JP2013160590A - Surface defect inspection method and surface defect inspection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To rate an inspected object on the basis of a minute defect that becomes a problem at the time of frequent occurrence.SOLUTION: A determination unit 17 executes the steps of: calculating a surface defect quantity in each unit area formed by dividing an inspected object 10 in longitudinal and width directions, on the basis of a type and level of surface defect; comparing the surface defect quantity with a defect quantity threshold and extracting a unit area with the surface defect quantity greater than the defect quantity threshold as a threshold exceeding area; determining whether or not a unit area adjacent in the longitudinal direction of the threshold exceeding area is the threshold exceeding area, with respect to each of the extracted threshold exceeding areas; extracting the threshold exceeding area as a longitudinally-sequential threshold exceeding area when the unit area adjacent in the longitudinal direction of the threshold exceeding area is the threshold exceeding area; calculating the number of longitudinally-sequential threshold exceeding areas in the inspected object 10; and rating the inspected object 10 on the basis of the calculated number of longitudinally-sequential threshold exceeding areas.

Description

  The present invention relates to a surface defect inspection method and a surface defect inspection apparatus for inspecting a surface defect of a strip-shaped object to be continuously conveyed.

  Conventionally, surface defects of a strip-shaped object such as a steel plate or an aluminum plate have been inspected. If a surface defect is detected in such an inspection, remove the surface defect part or mark the surface defect part so that the surface defect part can be easily re-inspected. Shipped. However, removing the surface defect portion or marking the surface defect portion is an over action depending on the quality required by the customer, and increases the manufacturing cost of the object to be inspected.

  Against this background, in recent years, surface defect inspection devices have been proposed that rank an object to be inspected in order to determine whether the object to be inspected can be shipped according to the quality required by the customer (Patent Literature). 1). Specifically, this apparatus determines a representative defect of each unit length region formed by dividing the object to be inspected for each unit length based on the type and degree of the defect, and the determined representative defect is covered. The pass / fail determination of the object to be inspected is performed based on the ratio of being mixed into the inspection object and the preset allowable range. According to such a surface defect inspection apparatus, it is possible to prevent overaction such as removing the surface defect portion or marking the surface defect portion, and to ship the inspection object according to the required quality on the customer side. At the same time, the manufacturing cost can be reduced.

JP 2006-242906 A

  In recent years, the level of customer requirements for the surface quality of the object to be inspected has increased, and there have been an increasing number of cases where minute defects of φ0.2 to 0.5 mm, which have not been a problem until now, become a problem at customers. Yes. Such a micro defect is not a problem with a single shot, but is a level that causes a problem when swarmed. However, the surface defect inspection apparatus described in Patent Document 1 can perform the rating of the inspected object based on the defect that causes a problem in a single shot, but performs the rating of the inspected object based on the defect that causes a problem when swarming. It is not possible. For this reason, it has been expected to provide a technique capable of grading an object to be inspected based on minute defects that become a problem when swarming.

  The present invention has been made in view of the above problems, and its object is to provide a surface defect inspection method and a surface defect inspection apparatus capable of rating an object to be inspected based on minute defects that become a problem when swarming. It is in.

  In order to solve the above problems and achieve the object, a surface defect inspection method according to the present invention is formed by dividing an object to be inspected in the longitudinal direction and the width direction based on the type and degree of surface defects. A first step of calculating the number of surface defects in each unit region, and a second step of extracting a unit region in which the number of surface defects is greater than a predetermined threshold as a region exceeding the threshold by comparing the number of surface defects with a predetermined threshold. For each extracted threshold crossing region, it is determined whether or not the unit region adjacent in the longitudinal direction of the threshold crossing region is a threshold crossing region, and the unit region adjacent in the longitudinal direction of the threshold crossing region is If the region exceeds the threshold, a third step of extracting the region exceeding the threshold as a longitudinal continuous threshold exceeding region, and the number of the longitudinal continuous threshold exceeding regions in the subject Out, characterized in that it comprises a fourth step of grading the object to be inspected, the based on the number of the calculated longitudinal continuous threshold beyond regions.

  In the surface defect inspection method according to the present invention, in the above invention, the first step multiplies the number of surface defects by a predetermined weighting factor determined according to the type and degree of the surface defect. The method includes a step of calculating the number of weighted defects according to the type and degree, and calculating the sum of the calculated number of weighted defects as the number of surface defects in each unit region.

  According to the surface defect inspection method according to the present invention, in the above invention, based on the type and degree of the surface defect, the representative defect in each unit length region formed by dividing the inspection object in the longitudinal direction is determined, A calculation step for calculating a mixing rate of representative defects in the inspection object, and a determination step for rating the inspection object based on the mixing rate of the representative defects and performing pass / fail determination of the inspection object based on the rating result. It is characterized by including.

  In the surface defect inspection method according to the present invention, in the above invention, the calculation step, the determination step, and the first to fourth steps are respectively performed, and passed by a rating based on a mixing rate of the representative defects, and the It is characterized by determining with the pass only with respect to the to-be-inspected object determined by the rating by the 1st-4th step.

  In order to solve the above problems and achieve the object, the surface defect inspection apparatus according to the present invention is formed by dividing the object to be inspected in the longitudinal direction and the width direction based on the type and degree of surface defects. Means for calculating the number of surface defects in each unit region, means for extracting a unit region in which the number of surface defects is greater than the predetermined threshold as a region exceeding the threshold by comparing the number of surface defects with a predetermined threshold, and extraction For each of the threshold-exceeding regions, it is determined whether or not a unit region adjacent in the longitudinal direction of the threshold-exceeding region is a threshold-exceeding region. If there is, means for extracting the region exceeding the threshold value as the longitudinal direction continuous threshold value exceeding region, calculating the number of the longitudinal direction continuous threshold value exceeding regions in the subject, and calculating the calculated longitudinal direction Based on the number of consecutive threshold beyond region, characterized in that it comprises means for grading the object to be inspected, the.

  According to the surface defect inspection method and the surface defect inspection apparatus according to the present invention, it is possible to rank an object to be inspected based on a minute defect that becomes a problem when clustering.

FIG. 1 is a block diagram showing a configuration of a surface defect inspection apparatus according to an embodiment of the present invention. FIG. 2 is a flowchart showing a flow of single defect rating processing according to an embodiment of the present invention. FIG. 3 is a schematic diagram for explaining the unit length region. FIG. 4 is a flowchart showing a flow of cluster defect rating processing according to an embodiment of the present invention. FIG. 5 is a schematic diagram for explaining a unit region. FIG. 6 is a schematic diagram for explaining the determination process of the region that exceeds the continuous threshold value in the longitudinal direction. FIG. 7 is a flowchart showing the flow of pass / fail determination processing according to an embodiment of the present invention.

  Hereinafter, a surface defect inspection apparatus and a surface defect inspection method thereof according to an embodiment of the present invention will be described with reference to the drawings.

[Configuration of surface defect inspection equipment]
First, with reference to FIG. 1, the structure of the surface defect inspection apparatus which is one Embodiment of this invention is demonstrated.

  FIG. 1 is a block diagram showing a configuration of a surface defect inspection apparatus according to an embodiment of the present invention. As shown in FIG. 1, the surface defect inspection apparatus according to an embodiment of the present invention includes a front surface side and a back surface of a strip-shaped object 10 having a relatively thin thickness, such as a steel plate or an aluminum plate that is continuously conveyed. Image input units 11a and 11b are provided opposite to each other. The image input units 11a and 11b perform optical correction with an image input unit such as a CCD camera or a photomultiplier tube, an optical system for guiding light from the front or back surface of the inspection object 10 to the image input unit. And a filter.

  Image processing units 12a and 12b are connected to the image input units 11a and 11b, respectively. The image processing units 12a and 12b include an amplifier that amplifies the electric signal from the image input units 11a and 11b, a filter that cuts a noise signal included in the electric signal from the image input units 11a and 11b, and the image input units 11a and 11b. Input means such as an A / D converter that converts an analog signal from a digital signal into a digital signal, various correction processes such as shading correction to remove the influence of formation noise from the input signal, preprocessing such as a spatial filter, and A processing unit that executes processing such as n-value conversion processing for classifying the obtained image into two or more values and extraction processing for extracting defect (fats) candidates based on a predetermined threshold.

  Feature amount calculation units 13a and 13b are connected to the image processing units 12a and 12b, respectively. The feature amount calculation units 13a and 13b are the length, width, and area of the defect candidates extracted by the image processing units 12a and 12b, the distance in the longitudinal direction from the inspected object reference line, and the width from the inspected object reference end. A feature amount of a defect candidate such as a direction distance is calculated. A storage unit 16 is connected to the feature amount calculation units 13a and 13b. The storage unit 16 stores the feature amounts of defect candidates calculated by the feature amount calculation units 13a and 13b.

  The defect type determination unit 14 determines the type of defect candidate from the feature amount of the defect candidate according to a predetermined algorithm. Further, the defect type determination unit 14 is connected to the defect degree determination unit 15, and the defect degree determination unit 15 determines the degree of defect candidates from the feature amount of the defect candidate and the defect candidate type determined by the defect type determination unit 14. Determine. Data relating to the types and degrees of defect candidates obtained by the defect type determination unit 14 and the defect level determination unit 15 are stored in the storage unit 16.

  A determination unit 17 is connected to the defect type determination unit 14 and the defect degree determination unit 15. Based on the data regarding the type and degree of defect candidates stored in the storage unit 16, the determination unit 17 determines the defect contamination rate on the surface, back surface, and both surfaces of the object to be inspected, the defect contamination rate for each defect degree, and the defect occurrence factor. The other defect mixing rate and the combined defect mixing rate are calculated, and the inspected object 10 is rated based on the calculation result. A result output unit 18 is connected to the determination unit 17, and the result output unit 18 outputs the determination defect to a display device such as a CRT, a printing device, a lighting device, and an annunciator such as a buzzer.

  The surface defect inspection apparatus having such a configuration performs a single defect rating process, a cluster defect rating process, and a pass / fail judgment process described below, and a single defect (defect that is a problem even with a single shot) and a cluster defect (single shot). In this case, the inspection object 10 is rated based on the minute defect that causes a problem when swarming, and the pass / fail determination of the inspection object 10 is performed based on the rating result. In the present embodiment, the size of the single defect has a size equal to or larger than the threshold value set to 0.5 to 1 mm or more, and the minute defect has a size smaller than the threshold value set in the range of 0.5 to 1.0 mm. It shall have However, this threshold value can be adjusted according to the quality level required for the device under test 10. In addition, regarding the cluster defect, when there are two or more minute defects in a unit area, a collection of these minute defects is collectively referred to as a cluster defect. Hereinafter, with reference to the flowcharts shown in FIGS. 2, 4, and 7, the operation of the surface defect inspection apparatus when executing the single defect rating process, the cluster defect rating process, and the pass / fail determination process will be described.

[Single defect rating process]
First, with reference to the flowchart shown in FIG. 2, the operation of the surface defect inspection apparatus when executing the single defect rating process for rating the inspected object 10 based on the single defect will be described.

  FIG. 2 is a flowchart showing a flow of single defect rating processing according to an embodiment of the present invention. The flowchart shown in FIG. 2 starts at the timing when the data regarding the type and degree of the defect candidate is determined by the defect type determination unit 14 and the defect level determination unit 15, and the single defect rating process proceeds to the process of step S1.

In the process of step S <b> 1, the determination unit 17 reads single defect data from the storage unit 16 and extracts a single defect for each unit length of the inspected object 10. In the present embodiment, as shown in FIG. 3, the determination unit 17 divides the longitudinal direction (length L) of the device under test 10 into a plurality of unit length regions _RA having a unit length n, Single defects are extracted for each of a plurality of unit length regions _RA . Further, when the single defect extends over two regions divided by the unit length, the determination unit 17 has a single defect in both regions, or, for example, a single defect having a longer single defect exists. A single defect is extracted as existing in either one of the regions. In addition, when there is a very long single defect extending over three or more regions, the determination unit 17 may exceptionally include single defects in all three or more regions. There is no limit. Thereby, the process of step S1 is completed and the single defect rating process proceeds to the process of step S2.

  In the process of step S2, the determination unit 17 determines a representative defect for each unit length of the object 10 to be inspected based on the process result of step S1. The representative defect is the single defect with the lowest degree. If there are a plurality of single defects of the same degree, the determination unit 17 sets the single defect having the highest priority according to the priority order of single defects as the representative defect. This is the case where, for example, “Defect type: Hege, degree: C”, “Defect type: Scratch, degree: C”, “Defect type: Pushing, degree: C” is detected, and the priority order is When it is higher in the order of the pressing bar, the scratch, and the scab, the determination unit 17 determines the representative defect as “defect type: scab, degree: C”. Thereby, the process of step S2 is completed and the single defect rating process proceeds to the process of step S3.

  In the process of step S3, the determination unit 17 calculates the mixing rate of the representative defect determined in the processing of step S2 in the inspection object 10 as the defect mixing rate by using the following formula (1). Note that the parameter m in Equation (1) indicates the number of representative defects in the entire inspection object 10, the parameter n indicates the unit length, and the parameter L indicates the length of the inspection object 10. Then, the determination unit 17 calculates a front surface defect mixing rate, a back surface defect mixing rate, a double-sided defect mixing rate, a defect mixing rate by defect degree, a defect mixing rate by defect generation factor, and a combined defect mixing rate described below. Thereby, the process of step S3 is completed and the single defect rating process proceeds to the process of step S4.

[Surface defect contamination rate, back surface defect contamination rate, double-sided defect contamination rate]
The determination unit 17 calculates the defect contamination rate due to the representative defects on the front surface and the back surface as the surface defect contamination rate and the back surface defect contamination rate, respectively. Further, the determination unit 17 determines the representative defects on both surfaces in the same manner as described above by comparing the representative defects on the front and back surfaces in the same unit length region, and the defect calculated from the determined representative defects. The mixing rate is calculated as the double-sided defect mixing rate. This means that the double-sided defect mixing rate is not counted separately for the front surface and the back surface, but as a single object. Specifically, there are “Defect type: Hege, degree: C” and “Defect type: Scratch, degree: B” on the front surface, and “Defect type: Pushing, degree: C” on the back surface. The determination unit 17 sets “defect type: baldness, degree: C” on the surface as a representative defect on both sides. In addition, when the representative defects on the front and back sides are the same defect type and the same level, the defect on either side is the same result as the representative defect, but for example, the defect on the front side is set to be preferentially adopted. It is desirable to keep it.

[Defect mixing rate by defect level]
The determination unit 17 calculates the defect mixing rate for each defect level when the defect level is divided into a plurality of ranks as the defect mixing rate for each defect level. Moreover, the determination part 17 calculates what accumulated all the defect mixture rates of the grade worse than a certain defect grade. Specifically, as shown in Table 1 below, when the degree of defects is set to five ranks A to E (the degree of defects worsens in the order of A, B, C, D, and E), the determination unit 17 calculates the defect mixing rate (defect mixing rate by defect level) x1 to x5 for each of the defects A to E. Note that the cumulative value of the defect mixing ratios x1 to x5 according to the degree of defects is 100% at the maximum. Further, when ranks C to E of the degree of defects are set as management items, the determination unit 17 calculates a value obtained by accumulating the defect mixture rates x3 to x5 of the ranks C to E of the degree of defects.

[Defect mixing rate by defect cause]
The determination unit 17 refers to the data stored in the storage unit 16 and displays representative defects according to the cause of the defect such as an original plate defect that occurs before the upper process and a self-line defect that occurs in the self-line. Classify and calculate the defect mixing rate (defect mixing rate by defect occurrence factor) for each factor of the representative defect. Specifically, the determination unit 17 classifies the representative defects based on the defect types, and controls the defect mixture rate as shown in Table 2 below for each defect type. Here, the defect types and the cause of defects are as follows: Hege and sliver are caused by steelmaking, scale is caused by hot-rolling, dross and non-plating are caused by plating, and scratches and pressing are caused by plate trouble There is a relationship like a defect.

[Combination defect mixing rate]
The determination unit 17 calculates a defect mixing rate by combining the above-described defect mixing rates. Specifically, in the case shown in Table 2, the determination unit 17 has a degree of C to E in each of a defect caused by steelmaking, a defect caused by hot rolling, a defect caused by plating, and a defect caused by a plate trouble. The cumulative value of the defect mixing rate is calculated, or the cumulative value of the defect mixing rate that combines the steel-making defect and the hot-rolling defect is calculated. The combination of defect types is appropriately set according to necessary information.

  In the process of step S4, the determination unit 17 ranks the inspected object 10 by comparing each defect mixture rate calculated by the process of step S3 with the allowable range of the defect mixture rate determined in advance for each customer requirement specification. I do. Examples of the allowable range of the defect mixing rate include the following ranges. Thereby, the process of step S4 is completed and a series of single defect rating processes are complete | finished.

[Example of acceptable range of defect contamination]
(1) Grade A products (products that can be sold to customers (or uses) α, β, γ) → The contamination rate of defects of grade C or higher (bad grades including grades C to E) is less than 1% (2 ) Grade B products (products that can be sold to customers (or uses) β and γ) → Less than 2% of defects with a degree C or higher (3) Grade C products (to customers (or uses) γ) Products that can be sold) → Less than 5% defect mixing rate (4) Products subject to scrap → More than 5% defect mixing rate> 5%

[Group defect rating processing]
Next, with reference to the flowchart shown in FIG. 4, operation | movement of the surface defect inspection apparatus at the time of performing the cluster defect rating process which ranks the to-be-inspected object 10 based on a cluster defect is demonstrated.

  FIG. 4 is a flowchart showing a flow of cluster defect rating processing according to an embodiment of the present invention. The flowchart shown in FIG. 4 starts at the timing when the defect type determination unit 14 and the defect degree determination unit 15 determine data regarding the type and degree of defect candidates, and the cluster defect rating process proceeds to the process of step S11.

In the process of step S11, the determination unit 17 divides the device under test 10 into a plurality of unit areas. Specifically, determining unit 17, as shown in FIG. 5, to form a plurality of unit regions R _B by dividing the object to be inspected 10 in the longitudinal direction and the width direction. Then, the determination unit 17 divides the defect information stored in the storage unit 16 into each unit region, and extracts data on a minute defect whose center position is within the unit region for each unit region. Thereby, the process of step S11 is completed and the swarm defect rating process proceeds to the process of step S12.

  In the process of step S12, the determination unit 17 calculates the number of weighted defects of minute defects for each unit region using the process result of step S11. Specifically, the determination unit 17 assumes that there are m types of minute defects (m = 1 to m), the number of defects of the mth minute defect is Nm, and the weight of the mth minute defect is Km. The sum of the number of weighted defects for each type of micro defect is calculated for each unit region as the number of weighted defects in the unit region by using the following formula (2).

  More specifically, there are four types (m = 4) of large, medium, small, and minute micro defects, and the number (Nm) of each micro defect in a unit region is 0, 1, 3, and 4, respectively. If the weight coefficient (Km) of each micro defect is 10, 8, 6, 2, respectively, the determination unit 17 calculates the number of weighted defects in the unit area as shown in Table 3 below. Thereby, the process of step S12 is completed and the swarm defect rating process proceeds to the process of step S13.

  In the process of step S13, the determination unit 17 compares the weighted defect number of each unit area calculated by the process of step S12 with a predetermined defect number threshold value, so that the weighted defect number is determined as the defect number threshold value. It is determined for each unit area whether or not it exceeds the limit. Then, the determination unit 17 is a unit region determination flag M (i, j) (i, j, where the number of weighted defects exceeds the defect number threshold value, and is a code indicating the position in the longitudinal direction and the width direction of the unit region, respectively. , I is an integer varying from 1 to i, and j is an integer varying from 1 to j).

Specifically, when the defect number threshold value is 50, and the weighted defect numbers of the unit regions R _B 1, R _B 2, R _B 3, and R _B 4 are 20, 40, 70, and 90, respectively, As illustrated in FIG. 5, the determination unit 17 sets the values of the determination flags M of the unit regions R _B 1, R _B 2, R _B 3, and R _B 4 to 0, 0, 1, and 1, respectively. In the present embodiment, the determination flag M = 1 indicates that the number of weighted defects exceeds the defect number threshold, and the determination flag M = 0 indicates that the number of weighted defects is equal to or less than the defect number threshold. The initial value of the determination flag M is set to 0. Thereby, the process of step S13 is completed and the swarm defect rating process proceeds to the process of step S14.

In the process of step S14, the determination unit 17 uses the result of the process of step S13, the front area adjacent to the longitudinal direction of the target unit area (i, j) (the area on the downstream side in the transport direction) (i− 1, j), it is determined for each unit area whether or not the number of weighted defects exceeds the defect number threshold. Then, the determination unit 17 determines that the unit region (i, j) in which the number of weighted defects in the front region (i-1, j) adjacent in the longitudinal direction exceeds the defect number threshold is a region that exceeds the continuous threshold in the longitudinal direction. . Specifically, as illustrated in FIG. 6, the determination unit 17 determines the value of the determination flag M (i, j) of the target unit region (i, j) and the front region (i−1) adjacent in the longitudinal direction. , J) is multiplied by the value of the determination flag M (i−1, j), and when the multiplication value is 1, the unit area (i, j) is determined to be an area that exceeds the continuous threshold value in the longitudinal direction. In the example shown in FIG. 6, since the multiplication values of the unit areas R _B 5, R _B 6, and R _B 7 are all 0, the unit areas R _B 5, R _B 6, and R _B 7 Is not determined. On the other hand, since the multiplication value of the unit region R _B 8 is 1, the unit region R _B 8 is determined to be a region exceeding the longitudinal direction continuous threshold value. Thereby, the process of step S14 is completed, and the cluster defect rating process proceeds to the process of step S15.

  In the process of step S15, the determination unit 17 calculates the number of areas exceeding the continuous threshold value in the longitudinal direction in the inspected object 10 using the processing result of step S14. Specifically, the determination unit 17 substitutes the value of the determination flag M (i, j) of each unit region (i, j) into the following formula (3), thereby increasing the length in the inspected object 10. The number of areas beyond the direction continuation threshold is calculated. Thereby, the process of step S15 is completed and the swarm defect rating process proceeds to the process of step S16.

  In the process of step S16, the determination unit 17 determines the number of areas in the inspected object 10 that exceed the continuous threshold value in the longitudinal direction and the number of areas that exceed the continuous threshold value in the longitudinal direction that are determined in advance for each customer requirement specification calculated in the process in step S15. The to-be-inspected object 10 is rated by comparing with the allowable range. The following ranges can be exemplified as the allowable range of the number of regions exceeding the longitudinal direction continuous threshold. Thereby, the process of step S16 is completed and a series of swarm defect rating processes are completed.

[Example of allowable range of the number of areas exceeding the continuous threshold in the longitudinal direction]
(1) Grade A products (products that can be sold to customers (or uses) α, β, γ) → Number of areas that exceed the threshold in the longitudinal direction is less than 2 (2) Grade B products (customers (or uses)) Products that can be sold for β and γ) → Number of areas that exceed the continuous threshold in the longitudinal direction is less than 4 (3) Grade C products (products that can be sold to customers (or applications) γ) → Area that exceeds the continuous threshold in the longitudinal direction Is less than 6 (4) Products subject to scrap → The number of areas exceeding the continuous threshold in the longitudinal direction is 6 or more

[Pass / fail judgment processing]
Finally, with reference to the flowchart shown in FIG. 7, the operation of the surface defect inspection apparatus when executing the pass / fail determination process of the inspected object 10 based on the single defect rating process and the swarm defect rating process will be described.

  FIG. 7 is a flowchart showing the flow of pass / fail determination processing according to an embodiment of the present invention. The flowchart shown in FIG. 7 starts at the timing when the single defect rating process and the swarm defect rating process are completed, and the pass / fail determination process proceeds to the process of step S21.

  In the process of step S21, the determination part 17 determines whether the rating determination of the to-be-inspected object 10 is a pass based on the result of the single defect rating process. For example, in the single defect rating process, when the inspected object 10 manufactured for the customer (or application) α is rated as a rating class B product, the determination unit 17 determines that the inspected object 10 is rejected. On the other hand, when the inspected object 10 manufactured for the customer (or application) α is rated as a grade A grade product in the single defect rating process, the determination unit 17 determines that the inspected object 10 is acceptable. As a result of the determination, when the rating determination of the device under test 10 is acceptable, the determination unit 17 advances the pass / fail determination process to the process of step S22. On the other hand, when the rating determination of the device under test 10 fails, the determination unit 17 advances the pass / fail determination process to the process of step S24.

  In the process of step S22, the determination part 17 determines whether the rating determination of the to-be-inspected object 10 is a pass based on the result of a cluster defect rating process. For example, when the inspected object 10 manufactured for the customer (or application) β is rated as a rated C grade product in the cluster defect rating process, the determination unit 17 determines that the inspected object 10 is rejected. On the other hand, when the inspected object 10 manufactured for the customer (or application) β is rated as a rated A grade product in the swarm defect rating process, the determination unit 17 determines that the inspected object 10 is acceptable. As a result of the determination, when the rating determination of the device under test 10 is acceptable, the determination unit 17 advances the pass / fail determination process to the process of step S23. On the other hand, when the rating determination of the device under test 10 fails, the determination unit 17 advances the pass / fail determination process to the process of step S24.

  In the process of step S <b> 23, the determination unit 17 determines that the inspection object 10 is acceptable, and outputs information indicating that the inspection object 10 is acceptable to the result output unit 18. Thereby, the process of step S23 is completed and a series of pass / fail determination processes are completed.

  In the process of step S <b> 24, the determination unit 17 determines that the object 10 is rejected, and outputs information indicating that the object 10 is rejected to the result output unit 18. Thereby, the process of step S24 is completed and a series of pass / fail determination processes are completed.

  As is clear from the above description, in the surface inspection apparatus according to an embodiment of the present invention, the determination unit 17 divides the device under test 10 in the longitudinal direction and the width direction based on the type and degree of surface defects. By comparing the number of surface defects and the defect number threshold in each unit region formed by the above, a unit region where the number of surface defects is larger than the defect number threshold is extracted as a region exceeding the threshold, and for each extracted region exceeding the threshold, It is determined whether or not a unit region adjacent to the longitudinal direction of the region exceeding the threshold is a region exceeding the threshold. If the unit region adjacent to the longitudinal direction of the region exceeding the threshold is a region exceeding the threshold, the region exceeding the threshold is continuously connected in the longitudinal direction. Extracted as a region exceeding the threshold value, calculating the number of longitudinal direction continuous threshold value exceeding regions in the inspection object 10, and inspecting object 1 based on the calculated number of longitudinal direction continuous threshold value exceeding regions The ranking. According to such a surface inspection apparatus, it is possible to rank an object to be inspected based on a minute defect that becomes a problem when swarming.

  Moreover, in the surface inspection apparatus which is one embodiment of the present invention, since the determination unit 17 performs the rating of the inspection object 10 due to a single defect in addition to the rating of the inspection object 10 due to the cluster defect, the defect that can be inspected As a result, the inspection can be performed in a wide range from a minute defect to a large defect, and there is no inspection omission and a highly accurate defect inspection can be performed.

  Although the embodiment to which the invention made by the present inventor is applied has been described above, the present invention is not limited by the description and the drawings that form a part of the disclosure of the present invention according to this embodiment. For example, the single defect rating process is executed, and when the result of the single defect rating process is acceptable in the process of step S21, the cluster defect rating process is executed, and the processes after step S22 are performed based on the result of the cluster defect rating process. May be executed. As described above, other embodiments, examples, operation techniques, and the like made by those skilled in the art based on the present embodiment are all included in the scope of the present invention.

11a, 11b Image input units 12a, 12b Image processing units 13a, 13b Feature amount calculation unit 14 Defect type determination unit 15 Defect degree determination unit 16 Storage unit 17 Determination unit 18 Result output unit

Claims (5)

A first step of calculating the number of surface defects in each unit region formed by dividing the object to be inspected in the longitudinal direction and the width direction based on the type and degree of surface defects;
A second step of extracting a unit region where the number of surface defects is greater than a predetermined threshold as a region exceeding the threshold by comparing the number of surface defects with a predetermined threshold;
For each extracted region exceeding the threshold, it is determined whether or not the unit region adjacent in the longitudinal direction of the region exceeding the threshold is a region exceeding the threshold, and the unit region adjacent in the longitudinal direction of the region exceeding the threshold is the region exceeding the threshold A third step of extracting the region exceeding the threshold as a region continuously exceeding the threshold in the longitudinal direction;
A fourth step of calculating the number of regions that exceed the longitudinal continuous threshold value in the body to be inspected, and ranking the device based on the calculated number of regions exceeding the continuous threshold value in the longitudinal direction;
A surface defect inspection method characterized by comprising:   The first step calculates the number of weighted defects according to the type and degree of surface defects by multiplying the number of surface defects by a predetermined weighting factor determined according to the type and degree of surface defects, The surface defect inspection method according to claim 1, further comprising a step of calculating a total sum of the calculated weighted defects as the number of surface defects in each unit region. A calculation step for determining a representative defect in each unit length region formed by dividing the object to be inspected in the longitudinal direction based on the type and degree of the surface defect, and calculating a mixing rate of the representative defect in the object to be inspected When,
A rating step that ranks the object to be inspected based on the mixing ratio of the representative defects, and performs pass / fail determination of the object to be inspected based on the rating result;
The surface defect inspection method according to claim 1, wherein   Each of the calculation step, the determination step, and the first to fourth steps is executed, and the pass is determined by the rating based on the mixing ratio of the representative defects, and the pass is determined by the rating by the first to fourth steps. The surface defect inspection method according to any one of claims 1 to 3, wherein it is determined that the test is accepted only for the object to be inspected. Based on the type and degree of surface defects, means for calculating the number of surface defects in each unit region formed by dividing the object to be inspected in the longitudinal direction and the width direction;
Means for extracting, as a region exceeding the threshold, a unit region in which the number of surface defects is greater than the predetermined threshold by comparing the number of surface defects with a predetermined threshold;
For each extracted region exceeding the threshold, it is determined whether or not the unit region adjacent in the longitudinal direction of the region exceeding the threshold is a region exceeding the threshold, and the unit region adjacent in the longitudinal direction of the region exceeding the threshold is the region exceeding the threshold Means for extracting the region exceeding the threshold as the longitudinal continuous threshold exceeding region,
Means for calculating the number of areas in the longitudinal direction beyond the continuous threshold value in the inspected body, and classifying the object to be inspected based on the calculated number of areas in the longitudinal direction continuous threshold value exceeding;
A surface defect inspection apparatus comprising:

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