of each divided area stored in the partial area storage memory 112b. cut. The coordinate data stored in the partial area storage memory 112b is coordinate data indicating the range of each partial area as described later with reference to FIG.

The matching judgment circuit 112g is a portion of the digital image of the partial area cut out by the area dividing circuit 112a, which corresponds to the partial area of the digital image stored in the reference image memory 108, and is the template. Template matching is performed while sequentially shifting by the shift circuit 112c. The shift of the digital images (templates) of the partial areas, which is sequentially performed by the template shift circuit 112c, is performed by the partial area memory 112.
The shift step storage memory has the shift movement range stored in the shift range storage memory 112d with the position in the digital image of the reference image memory 108 corresponding to the coordinates of the partial area stored in b as the center. This is to sequentially shift for each shift movement step amount stored in 112e. When sequentially shifting in this way, the accumulated shift amount is stored in the shift amount storage memory 112f. While sequentially shifting in this manner, the matching determination circuit 112g finds the coordinate position on the reference image memory 108 at which the digital image of the partial area cut out by the area dividing circuit 112a is the best match. At this time, the matching determination circuit 112g
The degree of similarity R (i, j) as shown by the following equation is obtained. The coordinate position and the similarity R (i, j) are output to the determination circuit 116.

R (i, j) = Σ ₁ Σ _k {(I _{(i, j)} (k, l) −T (k, l)} ² (1)

Here, the coordinates (i, j) are the coordinate position (relative shift position) of the shifted partial area with respect to the reference image, and the coordinates (k, l) are the respective positions in the digital image of the partial area. Image (pixel position) of I
_{(I, j)} (k, l) is the density value of each pixel of the shifted digital image of the partial area, and T (k, l)
Is the density value of the corresponding pixel in the reference image memory.

Incidentally, the judging circuit 116 is arranged so that the coordinate position (i, j) inputted from the matching judging circuit 112g is inputted.
) And the number of mismatched pixels N (i, j
) According to the above, the pass / fail judgment is made for the partial area cut out by the area dividing circuit 112a and then subjected to the template matching, that is, a defect candidate partial area that may have an image defect or a defect-free partial area. It is determined whether it is a region.

N (i, j) = {(I _{(i, j)} (k, l) -T (k, l))> D The number of pixels of the pixel} ... (2)

In the equation (2), D is a predetermined threshold value. When it is determined as a defect candidate partial area by such a determination, the determination circuit 116 causes the difference unit 112 to re-execute the positional deviation correction. At this time, the defect candidate partial area is further divided, and the shift range storage memory 11 is divided.
The values of 2d and the shift step storage memory 112e are set to smaller values, and re-execution is performed with finer positional deviation correction. It should be noted that, even though the defect correction partial area is reached, when the division of the partial area reaches the limit, the coordinate position (i
, J), the degree of similarity R (i, j), and the number of non-matching pixels N (i
, I) to the recording unit 118. At this output stage, it is determined that there is a defect in the defect candidate partial area.

FIG. 11 is an explanatory diagram of template matching performed by the difference section.

In FIG. 11, the number of pixels (N1 × N
The partial area Na of 1) is a partial area of the inspection image cut out by the area dividing circuit 112a. While performing the template matching by the matching determination circuit 112g, the coordinate position of the partial region sequentially shifted is (i, j). This coordinate position is stored in the shift amount storage memory 112f. On the other hand, the number of pixels (M1
The area Ma of × M1) is the shift range storage memory 11
It is a shift range (shift limit) in template matching, which is determined by the data stored in 2d.

FIG. 12 is a diagram showing an example of partial area division performed by the difference section.

In FIG. 12, the entire digital image N stored in the inspection image memory 110 is divided into a total of 16 partial areas. This division into a total of 16 corresponds to the division of the second layer described below. FIG. 10
The template matching as described above in step 1 is performed for each of the divided partial areas.

The digital image to be inspected of the present embodiment stored in the inspection image memory 110 is (256 ×
It is an image of 256 = 65536) pixels. Further, such digital images sequentially divided into four are defined as the 0th layer to the 7th layer as described below.

Layer 0: Number of partial areas: 1 Number of pixels per partial area 256 ² pixels: Layer 1: Number of partial areas 4: Number of pixels per partial area 1
28 ² pixels: Second layer: 6 partial areas: 6 pixels per partial area
4 ² pixels: 3rd hierarchy: 64 partial areas: 32 pixels per partial area: 4 ^2nd hierarchy: 256 partial areas: 16 pixels per partial area 16 ² pixels: 8 pixels shift range: 1 pixel Shift amount of 4 pixels: Fifth layer: Number of partial regions 1024: Number of pixels per partial region 8 ² pixels: Shift range 4 pixels: Shift amount of 2 pixels per time: Sixth layer: Number of partial regions 4096: Number of pixels per partial area 4 ² pixels: Shift range 2 pixels: 1 shift amount 1 pixel: 7th layer: Number of partial areas 16384: Number of pixels per partial area 2 ² pixels: Shift range 1 pixel: 1 time Shift amount 1
/ 2 pixels:

In this embodiment, the 0th to 3rd layers are used.
No processing such as template matching in the hierarchy is performed, and the digital image in the inspection image memory 110 is initially 256.
Will be divided. That is, only the processing from the fourth layer to the seventh layer is performed.

FIG. 13 is an explanatory diagram of the comparison inspection for each pixel between the inspection image and the reference image, which is performed in the difference section.

In FIG. 13, the pixel Np of the partial area Na cut out by the area dividing circuit 112a and the pixel Mp in the shift range Ma of the digital image stored in the reference image memory 108 are described above. The state of template matching according to the equation (1) is shown. This is the similarity R (i, which can be used by the matching determination circuit 112g for determining the presence or absence of a defective portion in the target partial area Na according to the equation (1) for each image.
j) is calculated, and template matching is performed based on this. Further, the determination circuit 116 is
According to the non-matching pixel number N (i, j) and a predetermined threshold value,
It is determined whether the area is a defect candidate partial area or a defect-free candidate partial area.

FIG. 14 is a hierarchical block diagram according to the partial area division performed by the difference section.

In FIG. 14, the 0th layer having the number of partial areas is 1, the fourth layer having the number of partial areas of 256, the fifth layer having the number of partial areas of 1024, and the number of partial areas. 4096 sixth layers and the number of partial areas is 163
There are 84 seventh hierarchies shown. Further, in FIG. 14, “●” indicates that there is some defect because the value of the number N (i, j) of the mismatched pixels after the template matching is completed by the difference unit 112 is equal to or more than a predetermined threshold value. It is a node that indicates a partial area that has been determined to have nature. on the other hand,
“O” is a node indicating a partial area in which the number N (i, j) of mismatched pixels is equal to or less than a predetermined threshold value and there is no possibility of a defect. Further, the coordinates (i, j) attached to the "●" mark are the shift amount in the corresponding layer for which template matching has been performed.

As shown in FIG. 14, in the present embodiment, only a node, that is, a partial area determined to have a possibility of a defect is further finely divided into partial areas, and the partial area is further divided. On the other hand, the processing by the difference unit 112 is re-executed. That is, with respect to the ∘ node, it is not divided into smaller partial areas, and the processing by the difference section 112 is not re-executed.

In this embodiment, the defect candidate partial area indicated by the ● node in the nth hierarchy is divided into smaller partial areas, and the difference section 11 in the (n + 1) th hierarchy is divided.
When the process of 2 is re-executed, the data written in the shift range storage memory 112d and the data written in the shift step storage memory 112e are rewritten. That is, in the (n +1) th layer, the shift range of shifts that are sequentially performed at the time of template matching in the difference unit 112 is narrower than in the nth layer, and one shift amount (shift step) The size is also reduced. That is, the higher the hierarchy, the coarser the positional deviation correction, and the lower the hierarchy, the finer the correction. Therefore, according to the present embodiment, the presence or absence of a defective portion is determined in a relatively higher hierarchy for a partial area of a pattern having little or no density difference. Therefore, it is possible to further reduce the processing amount and the processing time required for determining the presence / absence of a defect in the entire digital image of one frame written in the inspection image memory 110.

Although the present invention is not limited to this, in the present embodiment, as will be described later with reference to FIGS. 21 to 24, template matching in the difference section 112 in the seventh layer is performed. At the time of shifting, the density at the position between the adjacent pixels is obtained by interpolation from the density of the neighboring pixels, so that the positional deviation smaller than the distance of one pixel can be corrected. Further, in the present embodiment, as will be described later with reference to FIG. 25, at the time of template matching in the difference unit 112, not all pixels in the corresponding partial area are referred to, but a part of the partial area is referred to. Only areas are referenced and compared. As a result, the amount of processing and the processing time are reduced mainly in the matching processing for each pixel with the digital image stored in the reference pixel memory 108 in the matching determination circuit 112g at the time of template matching.

FIG. 15 is a flowchart of a first example of the processing performed by the difference section.

In the flowchart of FIG. 15, first, in step 602, the 0th layer is divided into the 4th layer. The number of pixels in the partial area after the division is (16 ×
16) Pixels. In step 604, the difference unit 1 is sequentially added to each of the partial areas divided in step 602.
Template matching and positional deviation correction in 12 are performed. In step 606, whether the pixel is a defect candidate partial area or not depending on the number N (i, j) of mismatched pixels in each partial area after the template matching in step 604,
Alternatively, it is determined that the area is a defect-free partial area. The processing performed in these steps 602 to 606 is processing corresponding to the fourth layer.

Subsequently, at step 610, the defect candidate partial area determined at step 606 is divided into four as a fifth layer. According to this 4-division, it is divided into partial areas of (8 × 8) pixels. In step 612, the template movement range, that is, the data to be written in the shift range storage memory 112d is calculated for each of the partial areas divided in step 610. In addition, this step 61
In 2, the data to be written in the shift step storage memory 112e is also calculated. In step 614, the difference part 1 is calculated for each of the partial areas divided in step 610.
Template matching and positional deviation correction in 12 are performed. In step 616, by comparing the size of the number N (i, j) of mismatched pixels after the misregistration correction in step 614 with a predetermined threshold value, for each partial area divided in step 610, It is determined whether the area is a defect candidate partial area or a defect-free partial area. The processing performed in these steps 610 to 616 is processing corresponding to the fifth layer.

Subsequently, step 620 and step 622.
Then, the same processing as the processing corresponding to the fourth layer described in steps 602 to 606 and the processing corresponding to the fifth layer described in steps 610 to 616 is performed.

Subsequently, at step 624, the partial area which has not been completely corrected by the processing from step 602 to step 622, that is, the number N (i, j) of mismatched pixels after the positional deviation correction at step 622 is performed. A residual image is generated for a defect candidate partial area whose value is equal to or larger than a predetermined threshold value. The generation of this residual image is an image of a defective portion in the digital image written in the inspection image memory 110.

16 to 19 are diagrams showing the second to fifth hierarchies by the partial area division performed in the difference section, respectively.

FIGS. 16 to 19 show that the defect candidate partial area is divided into four in the next layer for the same inspection image used in the layer configuration diagram of FIG. There is. 16 to 19, the hatched partial area and the partial area with a diagonal line to the lower left correspond to the defect candidate partial area indicated by the ● node in FIG. Further, in these FIGS. 16 to 19, the hatched partial regions are
Any of the four partial areas in the next layer is a defect-free partial area. On the other hand, the partial area with a diagonal line to the left is a candidate candidate partial area for at least one of the four partial areas in the next layer.

First, in FIG. 16, in the fourth layer, as shown in FIG. 14, a total of three partial areas are set as defect candidate partial areas. Subsequently, in FIG. 17, each of the defect candidate partial areas in FIG. 16 is divided into four as a fifth layer. Also, as shown in FIG. 14, in the fifth layer, a total of two partial areas after being divided into four are considered as defect candidate partial areas. Then, in FIG.
In the sixth hierarchy, the defect candidate partial area in FIG. 17 is further divided into four. Of these partial regions after being further divided into four, as shown in FIG. 14, a total of one is considered as a defect candidate partial region. Next, in FIG. 19, the defect candidate partial area in FIG. 17 is further divided into four as the seventh layer. In FIG. 19, as in FIG. 14, one after being divided into four is a defect candidate partial area.

FIG. 20 is a flowchart of the second example of the processing performed by the difference section.

In the process shown in the flowchart of FIG. 20, steps 650 and 652 are similar to the processes of steps 602 and 604 of FIG. 19, respectively.

In the flowchart of FIG. 20, in step 660, after the template matching and positional deviation correction in step 652, all the partial areas divided in step 650 are divided into four. After this division, each partial area becomes (8 × 8) pixels. Next, in step 662, for each partial area divided in step 660, the number N (i,
j) is obtained, and the number N (i, j) of mismatched pixels is compared with a predetermined threshold value to determine whether it is a defect candidate partial region or a defect-free partial region. Steps 664 and 666 following step 662 respectively perform the same processes as steps 612 and 614 of FIG. In these steps 664 and 666, data to be set in the shift range storage memory and data to be set in the shift step storage memory 112e are calculated for each partial area determined as the defect candidate partial area in step 662. The template matching and the positional deviation correction are performed by the difference unit 112.

The processing corresponding to the sixth layer in the following step 670 and the processing corresponding to the seventh layer in step 672 are the fourth layer and the fifth layer as described above from step 650 to step 666. The same process as the process corresponding to is performed. Note that step 674 in FIG. 20 is the same processing as step 624 in FIG.

FIG. 21 is an explanatory diagram showing the positional deviation correction for each pixel performed by the difference section. Also, FIG.
It is explanatory drawing which shows the misregistration correction in a pixel unit or less performed by the said difference part.

In these FIGS. 21 and 22, L1
Is a linear interpolation of the densities of pixels in one line in the raster scan direction in the reference image. Also, reference numeral L2a
And L2b are linear interpolations of the densities of the pixels of one line in the inspection image. Reference numeral P1 indicates the density of a predetermined pixel in the reference image. Reference symbols P2a to P
2d indicates the density of a predetermined pixel in the inspection image.

First, in FIG. 21, when the displacement of the inspection image is corrected pixel by pixel with respect to the reference image, a sufficient result cannot be obtained. This is the pixel P
This is because the concentration change is rapid near 1, P2a, P2c, and P2d. Therefore, even if the positional deviation correction is performed on a pixel-by-pixel basis, the density difference between the density of the code P1 and the density of the code P2a becomes relatively large.

For comparison, in FIG. 22, the density at the intermediate position between two adjacent pixels is obtained by interpolation from the density of the pixels at both ends. For example, the density at the intermediate position between these pixels, that is, the density at the position indicated by the reference symbol P2b is obtained from the interpolation of the density of the pixel indicated by the reference symbol P2a and the density of the pixel indicated by the reference symbol P2c. Further, in FIG. 22, while using the density obtained by such interpolation,
The positional deviation is corrected in pixel units. As a result, a better positional deviation correction result is obtained as compared with FIG. That is, the density difference between the density of the pixel indicated by the symbol P1 of the reference image and the density at the position of the symbol P2b of the inspection image that has been subjected to the positional shift correction is extremely small compared to the case of FIG. ing.

FIG. 23 is an explanatory diagram showing interpolation between a plurality of pixels performed by the difference section.

As shown in FIG. 23, in the present embodiment, the density of a position within a rectangle connecting the centers of four pixels adjacent to each other is determined by the following equation.

[0103] b (i, j) = a 1 (1-i) (1-j) + a 2 (1-i) j + a 3 i (1-j) + a 4 ij ... (3)

Here, a ₁ to a ₄ are respectively shown in FIG.
3 is the density of each pixel whose position is indicated by the same sign. or,
i and j indicate the distance from the position of b to the pixel a ₁ .

In the present embodiment, the interpolation from the densities of the neighboring pixels is performed by the linear interpolation method, but the present invention is not limited to this. For example, the cubic convolution interpolation method is used. Higher order interpolation methods may be used.

FIG. 24 is an explanatory diagram showing a process of positional deviation correction sequentially performed by the difference section.

This FIG. 24 is drawn corresponding to FIG. That is, the inspection image drawn in FIG. 24 is the same as the inspection image used in FIG. Reference numerals P3a to P3e in FIG. 24 correspond to the same reference numerals in FIG.

As shown in FIG. 24, the positional deviation is corrected by (+4, -4) in the fourth layer. On the fifth layer, the positional deviation is corrected by (+2, +2).
In the sixth layer, the positional deviation is corrected by (+1,0).
In the seventh layer, the positional deviation is corrected by (-0.5, +0.5). The unit of these misalignment corrections is the size (length of one side) of the pixels forming the inspection pixel.

As described above, in this embodiment, the coarser positional deviation correction is performed in the higher hierarchy, and the smaller positional deviation correction is performed in the lower hierarchy.

FIG. 25 is an explanatory diagram showing a reference area when the positional deviation is corrected in the difference section.

In FIG. 25, reference numeral Na is a partial area cut out by the area dividing circuit 112a. A symbol Ma is a shift range when template matching is performed by the partial area Na. Reference numeral Nb indicates a reference area.

In this embodiment, when the positional deviation correction amount is obtained while performing the template matching in the difference section 112, the partial area Na is matched with the corresponding reference image portion to form the partial area Na. Instead of comparing and referring to all the pixels, the reference is limited to the range of the reference region Nb. This reference area is predetermined for each of the partial areas Na, and
It is set to include the characteristic part of the picture inside. For example, in the partial area Na, the reference area Nb is set to include a boundary portion of a pattern having a large density difference and the pattern is not too fine.

As described above, in the present embodiment, only the pixels in the preset reference area Nb in the partial area Na are compared and referenced in the comparison and reference with the standard image in the correction of the positional deviation. I have to. This not only reduces the processing amount and processing time at the time of template matching, but also reduces the occurrence of errors at the time of template matching. For example, a template matching error may occur in a fine pattern portion, which can be prevented.

In this embodiment, as described above with reference to FIG. 12 and the like, the division into the partial regions is sequentially divided into four. However, the present invention is not limited to such division into partial areas, and may be division according to the pattern or the like of the printed matter to be inspected. In this case, the divided partial areas may not have the same width or shape. Further, such division into partial areas may be performed according to an attribute such as a differential value or a texture chair obtained from an image to be inspected.

[0115]

As described above, according to the present invention, it is possible to obtain the excellent effect that the influence of the distortion of the inspection image can be reduced and the processing amount during the inspection can be reduced. You can

[Brief description of drawings]

FIG. 1 is a flowchart showing the gist of the first invention of the present application.

FIG. 2 is a block diagram showing a configuration of a printing machine and a printed matter concentrated inspection apparatus to which the present invention is applied.

FIG. 3 is a side view of the detection unit of the printed matter concentration inspection apparatus seen from the printed matter running direction.

FIG. 4 is an electric circuit diagram of a detection unit electric circuit of the detection unit.

FIG. 5 is a block diagram showing a hardware configuration of a repeater of the printed matter concentrated inspection apparatus.

FIG. 6 is a block diagram showing a functional configuration of the repeater.

FIG. 7 is a block diagram showing a hardware configuration of a main body of the printed matter concentrated inspection apparatus.

FIG. 8 is a block diagram showing a functional configuration of the main body of the printed matter concentration inspection apparatus.

FIG. 9 is a block diagram showing a functional configuration of a determination unit of the main body of the printed matter concentration inspection apparatus.

FIG. 10 is a block diagram showing a functional configuration of a difference unit of the determination unit.

FIG. 11 is an explanatory diagram of template matching performed by the difference unit.

FIG. 12 is a diagram showing an example of division of partial regions performed by the difference unit.

FIG. 13 is an explanatory diagram of a comparison inspection for each pixel of an inspection image and a reference image, which is performed by the difference unit.

FIG. 14 is a hierarchical block diagram according to partial area division performed by the difference unit.

FIG. 15 is a diagram showing a fourth layer by partial area division performed by the difference unit.

FIG. 16 is a diagram showing a fifth layer by partial area division performed by the difference unit.

FIG. 17 is a diagram showing a sixth layer by partial area division performed by the difference unit.

FIG. 18 is a diagram showing a seventh layer by partial area division performed by the difference section.

FIG. 19 is a flowchart of a first example of processing performed by the difference unit.

FIG. 20 is a flowchart of a second example of processing performed by the difference unit.

FIG. 21 is an explanatory diagram showing pixel-by-pixel positional deviation correction performed by the difference unit.

FIG. 22 is an explanatory diagram showing positional deviation correction in pixel units or less performed by the difference unit.

FIG. 23 is an explanatory diagram showing interpolation between a plurality of pixels performed by the difference unit.

FIG. 24 is an explanatory diagram showing a process of positional deviation correction sequentially performed in the difference section.

FIG. 25 is an explanatory diagram showing a reference area when the positional deviation is corrected in the difference section.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Printed matter 10 ... Printing machine 12 ... Printing unit 14 ... Feed roll 16 ... Winding part 18 ... Rotary encoder 30 ... Detection part 32a ... Lamp house 32b ... Light source 33 ... Optical fiber 34 ... Light guide 34a ... Slit 34b ... Casing 34c ... Glass rod 34d ... Paint 36 ... Line sensor camera 38 ... Detection part electric circuit 38a ... A / D conversion part 38b ... Frame memory 38c ... Image compression circuit 38d ... Optical communication part 38e ... Driver 38g ... A / D converter 40 ... Relay Unit 40a ... CPU 40b ... ROM 40c ... RAM 40d ... Parallel input / output circuit 40e ... Counter 40f ... O / E converters 40g, 40h ... Serial converter 40i ... E / O converter 40j ... Bus 40m ... Image timing control unit 40n ... Memory 40p ... Image signal relay unit 50 ... CPU 52 ... Main memory device 54 ... Hard disk device 58 ... Floppy disk device 60 ... Input / output device 60a ... O / E converter 62 ... Keyboard 64a ... CRT control device 64b ... CRT 66 ... Network control device 68 ... Printer device 80 ... Printed matter intensive inspection device main body 82 ... Defect image storage unit 84 ... Defect display unit 86 ... Data aggregation unit 88 ... Network connection unit 100 ... Judgment unit 102 ... Optical reception unit 104 ... Image restoration unit 106 ... Switching means 108 ... Reference image memory 110 ... Inspection image memory 112 ... Difference Part 112a ... Region division circuit 112b ... Partial region storage memory 112c ... Template shift circuit 112d ... Shift range storage memory 112e ... Shift step storage memory 112f ... Shift amount storage memory 112g ... Matching determination circuit 114 ... Image coordinate determination unit 116 ... Determination circuit18 ... recording unit

Claims (5)

[Claims] 1. An image position shift correction method for correcting a position shift between one image and the other image in order to inspect the image to be inspected while comparing the image to be inspected with a reference image, At least one of the two images is divided into partial areas, and the positional deviation correction is performed for each of the partial areas. 2. An image position shift correction apparatus for correcting a position shift between one image and the other image in order to inspect the image to be inspected while comparing the image to be inspected with a reference image, An area dividing unit that divides at least a part of one of the two images into partial areas, and an area correction unit that performs the positional deviation correction for each partial area are provided. Image misregistration correction device. 3. The defect correction sub-region according to claim 2, wherein the region-by-region correction unit is a unit that performs a positional deviation correction with a predetermined accuracy K, and further, a defect candidate partial region is extracted due to a correction failure in the region-by-region correction unit. Then, the defect candidate partial area is set as an image to be divided by the area dividing means, the predetermined accuracy K is made higher, and the processing performed by the area dividing means and the area correcting means is re-executed. An image misregistration correction device comprising: 4. The method according to claim 2 or 3, wherein the two images are pixel images, and the correction unit for each area corrects the positional deviation.
An image misregistration correction apparatus, which is a means that can also perform misregistration correction finer than the distance of one pixel by obtaining the density at a position between pixels by interpolation from the densities of neighboring pixels. 5. An image inspection apparatus for detecting a defect in an image to be inspected while comparing the image to be inspected with a reference image, wherein at least a part of one of the two images is a partial area. Area dividing means for dividing into partial areas, area-by-area correction means for performing the positional deviation correction for each of the partial areas, and determination means for detecting a correction failure in the area-by-area correction means. An image inspection apparatus characterized by detecting a defect in an image to be inspected.