JP3548835B2 - Defect inspection apparatus and method - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a defect inspection apparatus and method for sequentially imaging a plurality of inspection objects, comparing the captured inspection images with a reference image, and inspecting the inspection objects for defects.
[0002]
[Prior art]
Conventionally, for example, in a defect inspection apparatus that performs a defect inspection of a pattern or the like on a printed matter on which the same pattern is repeatedly printed, basically, the pattern, which is an inspection target on the printed matter, is captured by a camera or the like, and the reference image is taken as a reference image. Defect inspection was performed for each pixel.
[0003]
Here, the inspection target such as a pattern repeatedly printed on a printed matter usually has a misalignment due to printing, and therefore, the pattern or the like on the printed matter on which the same pattern is repeatedly printed is defective. In the case where the inspection is to be performed, after the positional deviation is corrected, a defect inspection based on comparison with a reference image is performed.
[0004]
In addition, at the time of defect inspection, in order to simplify the defect inspection process, a master method in which a reference image is preset and fixed and sequentially compared with the inspection image, and the defect inspection process itself are more complicated than the master method, A scroll system in which a reference image is updated with a normal inspection image as a result of a defect inspection so as to be able to cope with an image change due to an external factor affecting an input image such as illumination is adopted.
[0005]
Therefore, when the conventional defect inspection apparatus adopts the master inspection method and also performs the positional deviation correction, a series of processing of inputting the image data, correcting the positional deviation, and comparing with the reference image is performed by each inspection. When the image data which is the object is repeatedly input and the position correction is performed by adopting the scroll inspection method, the input of the image data, the position correction, the comparison with the reference image, the reference The process of updating the image is repeatedly performed each time image data as each inspection object is input.
[0006]
[Problems to be solved by the invention]
However, in such a conventional defect inspection apparatus, even when a master inspection method that does not update a reference image is adopted, a series of processing of inputting image data, correcting positional deviation, and comparing with a reference image is performed by a captured image. It has to be repeated every time the image data is input, so that a huge processing time is required.
[0007]
In particular, if the pattern on the print sheet on which the same pattern is repeatedly printed is to be inspected, and the image data of the pattern is continuously input at high speed, it cannot follow the inspection image input at high speed. There was a problem.
[0008]
Accordingly, the present invention has been made in view of such a problem, and provides a defect inspection apparatus and method capable of reducing the inspection processing time in both the master inspection method and the scroll inspection method. The purpose is to:
[0009]
[Means for Solving the Problems]
In order to achieve the above object, according to the first aspect of the present invention, a plurality of inspection objects are sequentially imaged, and a positional deviation amount of the captured image is corrected, and then compared with a reference image to inspect a defect of the inspection object. Image input means for sequentially capturing a plurality of inspection objects, and sequentially inputting image data of the captured image,A plurality of image storage means for sequentially storing the captured images and a comparison between the captured images and a preset template image for calculating a positional shift are used to calculate a positional shift amount, and an image is calculated as the positional shift amount of the image. A position shift amount calculating means for adding to and storing the data, and correcting the position shift amount of the image based on the position shift amount of the reference image, and then obtaining a reference image of the image data and the reference image for defect determination. A defect determining unit that compares data with a defect to determine a defect of the inspection object; and a connection between the plurality of image storage units, the image input unit, the displacement amount calculating unit, and the defect determining unit. Each time a new image is input, comprising: an image switching control means for switching one of a plurality of image storage means to the image input means. The image storage means, which has been the input image storage means, is connected to the displacement amount calculating means to store the image data for calculating the displacement amount and the calculated displacement amount. Inspection image storage means serving as a position shift amount calculation storage means for storing, and image storage means serving as a position shift amount calculation storage means being connected to defect determination means for storing image data to be inspected and a position shift amount Therefore, every time new inspection target image data is input, the displacement calculation of the inspection target image and the defect determination of the inspection target image are simultaneously performed in parallel.It is characterized by.
[0010]
The invention of claim 2 is the invention according to claim 1,When the defect determination of the inspection target image is determined to be no defect, when a new image is input by the image input unit, the image storage unit, which has been the inspection image storage unit, is further changed by the image switching control unit. , A reference image storage means, and the image of the reference image storage means is used as a reference image of the defect determination means.It is characterized by the following.
[0011]
The invention of claim 3 is:In a defect inspection method of sequentially imaging a plurality of inspection objects in synchronization with a predetermined synchronization signal and inspecting a defect of the inspection object, sequentially input a plurality of images of the inspection objects and sequentially capture the captured images. A first step of storing the obtained image in the memory, and a second step of comparing the position shift amount of the image stored in the first step with a preset position shift calculation template image to calculate the position shift amount. And correcting the positional deviation of the image based on the positional deviation amount of the image calculated in the second step and the positional deviation amount of the reference image. A third step of determining a defect; and a fourth step of updating the image determined as having no defect as a reference image for the next determination when it is determined that there is no defect in the third step. , First to fourth Step is performed simultaneously in parallel in synchronism with the sync signalIt is characterized by the following.
[0012]
The invention of claim 4 is:In the invention according to claim 3, four memories are provided as the memories, and in each of the first to fourth steps, one of the four memories sequentially switched in synchronization with a synchronization signal is targeted. The screen input in the first step, the displacement calculation in the second step, the defect determination in the third step, or the reference image update in the fourth step are performed.It is characterized by the following.
[0013]
The invention of claim 5 isIn a defect inspection method of sequentially imaging a plurality of inspection objects in synchronization with a predetermined synchronization signal and inspecting a defect of the inspection object, sequentially input a plurality of images of the inspection objects and sequentially capture the captured images. A first step of storing the obtained image in the memory, and a second step of comparing the position shift amount of the image stored in the first step with a preset position shift calculation template image to calculate the position shift amount. And correcting the positional deviation of the image based on the amount of positional deviation of the image calculated in the second step, and comparing with a reference image for defect determination stored in advance to determine the defect of the inspection object. And a third step, wherein the first to third steps are performed simultaneously and in parallel in synchronization with the synchronization signal.It is characterized by the following.
[0014]
The invention of claim 6 isThe invention according to claim 5, wherein the memory has at least three memories, and each of the first to third steps targets one of the at least three memories sequentially switched in synchronization with a synchronization signal. Then, the screen input of the first step, the displacement calculation of the second step, or the defect determination of the third step are performed.It is characterized by the following.
[0020]
Claims7The invention of claim 1 to claim 16In the invention, the plurality of inspection objects are patterns repeatedly printed on a printed matter.
[0021]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of a defect inspection apparatus and method according to the present invention will be described with reference to the drawings.
[0022]
FIG. 1 shows an external configuration of a defect inspection apparatus according to the present invention.
[0023]
This defect inspection apparatus targets the pattern on the print sheet P on which the same pattern has been repeatedly printed by the printing plate cylinder 1 to be inspected, and inspects the print defect. The rotary encoder 2, the light source 3, and the line sensor 4 , A signal processing transmission unit 5, an image processing unit 6, and a display unit 7 for displaying inspection results by an LED, an LCD, or the like.
[0024]
Here, the rotary encoder 2 is interlocked with the printing plate cylinder 1 and determines the time required for the printing plate cylinder 1 to make one rotation, for example, 2¹⁰The pulse signal divided at = 1024 is output to the line sensor 4.
[0025]
The light source 3 irradiates the print sheet P with a predetermined brightness in order to image the print sheet P.
[0026]
The line sensor 4 is a CCD sensor or a CCD camera that captures an image of the print sheet P, scans the print sheet P in synchronization with a pulse signal from the rotary encoder 2, and sends the captured image signal to the signal processing transmission unit 5. It is configured to transmit.
[0027]
The signal processing transmission unit 5 performs A / D conversion on the imaging signal received from the line sensor 4 to convert one pixel into image data of 8-bit gradation, and converts the converted image data into an image processing unit. 6 is transmitted.
[0028]
The image processing unit 6 inspects the print sheet P for a defect based on a signal from the signal processing transmission unit 5, and the detailed configuration will be described with reference to FIGS.
[0029]
The display unit 7 includes an LED, an LCD, and the like, and is configured to display a result of the defect inspection in the image processing unit 6.
[0030]
FIG. 2 shows a configuration of the print image processing unit 6 of the defect inspection apparatus according to the first embodiment.
[0031]
In the first embodiment, a description will be given assuming that a scroll inspection method for updating a reference image is adopted.
[0032]
The image processing unit 6 is configured as shown in FIG. 2, and includes an image data input unit 61 and a position shift amount calculating unit incorporating a template memory 62a.(Position shift amount calculation means)62 and a defect determination unit(Defect determination means)63,imageSwitching control section (Image switching means) 64, four image memories 65 (image memory 1), 66 (image memory 2), 67 (image memory 3), 68 (image memory 4) and image memories 65, 66, 67, 68. The position shift register 65a (shift register 1), 66a (shift register 2), 67a (shift register 3), and 68a (shift register 4).
[0033]
Here, the image data input unit 61 inputs image data from the signal processing transmission unit 5 and converts the image data.imageThe output is sequentially output to the four image memories 65, 66, 67, 68 via the switching control unit 64. Further, each time the image data is output, the image synchronization signal is output to the position shift calculation unit 62, the defect determination unit 63,imageIt is configured to transmit to the switching control unit 64.
[0034]
The position shift amount calculation unit 62 is input from the image data input unit 61 in the previous cycle based on the image synchronization signal from the image data input unit 61, and is input to any of the four image memories 65, 66, 67, and 68. The stored image data for position shift calculation is read out, and based on the template image for position shift calculation stored in the template memory 62a in advance, the amount of position shift of the read image data with respect to the template image is calculated, and again.imageThe image data is stored in a position shift amount register of the same image memory via the switching control unit 64. For example, when the image data is read from the image memory 66, the calculation result in the displacement amount calculating section 62 is stored in the displacement amount register 66a in the image memory 66.
[0035]
The template image is set in the template memory 62a before the start of the inspection.
[0036]
The defect determination unit 63imageThe inspection image input unit 63a to which data is input and the reference imageimageA reference image input unit 63b into which data is input, and the inspection image data stored in any of the four image memories 65, 66, 67, 68 based on the image synchronization signal from the image data input unit 61. And the position shift amount stored in the position shift amount register in the image memory, as well as the reference image data stored in any of the four image memories 65, 66, 67, and 68, and the reference image data in the image memory. The positional deviation amount stored in the positional deviation amount register is read, and the inspection image and the reference image are compared with each other while performing positional deviation correction based on the respective positional deviation amounts, and the inspection image is determined by determining the presence or absence of a defect. The result is output to the display unit 7, and if there is a defect, a defect occurrence signal is output.imageIt is configured to transmit to the switching control unit 64.
[0037]
imageThe switching control unit 64 is composed of a plurality of multiplexers for switching data buses, and as described later in detail, based on an image synchronization signal from the image data input unit 61, the image data input unit 61 Terminals 71 to 85 are provided for switching the connection between the quantity calculation unit 62 and the defect determination unit 63 and the four image memories 65, 66, 67, and 68.
[0038]
That is, the terminal 71 connected to the image data input unit 61, the terminals 72 and 73 connected to the displacement amount calculation unit 62, the terminals 74, 75, 76, 77 connected to the defect determination unit 63, and the image memory 65 A connected terminal 78, a terminal 79 connected to the displacement amount register 65a of the image memory 65, a terminal 80 connected to the image memory 66, a terminal 81 connected to the displacement amount register 66a of the image memory 66, an image memory A terminal 82 connected to the image memory 67, a terminal 83 connected to the displacement amount register 67a of the image memory 67, a terminal 84 connected to the image memory 68, and a terminal 85 connected to the displacement amount register 68a of the image memory 68. Is provided.
[0039]
AndimageThe switching control unit 64 is based on the image synchronization signal from the image data input unit 61, and the four image memories 65, 66, 67, and 68 including the image data input unit 61, the position shift amount calculation unit 62, and the defect determination unit 63. While the connection with the side is switched, when a defect occurrence signal is input from the defect determination unit 63,As explained later, change the way of switching the connection,The update of the reference image data and the positional deviation amount data at that time is stopped.
[0040]
In the first embodiment, since the scroll inspection method is employed, before the start of the inspection, the reference image is stored in any image memory and its displacement amount register.dataNo positional shift amount data is stored, and the reference image data and the positional shift amount data are stored for the first time in the fourth cycle after the operation starts.
[0041]
Next, a brief description will be given of a method of calculating a position shift amount in the position shift amount calculation unit 62 and a defect determination method by a scroll inspection method.
[0042]
FIG. 3 shows a template image D1 and a displacement amount calculation image D2.
[0043]
The template image D1 is an image used as a reference when calculating the positional shift, and for example, refers to a partial image D1 in a rectangular small area D11 in which a pattern with a steep gradation change of print image data exists. The X1 and Y1 addresses of the image D1 are set as template image data in the template memory 62a of the displacement calculator 62 before the start of the inspection.
[0044]
Then, based on the image synchronization signal from the image data input unit 61, the position shift amount calculation unit 62 reads out the position shift calculation image data stored in any of the image memories, and includes the template image in the image data. The coordinates X2 and Y2 of the portion corresponding to X1 and Y1 of D1 are searched for by a correlation operation or the like, and then the operations of X1-X2 and Y1-Y2 are performed to obtain the displacement XX of the image in the X and Y directions. , ZY are obtained and stored in the displacement amount register.
[0045]
The calculation of the amount of displacement is performed every time image data is input, that is, within one cycle until the next image synchronization signal is input.
[0046]
FIG. 4 shows a procedure for updating the reference image in the defect determination unit 63 by the scroll inspection method.
[0047]
The scroll inspection method compares a reference image with an inspection image, and when the inspection image is normal (non-defective), uses this inspection image as a reference image and uses it when comparing with the next inspection image This is an inspection method in which the reference image to be scrolled is sequentially scrolled, and in the case of an abnormality (defective product), the reference image is not scrolled.
[0048]
Specifically, as shown in this figure, the inspection images of numbers N to N + 3 are sequentially read, and if the inspection image of number N + 2 has a defect, the N + 2th input image is determined to be defective. Therefore, in the case of the comparison of the inspection image of the number N + 3, this refers to an inspection method in which the inspection image of the number N + 2 is not used as the reference image, and the inspection image of the number N + 1 is used as it is as the reference image.
[0049]
Next, the operation of the thus configured defect inspection apparatus according to the first embodiment will be described with reference to the drawings.
[0050]
First, as shown in FIG. 1, when the printing plate cylinder 1 starts rotating and printing starts, a pulse signal obtained by dividing one rotation of the printing plate cylinder 1 into 1024 from the rotary encoder 2 linked to the printing plate cylinder 1 is output. It is transmitted to the line sensor 4.
[0051]
The line sensor 4 that has received the pulse signal scans the inspected portion of the printing sheet P printed by the printing plate cylinder 1 illuminated by the light source 3 in synchronization with the pulse signal, and transmits the image data by signal processing. Transmit to section 5. In this example, there are 1024 pixels per scan.
[0052]
The signal processing transmission unit 5 that has received the image data from the line sensor 4 performs A / D conversion on the image data to convert the image data into image data of 8-bit gradation data, and transmits the image data to the image processing unit 6.
[0053]
In the image processing unit 6, the image data input unit 61 inputs the image data, and the input image data isimageThe image data is stored in an empty image memory among the four image memories 65, 66, 67, 68 via the switching control unit 64, but is initially stored in the image memory 65.
[0054]
Further, the image data input unit 61 includes a position shift calculating unit 62, a defect determining unit 63,imageAn image synchronization signal, which is an operation timing signal, is transmitted to the switching control unit 64.
[0055]
imageWhen the switching control unit 64 receives the image synchronization signal from the image data input unit 61 while not receiving the defect occurrence signal from the defect determination unit 63,imageThe connection of the data bus in the switching control unit 64 is simultaneously switched, for example, as shown in FIG.
[0056]
That is,imageAs shown in FIG. 5, the switching control unit 64 connects the output terminal 71 of the image data input unit 61 with the image memory 65, connects the input terminal 72 of the position shift calculation unit 62 with the image memory 68, and performs the position shift calculation. The output terminal 73 of the unit 62 is connected to the displacement amount register 68a, the inspection image input terminal 74 of the defect determination unit 63 is connected to the image memory 67, and the inspection image position deviation amount input terminal 75 of the defect determination unit 63 is shifted to the position. The amount register 67a is connected, the reference image input terminal 76 of the defect determination section 63 is connected to the image memory 66, and the reference image position deviation amount input terminal 77 of the defect determination section 63 is connected to the position deviation register 66a.
[0057]
Therefore, in one cycle until the next image synchronization signal is input, the image memory 65Input image storage meansThe image memory 68 is used as an input image data area., The displacement amount calculation image storage meansIt is used as a displacement image data area and the image memory 67, Inspection image storage meansUsed as an inspection image data area, the image memory 66Of the reference image storage meansIt will be used as a reference image data area.
[0058]
In addition, the position shift amount calculation unit 62 and the defect determination unit 63 calculate the position shift amount and determine the defect based on the image synchronization signal from the image data input unit 61, respectively.
[0059]
At this time, the position shift amount calculation unit 62 performs the position shift amount calculation as shown in FIG. 3 described above, while the defect determination unit 63 compares the reference image and the inspection image with each position shift amount. After the correction, the defect is compared and determined.
[0060]
For example, when the displacement amounts ZX and ZY of the inspection image are (5, 8) and the displacement amounts ZX and ZY of the reference image are (3, 11), the displacement amount of the inspection image with respect to the reference image is (−2, 3), the pixel address of the inspection image is corrected by this number of pixels, and then the inspection image after the positional deviation correction is compared with the reference image in pixel units, and for example, the number of pixels having a difference equal to or more than a certain value is determined. Counting is performed, and if the number of pixels is equal to or more than a predetermined number of pixels, it is determined that the pixel is defective. This defect determination is performed each time image data is input, that is,Image sync signalTo be done before input.
[0061]
Thereafter, the position shift amount calculation unit 62 calculates the calculated position shift amount.Position shift amount calculation image storage meansWhile transmitting to the position shift amount register 68a, the defect determination unit 63 displays the determination result on the display unit 7 and, when there is a defect, a defect occurrence signal.imageIt is transmitted to the switching control unit 64.The position shift amount transmitted to the position shift amount register 68a of the position shift amount calculation image storage means is stored in the position shift amount register 68a.
[0062]
As described above, in the image processing unit 6, every time the image data input unit 61 inputs the image data from the signal processing transmission unit 5, based on the image synchronization signal output from the image data input unit 61,imageThe switching control unit 64 switches the connection destination of the data bus to update the image data and the like, and causes the position shift amount calculation unit 62 to calculate the position shift amount based on the new position shift calculation image data. NewInspection imageIs repeatedly determined.
[0063]
When the defect determination unit 63 determines that there is no defect in the inspection image,imageThe switching control unit 64 subsequently switches the connection of the data bus to the state shown in FIG.
[0064]
That is,imageAs shown in FIG. 6, the switching control unit 64 connects the output terminal 71 of the image data input unit 61 to the image memory 66, connects the input terminal 72 of the position shift operation unit 62 to the image memory 65, and executes the position shift operation. The output terminal 73 of the unit 62 is connected to the displacement register 65a, the inspection image input terminal 74 of the defect determination unit 63 is connected to the image memory 68, and the inspection image displacement amount input terminal 75 of the defect determination unit 63 is shifted to the position. The amount register 68a is connected, the reference image input terminal 76 of the defect determination unit 63 is connected to the image memory 67, and the reference image position deviation amount input terminal 77 of the defect determination unit 63 is connected to the position deviation register 67a.
[0065]
Therefore, in one cycle until the next image synchronization signal is input, the image memory 66Input image storage meansUsed as an input image data area, the image memory 65, The displacement amount calculation image storage meansIt is used as a displacement image data area, and the image memory 68, Inspection image storage meansUsed as an inspection image data area, the image memory 67Of the reference image storage meansIt will be used as a reference image data area.
[0066]
On the other hand, when the defect determination unit 63 determines that the inspection image has a defect, a defect occurrence signal is output.imageTransmitted to the switching control unit 64,imageThe switching control unit 64 switches the connection of the data bus to the state shown in FIG.
[0067]
That is,imageAs shown in FIG. 7, the switching control unit 64 connects the output terminal 71 of the image data input unit 61 to the image memory 67, connects the input terminal 72 of the position shift operation unit 62 to the image memory 65, and executes the position shift operation. The output terminal 73 of the unit 62 is connected to the displacement register 65a, the inspection image input terminal 74 of the defect determination unit 63 is connected to the image memory 68, and the inspection image displacement amount input terminal 75 of the defect determination unit 63 is shifted to the position. The amount register 68a is connected, the reference image input terminal 76 of the defect determination section 63 is connected to the image memory 66, and the reference image position shift amount input terminal 77 of the defect determination section 63 is connected to the position shift register 66a.
[0068]
Therefore, in one cycle until the next image synchronization signal is input, the image memory 67Input image storage meansUsed as an input image data area, the image memory 65, The displacement amount calculation image storage meansIt is used as a displacement image data area, and the image memory 68, Inspection image storage meansUsed as an inspection image data area, the image memory 66Of the reference image storage meansIt will be used as a reference image data area.
[0069]
In this way, when the inspection image is determined to be defective, the reference imageimageIs not updated. Defect image as reference imageimageBecause it cannot be done.
[0070]
FIG. 8 shows the storage contents of the image memories 65 to 68 of the first embodiment at the image synchronization signal input timings T1 to T7. In FIG. 8, the image memory 65 corresponds to the memory 1, the image memory 66 corresponds to the memory 2, the image memory 67 corresponds to the memory 3, and the image memory 68 corresponds to the memory 4.
[0071]
FIG. 8 shows that the functions of the image memories 65 to 68 change every time the image data input unit 61 inputs the image data of the numbers N to N + 6. It should be noted that the image data of the number N + 2 is denoted by “x”, indicating that there is a defect.
[0072]
Therefore, at the image input timing T5, the defect determining unit 63 sets the inspection image of the number N + 2 stored in the image memory 3(data)And the reference image of the number N + 1 stored in the image memory 2(data)At this time, since the inspection image with the number N + 2 has a defect, the data in the image memory 2 is used as the reference image even at the input timing T6.
[0073]
Therefore, according to the first embodiment, every time new inspection target image data is input, the displacement of the inspection target image is calculated,imageThe defect determination of the reference image and the update processing of the reference image with the normal inspection image are performed simultaneously and in parallel in a pipeline process, so that the inspection image can be continuously inspected every time the inspection target image data is input, and the defect inspection can be performed. The processing time can be shortened.
[0074]
Next, a second embodiment of the defect inspection apparatus according to the present invention will be described.
[0075]
The second embodiment employs a master inspection method that does not update the reference image at the time of defect inspection, unlike the first embodiment that employs the scroll inspection method of updating the reference image at the time of defect inspection, Further, it is characterized in that simultaneous parallel processing of defect inspection is enabled every time new image data is input.
[0076]
Since the hardware configuration of the second embodiment is the same as the hardware configuration of the first embodiment, the content of the second embodiment will be described below using the member names used in the description of the first embodiment. I do.
[0077]
In the second embodiment, a template image is extracted from an input image before the start of an inspection, and stored in a template memory 62a of a position shift calculating unit 62. Further, the input image is stored in the image memory 68 (memory 4) in order to be used as the fixed reference image S. Since the reference image S is an image obtained by extracting the template, the displacement amount is (0, 0), and (0, 0) is set in the displacement amount register 68a.
[0078]
FIG. 9 shows the stored contents of the image memories 65 to 68 of the second embodiment at the image synchronization signal input timings T1 to T7. Also in FIG. 9, the image memory 65 corresponds to the memory 1, the image memory 66 corresponds to the memory 2, the image memory 67 corresponds to the memory 3, and the image memory 68 corresponds to the memory 4. Each time the image data input unit 61 inputs the image data of the numbers N to N + 6, the functions of the image memories 65 to 67 change, but the image memory 68 (memory 4)dataIs stored and used in a fixed manner.
[0079]
Input of image data is started by the start of the inspection.image(1024 × 1024 pixelsScreen) Occurs at every inputimageIn sync with the sync signalimageThe switching of the data bus of the switching control unit 64 and the processing of each unit are performed in parallel, but until the timing T2, a preparation period for aligning data for four surfaces is performed, so that the determination processing is not performed. Defect determination is started from timing T3,imageThe switching of the data bus of the switching control unit 64 and the processing of each unit are performed in parallel.
[0080]
It should be noted that the image data of the number N + 2 is denoted by “x”, indicating that there is a defect.
[0081]
Also in the second embodiment, every time new inspection target image data is input, the displacement of the inspection target image is calculated,imageIs simultaneously and parallelly processed in a pipeline process, so that the inspection image can be continuously inspected every time the inspection object image data is input, and the processing time for the defect inspection can be shortened.
[0082]
【The invention's effect】
As described above, in the present invention, every time new inspection target image data is input, the displacement of the inspection target image is calculated,imageDefect determination and updating of the reference image with a normal inspection imagepipeSince simultaneous and parallel processing is performed in line processing, every time image data to be inspected is input, continuous inspection of inspection images is possible, and processing time for defect inspection can be shortened.
[0083]
For this reason, in particular, when the same pattern or the like on a printed matter on which the same pattern is repeatedly printed is set as a defect inspection target, the defect target is continuously input at a high speed. It is possible to follow that speed.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing an external configuration of a defect inspection apparatus according to the present invention.
FIG. 2 is a block diagram illustrating a configuration of a print image processing unit of the defect inspection device according to the first embodiment.
FIG. 3 is an explanatory diagram showing a template image and a displacement amount calculation image.
FIG. 4 is an explanatory diagram showing a procedure for updating a reference image by a scroll inspection method in a defect determination unit.
FIG. 5 is an explanatory diagram showing a data bus switching state in a screen switching control unit.
FIG. 6 is an explanatory diagram illustrating a data bus switching state in a screen switching control unit when the defect determining unit determines that there is no defect.
FIG. 7 is an explanatory diagram showing a data bus switching state in a screen switching control unit when a defect occurrence signal is generated.
FIG. 8 is an explanatory diagram showing stored contents at each timing of each image memory of the first embodiment.
FIG. 9 is an explanatory diagram showing the stored contents of each image memory at each timing in the second embodiment.
[Explanation of symbols]
1 printing plate cylinder
2 Rotary encoder
3 Light source
4 Line sensor
5 Signal processing transmission section
6 Image processing unit
7 Display
P print sheet
61 Image data input section
62 Position shift calculator
63 Defect judgment unit
63a inspection image input unit
63b Reference image input section
64 screen switching control unit
65 Image memory (Image memory 1)
66 Image memory (Image memory 2)
67 Image memory (Image memory 3)
68 Image memory (Image memory 4)
65a Position shift amount register
66a Position shift register
67a Position shift amount register
68a Position shift register
71-85 terminals

Claims (7)

In a defect inspection apparatus that sequentially images a plurality of inspection objects, corrects a positional shift amount of the captured image, compares the corrected image with a reference image, and inspects a defect of the inspection object.
Image input means for sequentially capturing a plurality of inspection objects and sequentially inputting image data of the captured image,
A plurality of image storage means for sequentially storing the captured images;
A position shift amount calculating means for comparing the captured image with a preset template image for position shift calculation to calculate a position shift amount, and adding and storing the position shift amount of the image to image data as a position shift amount;
After correcting the positional shift amount of the image based on the positional shift amount of the reference image, the image data is compared with the reference image data of the reference image for defect determination to determine the defect of the inspection object. Defect determination means for performing
An image switching control unit that switches the connection between the plurality of image storage units and the image input unit, the displacement amount calculation unit, and the defect determination unit each time the image input unit inputs a new image,
According to the image switching control means, one of the plurality of image storage means is connected to the image input means and serves as an input image storage means for storing image data. Means for storing the image data for calculating the amount of positional deviation and the calculated amount of positional deviation connected to the means; The image data to be inspected and the amount of displacement are connected to the inspection image storage means. Each time new inspection image data is input, the displacement of the inspection image is calculated, A defect inspection apparatus characterized in that the defect determinations are performed simultaneously and in parallel . When the defect determination of the inspection target image is determined to be no defect, when a new image is input by the image input unit, the image storage unit, which has been the inspection image storage unit, is further changed by the image switching control unit. The defect inspection apparatus according to claim 1 , wherein the reference image storage means is used as a reference image storage means, and the image of the reference image storage means is used as a reference image of the defect determination means . In a defect inspection method for sequentially imaging a plurality of inspection objects in synchronization with a predetermined synchronization signal and inspecting defects of the inspection objects,
A first step of sequentially capturing a plurality of inspection objects and sequentially inputting the captured images, and storing the input images in a memory;
A second step of comparing the position shift amount of the image stored in the first step with a preset position shift calculation template image to calculate the position shift amount;
The position deviation of the image is corrected based on the position deviation amount of the image calculated in the second step and the position deviation amount of the reference image, and the defect of the inspection object is determined by comparing with the reference image for defect determination. A third step to
A fourth step of updating the image determined as having no defect as a reference image at the next determination when it is determined that there is no defect in the third step,
A defect inspection method, wherein each of the first to fourth steps is performed simultaneously and in parallel in synchronization with a synchronization signal. Four memories are provided as the memories, and in each of the first to fourth steps, the screen input of the first step is performed for one of the four memories sequentially switched in synchronization with the synchronization signal. 4. The defect inspection method according to claim 3, wherein a position shift amount calculation in the second step, a defect determination in the third step, or a reference image update in the fourth step is performed. In a defect inspection method for sequentially imaging a plurality of inspection objects in synchronization with a predetermined synchronization signal and inspecting defects of the inspection objects,
A first step of sequentially capturing a plurality of inspection objects and sequentially inputting the captured images, and storing the input images in a memory;
A second step of comparing the position shift amount of the image stored in the first step with a preset position shift calculation template image to calculate the position shift amount;
The third step of correcting the positional deviation of the image based on the positional deviation amount of the image calculated in the second step and comparing the image with a reference image stored in advance for defect determination to determine the defect of the inspection object. And steps,
The first to third steps are performed simultaneously and in parallel in synchronization with a synchronization signal. A defect inspection method characterized by the above-mentioned. At least three memories are provided as the memory. In each of the first to third steps, one of the at least three memories sequentially switched in synchronization with a synchronization signal is targeted. 6. The defect inspection method according to claim 5, wherein a screen input, a displacement calculation in a second step, or a defect determination in a third step is performed. The defect inspection apparatus or method according to claim 1, wherein the plurality of inspection objects are patterns repeatedly printed on a printed matter.

Images