JP2003262594A - Defect inspection machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To surely fetch an image of a single defect. <P>SOLUTION: An image signal from a receiver board 23 is processed by a data processing board 25, and image data on a defect is sent to a defect-image display device 15. The image signal from the receiver board 23 is digitized by an A/D converter 50. Digitized data is written in an SDRAM 51 for each scan by an FGPA-A 53, a FIFO-E 54 and a FIFO-O 55. A defect signal and defect position data are input to an FPGA-B 57. In a CPU 56, the continuity of the defect in each scan is decided on the basis of the defect signal. In the case of a continuous defect, the image is fetched in each predetermined prescribed number of scans. In the case of the single defect, a defect image is fetched every time. Since the number of times of a fetching operation by the continuous defect is limited, defect image data due to other single signals can be fetched, and a fetching oversight in a single defect image is reduced. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a defect inspection machine for scanning the surface of a steel plate, paper, plastic film, IC wafer or the like to display an image containing a defect on a display and making the defect visible. .

[0002]

2. Description of the Related Art Optically scanning the surface of a steel plate or paper,
Various surface inspection apparatuses have been proposed in which defects such as scratches appearing on the surface are displayed on a display and the presence / absence, size, type, etc. of the defects can be determined by visually observing the defects.

[0003] For example, Japanese Patent No. 2577765 discloses that
A bulk memory for sequentially reading and storing a continuous predetermined number of scanning lines of a material to be inspected, a defect discriminating means for discriminating a defect of the material to be inspected from the image signal, and a material for the material to be inspected stored in the bulk memory. Block discriminating means for dividing the surface into a plurality of blocks to obtain a block containing the detected defect, and write control means for temporarily suspending writing in the bulk memory when a scan line of a predetermined number of blocks including the block containing the defect is read. A surface inspection apparatus is provided, which includes a cutout control unit that cuts out a predetermined number of blocks including a block including a defect from the data in the bulk memory and transfers the block to a frame memory, and a monitor unit that displays the contents of the frame memory. ing.

Furthermore, a plurality of bulk memories are provided, and one of the write control means continues writing to the other while the writing is stopped, thereby making it possible to image even if defects occur continuously. Has been done.

[0005]

By the way, there are cases where sporadic defects are continuous in the material to be inspected, or defects are continuous in the running direction and sporadic in the width direction. In order to be able to deal with the above, it is necessary to design the number of bulk memories assuming a defect generation pattern. For example, if more defects than the designed number of bulk memories occur, it becomes impossible to cut out scan lines to the frame memory. This can be dealt with by increasing the number of bulk memories, and the more the number of bulk memories is increased, the less frequently the scan lines cannot be cut out. However, the range in which the CPU can directly access the memory is limited, and there is also a limit in increasing the number of bulk memories.

The present invention has been made to solve the above-mentioned problems, and it is not necessary to increase the bulk memory, and even if a continuity defect occurs, it is not affected by the continuity defect. It is an object of the present invention to provide a defect inspection machine capable of displaying defects as well.

[0007]

In order to achieve the above object, the present invention provides a defect inspecting apparatus for detecting a defect of a material to be inspected from an image signal obtained by scanning an inspection surface of the material to be inspected, First storage means for sequentially reading and storing data of a predetermined number of continuous scanning lines of the inspection material, and defect determining means for determining a defect of the inspection material from the image signal,
A second storage unit that cuts out a predetermined area including the defect from the data of the scanning line of the first storage unit and stores it as defect image data; and the second storage unit,
The continuity of the defects is determined, and when the defects are continuous, when the continuous defect is cut, a predetermined area including the defect is cut out. In addition, a defect specifying unit for specifying the position of the defect based on the position data in the main scanning direction and the position data in the web traveling direction of the defect is provided, and the position data is stored in the second storage unit together with the defect image data. Is preferred.

The first storage means and the second storage means are SDRAM, a converter for AD-converting the image signal into data of the scan line, and scan line data from the converter of the SDRAM. Writing means for writing to the bulk memory area, the defect image data is cut out from the bulk memory area based on the defect signal from the defect determining means and the position data from the defect specifying means, and the cut out defect image data is SD
It is preferable that the cutting-out means stores the defective image data storage area of the RAM and the transfer means that transfers the data of the defective image data stored in the image data storage area. In this case, the cutting-out of the defective image is performed. Can be performed at high speed, the number of defective images that cannot be cut out can be reduced accordingly, and the cut-out of defective images can be reduced. Further, it is preferable that the cutout unit stores the defect image data and the defect information obtained from the scanning line data corresponding to the defect image data in association with each other. Further, it is preferable that the apparatus further comprises a defect image display means for restoring the defect image data transferred from the transfer means and displaying it on a display, and a storage means for compressing and storing the restored defect image. In this case, the number of stored defective image data can be increased, and the image quality is hardly deteriorated by adopting a compression method such as JPEG.

[0009]

1 shows a schematic view of a defect inspection machine of the present invention. The defect inspection machine 10 includes a web 11 as a material to be inspected, which is manufactured in various film forming lines and coating lines.
Inspect the surface for defects, shape of defects, etc. The web 11 is fed in the direction of arrow A1 in the figure and continuously runs. An image of the surface of the web 11 is read by the image detecting means 12 of the flying spot system, and various defects are identified based on the image data.

The defect inspection machine 10 comprises a plurality of inspection machine bodies 13a and 13b and a plurality of these inspection machine bodies 13a and 13b.
a and 13b are composed of a defective image display device 15 connected via a switching hub 14 and a general computer 16. The first inspection machine body 13a includes a scanner 20 and a light receiver 21, which form the image detection means 12, an inspection machine body computer 22, and C of the computer 22.
It is provided with a receiver board 23, a data processing board 25, an I / O board (not shown) according to the SCSI2 standard for connecting the inspection machine bodies 13a and 13b to the central computer 16, which are connected to the PU data bus. The second inspection machine body 13b has the same configuration as the first inspection machine body 13a.

The image detecting means 12 supplies the laser light emitted from the laser light source 30 of the scanner 20 to the motor 3
The polygon mirror 32 rotated by 1 scans the web 11 in the width direction (main scanning), and
The light that has passed through 1 is received by the light receiver 21.

The light receiver 21 comprises a light receiving rod 33 and a pair of light receiver main bodies 34a and 34b. The light receiving rod 33 is arranged in close proximity to and parallel to the main scanning line 35 of the laser light, and when the transmitted light is received, it is totally reflected by the inner surface of the light receiving rod 33 and guided to both ends thereof. On the light receiving surface 36 of the light receiving rod 33, a mask 37 is formed long in the main scanning direction. When there is no defect on the surface of the web 11, the light transmitted through the web 11 hits the mask 37 and does not enter the light receiving rod 33. When the surface of the web 11 has a defect, the light transmitted through the web 11 is scattered by the defect and enters the light receiving rod 33 from the outside of the mask 37. The light receiver main bodies 34a and 34b are arranged at both ends of the light receiving rod 33, and are composed of a photomultiplier (photomultiplier tube) or the like.

The signals from the respective light receiver main bodies 34a and 34b are sent to the receiver board 23. Receiver board 23
In addition to the preamplifier and the main amplifier (both not shown), an addition circuit 40, a signal processing circuit 41, a defect determination circuit 45,
A defect position specifying circuit 46 and the like are provided. First, a signal is amplified and waveform-shaped by using a preamplifier and a main amplifier (not shown), and becomes analog image signals a ₁ and a ₂ as shown in FIG.

In FIG. 2, signals corresponding to successive different main scanning lines 35 appear in each of the signals a ₁ and a ₂ at regular time intervals in the time axis direction. Also, d ₁₁ , d ₁₂ ,
d _21, d _{2 2} corresponds to the defect of the surface of the web 11. As described above, the levels of the signals a ₁ and a ₂ decrease when the scanning position of the laser light on the main scanning line 35 is far from the light receiver main bodies 34a and 34b, and the level rises when the scanning positions are close to each other. Change. Therefore, the two signals a ₁ and a ₂ are added by the adder circuit 40, and the influence of the change of the scanning position on the main scanning line 20 is removed. The added analog image signal a is differentiated in the signal processing circuit 41,
The analog image signal a ₃ is used. This signal a ₃ includes pulses d ₃₁ and d ₃₂ that change between positive and negative when there is a defect. This analog image signal a ₃ is sent to the data processing board 25.

The defect discriminating circuit 45 detects the presence or absence of a defect by comparing the signal a ₃ with a comparison voltage v of a predetermined level (see FIG. 2). That is, pulses d ₃₁ and d ₃₂ indicating a defect
Outputs a defect signal d which becomes a pulse when becomes smaller than the comparison voltage v.

The defect position specifying circuit 46 uses the defect signal d.
The scanning position of the laser light at the time when the pulse is output, that is, the coordinates (address) of the leading portion of the defect appearing by the scanning are obtained. The coordinates of the laser light in the main scanning direction are detected based on the rotation angle of the bolgon mirror 32 or a starting point detector such as a photosensor in the main scanning direction, and the elapsed time after the laser light passes through this point. Further, the coordinate in the sub-scanning direction, which is the position of the web 11 in the feed direction, is detected based on the feed amount of the web.

The analog image signal a is the data processing board 2
At 5, the predetermined area including the digitized data is stored as defect image data. Hereinafter, data processing in the data processing board 25 will be described.

As shown in FIG. 3, the analog image signal a
Is converted into a digital image signal by the A / D converter 50 and stored in the bulk memory area in the SDRAM 51. The SDRAM 51 has a storage capacity of 128 Mbytes, of which 64 Mbytes are used as a bulk memory, 32 Mbytes are used as a memory area for defective image data, and the remaining 32 Mbytes are used as a program write area. SDRAM 51 is synchronous D
A RAM, which exchanges data, addresses, and commands in synchronization with a clock faster than a normal DRAM. Reference numeral 48 indicates a data bus of the CPU 56, and 49 indicates an address bus of the CPU 56.

In the memory area for defective image data, 400 × 400 pixel data at the time of occurrence of a defect is written for 100 images, for example. In the program area, the ROM 52
The program written in ROM5 is stored in ROM5 when the power is turned on.
2 is copied to the SDRAM 51. This is a ROM
This is because the SDRAM 51 has a higher operation speed than the SDRAM 52.

The A / D converter 50 digitizes the analog signal and outputs 8-bit data at 33 MHz. Data rate conversion and timing control FPGA (Field Programmable Gate Array, hereinafter simply referred to as FPGA-A) 53 widens the bit width of data to 64 bits, and the frequency is ¼ as much.
To

The FPGA-A53 has two FIFOs.
(Fast In Fast Out Memory) 54 and 55 are also controlled. The data buses of the FIFOs 54 and 55 are divided into an input and an output, and are preferably used between devices having different data rates. In addition, the FIFO 54, 55
Does not have an address bus. Then, reading and writing are performed at the rising edge of each clock. Then, the rising edge of the clock is counted up to determine the read / write address. The write is data from the AD converter 50, and the read is from the CPU 56. The write and read clocks are created by the FPGA-A53.

Two sets of FIFOs 54 and 55 are prepared for even numbers and odd numbers. Then, after one scan is taken into one even-numbered FIFO (hereinafter, FIFO-E) 54, the data of the FIFO-E 54 is DMA (Direct Access Memory: DMA) in the SDRAM 51 in the next scan.
Move the data at high speed without depending on the CPU). Then, the data of the FIFO-E54 is transferred to the SDRAM.
While moving to 51, the data from the AD converter 50 is written to the FIFO-O 55. In the next scan, the relationship between the FIFO-E 54 and the FIFO-O 55 is reversed, and the data for each scan is continuously written in the bulk memory area of the SDRAM 51 by repeating the following alternately.

As described above, A
All the data from the D converter 50 is written in the bulk memory area in the SDRAM 51 by the storage capacity. That is, the product N × n of the number N of pixels of the main scanning line 35 and the number n of main scanning lines is stored in the bulk memory area. Then, when the storage capacity of the bulk memory area becomes full, new data is sequentially overwritten on the oldest data. As a result, for example, 4000 scans of the main scan line are stored in the bulk memory area.

The defective signal from the receiver board 23 is sent to the timing control FPGA (hereinafter simply referred to as FPGA-
B) 57. In addition to the defect signal, position data is sent from the defect position specifying circuit 36 to the FPGA-B 57. The CPU 56 determines, based on the signal from the FPGA-B 57, whether the defects are continuous or one-off. Then, when the defect is cut off, the SDRAM 5
Image data of a certain area including a defect is cut out from one bulk memory area and transferred to a frame memory (a storage area corresponding to 32 Mbytes of the SDRAM 51).

FIG. 4 to FIG. 9 are for explaining the logic of continuous and one-shot defects. FIG. 4 shows an example of image cutout for a defect when the continuity determination value Y is set to 1. Here, the continuity determination value Y is a value for determining whether or not defects are continuous for each scan,
In the case of "1", when no defect is detected in the next scan, it is determined that the continuity is interrupted here. Further, in the case of "2", it is determined that the continuity is interrupted here when no defect is detected in the next scan and two scans of the next scan.

First, when the defect position in the next scan is within the width of X on both sides in the main scanning direction with respect to the position of the previous defect with respect to the position where the defect is first detected, it is regarded as a continuous defect. , Do not cut out. Hereinafter, the above continuity is similarly determined for each scan. And
Starting with a scan where there are no defects within the width of X,
Determined as continuous defect. If the defect (continuous defect) determined to have continuity in this way has a length of 200 scans or less, 400 × 400 pixels centered on the defect position of the scan line where the first defect position appears. Minutes are cut out from the bulk memory area. Further, when the continuous defect has a length exceeding 200 scans, the defect position of the 200th scanning line is set as the first defect position, and the defect image is centered on this defect position by 400 × 400 pixels from the bulk memory. To be separated. It should be noted that the hatched defect position is the center position of the cutout of the defect image.

FIG. 5 shows a case where the continuity judgment value Y is set to 2. In this case, even if the defect is interrupted for one scan, the defect is not confirmed here and the defect is interrupted for two scans or more. Sometimes to determine continuous defects. The center of the cutout of the continuous defect is the same as that of FIG. 4, and when the continuous defect is 200 scans or less, the bulk of 400 × 400 pixels is centered on the defect position of the scan line where the first defect position appears. It is cut out from memory. When the continuous defect exceeds 200 scans, the defect position of the 200th scanning line is set as the first defect position.

FIG. 6 shows the case where the continuity judgment value Y is set to 3, FIG. 7 shows the case where the continuity judgment value is set to 4, and FIG. 8 shows the case where the continuity judgment value is set to 3 and the number of continuous defect scans. When the number becomes 150, this continuous defect is cut out.

In FIG. 9, the continuous judgment value is 3, and the number of continuous defect scans is 1100. In such a case where the clipping is forcibly performed and the number of continuous scans is set to be large, the clipping center position is newly set every time the number of scans exceeds 200. Therefore,
When the number of continuous defect scans exceeds 1100, the defect image is cut out at the 1100th scan, and the cutout center position at this time is the 1000th scan.

The image data of each defect cut out in this manner includes an LMC count value for specifying a position in the main scanning direction, a length measurement count value for specifying a position in the feed direction, and a defect type ( The channel) is stored as header information in the image data storage area of the SDRAM 51. The defect image data stored in this way is Et
hernet (R) cont CPLD (Complex Plogram L
input to the ogic device) 58. This CPLD58
Is used to absorb the difference between the data bus and the address bus between the CPU 56 and the Ethernet (registered trademark) controller 60. Ethernet controller 60 is 1
A 28 kbyte buffer memory 61 is provided, and defective image data is temporarily stored in this buffer memory 61. Then, this defective image data is output from the Ethernet controller 60 to the outside through the Ethernet PHY transceiver 62.

As shown in FIG. 1, the data processing board 25
The defect image display device 15 via the switching hub 14.
It is connected to the. As the data transfer means between the data processing board 25 and the defective image display device 15, I
It is common to use SA bus, PCI bus, etc., but ISA bus has a transfer speed of 8 Mbps and 100 m
Although it is possible to transfer data over a certain distance, it is becoming difficult to obtain a computer equipped with an ISA bus. Further, although the PCI bus has a transfer speed of 32 Mbps and is capable of high-speed data transfer, the maximum transfer distance is 50 m under the optimum condition and tens of meters under the normal condition, which is a problem in terms of versatility.

For this reason, in the present embodiment, the Ethernet LAN chip as described above is mounted on the data processing board 25, and the data processing board 25 and the defect image display device 1 are installed.
The data between 5 and 5 are connected by Ethernet, and the data is sent by IP packet transfer. As a result, even if the inspection machine main body 13a and the defect image processing device 15 are separated from each other, image data and the like can be transferred at high speed.

The defect image display device 15 restores the defect image data transferred by the IP packet and displays it on the display 15a. In addition, by compressing the digitized data, the defective image data can be stored in a hard disk, MO, DVDRAM by a well-known image compression technique such as JPEG.
(Both not shown) and the like are stored. As described above, by using JPEG, a large number of defect images can be efficiently saved when stored in a hard disk or the like. Moreover, because of JPEG, there is almost no deterioration in image quality. Further, the hard disk of the defect image display device 15 is duplicated and mirroring is performed. This makes it possible to be prepared for data loss and the like.

When the installation conditions of the inspection machine bodies 13a and 13b, the number of faces of the polygon mirror 32, the number of revolutions of the polygon mirror 32, and the traveling speed of the web 11 are known, the resolution per sampling in the scanning direction and the traveling direction can be determined. It is possible to understand each of them, perform image processing based on them, and display them on the display in a physical similarity form. The above items 1 to 3 are set in the defect image display device 15 according to the conditions of the inspection machine bodies 13a and 13b. Regarding the item, since the traveling speed is constant for each product type, a correspondence table of the product type and the traveling speed is registered, and since the product type can be known from the defect information from the data processing board 25, image processing is performed and displayed according to the conditions. .

FIG. 10A shows an example of the display screen 70 of the defect image display device 15. On the display screen 70, in addition to the defect image 71, the maximum voltage, the minimum voltage, the density (+), the density (-), the width (+), the width (-), etc. are based on the data in the defective image cutout area. Various inspection information images 72 are displayed. 10B to 10D show inspection waveforms of each scan due to the above defects. In this defect, the maximum voltage VMax = +
X1, the minimum voltage Vmin = -X2, the density (+) = 3, the density (-) = 3, the width (+) = 5, and the width (-) = 4 with respect to the threshold value THLD. In addition,
Density indicates continuity in the feed direction (sub-scanning direction), and 3 indicates that each scan is continuous three times at maximum. Further, the width indicates continuity in the main scanning direction, and 5 indicates that a maximum of 5 pieces are continuous in the main scanning direction. By displaying these inspection information images 72 on the display screen 70 adjacent to the defect image 71,
The operator can accurately and accurately determine the type of defect. Further, based on the detected actual defect and the information on the defect displayed on the display screen 70, optimum conditions for the inspection machine main body can be obtained.

As shown in FIG. 1, the overall computer 16
Controls the first and second inspection machine bodies 13a and 13b and the defect image display device 15 as a whole. The integrated computer 16 also has a dual hard disk and mirroring is performed.

In this embodiment, the normal light is shielded by the mask, and only the abnormal light is made incident on the photodetector to detect the defect by increasing the output thereof. It is also possible to adopt a normal light receiving method in which only normal light is made incident on the photodetector through the light receiving window and the defect is detected by its output fluctuation. Further, in the above-described embodiment, the defect is detected based on the transmitted light of the web, but the present invention may be applied to a method of detecting the defect using the reflected light of the web.

[0038]

According to the present invention, the first storage means for sequentially reading and storing the data of the predetermined number of continuous scanning lines of the material to be inspected and the defect discrimination for discriminating the defect of the material to be inspected from the image signal. Means and a second storage means for cutting out a predetermined area including a defect from the data of the scanning line of the first storage means and storing it as defect image data, wherein the second storage means stores the continuity of the defects. If it is determined that the defects are continuous, when the continuous defects are cut, a predetermined area including the defect is cut out, so that continuous defects may be displayed on each scanning line. Disappear. Therefore, the single defect can be surely displayed by this amount.

[Brief description of drawings]

FIG. 1 is a schematic view showing a defect inspection machine of the present invention.

FIG. 2 is an output waveform diagram of an image signal or the like.

FIG. 3 is a block diagram showing a configuration of a data processing board.

FIG. 4 is an explanatory diagram showing determination of continuity of defect images with a continuity determination value of 1.

FIG. 5 is an explanatory diagram showing determination of continuity of defect images with a continuity determination value of 2;

FIG. 6 is an explanatory diagram showing determination of continuity of defect images with a continuity determination value of 3;

FIG. 7 is an explanatory diagram showing determination of continuity of defect images with a continuity determination value of 4;

FIG. 8 is an explanatory diagram showing the determination of the continuity of defect images with a continuity determination value of 3 and a forced cutout value of 150.

FIG. 9 is an explanatory diagram showing the determination of the continuity of defect images with a continuity determination value of 3 and a forced cutout value of 1100.

FIG. 10 is an explanatory diagram showing a defect image, an inspection waveform at this time, and defect information obtained based on this inspection waveform.

[Explanation of symbols]

10 defect inspection machine 11 Web 12 Image detection means 13a, 13b Inspection machine body 15 Defect image display device 16 Controlling computer 23 receiver board 25 Data processing board

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2F065 AA49 BB01 CC02 CC06 CC19                       FF42 FF59 GG04 GG12 HH04                       JJ01 JJ05 JJ17 JJ23 LL01                       LL13 LL62 MM16 QQ03 QQ13                       QQ24 QQ27                 2G051 AA34 AA37 AA41 AA51 AB07                       BA10 BB11 CA02 CA07 CB02                       CC07 EA12 EA14 EA16 EB01                       EB09 ED08 ED30                 5B057 AA01 AA03 AA17 BA02 CA08                       CA12 CA16 CE09 CH11 CH14                       DA03 DB02 DB09 DC30

Claims (5)

[Claims] 1. A defect inspection machine for detecting defects in a material to be inspected from an image signal obtained by scanning an inspection surface of the material to be inspected, wherein data of a predetermined number of continuous scanning lines of the material to be inspected is sequentially obtained. First storage means for reading and storing, defect determination means for determining a defect of a material to be inspected from the image signal, and a predetermined area including the defect is cut out from data of a scanning line of the first storage means to detect a defect. Second storage means for storing as image data, wherein the second storage means determines continuity of the defect, and when the defect is continuous, when the continuous defect is cut off, A defect inspection machine, which cuts out a predetermined area including a defect. 2. A defect specifying unit for specifying the position of the defect based on the position data in the main scanning direction and the position data in the web running direction of the defect, and the position data together with the defect image data is stored in the second storage unit. The defect inspection machine according to claim 1, which is stored. 3. The first storage means and the second storage means, an SDRAM, a converter for AD-converting the image signal into data of the scan line, and scan line data from the converter. The defective image data is cut out from the bulk memory area based on the write means for writing in the bulk memory area of the SDRAM, the defect signal from the defect determining means and the position data from the defect specifying means, and the cut out defect image SD data
3. The defect inspection machine according to claim 2, further comprising: a cutout unit for storing the defect image data in the RAM and a transfer unit for transferring the data of the defect image data stored in the image data storage region. . 4. The defect inspection machine according to claim 3, wherein the cut-out means stores defect image data and defect information obtained from the scanning line data corresponding to the defect image data in association with each other. . 5. A defect image display means for restoring the defect image data transferred from the transfer means and displaying it on a display, and a storage means for compressing and storing the restored defect image. The defect inspection machine according to claim 4, which is characterized in that.