Inspection device

Abstract

To provide an inspection device that accurately photographs an inspection area, and reduces the occurrence of a failure in inspection resulting from a malfunction in an instrument.SOLUTION: An inspection device inspects a tooth surface of a gear, and comprises: a rotating table 11 on which the gear is mounted; a photographing unit 12 that photographs the gear; a vibration measuring unit 14 that measures vibration of the rotating table 11; and a processing unit 15 that controls the operation of the photographing unit 12 according to the vibration of the rotating table 11 measured by the vibration measuring unit 14, and performs image processing on an image photographed by the photographing unit 12. When the magnitude of the vibration measured by the vibration measuring unit 14 exceeds a predefined threshold during the photographing of the gear by the photographing unit 12, the processing unit 15 causes the photographing unit 12 to stop the photographing and execute photographing again.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a gear tooth flank inspection device. [Background technology]

[0002] In recent years, gears are produced by cutting. In order to prevent defective gears from being produced after cutting, visual inspection is performed. However, since there is a risk of overlooking something when inspected by humans, image inspection that does not rely on human senses is more effective.

[0003] Patent Document 1 discloses an inspection method in which an image is taken every 1 / n pitch while rotating a gear under inspection, and image processing is applied to the captured images. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2020-038066 A Summary of the Invention [Problem to be solved by the invention]

[0005] When performing image inspection using an inspection device, it is necessary to clearly capture the inspection location. As shown in Patent Document 1, a method for capturing images of an object having a convex shape such as a gear includes a mechanism for rotating the object and synchronizing the timing of the rotation and the capture. However, this method requires frequent capture instructions at 1 / n pitch intervals, and there is a risk that the inspection cannot be performed normally if there is a communication error or image processing cannot keep up. In addition, since the tooth surface has depth and is curved, it is difficult to illuminate it uniformly.

[0006] Furthermore, because the gear to be photographed has multiple convex shapes, the area that can be photographed in one shot by the area camera is limited. Therefore, if the timing of the photograph is off, the tooth crest adjacent to the tooth surface to be photographed may be cast in shadow, and the inspection area may not be captured.

[0007] Furthermore, since line cameras are vulnerable to vibrations, measures must be taken in case vibrations occur during shooting. For these reasons, there has been a demand for an inspection device that can accurately capture images of the inspection area and is less susceptible to inspection failures caused by malfunctions in the equipment used to capture the inspection images.

[0008] The present disclosure provides an inspection device that accurately captures an inspection area and is less susceptible to inspection failures due to equipment malfunctions. [Means for solving the problem]

[0009] The inspection device according to the present disclosure is an inspection device for inspecting the tooth surface of a gear, and includes a rotating table on which the gear is placed, an imaging unit for photographing the gear, a vibration measuring unit for measuring the vibration of the rotating table, and a processing unit for controlling the operation of the imaging unit in accordance with the vibration of the rotating table measured by the vibration measuring unit and for performing image processing of the image photographed by the imaging unit, wherein if the magnitude of the vibration measured by the vibration measuring unit exceeds a predetermined threshold while the imaging unit is photographing the gear, the processing unit stops photographing by the imaging unit and causes the imaging unit to re-take the image. This allows you to immediately start shooting again if vibration occurs during shooting. Effect of the Invention

[0010] According to the present disclosure, it is possible to provide an inspection device that can accurately capture an inspection area and is less likely to experience inspection failures due to equipment malfunctions. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a diagram showing a configuration of an inspection device according to a first embodiment. [Diagram 2] FIG. 4 is a diagram showing an example of an operation flow of the inspection device according to the first embodiment. [Diagram 3] 2 is a diagram illustrating an image captured by an image capturing unit according to the first embodiment and image processing performed on the captured image. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] First embodiment Hereinafter, an inspection device according to the present embodiment will be described with reference to the drawings. As shown in Fig. 1, the inspection device 1 includes a turntable 11 on which an object 2 is placed and rotated, an imaging unit 12 that images the object 2, an illumination unit 13 that shines light on the object 2, a vibration measurement unit 14 that measures the vibration of the turntable 11, and a processing unit 15. Here, the object 2 will be described as a ring-shaped gear, but is not limited to this.

[0013] The rotating table 11 is a table that operates with the gear, which is the target object 2, placed thereon to rotate the gear around its central axis. Here, the gear is assumed to be placed on the rotating table 11 with its teeth arranged so that it can be photographed at least by the photographing unit 12, which will be described later.

[0014] The photographing unit 12 is disposed above the rotating table 11 and the gear, and photographs the gear. In the following, a description will be given assuming that a line camera is used for the photographing unit 12. Specifically, the line camera of the photographing unit 12 is disposed above the gear and faces downward, and photographs the teeth of the gear placed on the rotating table 11 and rotating.

[0015] Illumination unit 13 irradiates light toward the teeth of the gear placed on turntable 11. For example, a light source of illumination unit 13 is disposed diagonally above the gear placed on turntable 11. As one example, illumination unit 13 is disposed in a position close to imaging unit 12, and the light irradiation direction is set in advance so that illumination unit 13 irradiates light toward a location where imaging unit 12 will image the teeth of the gear placed below.

[0016] In other words, the illumination unit 13 shines light onto the gear teeth, and the photographing unit 12 photographs the gear teeth illuminated by the light from the illumination unit 13, thereby allowing the unevenness of the gear teeth to be clearly photographed.

[0017] The vibration measuring unit 14 is connected to the rotating table 11 and measures the vibration of the rotating table 11. Typically, the vibration measuring unit 14 outputs information on the measured vibration of the rotating table 11 to the processing unit 15.

[0018] The processing unit 15 controls the photographing by the photographing unit 12 in response to information on the vibration of the turntable 11 input from the vibration measuring unit 14. For example, the processing unit 15 can be a computer having a main storage device, a central processing unit, an auxiliary storage device, etc., but is not limited to this. Also, for example, the processing unit 15 may be connected to the turntable 11, the photographing unit 12, and the vibration measuring unit 14 by wire or wirelessly in order to transmit and receive operation control signals and information.

[0019] Furthermore, the processing unit 15 can perform image processing for the image captured by the imaging unit 12 to facilitate image inspection, such as by template matching or filter processing using a brightness-constant image, which will be described later. The processing unit 15 can also execute image inspection.

[0020] Next, an example of an operation flow of the inspection device 1 will be described with reference to FIG.

[0021] The rotating table 11 starts operation with the gear placed on it. As a result, the gear starts rotating around the central axis on the rotating table 11 (step S1). For example, the rotating table 11 can start rotating in response to control from the processing unit 15.

[0022] The vibration measuring unit 14 starts measuring the vibration of the rotating table 11 that is in operation (step S2). The vibration measuring unit 14 outputs information about the measured vibration to the processing unit 15.

[0023] The line camera of the photographing unit 12 photographs the gear rotating on the rotating table 11 (step S3). The photographing unit 12 can control the execution of photographing in response to a control signal received from the processing unit 15. The lighting unit 13 irradiates light toward the location being photographed while the photographing unit 12 photographs the gear.

[0024] Typically, the vibration measuring unit 14 continuously measures vibrations while the photographing unit 12 is continuously photographing the rotating gear, and can sequentially output the measurement results to the processing unit 15.

[0025] Here, Fig. 3(a) is an image of an image captured when the gear, which is the target object 2, is a hypoid gear. The image shown in Fig. 3(a) is an example of an image captured when the upper part of the line camera is placed in the direction of rotation of the gear.

[0026] Next, the processing unit 15 judges whether or not the magnitude of the vibration measured by the vibration measuring unit 14 exceeds a predetermined threshold value while the photographing unit 12 is photographing the gear (step S4). When a line camera is used as the photographing unit 12, the influence of vibration is large. Fig. 3(b) shows an example of a state in which an acquired image is blurred when vibration occurs in the photographing unit 12 or the gear due to a disturbance while photographing by the photographing unit 12.

[0027] If the processor 15 determines that the magnitude of the measured vibration exceeds the predetermined threshold (Yes in step S4), the imaging is stopped and the process returns to step S3 to perform imaging again. For example, in the inspection device 1, if the processor 15 determines that vibration exceeding the predetermined threshold has occurred while the imaging unit 12 is acquiring a series of consecutive images of multiple teeth on one gear, the imaging is stopped and imaging is restarted from the beginning.

[0028] Here, the inspection device 1 can perform the process of redoing the image capture from the beginning when it is determined that the magnitude of the vibration sequentially output from the vibration measuring unit 14 to the processing unit 15 exceeds a threshold value. In other words, when the inspection device 1 starts a series of image acquisition and determines that re-imaging is required due to vibration before completing the series of image acquisition, it can immediately stop the image capture and re-imaging.

[0029] On the other hand, if the processor 15 determines that the magnitude of the measured vibration does not exceed the predetermined threshold (No in step S4), the imager 12 continues to acquire a series of continuous images of multiple teeth on one gear until the end. Then, the process proceeds to step S5.

[0030] The processing unit 15 processes the image (step S5). As shown in Fig. 3(a), all the teeth are collected in one image captured by the imaging unit 12. Therefore, as an example, the processing unit 15 extracts the teeth by using template matching and a non-maximum suppression algorithm, as shown in Fig. 3(c).

[0031] More specifically, the processing unit 15 performs template matching processing and detects similar regions by comparing with the master image from which one tooth has been extracted. After that, the processing unit 15 performs processing using a Non Maximum Suppression algorithm for the results of overlapping and matching with one tooth, so that only the master image and the maximum value of the local region with the strongest remaining response are ultimately retained.

[0032] This allows the processing unit 15 to limit the number of detections for one tooth to one. In other words, the processing unit 15 can extract each tooth from the images acquired by the imaging unit 12.

[0033] Then, in the processing unit 15, a filter for making brightness uniform, shown in FIG. 3(d), is applied to the images extracted one tooth at a time, thereby making it possible to eliminate uneven brightness in the tooth surface images.

[0034] Thereafter, the processing unit 15 performs image inspection on the extracted gear teeth one by one (step S6).

[0035] This allows the inspection device 1 to apply a brightness stabilization filter to eliminate uneven brightness in the tooth surface images extracted one tooth at a time and perform image inspection. Therefore, the inspection device 1 can perform image inspection with high accuracy.

[0036] Furthermore, in the inspection device 1, if it is determined that vibration has occurred before a series of image acquisitions is completed, the imaging can be stopped immediately and imaging can be performed again. Therefore, in the inspection device 1, it is possible to eliminate unnecessary imaging time and shorten the time required for inspection, compared to when imaging is continued to the end even if vibration has occurred.

[0037] The present invention is not limited to the above-described embodiment, and can be modified as appropriate without departing from the spirit of the present invention. In other words, the above description has been omitted or simplified as appropriate for the purpose of clarity, and a person skilled in the art can easily modify, add, or convert each element of the embodiment within the scope of the present invention.

[0038] For example, in step S5, the processing unit 15 applies a brightness uniformity filter to the acquired image after extracting each tooth by template matching or the like. This is because the brightness uniformity filter in the above method is applied to each tooth, and it is difficult to apply the filter until the area of ​​each tooth is clearly defined by performing template matching. On the other hand, if general brightness uniformity processing is desired, it is also possible to perform brightness uniformity processing before template matching. In addition, other image processing can be performed in step S5. [Explanation of symbols]

[0039] 1. Inspection equipment 2. Object 11 Rotating table 12. Photography Department 13 Lighting Department 14 Vibration measurement section 15 Processing section

Claims

[Claim 1] An inspection device for inspecting a gear tooth surface, comprising: A rotating table on which the gear is mounted; An imaging unit that images the gear; a vibration measuring unit for measuring vibration of the rotary table; a processing unit that controls an operation of the photographing unit in response to the vibration of the turntable measured by the vibration measuring unit and processes an image photographed by the photographing unit, The processing unit includes: When the magnitude of the vibration measured by the vibration measuring unit exceeds a predetermined threshold value during the photographing of the gear by the photographing unit, the photographing by the photographing unit is stopped and photographing is performed again. Inspection equipment.

Images