JP2019207114A - Acceptance/rejection determination method and acceptance/rejection determination device for dull-finished material surface - Google Patents

Abstract

To provide an acceptance/rejection determination method and an acceptance/rejection determination device for a dull-finished material surface which can perform acceptance/rejection determination for the dull-finished material surface more accurately and efficiently than before.SOLUTION: An acceptance/rejection determination device 1 uses a color image acquired by one color camera 3. The acceptance/rejection determination device, not requiring setting of two cameras as is conventionally done, does not involve generation of a difference in an imaging position and therefore can more accurately perform acceptance/rejection determination for a dull-finished material surface 10a. In addition, the acceptance/rejection determination device 1, when performing the acceptance/rejection determination for the dull-finished material surface 10a, is simply required to determine a ratio of hues in the color image and therefore can efficiently perform the acceptance/rejection determination for a wide range of the dull-finished material surface 10a.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a quality determination method and quality determination device for a dull finish material surface.

  A building material used for the exterior of a building is one of the materials that are strongly required to be aesthetic. For example, a dull finish material having fine irregularities formed on the surface is known. For such a dull finish material, the quality control of the dull finish material surface is performed by visual confirmation by an operator in the factory and a measurement value by a gloss meter.

  However, even if the glossiness is the same value, the color tone may be different if it is visually confirmed under sunlight. It is difficult to accurately determine the quality of the surface of the finishing material.

  Here, as an inspection apparatus for inspecting the surface state of an object, Patent Document 1 discloses an inspection apparatus using one illumination light source and two cameras. In Patent Document 1, specularly reflected light on the object surface is detected by one camera, diffusely reflected light on the object surface is detected by another camera, and based on the obtained detection results, Object surface information such as roughness and glossiness is acquired.

  Patent Document 2 discloses a configuration in which one camera is installed at an angle of 70 degrees or more with respect to one illumination light source in order to detect color unevenness of a stainless steel plate.

Japanese Patent Laid-Open No. 61-264209 JP 2001-272341 A

  However, in Patent Document 1, the imaging range of each camera is accurately aligned so that the same position can be imaged by two cameras, or the same position on the object surface is specified in the image obtained by each camera. It is very difficult to do so, and there is a possibility that the imaging positions of the two cameras may be shifted. In this case, there is a problem that the quality determination of the object surface cannot be performed accurately.

  Further, in Patent Document 2, since a monochromatic illumination light source is used, luminance unevenness occurs in an image due to a decrease in the amount of light around the lens. In Patent Document 2, since it is necessary to perform shading correction on a captured image in order to remove such luminance unevenness, it is impossible to perform pass / fail determination regarding a defect having an area with respect to a measurement surface. Therefore, in patent document 2, there existed a problem that it was difficult to determine the quality of a measurement surface efficiently.

  The present invention has been made in view of the problems as described above, and the dull finish material surface quality determination method and quality determination can be performed more accurately and efficiently than the conventional dull finish material surface quality determination. An object is to provide a determination device.

  The dull finish material surface quality determination method according to the present invention is a dull finish material surface quality determination method that determines the quality of a dull finish material surface on which irregularities are formed. The first illumination light irradiation step of irradiating the surface of the dull finish material with the first illumination light of a predetermined color from one angle, and the first illumination light from the second angle in the irregular reflection direction with respect to the color camera Second illumination light irradiation step of irradiating the second illumination light of a different color to the same illumination area as the first illumination light on the surface of the dull finish material, and regular reflection of the first illumination light on the surface of the dull finish material Acquisition step of acquiring a color image obtained by simultaneously capturing light and diffusely reflected light on the surface of the dull finish material of the second illumination light with one color camera; and hue of the regular reflection light in the color image And the diffuse reflection On the basis of the ratio of the hue of, in which and a quality determination step of determining acceptability of the dull finish material surface.

  In addition, the dull finish material surface quality determination device according to the present invention is a color camera that images the dull finish surface in the dull finish material surface quality determination device that determines the quality of the dull finish material surface on which irregularities are formed. And a first illumination light source that irradiates the surface of the dull finish material with a first illumination light of a predetermined color from a first angle that is a regular reflection direction with respect to the color camera, and an irregular reflection direction with respect to the color camera. A second illumination light source that irradiates the same illumination area as the first illumination light on the surface of the dull finish material with a second illumination light of a color different from the first illumination light from a second angle; and the first illumination light An acquisition unit for acquiring a color image obtained by simultaneously capturing the regular reflected light on the surface of the dull finish material and the irregularly reflected light on the surface of the dull finish material of the second illumination light with the color camera; Within That on the basis of the ratio of the hue of the hue of the specular reflection light and the diffuse reflection, in which and a quality deciding section that decides the quality of the dull finish material surface.

  According to the present invention, since a color image acquired by one color camera is used, it is not necessary to set two cameras as in the prior art, and there is no shift in the imaging position. Therefore, the quality of the surface of the dull finish can be accurately determined. Further, when determining the quality of the dull finish material surface, it is only necessary to obtain the hue ratio in the color image. Therefore, it is possible to efficiently determine the quality of a wide range of the dull finish material surface.

It is the schematic which shows the whole structure of the quality determination apparatus of a dull finish material surface. It is the schematic for demonstrating the installation position of a 1st illumination light source, a 2nd illumination light source, and a color camera. FIG. 3A is a color image when a black material is imaged, FIG. 3B is a color image when a normal material 1 is imaged, and FIG. 3C is an image of a mottled material 1. It is a color image when imaged. It is a block diagram which shows the circuit structure of an arithmetic processing unit. It is the graph which showed the hue distribution data acquired from each color image which imaged the black material, the normal material 1, the normal material 2, the mottled material 1, and the mottled material 2, respectively. It is the graph which showed the relationship between the 2nd angle used as a diffused reflection direction with respect to a color camera, and a hue peak difference.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In the following description, the same components are denoted by the same reference numerals, and redundant descriptions are omitted.

<Configuration of Dull Finishing Material Surface Quality Determination Device>
FIG. 1 is a schematic diagram illustrating the overall configuration of a quality determination device 1 for a dull finish material surface 10a. Here, the dull finish material 10 is made of, for example, a titanium material and is conveyed along the longitudinal direction. In the dull finish material 10, the dull finish material surface 10a is formed in a satin-like shape by, for example, a cold rolling roll, and the dull finish material surface 10a is finished in a non-glossy or slightly glossy state. .

  The quality determination apparatus 1 of the present invention performs quality determination on the difference in the surface state of the dull finish material surface 10a for various dull finish materials 10 conveyed along the conveyance direction x based on the hue. In FIG. 1, the direction of the surface normal line Z1 of the dull finish material surface 10a is defined as the surface normal direction z, and the direction orthogonal to the transport direction x and the surface normal direction z is defined as the width direction y of the dull finish material 10. To do.

  The quality determination apparatus 1 includes a color camera 3, a first illumination light source 4, a second illumination light source 5, and an arithmetic processing device 6. The 1st illumination light source 4 and the 2nd illumination light source 5 are the rod-shaped LED light sources extended | stretched along the width direction y of the dull finish material 10, for example, and each is arrange | positioned in order along the conveyance direction x. . In the case of the present embodiment, the first illumination light source 4 and the second illumination light source 5 are arranged to face the color camera 3 across a plane including the width direction y of the dull finish material 10 and the surface normal line Z1. ing.

  The first illumination light source 4 and the second illumination light source 5 have a predetermined width in the conveyance direction x centered on the illumination position y1 of the dull finish material surface 10a with respect to the dull finish material surface 10a conveyed in the conveyance direction x. And the 1st illumination light and the 2nd illumination light are irradiated to the predetermined area | region (henceforth an illumination area | region) extended in the width direction y of the dull finish material 10. FIG. Moreover, the 1st illumination light source 4 and the 2nd illumination light source 5 are the 1st of uniform brightness | luminance in the whole width direction y of the dull finish material surface 10a in the illumination area | region centering on the illumination position y1 of the dull finish material surface 10a. Illumination light and second illumination light are irradiated.

  Thus, the 1st illumination light source 4 and the 2nd illumination light source 5 irradiate 1st illumination light and 2nd illumination light to the whole illumination area | region centering on the illumination position y1 of the dull finish material surface 10a, and sunlight. The dull finish surface 10a is brought close to the same state as that observed below. At this time, the first illumination light source 4 and the second illumination light source 5 irradiate the dull finish material surface 10a with directional and straight first illumination light and second illumination light.

  The first illumination light source 4 irradiates the dull finish material surface 10a with the first illumination light of a predetermined color from the first angle θ2 that is a regular reflection direction with respect to the color camera 3. In this case, the 1st illumination light source 4 irradiates red 1st illumination light toward the illumination position y1 of the dull finish material surface 10a.

  The second illumination light source 5 has the same second illumination light of a color different from the first illumination light as the first illumination light on the dull finish material surface 10a from the second angle θ3 that is in the direction of irregular reflection with respect to the color camera 3. Irradiate the illumination area. In this case, the second illumination light source 5 irradiates blue second illumination light having a wavelength different from that of red toward the illumination position y1 of the dull finish material surface 10a.

  In addition, although the 1st illumination light which produces | generates regular reflection light is made into red, and the 2nd illumination light which produces irregular reflection light is made into blue, this invention is not limited to this, The 1st illumination light which produces | generates regular reflection light is used. Blue may be used, and the second illumination light that generates diffusely reflected light may be red.

  Moreover, if the regular reflection light by the 1st illumination light and the irregular reflection light by the 2nd illumination light can be distinguished in the color image acquired with the color camera 3 mentioned later, for example, the 1st illumination light or the 2nd illumination light is green, etc. Various colors may be used.

  Here, the blue and red wavelengths generally have a blue wavelength of 435 nm to 480 nm (blue (B) is 435.8 nm in the international standard defined by the International Lighting Commission), and the red wavelength is 610 nm to 750 nm (in the international standard established by the International Commission on Illumination, red (R) is 700 nm). Therefore, in this embodiment, since the first illumination light is red and the second illumination light is blue, the quality of the dull finish material surface 10a can be determined. Therefore, the wavelength difference between the first illumination light and the second illumination light. Is preferably from 130 nm to 315 nm, preferably 265 ± 10 nm.

  The color camera 3 is, for example, a color line camera, and captures images so as to capture regular reflection light on the dull finish material surface 10a by the first illumination light and irregular reflection light on the dull finish material surface 10a by the second illumination light. An angle θ1 is set. The color camera 3 acquires a color image in which the red regular reflection light and the blue irregular reflection light on the dull finish material surface 10 a are reflected, and outputs this to the arithmetic processing unit 6.

  Here, in the dull finish material surface 10a irradiated with the first illumination light and the second illumination light, the regular reflection and the irregular reflection are mixed according to the unevenness of the dull finish material surface 10a. In the color image, red of specular reflection light and blue of irregular reflection light appear according to the reflection characteristics at each position of the dull finish surface 10a, and the color changes at each position of the dull finish surface 10a. . That is, a color image with a strong red color is obtained in the uneven state in which regular reflection appears strongly. In the uneven state in which irregular reflection appears strongly, a color image with a strong blue color is obtained.

  When the arithmetic processing unit 6 receives the color image, the arithmetic processing unit 6 performs arithmetic processing to be described later, and determines whether the dull finish material surface 10a has a color tone abnormality based on the distribution state of two hues in the color image. I do.

<About the installation positions of the first illumination light source, the second illumination light source, and the color camera>
First, the arrangement configuration of the first illumination light source 4, the second illumination light source 5, and the color camera 3 will be described in detail. FIG. 2 is a schematic view of the first illumination light source 4, the second illumination light source 5, and the color camera 3 as seen from the side surface direction of the dull finish material 10.

  As shown in FIG. 2, the first angle θ2 formed by the optical axis a2 of the first illumination light emitted from the first illumination light source 4 and the surface normal Z1 of the dull finish material surface 10a is the first illumination light dull. The specularly reflected light L <b> 1 that is generated by being reflected by the finishing material surface 10 a is selected at an angle at which the color camera 3 can capture an image.

  In the case of the present embodiment, the first angle θ2 that is the regular reflection direction with respect to the color camera 3 is desirably 0 degrees or more and 20 degrees or less from the surface normal line Z1. The reason why the first angle θ2 is desirably 20 degrees or less is that when the first angle θ2 exceeds 20 degrees, the irregular reflection component of the reflected light increases and the light returning to the color camera 3 as the regular reflection component decreases. It is to do.

  The second angle θ3 formed by the optical axis a3 of the second illumination light emitted from the second illumination light source 5 and the surface normal line Z1 of the dull finish material surface 10a is the second illumination light at the dull finish material surface 10a. The diffusely reflected light L2 generated by reflection is selected at an angle at which the color camera 3 can capture an image.

  In the case of this embodiment, it is desirable that the second angle θ3 that is the irregular reflection direction with respect to the color camera 3 is 60 degrees or more from the surface normal Z1. By setting the second angle θ3 to 60 degrees or more, irregular reflection on the dull finish material surface 10a is increased, and the irregular reflection light L2 can be more reliably imaged by the color camera 3. A verification test of the second angle θ3 will be described later with reference to FIG.

  Further, the upper limit value of the second angle θ3 in the irregular reflection direction with respect to the color camera 3 is, for example, 90 degrees or less, and is an angle at which the irregularly reflected light L2 can be generated on the dull finish material surface 10a.

  The imaging angle θ1 formed by the optical axis a1 of the lens in the color camera 3 and the surface normal Z1 of the dull finish material surface 10a is the regular reflection light L1 from the first illumination light and the irregular reflection light L2 from the second illumination light. The angle is selected so that images can be captured simultaneously.

  In the present embodiment, the imaging angle θ1 is desirably θ1 = θ2 ± 5 degrees with respect to the first angle θ2 of the first illumination light source 4, and more preferably the first angle θ2 of the first illumination light source 4. It is desirable that the same angle is selected. In addition, by shifting the imaging angle θ1 by about ± 5 degrees from the first angle θ2 of the first illumination light source 4, the light of the regular reflected light L1 when the color camera 3 captures the regular reflected light L1 and the irregularly reflected light L2 at the same time. The intensity can be reduced, and the irregularly reflected light L2 can be reliably imaged.

  The first angle θ2, the second angle θ3, and the imaging angle θ1 are angles in a plane including the surface normal line Z1 of the dull finish material surface 10a and the conveyance direction (longitudinal direction of the dull finish material 10) x. desirable.

<Color images when samples with different surface conditions are imaged>
Here, the verification test which confirms how the color image obtained by the color camera 3 changes by changing a sample was done. Here, the configuration of the apparatus is as shown in FIGS. 1 and 2, and the imaging angle θ1 of the color camera 3 is 4 degrees, and the first illumination light that is reflected by the dull finish material surface 10a and becomes the specularly reflected light L1. The first angle θ2 is 7 degrees, and the second angle θ3 of the second illumination light that is reflected by the dull finish material surface 10a and becomes the irregularly reflected light L2 is 80 degrees.

  The first illumination light for obtaining the regular reflection light L1 was red, and the second illumination light for obtaining the irregular reflection light L2 was blue. As the color camera 3, Piranha 2 manufactured by DALSA was used.

  And as the dull finish material 10 used as a sample, a black material made of a titanium material, a normal material 1 made of a titanium material, and a mottled material 1 made of a titanium material were prepared. The black material, the normal material 1 and the mottled material 1 have different surface dull finishes and different surface irregularities.

  The prepared black material has a surface irregularity smaller than that of the normal material 1, and is a plate material that looks darker than the normal material 1 depending on the viewing angle. Further, the mottled material is a plate material having surface irregularities larger than those of the normal material 1.

  When the sample surface was imaged with the color camera 3 for these samples, a color image as shown in FIG. 3 was obtained. FIG. 3A shows a color image when the surface of the black material is imaged by the color camera 3. FIG. 3B shows a color image when the surface of the normal material 1 is imaged by the color camera 3. FIG. 3C shows a color image when the surface of the mottle 1 is imaged by the color camera 3.

  3A, 3B, and 3C, in the color image obtained by copying the black material in FIG. 3A, the blue distribution amount is small and the red distribution amount is large. On the other hand, in the color image obtained by copying the mottled material 1 in FIG. 3C, the blue distribution amount is large and the red distribution amount is small. In the color image obtained by copying the normal material 1 in FIG. 3B, the distribution amounts of red and blue are intermediate between the black material and the mottled material 1.

  Thus, it was confirmed that the red and blue distribution states differ depending on the surface state, and that the quality of the dull finish material surface 10a can be determined by analyzing the hue distribution in the color image.

<Arithmetic processing device>
Next, the arithmetic processing device 6 that performs the pass / fail determination of the dull finish material surface 10a based on the color image captured by the color camera 3 will be described below. As illustrated in FIG. 4, the arithmetic processing device 6 includes an acquisition unit 13, a conversion unit 14, a reflection intensity ratio calculation unit 15, a quality determination unit 16, and a display unit 17. The acquisition unit 13 acquires a color image from the color camera 3 and outputs it to the conversion unit 14 and the display unit 17.

  The conversion unit 14 removes noise in the color image by applying, for example, a smoothing filter, and then performs, for example, HSL conversion processing on the color image to convert the color image represented by the three colors RGB into the HSL color space. A converted image is generated. Next, the conversion unit 14 extracts the hue from the obtained converted image, acquires the hue distribution data (described later in FIG. 5) indicating the distribution state of the hue in the converted image, and obtains the reflection intensity ratio. It outputs to the calculation part 15 and the display part 17.

  The HSL color space expresses a color image with three elements of hue, saturation, and lightness, and a color space closer to human sense than the RGB color space can be obtained. Therefore, by using the hue distribution data that shows the hue distribution state by converting the color image into the HSL color space, the quality of the dull finish material surface 10a is determined based on the difference in hue, thereby making a determination close to human sensitivity. It can be performed.

  In the present embodiment, the case where the HSL conversion process is performed as the conversion process for converting the RGB color image into the conversion image including the hue, and the hue distribution data indicating the hue distribution state is obtained has been described. The present invention is not limited to this, and various conversion processes may be applied as long as the hue distribution data indicating the hue distribution state can be obtained from the color image.

  For example, an HSV conversion process is performed as a conversion process, a converted image expressed by three elements of hue, saturation, and lightness (Value) is obtained, and a hue distribution state is shown from the converted image. Hue distribution data may be obtained.

  Next, the hue distribution data will be described. FIG. 5 shows hue distribution data obtained by the conversion unit 14. The hue distribution data shown in FIG. 5 has a device configuration as shown in FIGS. 1 and 2, and the imaging angle θ1 of the color camera 3 is reflected by the dull finish material surface 10a and the specularly reflected light L1. Obtained when the first angle θ2 of the first illumination light to be 7 degrees and the second angle θ3 of the second illumination light reflected by the dull finish material surface 10a to be irregularly reflected light L2 is 80 degrees and the verification test is performed. It is a thing.

  As the dull finish material 10 as a sample, the black material described above, the normal material 1 described above, the normal material 2 described above, the mottled material 1 described above, and the mottled material 2 described above were used. The normal material 2 is a material having a larger surface irregularity than the normal material 1. Further, the mottled material 2 is a material that has less surface irregularities than the mottled material 1.

  The sample surface was imaged with the color camera 3 for these samples. Then, after applying a smoothing filter to remove noise in each color image, the RGB color image was subjected to HSL conversion processing to obtain a converted image converted into the HSL color space. Next, hue distribution data was obtained by extracting the hue from the obtained converted image.

  Thereby, the result as shown in FIG. 5 was obtained. In FIG. 5, the horizontal axis represents hue (256 gradations), and the vertical axis represents hue intensity. In FIG. 5, H1 represents the hue distribution data of the black material, H2 represents the hue distribution data of the normal material 1, H3 represents the hue distribution data of the normal material 2, and H4 represents the hue distribution data of the mottled material 1. H5 indicates the hue distribution data of the mottled material 2.

  In FIG. 5, the 181 gradation around the horizontal axis shows a hue corresponding to blue due to irregular reflection, and the 241 gradation around shows a hue corresponding to red due to regular reflection. From FIG. 5, it was confirmed that the hue distribution was different for each sample.

  When the reflection intensity ratio calculation unit 15 receives the hue distribution data as shown in FIG. 5 from the conversion unit 14, the reflection intensity ratio calculation unit 15 calculates the reflection intensity ratio I according to the following equation (1), and this is calculated as the pass / fail determination unit 16 and the display unit. 17 to send.

  I = diffuse reflected light hue intensity sum / (diffuse reflected light hue intensity sum + regular reflected light hue intensity sum) (1)

  Here, the sum of the intensity of the diffuse reflection light hue indicates the distribution degree of the hue of the diffuse reflection light that appears in the hue distribution data by imaging the diffuse reflection light L2 from the dull finish surface 10a with the color camera 3. In this case, the diffuse reflected light hue intensity sum is a value obtained by adding the intensity of the hues appearing in the hue area indicating diffusely reflected light in FIG. 5 (a region of ± several tone centered on 181 tone indicating blue).

  Further, the sum of the intensity of the specular reflection light hue indicates the distribution degree of the hue of the specular reflection light appearing in the color distribution data when the color camera 3 images the specular reflection light L1 from the dull finish material surface 10a. In this case, the regular reflected light hue intensity sum is a value obtained by adding the intensities of the hues appearing in the hue area indicating regular reflected light (an area of ± several tones centered on 241 gradation indicating red) in FIG.

  When the reflection intensity ratio calculation unit 15 calculates the reflection intensity ratio I from the hue distribution data based on the above formula (1), the reflection intensity ratio calculation unit 15 outputs the calculation result to the pass / fail determination unit 16. The pass / fail judgment unit 16 stores the reference reflection intensity ratio value ERI representing the desired dull finish material surface 10a, and the reflection intensity ratio I received from the reflection intensity ratio calculation unit 15 and the reference reflection intensity ratio value ERI. Compare.

  Accordingly, when the pass / fail judgment unit 16 determines that the reflection intensity ratio I received from the reflection intensity ratio calculation unit 15 is included in the reference reflection intensity ratio value ERI, the dull finish material surface 10a from which the color image is acquired. Is determined to be in the desired surface condition.

  Here, the reflection intensity ratio I is used to comprehensively evaluate the regular reflection light L1 and the irregular reflection light L2 by using the reflection intensity ratio I, and cancel the influence caused by the optical system and shape change. Because it can. For example, even when the sensitivity is different between the center and the periphery of the image as a characteristic of the optical system, the difference between the center and the periphery can be canceled by using the reflection intensity ratio I instead of the mere intensity. And more accurate measurement is possible. Further, even when the dull finish material 10 is inclined with an overall tendency, the difference in luminance due to the inclination can be offset, and more accurate measurement is possible. Furthermore, even when the dull finish material 10 vibrates, the influence on the measurement of vibration can be reduced.

  If the pass / fail determination unit 16 determines that the reflection intensity ratio I received from the reflection intensity ratio calculation unit 15 is a value outside the reference reflection intensity ratio value ERI, the dull finish material surface 10a from which the color image is acquired is desired. It is determined that the surface is not present. The pass / fail judgment unit 16 outputs the obtained judgment result to the display unit 17 and presents the judgment result to the operator via the display unit 17.

  The display unit 17 includes a color image acquired by the acquisition unit 13, a converted image and hue distribution data obtained after the HSV conversion process obtained by the conversion unit 14, and a reflection intensity ratio I obtained by the reflection intensity ratio calculation unit 15. Etc. are also displayed and presented to the operator.

  Accordingly, the operator comprehensively considers not only the determination result but also the hue distribution state of the regular reflection light L1 and the irregular reflection light L2 in the color image or the converted image, the tendency of the hue distribution data shown in FIG. Whether or not the dull finish material surface 10a is in the desired surface state can be determined.

<Verification test for the second angle in the diffuse reflection direction with respect to the color camera>
Here, a verification test for confirming an optimum angle with respect to the second angle θ <b> 3 that becomes the irregular reflection direction with respect to the color camera was performed. Here, a dull finish material 10 made of a titanium material was prepared. Then, as shown in FIG. 2, the imaging angle θ1 of the color camera 3 is fixed to 4 degrees, and the first angle θ2 of the first illumination light that is reflected by the dull finish material surface 10a and becomes the regular reflection light L1 is 7 degrees. Fixed to.

  On the other hand, when the second angle θ3 of the second illumination light that is reflected by the dull finish surface 10a and becomes the irregularly reflected light L2 is changed to 20, 45, 60, and 80 degrees, and the second angle θ3 is changed. The dull finish surface 10a was imaged with the color camera 3. The first illumination light for obtaining the regular reflection light L1 was red, and the second illumination light for obtaining the irregular reflection light L2 was blue.

  And the color image which imaged the regular reflection light L1 and irregular reflection light L2 of the dull finish material surface 10a when changing 2nd angle (theta) 3 of 2nd illumination light was acquired. Next, after applying a smoothing filter to remove noise in the color image, HSL conversion processing was performed on the RGB color image to obtain a converted image converted into the HSL color space. Hue is extracted from the obtained converted image to obtain hue distribution data, and the difference between the hue intensity at the gradation position indicating red and the hue intensity at the gradation position indicating blue is calculated as a hue peak difference. did.

  As a result, a result as shown in FIG. 6 was obtained. As shown in FIG. 6, it was confirmed that the hue peak difference suddenly increased when the second angle θ3 exceeded 45 degrees. It was also confirmed that a large hue peak difference was obtained from around 60 degrees. From the above, it was confirmed that the second angle θ3 of the second illumination light that becomes the irregularly reflected light L2 with respect to the color camera 3 is desirably more than 45 degrees, and more desirably 60 degrees or more.

<Action and effect>
In the above configuration, the dull finish material surface 10a quality determination device 1 irradiates the dull finish material surface 10a with red first illumination light from the first angle θ2 in the regular reflection direction with respect to the color camera 3 ( First illumination light irradiation step). Further, the quality determination device 1 irradiates the second illumination light in blue to the same illumination area as the first illumination light on the dull finish material surface 10a from the second angle θ3 which is the irregular reflection direction with respect to the color camera 3 (first 2 illumination light irradiation process).

  The pass / fail determination apparatus 1 simultaneously captures the regular reflection light L1 on the dull finish material surface 10a of the first illumination light and the irregular reflection light L2 on the dull finish material surface 10a of the second illumination light with one color camera 3. Then, the color image is acquired (acquisition step). Then, in the quality determination device 1, the dull finish material surface 10a is based on the reflection intensity ratio I between the hue of the regular reflection light L1 and the hue of the irregular reflection light L2 in the color image. Pass / fail is determined (pass / fail determination step).

  As described above, since the pass / fail judgment apparatus 1 uses the color image acquired by one color camera 3, it is not necessary to set two cameras as in the conventional case, and the imaging position may be shifted. Therefore, the quality determination of the dull finish material surface 10a can be accurately performed accordingly. In addition, since the quality determination device 1 simply determines the hue ratio in the color image when determining the quality of the dull finish material surface 10a, it can efficiently determine the quality of a wide range of the dull finish material surface 10a. it can.

<Other embodiments>
In addition, this invention is not limited to this embodiment, A various deformation | transformation implementation is possible within the range of the summary of this invention. For example, as the dull finish material, the dull finish material 10 formed of a titanium material is applied, but a dull finish material formed of various other materials such as a steel material and a stainless steel material may be applied.

  In the above-described embodiment, the hue distribution data is generated from the color image, and the reflection intensity ratio I representing the ratio between the hue of the regular reflection light L1 and the hue of the irregular reflection light L2 is calculated. The quality of the dull finish surface 10a is determined based on the above, but the present invention is not limited to this.

  For example, the quality of the dull finish material surface 10a may be determined by calculating the reflection intensity ratio I between the hue of the regular reflection light L1 and the hue of the irregular reflection light L2 from the color image. Further, without calculating the reflection intensity ratio I, the operator visually confirms the hue distribution data, the color image, and the hue distribution state of the converted image after the HSL conversion process (hue conversion process), and the dull finish surface 10a. You may make it perform the quality determination of.

  The color image and the converted image described above include not only a form as a specific image displayed on a display or the like but also data before being generated as an image.

DESCRIPTION OF SYMBOLS 1 Quality determination apparatus 3 Color camera 4 1st illumination light source 5 2nd illumination light source 6 Arithmetic processing apparatus 13 Acquisition part 16 Quality determination part

Claims (5)

In the method of judging the quality of the dull finish material surface, which judges the quality of the dull finish material surface where the irregularities are formed,
A first illumination light irradiation step of irradiating the surface of the dull finish material with a first illumination light of a predetermined color from a first angle that is a regular reflection direction with respect to the color camera;
A second illumination light having a color different from that of the first illumination light is applied to the same illumination area as the first illumination light on the surface of the dull finish material from a second angle that is a diffuse reflection direction with respect to the color camera. 2 illumination light irradiation process;
A color image obtained by simultaneously imaging the regular reflection light of the first illumination light on the surface of the dull finish material and the irregular reflection light of the second illumination light on the surface of the dull finish material is acquired by one color camera. Acquisition process;
A quality determination method for the surface of the dull finish material, comprising: a quality determination step for determining quality of the surface of the dull finish material based on a ratio between the hue of the regular reflection light and the hue of the irregular reflection light in the color image. . The acquisition step includes
Obtaining the color image having different hues between the regular reflection light and the irregular reflection light;
The pass / fail judgment step includes
The quality of the dull finish material surface is determined by calculating a ratio between the hue of the regular reflection light and the hue of the irregular reflection light based on the hue distribution data acquired from the color image. A method for judging the quality of the surface of a dull finish.   The dull finish material surface according to claim 1 or 2, wherein the first illumination light is red or blue, and the second illumination light is the blue or the red having a color different from that of the first illumination light. Pass / fail judgment method. The dull finish material is made of titanium material,
The quality determination method of the dull finish material surface of any one of Claims 1-3 whose said 2nd angle is 60 degree | times or more with respect to the surface normal of the said dull finish material surface. In the dull finish material surface pass / fail judgment device, which judges the quality of the dull finish material surface where irregularities are formed,
A color camera for imaging the dull finish surface;
A first illumination light source that irradiates the surface of the dull finish material with a first illumination light of a predetermined color from a first angle that is a regular reflection direction with respect to the color camera;
A second illumination light having a color different from that of the first illumination light is applied to the same illumination area as the first illumination light on the surface of the dull finish material from a second angle that is a diffuse reflection direction with respect to the color camera. Two illumination light sources;
An acquisition unit that acquires a color image obtained by simultaneously capturing the regular reflection light of the first illumination light on the surface of the dull finish material and the irregular reflection light of the second illumination light on the surface of the dull finish material simultaneously with the color camera. When,
A dull finish material surface pass / fail judgment device comprising: a pass / fail judgment unit for judging pass / fail of the dull finish material surface based on a ratio between the hue of the regular reflection light and the hue of the irregular reflection light in the color image. .

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