JP4484200B2 - Development method of tooth surface perspective image - Google Patents

Description

  The present invention relates to a method for developing a tooth surface perspective image in which each pixel of a tooth surface perspective image obtained by photographing a gear of a differential device is transferred to a template image for development.

Conventionally, gears such as a ring gear and a pinion gear incorporated in a differential of an automobile have been subjected to a tooth contact inspection in order to prevent generation of noise and abnormal noise. This tooth contact inspection is performed by applying Komyotan or Shin-Akitan to the ring gear and then transferring the tooth-contact surface of the ring gear on which the pinion gear is meshed and scraped off to the tape. Was inspecting the center of gravity and area. However, since manual inspection requires skill and time and is inefficient, various methods for automating the inspection have been proposed. For example, a color image is taken of a tooth surface that has been applied to a gear and meshed with a gear to generate a tooth-contact surface, and the RGB color image thus taken is a three component R (Red) G (Green) B (Blue) In addition, there is a tooth contact measuring machine that performs binarization and inspection for each RGB component (see, for example, Patent Document 1). In addition, a yellow paint different from RGB is applied to the gear, and the tooth surface where the tooth contact surface is generated by meshing the gear is transferred to a tape, and the color image is taken, and the tooth surface of the photographed RGB color image is obtained. There is a method for extracting a surface situation in which surface contact is inspected by image processing (see, for example, Patent Document 2).
However, according to Patent Document 1, image processing is performed using a photographed perspective image as it is, and therefore there is distortion and the shape differs from an actual tooth contact surface. In addition, there is a problem that the image processing becomes complicated because the tooth tip, the background, or other tooth surfaces are reflected in the perspective image. According to Patent Document 2, the tooth contact surface is transferred to a tape one by one, and the tooth contact surface is inspected by performing image processing based on a photographed image obtained by photographing the transferred tape. Although it is expensive, the inspection takes time, and it has been technically impossible to perform line inspection by this method. In addition, the inspection of the tooth contact surface is subtle and depends on the season with different temperatures, the old and new lighting devices, changes over time after applying the light or new light, etc., so it is necessary to always make corrections. This correction was performed by visual inspection of the tooth-transferred tape. For this reason, in order to perform correction with high accuracy, it is preferable that the image-processed tooth surface image has the same information as that obtained by tape transfer.
Japanese Patent Application Laid-Open No. 3-115829 JP-A-9-89533

  An object of the present invention is to develop a tooth surface perspective image that can be easily corrected and can increase inspection accuracy.

In order to achieve the above-described object, the present invention takes a ring gear by illuminating the illumination device by highlighting the tooth tip edge and the tooth side edge of the ring gear, and from the tooth surface perspective image of the photographed ring gear, Generate cut-out lines by setting both ends, generate cut-out lines from the upper and lower two points of the tooth side edge, cut out the tooth surface for one tooth, and the vertical position ratio and horizontal position ratio of each pixel in the tooth surface image Each pixel is transferred to the same vertical position ratio and horizontal position ratio position on the development template image, and the non-placement position of the pixel generated on the development template image is the color information of the adjacent pixel. According to a first aspect of the present invention, there is provided a method for developing a tooth surface perspective image in which pixels to which color information as an average value is given are arranged. In the invention of claim 1, the tooth surface perspective image and the template image for development are used at the same ratio. Tooth surface divided into multiple parts The method of developing a visual image is the invention of claim 2, and in the invention of claim 1 or 2, the vertical position ratio and the horizontal position ratio of each pixel in the tooth surface perspective image are based on XY lines intersected by pixels. The method for developing a tooth surface perspective image to be calculated is the invention according to claim 3, and in the invention of claim 3, the XY lines intersecting with the pixels of the tooth surface perspective image are the upper and lower outer shapes of one tooth surface in the tooth surface perspective image. And a method of developing a tooth surface perspective image that passes through the intersection of the respective external extension lines extended along the left and right external shapes.

In the present invention, the ring gear is photographed by highlighting and illuminating the tooth tip edge and the tooth side edge of the ring gear by the lighting device , and the upper and lower ends of the tooth tip edge are set from the photographed tooth surface perspective image of the ring gear and the cut line Generating a cut-out line from the upper and lower two points of the tooth side edge, cutting out the tooth surface for one tooth, obtaining the vertical position ratio and the horizontal position ratio of each pixel in the image of the tooth surface , The image is transferred to the same vertical position ratio and horizontal position ratio position on the development template image, and color information that is an average value of the color information of adjacent pixels is displayed at the non-placement position of the pixel generated on the development template image. Since the given pixels are arranged, the same information as the visual inspection performed on the tape can be obtained, so it is possible to easily tune whether or not an accurate inspection result was obtained by comparing with the tape data. That. In addition, it is possible to easily correct the effects of changes in the temperature of the season, lighting equipment, old and new lighting, changes over time after application of light or new light compared to tape data, Inspection accuracy can be greatly increased. Moreover, it can be incorporated into the line inspection.
As in claim 2, by dividing the tooth surface perspective image and the development template image into a plurality at the same ratio, the arc of the tooth surface can be treated as a straight line, so that the calculation of the pixel position is simplified, The load on the computer can be reduced and the processing speed can be increased.
According to the third aspect, by calculating the vertical position ratio and the horizontal position ratio of each pixel in the tooth surface perspective image based on the XY lines intersecting with each other, the pixel position can be easily determined.
As in claim 4, the XY line that intersects with the pixel of the tooth surface perspective image passes through the intersection of the upper and lower outer shapes of the tooth surface along the left and right outer shapes in the tooth surface perspective image. By doing so, it is possible to more easily calculate the pixel position.

Hereinafter, a preferred embodiment of the present invention will be described in detail based on the apparatus shown in FIG.
In FIG. 1, 1 is a tooth contact inspection device, and the tooth contact inspection device 1 comprises an image processing device 3 controlled by a computer 2, a photographing device 4 for photographing a gear, and an illumination device 5 for illuminating the gear. It is.

  The computer 2 controls an image processing instruction by the image processing device 3, a photographing timing by the photographing device 4, an illumination time of the lighting device 5, and the like.

  In addition, the image processing device 3 cuts out and extracts only one tooth surface from the tooth surface perspective image captured by the image capturing device 4, and transfers the extracted tooth surface perspective image pixels to the development template image. To do.

  The photographing device 4 is composed of a 3CCD color camera that separately captures R, G, and B components of a photographed image into each of the R, G, and B image sensors, and each of the R, G, and B image sensors of the 3CCD color camera. R, G, and B components of the RGB color image captured in can be directly output to the image processing apparatus 3.

  The illumination device 5 is for illuminating the gear, and is arranged at an illumination position where the illumination light can emphasize the tooth boundary, and at an illumination position where the illumination light can enhance the tooth side boundary. There are two things to be arranged. The illuminating device 5 is reduced in size by using an LED and can be disposed in the differential case, and the durability and power consumption are reduced. Further, the illumination device 5 emits blue illumination light as enhanced color light with respect to the colors of Komyotan and Shin-Akitan.

  The ring gear is photographed through the inspection opening of the differential case while being stored in the differential case (not shown) of the differential.

  In order to carry out the method of the present invention using the apparatus constructed as described above, first, a light gear or a new light dust is applied to a ring gear (hypoid gear) as shown in FIG. Then, a drive motor (not shown) for rotating the differential gear is connected to the ring gear in order to scrape off the light or new light, and then the drive motor is driven. Next, the photographing device 5 is arranged so as to face the gear from the inspection opening of the differential case, and the toothed surface of the ring gear is arranged as parallel as possible to the photographing device so that the photographed image becomes a perspective image as much as possible. suppress.

  Then, the illumination device 5 irradiates the ring gear with blue light that is the highlight color light of the light or new light. This illuminating device 5 uses two illuminating devices 5 arranged at the illuminating position for emphasizing the tooth tip edge and the illuminating position for emphasizing the tooth side edge, or alternately turns on or moves one illuminating device 5. The tooth tip edge or the tooth side edge may be emphasized. As shown in FIGS. 2 and 3, the highlight illumination of the tooth tip edge can be clearly identified from the upper and lower edges of the tooth tip by irradiating from the oblique upper part of the gear. Further, as shown in FIGS. 4, 5, and 6, the emphasis illumination of the tooth side edges can be clearly identified by irradiating from the side of the gear.

  In this way, photographing is performed for each of R, G, and B with the photographing device 4 including the 3CCD color camera. Since the photographed RGB color image is input to the R, G, and B image sensors, the G and B components are extracted from the RGB image sensors, and the tooth surface is extracted by the image processing device 3 based on the luminance difference. I do. This is because by using the G / B component, the luminance difference between the portion irradiated with the blue illumination light and the non-irradiated portion increases, and it becomes easy to detect the upper and lower edges of the tooth tip and both edges of the tooth side. .

  When the tooth surface is extracted based on the luminance difference in the image processing device 3, each of the R, G, and R The average luminance of the G component and B component in the image for each B component is 33 and 75, the difference is 42, and when the light red tint is applied to the tooth tip, the G component and B in the image The average luminance of the components is 24 and 35, and the difference is 11. For this reason, it is necessary to change the threshold value when detecting an edge due to the difference in color of Komyotan, and the boundary is a point where a luminance difference equal to or greater than this threshold value is set to 42 × 1.5 = 63 in brownish Komyotan. Further, in red-based light alumina, the threshold is set to 11 × 2 = 22, and a point where a difference equal to or greater than the threshold is generated is defined as a boundary. When the difference in luminance is large, the boundary can be detected without making the threshold too high, but the difference in luminance is small. In this case, it is difficult to detect the boundary unless the threshold range is slightly widened.

  As shown in FIG. 7, the photographing range photographed by the photographing device 4 includes other tooth surfaces, backgrounds, tooth tips, and the like of the gears, so only the tooth surface for one tooth is cut out. This cutting out removes adjacent tooth tips, backgrounds, and tooth surfaces that are not subject to inspection. Therefore, the tooth surface is cut out with reference to both the upper edge, the lower edge, and the tooth side surface of the adjacent tooth tip representing the boundary of the tooth surface in the photographed tooth surface perspective image. As shown in FIG. 7, the lower edge represents an unnecessary tooth surface, and therefore the unnecessary portion is removed by shifting the lower edge upward by a certain distance. Then, as shown in FIG. 8, a cut line is generated by three points pointed at a plurality of average positions of pixels representing the upper edge and the shifted lower edge. This cut line is represented by a curve. The tooth surface is cut out by the cut line because the upper and lower edges of the tooth surface perspective image are uneven, and unless the cut line is generated, the matching standard is unclear and it becomes difficult to fit the actual size image development template. .

  Further, as the three points to be pointed, by setting both ends and the center of the upper and lower edges, an arc cut line with a small deviation from the edges is generated. Subsequently, as shown in FIG. 8, a cut line is generated by two upper and lower points pointed at a plurality of average positions of pixels representing both edges of the tooth side surface. This cut line is represented by a straight line. Then, based on the cut line formed by the curved line and the straight line generated in this way, only the tooth surface for one tooth is cut out, and the other pixels are set to the background color or colorless so that it can be adjusted to the template image for development. A tooth surface perspective image is obtained.

  Next, the image processing apparatus 3 develops each pixel of the cut tooth surface perspective image by transferring each pixel to the development template image. In transferring the tooth surface perspective image to the development template image of each pixel, first, as shown in FIG. 9, the tooth surface perspective image and the development template image are divided at the same ratio. In order to simplify the explanation, the number of divisions is two on the top and bottom and five on the left and right. Specifically, the top and bottom are divided into five and the left and right are divided into ten, but may be further subdivided. However, since the processing becomes complicated if it is subdivided too much, the optimum number is determined according to the capacity of the computer and the processing speed. Then, the pixels extracted from the section of the tooth surface perspective image are transferred to the same section of the development template image.

  In this pixel transfer, as shown in FIG. 10, the intersection point U is obtained from the external extension line EX extended along the upper and lower external shapes of the tooth surface perspective image divided into a plurality of sections, and the plurality of sections are divided. The intersection point V is obtained from the external extension line EY extended along the external side surface of the tooth surface perspective image. The pixel P in the tooth surface perspective image is connected by an XY line passing through the intersection U and the intersection V. Based on the XY line, the vertical position ratio and the horizontal position ratio of the pixel P in the tooth surface perspective image are calculated. Based on these ratios, the pixel P is transferred to the Q position of the development template image having the same vertical position ratio and horizontal position ratio. The external extension line extended along the upper and lower external shapes of the tooth surface is a straight line that does not exactly follow the external arc, but XY for determining the vertical position ratio and the horizontal position ratio of the pixels in the tooth surface perspective image. There is no problem in accuracy because only the intersection point of drawing the line is obtained. In addition, when the distortion of the tooth surface perspective image is small, it is a matter of course that the vertical position ratio and the horizontal position ratio of the pixel may be obtained by drawing a line parallel to the XY direction without obtaining the intersection.

  Then, when the pixels of the tooth surface perspective image are transferred and developed on the development template image, a non-placement position of a pixel in which the pixel is not necessarily placed is necessarily generated. This inevitably occurs because the perspective image is developed into a development template image. For this reason, when a pixel non-arranged position occurs, a pixel provided with color information that is an average value of color information of adjacent pixels is disposed at the pixel non-arranged position. In the case where the number of unplaced pixels is not one, but there are a plurality of upper and lower or left and right pixels, an average value of color information of left and right pixels or upper and lower pixels is given. The pixel transfer development described above is similar to the morphing technique, but morphing is an animation technique that smoothly changes between different images. This technique is not possible.

  In this way, the tooth surface is developed as an actual size image, so that the development template is obtained by the method of Japanese Patent Application No. 2003-5716 already filed by the applicant based on the development template image. The tooth contact inspection may be performed by performing image processing of pixels appearing in the image. The development template image obtained in this way can be easily compared with the tape data with the tooth surface transferred, so it is possible to apply tuning, temperature, seasoning, old and new lighting devices, Komyotan or Shin-Amitan. It is possible to easily perform correction when it is subtly influenced by a change with time from the time point.

  In the preferred embodiment, only the tooth surface for one tooth is cut out and transferred to reduce the load on the computer. However, a plurality of tooth surfaces are transferred to the development template image. Of course, it is also good.

It is the schematic explaining preferable embodiment of this invention. It is a front view which shows the tooth surface imaging | photography which emphasizes a tooth tip edge in preferable embodiment of this invention. It is a top view which shows the arrangement position of the illuminating device at the time of imaging | photography which emphasizes the tooth-tip edge in preferable embodiment of this invention. It is a front view which shows the tooth surface imaging | photography which emphasizes the tooth | gear side edge in preferable embodiment of this invention. It is a top view which shows the arrangement position of the illuminating device at the time of imaging | photography which emphasizes the tooth side edge in preferable embodiment of this invention. It is a side view which shows the arrangement position of the illuminating device at the time of imaging | photography which emphasizes the tooth | gear side edge in preferable embodiment of this invention. It is a top view which shows the picked-up image of the gearwheel by the imaging device in preferable embodiment of this invention. It is explanatory drawing which shows extraction of a tooth surface from the picked-up image in preferable embodiment of this invention. It is explanatory drawing which shows the state which divided | segmented the tooth surface perspective image and the expansion | deployment model image in the preferable embodiment of this invention into the division for several transfer. It is explanatory drawing which shows the method of transcribe | transferring the pixel in the division of the tooth surface perspective image in the preferable embodiment of this invention to the division of the model image for an expansion | deployment. It is a top view which shows the ring gear which inspects.

Explanation of symbols

3 Image processing device 4 Imaging device 5 Illumination device

Claims (4)

The ring gear is photographed by emphasizing and illuminating the tooth edge and tooth side edge of the ring gear by the lighting device, and the cut line is generated by setting the upper and lower ends of the tooth edge from the photographed tooth surface perspective image of the ring gear, A cut line is generated from the upper and lower two points of the tooth side edge, the tooth surface for one tooth is cut out, the vertical position ratio and the horizontal position ratio of each pixel in the image of the tooth surface are obtained, and each pixel is developed as a template for development. A pixel that has been transferred to the same vertical position ratio and horizontal position ratio position on the image, and that has given color information that is an average value of the color information of adjacent pixels at the non-placement position of the pixel generated on the development template image. A method for developing a perspective image of a tooth surface, wherein the method is arranged.   The method of developing a tooth surface perspective image according to claim 1, wherein the tooth surface perspective image and the development template image are divided into a plurality of parts at the same ratio.   The method for developing a tooth surface perspective image according to claim 1 or 2, wherein a vertical position ratio and a horizontal position ratio of each pixel in the tooth surface perspective image are calculated based on XY lines intersecting with each other. . The XY line intersecting at the pixel of the tooth surface perspective image passes through the intersection of the upper and lower outer shapes of the tooth surface along the left and right outer shapes in the tooth surface perspective image. The method for developing a tooth surface perspective image according to claim 3.

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