JP2008014907A - Surface evaluation device and painting sample - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface evaluation device capable of accurately evaluating a painted surface, and a painting sample. <P>SOLUTION: The painted surface of the sample 5 is irradiated with light from a diagonal direction by an illuminating device 30, and brightness image data on the painted surface of the sample 5 is acquired by an image acquisition device 10. The acquired brightness image data is binarized, quantity of recesses per unit area in the painted surface is calculated, and the state of the surface is evaluated by an arithmetic evaluation device 20 based on the quantity. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a surface evaluation apparatus and a coated specimen.

  Conventionally, what was described in the following patent gazette is known as an evaluation method of the coating surface which has an unevenness | corrugation.

In this evaluation method, first, light is applied obliquely to a painted surface having irregularities, and the painted surface is photographed with a camera. Next, a shading histogram is obtained based on the image data output from the camera. Thereafter, the half width of the histogram is calculated, and the paint surface is evaluated based on the half width.
Japanese Patent Laid-Open No. 62-12806

  However, since the surface condition is evaluated based on the powder density in the above evaluation method, there is a problem that an accurate evaluation cannot be performed when the powder is partially collected.

  The present invention has been made in view of such circumstances, and a problem thereof is to provide a surface evaluation apparatus and a coating specimen that can accurately evaluate a coating surface.

  In order to solve the above-mentioned problem, the invention according to claim 1 is to obtain irradiation means for irradiating light on the coating surface of the object to be measured from an oblique direction, and obtaining luminance image data of the coating surface irradiated with light by the irradiation means. And binarizing the luminance image data acquired by the image data acquisition means to calculate the number of recesses per unit area of the coating surface, and based on the quantity, the surface state is calculated Computation evaluation means for evaluating is provided.

  According to a second aspect of the present invention, in the surface evaluation apparatus according to the first aspect, the calculation evaluation unit performs shading correction of the luminance image data before binarizing the luminance image data. To do.

  According to a third aspect of the present invention, in the surface evaluation apparatus according to the first aspect, the arithmetic evaluation unit is configured to contrast the luminance image data based on the luminance image data before binarizing the luminance image data. It is characterized in that processing for emphasizing is performed.

  According to a fourth aspect of the present invention, in the surface evaluation apparatus according to any one of the first to third aspects, display means for displaying the evaluation result acquired by the arithmetic evaluation means for visual inspection in a manufacturing process. It is characterized by having.

  The invention according to claim 5 comprises a plurality of coated articles in which the number of recesses per unit area measured from image data of each painted surface is grasped, and the same painted color is applied to the plurality of coated articles. It is a painted specimen characterized by presenting and having different numbers of the concave portions formed on the painted surface.

  According to this invention, the coating surface can be accurately evaluated.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing a surface evaluation apparatus according to an embodiment of the present invention.

  The surface evaluation apparatus includes an image acquisition device (image data acquisition means) 10, a calculation evaluation device (calculation evaluation means) 20, and an illumination device (illumination means) 30.

  The illuminating device 30 irradiates light on the coating surface of the object to be measured 5 obliquely from above.

  An example of the image acquisition device 10 is an optical microscope having an objective lens 11 having a magnification of 4 to 0.8 times. The painted surface of the object to be measured 5 can be observed from above with the image acquisition device 10.

  The image acquisition apparatus 10 includes a CCD camera (not shown), and can capture the luminance image data by imaging the painted surface of the object 5 to be measured via an optical system such as the objective lens 11.

  The CCD camera has a pixel number of 2560 × 1920 pixels, and luminance image data is acquired with a gradation of 256 bits per pixel.

  The image input device 10 can acquire luminance data of the painted surface of the measurement object 5 irradiated by the irradiation device 30.

  In the image analysis device 20, the luminance image data acquired by the image input device 10 is converted from an analog signal to a digital signal by an analog-digital conversion circuit, and this is stored in the memory 21. For example, a personal computer is used as the image analysis apparatus 20.

  In the image analysis device 20, the luminance image data stored in the memory 21 is binarized, and the number of concave portions 5 a (see FIGS. 3 and 4) per unit of the coating surface of the object to be measured 5 is calculated by a CPU (not shown). Based on the calculated quantity, the painted surface of the object to be measured 5 is evaluated.

  Next, a method for calculating the recess 5a will be described.

  FIG. 2 is a flowchart for explaining a method for calculating a concave portion, FIG. 3 is a diagram showing luminance image data of a painted surface before image analysis captured by the image acquisition device, and FIG. 4 is a luminance image of the painted surface after image analysis. It is a figure which shows data.

  First, the painted surface of the DUT 5 is imaged by the image acquisition device 10 to obtain luminance image data (see FIG. 3) (S1).

  Next, shading correction is performed on the obtained luminance image data to remove illumination unevenness (S2). Shading correction is performed as follows. First, the luminance image data is averaged using a 100 × 100 mask filter. Next, the value of the luminance image data (luminance value) is divided from the value of the original luminance image data for each pixel, and 128 is added. As a result, the center of the luminance value of each pixel is 128.

  Thereafter, the contrast of the luminance image data is increased so as to emphasize the difference in contrast (see FIG. 4) (S3).

  Next, binarization is performed by setting the threshold value of the luminance image data to 40, and the luminance image data having the threshold value of 40 or less is regarded as the concave portion 5a to calculate the number of concave portions 5a per unit area (S4).

  Next, Table 1 shows a comparison between the result of sensory evaluation of the painted surface visually and the result of quantitative evaluation obtained by this embodiment.

官能評価では塗装表面の状態を下限限界不良品、下限限界良品、基準品、上限限界良品及び上限限界不良品の５段階に分類し、定量評価では単位面積当たりの凹部５ａの個数（個数／ｍｍ²）を５段階に分類した。

In sensory evaluation, the state of the coating surface is classified into five stages: lower limit limit defective product, lower limit limit non-defective product, reference product, upper limit limit non-defective product, and upper limit limit non-defective product. In quantitative evaluation, the number of recesses 5a per unit area (number / mm ² ) was classified into 5 levels.

  It can be seen from Table 1 that there is a correlation between visual sensory evaluation and evaluation according to this embodiment.

  Therefore, it is possible to quantitatively determine the quality of the painted surface of the DUT 5 using Table 1.

  The evaluation result is displayed on the display device 25.

  Further, in order to more easily evaluate the coated surface during the manufacturing process, it is preferable to prepare a plurality of coated articles having different numerical values when the number of the concave portions is previously measured with the same color by the surface evaluation apparatus of the present embodiment. By using these as specimens, the manufactured article is compared with the specimen, and the coating evaluation of the manufactured article is made according to which specimen is close, so that the correct quality can be obtained regardless of the skill level of the inspector. An evaluation can be obtained.

  Furthermore, as the coated article constituting the specimen, the number of concave portions per unit area is measured with the surface evaluation apparatus of the present embodiment for each coated article for which a skilled inspector has made a pass / fail determination. A pass / fail criterion is determined based on the number of recesses relative to. Then, the coating conditions are changed so that the number of recesses changes, and a plurality of coated articles having different numbers of recesses of unit area are prepared, and a pass / fail judgment result is attached to the coated article. This is a sample.

  Then, the inspector compares the specimen with the pass / fail judgment result with the manufactured article, and makes a pass / fail judgment on the coating state of the manufactured article depending on which coated article is near.

  According to this embodiment, since the brightness image data of the paint surface is binarized and the number of recesses 5a per unit area of the paint surface is calculated to evaluate the condition of the paint surface, the condition of the paint surface is accurately evaluated. can do. In addition, it becomes easy to binarize the shading correction and the process of emphasizing the difference in contrast, so that more accurate evaluation can be performed. Furthermore, since the quality of the coating surface of the object to be measured 5 can be quantitatively determined, visual inspection can be facilitated.

FIG. 1 is a block diagram showing a surface evaluation apparatus according to an embodiment of the present invention. FIG. 2 is a flowchart for explaining a method for calculating a recess. FIG. 3 is a diagram showing luminance image data of the painted surface before image analysis, which is captured by the image acquisition device. FIG. 4 is a diagram showing luminance image data of the painted surface after image analysis.

Explanation of symbols

  5: measurement object, 5a: recess, 10: image acquisition device (image data acquisition means), 20: calculation evaluation device (calculation evaluation means), 30: illumination device (illumination means).

Claims (5)

Irradiation means for irradiating light on the painted surface of the object to be measured from an oblique direction;
Image data acquisition means for acquiring luminance image data of the painted surface irradiated with light by the irradiation means;
A calculation evaluation unit that binarizes the luminance image data acquired by the image data acquisition unit, calculates the number of recesses per unit area of the coating surface, and evaluates the state of the surface based on the number; A surface evaluation apparatus comprising:   The surface evaluation apparatus according to claim 1, wherein the calculation evaluation unit performs shading correction of the luminance image data before binarizing the luminance image data.   The surface evaluation apparatus according to claim 1, wherein the calculation evaluation unit performs a process of enhancing a contrast of the luminance image data based on the luminance image data before binarizing the luminance image data. .   The surface evaluation apparatus according to any one of claims 1 to 3, further comprising display means for displaying an evaluation result acquired by the arithmetic evaluation means for visual inspection in a manufacturing process.   It consists of a plurality of coated articles in which the number of recesses per unit area measured from the image data of each painted surface is known, and the plurality of coated articles have the same paint color and have different numbers of the recesses. A coated specimen formed on the painted surface.

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