JPH03257308A - Checking apparatus of outer appearance - Google Patents

Abstract

PURPOSE:To inspect an insulator outdoors by detecting a part where a straight part of the photographed line image of the insulator is shifted from a straight line. CONSTITUTION:An image input means 7 stores image of an insulator 7 into an input memory 21. An area setting means 31 indicates a checking area 50 of the input image to an image processing part 24 which in turn extracts a part of a large difference of the concentration in the indicated area, and forms and stores a line image into an image memory 25. A periodic evaluating means 51 provides sampling lines 81-85 in a longitudinal direction with a suitable distance within the area 50, with measuring the relative distance of crossing points between each sampling line and a straight line corresponding to each fold of the insulator 7 and, feeding the data to an abnormality judging means 6. A continuity evaluating means 52 traces the line straight corresponding to each fold, thereby feeding the data of interruption and divergence to the means 6. An inclination change evaluating means 53 obtains an inclination of the straight line corresponding to each fold at each point on the sampling line, and further obtains the difference of the inclinations of the adjacent two points. The difference is fed to the means 6. In this manner, the means 6 can detect the presence or absence of abnormality of each fold of the insulator from the data.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a visual inspection device for detecting abnormalities in the visual appearance of insulators in, for example, substations.

[Prior Art] Currently, workers at substations regularly patrol and visually inspect insulators for appearance abnormalities such as cracks and chips.

Although there is no example of automating this work yet, as a device for monitoring abnormalities in the appearance of the inspected object, for example, as shown in Japanese Patent Application Laid-open No. 82-222393 shown in Fig. It is conventionally known to compare images of

In FIG. 5, (1) is an image processing means that converts the image signal of the object to be inspected into a quantity f, and (2) is an image processing means, which includes a human image memory (21) that sequentially stores the human images, and A reference image memory (22) that stores in advance an image when no abnormality exists in the image, and an image processing unit (23) that compares the stored contents of the human image memory (21) and the reference image memory (22) and extracts a changed image. ). (3) is an abnormality determination means for determining the presence or absence of an abnormality based on the information from the image processing means (2), (4) is an output means for outputting the abnormality determination result, and (31) is an area for setting the area to be monitored. The setting means (321) to (32,) are a plurality of detection area memories that store set detection areas.

Next, the operation will be explained. The images of the monitoring area obtained by the image processing (1) are sequentially input to the image memory (21) in the image processing (1) (2) means (2). The reference image memory (22) stores in advance an image when no abnormality exists in the monitoring area. The image processing section (23) compares the stored contents of the human image memory (21) and the reference image memory (22) and extracts a changed partial image. The abnormality determination means (3) outputs an output means (4) when there is a brightness change in the area indicated by the detection area memory (3L).
to issue an alarm. The reason why a plurality of detection area memories are provided is to set a plurality of locations as detection areas.

[Problem to be Solved by the Invention] Since the conventional appearance inspection device is configured as described above, the image of an insulator in an outdoor environment changes depending on the illuminance and direction of the light, which becomes feminine over time. There is a problem in that it is difficult to detect abnormalities in appearance by comparison with a reference image.

This invention was made in order to solve the above-mentioned problems, and it can be used in an outdoor environment without being affected by the illuminance or direction of the light. ) The purpose is to obtain an appearance inspection device that can inspect Y-.

[Means for Solving the Problems] The appearance inspection apparatus according to the present invention includes an image processing means for extracting a portion with a large black-and-white density difference from an image obtained by imaging an insulator having folds and converting it into a line image; The apparatus is equipped with an image defect detection means for detecting, as a defect, a portion in the line image in which a straight line portion corresponding to an edge of the fold deviates from a straight line.

[Operation] The image processing means of the appearance inspection apparatus according to the present invention detects a location where a straight line part in a line image taken of an insulator deviates from a straight line.

[Embodiments of the Invention] Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the apparatus of the present invention. In the figure, (
2) is an image processing means, which includes a human image memory (21), an image processing unit (24) that extracts a portion with a large black-and-white density difference of the image obtained by the image human power means (1) and converts it into a line image, and an image processing unit. It is composed of an image memory (25) that stores the image processing results by the section (24). (5) is an image defect detection means, which includes a periodicity evaluation means (51) for evaluating periodicity in line images (3) and (4), a continuity evaluation means (52) for evaluating continuity, and a change in slope, respectively. It consists of a slope change evaluation means (53) for evaluating (6
) is an abnormality determining means that determines whether or not the image is defective based on the information from the image defect detecting means (5). The other parts are the same as the corresponding parts of the conventional device shown in FIG.

FIG. 2 is a diagram showing an image of an insulator that is an object to be inspected, FIG. 3 is a diagram showing its line image, and FIG. 4 is an explanatory diagram of periodicity evaluation. In the figure, (7) is the insulator, (50) is the inspection area, (71) is the missing part of the fold, and (81) to (85) are the sampling lines provided vertically in the line image in Figure 3, respectively. be.

Next, the operation will be explained. First, an image of an insulator (7) having folds, which is an object to be inspected, is converted into an image by the human image means (1) as shown in FIG. 2, and is stored in the human image memory (21). Since the position and direction of imaging are determined in advance, the area setting means (31) sets the inspection area (5) of the manual image.
0) to the image processing unit (24). Image processing section (2
4) sequentially performs differential processing, binarization processing, and thinning processing only on the designated area to convert it into a line image as shown in the third section, and stores it in the image memory (25). The part corresponding to the edge of the folds of the insulator (7) is a straight line, but the chipped part (71) has a deformed shape compared to the other lines, an extra line, or a chipped part (71). Depending on the combination of and sunlight conditions, the line in the - section may fade. The periodicity evaluation means (51) is configured to measure the line image of FIG. 3 at appropriate intervals in the inspection area (50) indicated by the area setting means (31) in the vertical direction. Sampling lines (81) to (85) are provided to
), measure the distance between the points that intersect with the straight line corresponding to the folds,
The data is delivered to the abnormality determining means (6). In FIG. 4, the interval between the folds of the fifth and sixth wood grains from L on the sampling lines (84) and (85) is shorter than the other folds.

The continuity evaluation means (52) performs the following on the line image of FIG.
From the left edge of the inspection area (50) indicated by the area setting means (31), trace straight lines corresponding to the edges of each fold to the right until reaching the right edge of the inspection area (50) (5) (6). , it is checked whether the line is a single uninterrupted line, there is a break in the middle, or there is a branch, and the data is delivered to the abnormality determining means (6). In FIG. 3, the sixth line from the top branches in the middle.

The inclination change evaluation means (53) calculates sampling lines (81) to (81) for each straight line corresponding to each fold with respect to the line image in FIG.
85) Find the slope of the line that contrasts with the fold at each point above, then find the difference in slope between two adjacent points, and find the position where the absolute value of the difference is maximum and the value of the difference in slope. Abnormality determination means (6
). This means finding the point where the angle of the straight line corresponding to each fold changes the most. The slope at each point of the fold line can be obtained, for example, by dividing by 6 the difference between the Y coordinate of a point on the line 3 pixels to the right of that point and the Y coordinate of a point on the line 3 pixels to the left of that point. In addition, for lines that branch in the middle, such as the fold line of the sixth grain from the top in FIG. 3, the above evaluation is also performed for the branched line.

The abnormality determining means (6) receives the output data from the image defect detecting means (5) and determines whether or not there is an abnormality in each fold of the insulator (7). As shown in the image in Figure 2, if a part of the fold is missing and falls within the inspection area (50), the extracted line of the fold will be as shown in Figure 3. If there is a part where the interval is larger or smaller than the average value of the values measured by the periodicity evaluation means (51) by -window or more, it is considered abnormal. In addition, if the fold line is interrupted or branched in the middle, it is considered abnormal. If the fold line deviates at an angle greater than a predetermined value, it is determined to be abnormal.

If the abnormality determination means (6) determines that there is an abnormality, an alarm is issued by the output means (0).

In the above embodiment, the case where the folds of the insulator (7) are missing has been described, but an abnormality when a foreign object flies and adheres to the insulator (7) can be similarly detected.

In addition, in the L-notation example, only the inspection area (50) was evaluated, but the same inspection as in the above example was performed by changing the imaging position around the insulator f (7), and the entire insulator (7) was evaluated. Inspect the circumference.

[Effects of the Invention] As described above, according to the present invention, the appearance inspection device (7) (8) can be used to extract a portion with a large black-and-white concentration difference in an image obtained by imaging an insulator having folds. The structure is equipped with an image processing means for converting into a line image, and an image defect detection means for detecting as a defect a part of the line image in which the straight line portion corresponding to the edge of the fold deviates from the straight line. This has the effect of providing a visual inspection device that can inspect insulators without being affected by illuminance or direction.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing an appearance inspection apparatus according to an embodiment of the present invention, FIG. 2 is a diagram showing an image of an insulator that is an object to be inspected,
FIG. 3 is a diagram showing the line image, FIG. 4 is an explanatory diagram of periodicity evaluation, and FIG. 5 is a configuration diagram showing a conventional appearance inspection device. In the figure, (2) is an image processing means, (5) is an image defect detection means, and (7) is an insulator. In addition, the same symbols in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] an image processing means for extracting a portion with a large black-and-white density difference from an image obtained by imaging an insulator having pleats and converting it into a line image; 1. An appearance inspection apparatus, comprising: an image defect detection means for detecting a location as a defect, and detecting an abnormality in the appearance of the insulator.