JP2006208333A - Visual observation feeling evaluation method and system, metallic coating face evaluation device, operation program therefor, and visual observation feeling evaluation method for metallic coating face - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To quantitatively evaluate visual observation feeling (particle feeling) of a metallic coating sheet in a state near to visual observation feeling viewed by eyes by the human being. <P>SOLUTION: This method/system/device is provided with an imaging means 1 for photoelectrically converting an optical image of the metallic coating sheet into a two-dimensional image, an image processing means 3 for image-processing the resolution of the two-dimensional image to be matched to the resolution of the eyes by the human being, by space digital filter or the like, so as to generate a processed image, and a computing means 4 for extracting an evaluation parameter about the visual observation feeling by the human being on the basis of a feature amount of the processed image. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method, an apparatus, and a program for objectively evaluating a visual feeling of, for example, a metallic painted surface that exhibits different colors depending on illumination or observation direction.

  Metallic paint and pearl color paint (generally referred to as “metallic paint” in this specification), which are widely used for automobile coating, etc., are flaky aluminum pieces and mica pieces called glitter materials in the paint film. It is included and exhibits a so-called metallic effect and pearl effect. This is because the contribution of the glitter material to the reflection characteristics varies depending on the illumination and observation direction. The visual feeling of the metallic coating surface varies depending on the change in brightness of light due to the size, distribution density, orientation and the like of the glitter material. Such a visual feeling that is dependent on the glittering material is particularly called “particle feeling” (sometimes referred to as glitter feeling or glitter feeling, but in this specification “particle feeling”). Since the particle feeling is subjective and differs depending on the observer, it is necessary to measure the particle feeling quantitatively, for example, for quality control of a metallic painted surface in an automobile body or the like.

  As such a quantification measurement method, for example, illumination light is irradiated onto a predetermined measurement area of the metallic coating surface, and the reflected light is received (photoelectrically converted) by a two-dimensional imaging device such as a CCD (charge coupled device). There is a method of acquiring a two-dimensional image (luminance information) of the measurement area and performing an evaluation based on a predetermined feature amount extracted from the image.

With respect to such an evaluation method, for example, Patent Document 1 discloses a method for evaluating the depth of a metallic coating surface by comparing the average luminance with the most frequent luminance, using the luminance distribution of the measurement area as basic information. . Patent Document 2 discloses a method of binarizing the two-dimensional image with a predetermined luminance threshold value and evaluating the feeling of depth of the metallic coating surface from the variation in the area of the high luminance portion. Furthermore, in Patent Document 3, a luminance threshold value is selected and binarized in a range of 1.05-1.50 times the average luminance in the two-dimensional image, and the glitter feeling is quantitatively evaluated from the sum of luminance values equal to or higher than the luminance threshold value. A method is disclosed. Patent Document 4 discloses a method for obtaining a glitter feeling and a grain feeling based on the area and volume of a high-luminance portion when the two-dimensional image is binarized with two threshold values.
JP-A-6-117934 JP-A-7-55705 JP-A-10-170436 JP 2000-304696 A

  By the way, a two-dimensional image of a metallic coating surface, which is a base for evaluating the feeling of particles, is captured by a CCD or the like, but the resolution of the CCD is generally different from the resolution of the human eye. Depending on the number of pixels and the like, in this type of evaluation apparatus, a CCD having a resolution higher than the resolution of the human eye is usually used so that highly accurate evaluation parameter measurement can be performed. That is, a fine contrast that cannot be identified by the human eye appears in the captured image by the CCD.

  However, this can be a factor that deteriorates the correlation with the particle feeling seen by the human eye. That is, a two-dimensional image acquired by a high-resolution CCD is different from an image felt by human eyes, and an evaluation parameter for obtaining particle feeling is extracted by calculation based on the feature amount of such a two-dimensional image. However, the particle feeling based on the human eye cannot be evaluated with good correlation. Furthermore, since the sensitivity of the human eye has a habit of feeling brightness logarithmically with respect to luminance, in the method of setting a threshold value associated with the average luminance of a two-dimensional image captured when evaluating the brightness, Since the average brightness perceived by the eye may deviate from the average brightness derived from the photographed image, a factor that cannot be correlated may also occur in this respect. These points are not taken into consideration in the evaluation methods of Patent Documents 1 to 4, and as a result, there is a problem that particle feeling evaluation that is sufficiently correlated with visual observation cannot be performed.

  The present invention has been made in view of the above points, and in the visual feeling evaluation method and system, particularly in metallic coating, the visual feeling of the measurement object can be quantitatively evaluated in a state closer to the visual feeling seen by human eyes. It is an object of the present invention to provide a metallic painted surface evaluation apparatus capable of quantitatively evaluating the particle feeling, an operation program thereof, and a visual feeling evaluation method for the metallic painted surface.

  The visual evaluation method according to claim 1 of the present invention is an image in which a light image of a measurement object is photoelectrically converted to obtain a two-dimensional image of the measurement object, and the resolution of the image is adjusted to the resolution of a human eye. Processing is performed, and evaluation parameters relating to human visual perception are extracted based on the feature amount of the image after the image processing.

  According to this method, since the image processing for matching the resolution of the two-dimensional image acquired from the measurement object with the resolution of the eye is performed and the evaluation parameter is acquired using the feature amount of the image after the image processing, The correlation between the evaluation value and the measurement value can be increased. The contrast sensitivity that can be sensed by the human eye is a characteristic as shown in FIG. 1 with respect to the spatial frequency. Here, the spatial frequency on the horizontal axis indicates the number of stripe patterns (unit: “cycle / cycle”) included in the 1 ° field of view when a predetermined striped pattern chart (for example, Campbell-Robson CSF chart) is observed in the 1 ° field of view. 1 ° "), and the contrast sensitivity on the vertical axis is represented by the reciprocal of contrast. As shown in FIG. 1, the human eye has the minimum luminance ratio necessary for recognizing a striped pattern at a spatial frequency in the vicinity of 5 cycles / 1 ° (there are five striped patterns in a 1 ° field of view) ( That is, a striped pattern can be recognized even at a low contrast), but a striped pattern (particle) smaller than 60 cycles / 1 ° cannot be perceived no matter how high the luminance ratio is.

  On the other hand, the resolution of an image sensor such as a CCD generally has different characteristics from those shown in FIG. Usually, the image sensor has a higher resolution, and an image is acquired in a state where a striped pattern smaller than, for example, 60 cycles / 1 ° is also identified. Therefore, when an evaluation parameter is extracted based on a predetermined feature amount based on an image deviating from the resolution of the human eye and a predetermined visual feeling evaluation (for example, particle feeling evaluation of a metallic painted surface) is performed, human visual inspection is performed. The evaluation parameter may be extracted from an image that matches the resolution of the human eye by performing image processing that matches the resolution of the image with the resolution of the human eye. It becomes like this.

  In the above configuration, it is desirable that the image processing is a filter processing that matches the resolution of the acquired two-dimensional image with the resolution of a human eye (claim 2). According to this configuration, for example, by applying a spatial filter or the like equivalent to the human eye to the acquired two-dimensional image, the resolution of the two-dimensional image can be matched with the resolution of the human eye.

  In this case, the filtering process can be a process of applying a bandpass filter approximated to the contrast sensitivity of the human eye to the spatial frequency to the acquired two-dimensional image. According to this configuration, it is possible to match the resolution of the acquired two-dimensional image with the resolution of the human eye over the entire spatial frequency.

  Alternatively, the filtering process may be a process of applying a low-pass filter that approximates the characteristics of the high-frequency part in the contrast sensitivity of the human eye with respect to the spatial frequency to the acquired two-dimensional image. According to this configuration, it is possible to match the resolution of the acquired two-dimensional image with the resolution of the human eye for at least the high-frequency part that substantially affects the resolution of the human eye.

In the above configuration, the feature amount of the image may be at least one feature amount selected from the group consisting of the following (1) to (3) in the image after the image processing (claim). Item 5)
(1) Image brightness and brightness distribution (2) Black and / or white area when the image is binarized with a predetermined threshold (3) The image is binarized with a predetermined threshold In this case, the number of independent black and / or white portions is as follows. According to this configuration, the feature quantity that affects the visual feeling can be easily compared with the above-mentioned (1) to (3). Either or a combination thereof is taken out.

  In the above-described configuration, it is desirable that the evaluation parameter is an evaluation parameter for evaluating the influence of reflected light from particles contained in the measurement object on human visual perception (Claim 6). According to this configuration, it is possible to quantitatively evaluate the degree of contribution of the particles to the light reflection characteristics in the measurement object including various light reflective particles.

  In the above configuration, as the image processing, image processing for converting the brightness of the acquired image into brightness perceived by humans is performed together with image processing for matching the resolution of the acquired image with the resolution of human eyes. (Claim 7). In this case, the image processing for converting the brightness converts the brightness of the acquired image into a human sensitivity by making the output nonlinearly compressed as the brightness increases. It is desirable that the image processing is to be combined (claim 8).

  As described above, the sensitivity of the human eye has a habit of feeling brightness logarithmically with respect to luminance, while an image pickup device such as a CCD can obtain logarithmic output unless specific circuit processing or the like is performed. However, there is a tendency that an image in which brightness is linearly expressed is obtained. Therefore, according to these configurations, it is possible to acquire a predetermined evaluation parameter from an image that matches human perception with respect to a visual feeling related to brightness.

  In the configuration according to any one of claims 1 to 8, it is desirable that the measurement object is a metallic paint surface (claim 9). According to this configuration, it is possible to quantitatively evaluate the particle feeling, which can be said to be the degree of contribution of the bright material to the light reflection characteristics on the metallic coating surface.

  In this case, in the image processing, it is desirable to further perform image processing for removing coating unevenness on the metallic coating surface. On the metallic coating surface, uneven brightness may occur due to uneven coating. Such unevenness in brightness is of a low frequency that is lower than the particulate spatial frequency usually caused by a bright material. According to this configuration, the influence of the uneven brightness can be removed by performing image processing such as applying a predetermined high-pass filter to the acquired image.

  A visual evaluation system according to an eleventh aspect of the present invention includes an imaging unit that photoelectrically converts a light image of a measurement object to obtain a two-dimensional image of the measurement object, and at least the resolution of the image is determined by human eyes. Image processing means for generating a predetermined processed image by performing image processing that matches the resolution, and arithmetic means for extracting an evaluation parameter relating to human visual perception based on the feature amount of the processed image And

  According to this configuration, the image processing is performed so that the resolution of the two-dimensional image acquired from the measurement object by the imaging unit matches the resolution of the human eye by the image processing unit. And since an evaluation parameter is acquired by the calculating means using the feature amount of the image after the image processing, the correlation between the visually evaluated value and the measured value can be increased.

  In the above configuration, it is desirable that the image processing unit includes a spatial digital filter for matching the resolution of the two-dimensional image acquired by the imaging unit with the resolution of the human eye. According to this configuration, for example, by applying a spatial digital filter whose filter characteristics are set to be equivalent to the human eye to the two-dimensional image acquired by the imaging unit, the resolution of the two-dimensional image is the human eye. It will be able to match the resolution.

  In this case, filter characteristic specifying means for specifying the characteristics of the spatial digital filter as an arbitrary characteristic, and filter characteristic setting means for setting the characteristics of the spatial digital filter to the filter characteristics specified by the filter characteristic specifying means are provided. It is desirable to adopt a configuration that does this (claim 13). According to this configuration, the user can set the characteristic of the spatial digital filter to an arbitrary characteristic by the filter characteristic specifying means, and thus the visual evaluation system can be utilized according to the measurement purpose.

  In the above configuration, it is preferable that the image processing unit further includes a gamma correction processing unit that converts the brightness of the two-dimensional image acquired by the imaging unit into a brightness perceived by a human. ). According to this configuration, the calculation means can acquire a predetermined evaluation parameter from an image that matches the human perception with respect to the visual feeling related to brightness.

  In the configuration according to any one of claims 11 to 14, it is desirable to include a psychophysical quantity calculation unit that obtains an evaluation index related to human visual perception based on the evaluation parameter extracted by the calculation unit. 15). According to this configuration, the visual sensation by the human eye (for example, the particle sensation on the metallic paint surface) can be quantitatively automatically calculated as a predetermined evaluation index by the psychophysical quantity calculation unit based on the evaluation parameter extracted by the calculation unit. It becomes like this.

  According to a sixteenth aspect of the present invention, there is provided a metallic paint surface evaluation apparatus that quantitatively evaluates a particle feeling, which is an effect of reflected light from a glittering material contained in a metallic paint surface on human visual perception of the metallic paint surface. An imaging means for irradiating a predetermined measurement area of a metallic painted surface to be measured with illumination light and photoelectrically converting the reflected light to obtain a two-dimensional image of the measurement area And an image processing means for generating a predetermined processed image by performing image processing that matches at least the resolution of the image with the resolution of the human eye, and an evaluation parameter related to human visual perception based on the feature amount of the processed image And calculating means for extracting.

  According to this configuration, image processing is performed so that the resolution of the two-dimensional image formed from the reflected light from the predetermined measurement area of the metallic paint surface obtained by the imaging unit matches the resolution of the human eye by the image processing unit. Done. And since the evaluation parameter regarding the particle | grain feeling of a metallic coating surface is acquired by the calculating means using the feature-value of the image after the said image processing, the correlation with a visual evaluation value and a measured value can be improved.

  In the above configuration, the image processing unit includes a spatial digital filter for matching the resolution of the two-dimensional image acquired by the imaging unit with the resolution of the human eye, and further, the characteristics of the spatial digital filter are set to arbitrary characteristics. It is desirable to have a configuration having filter characteristic designating means for designating and filter characteristic setting means for setting the characteristics of the spatial digital filter to the filter characteristics designated by the filter characteristic designating means (claim 17). According to this configuration, the user can set the characteristic of the spatial digital filter to an arbitrary characteristic by the filter characteristic specifying means, and thus the metallic painted surface evaluation apparatus can be utilized according to the measurement purpose.

  In this case, it is desirable that the filter characteristic setting means can set a filter characteristic capable of removing low-frequency unevenness caused by unevenness of the coating on the metallic paint surface (claim 18). According to this configuration, for example, for a high-frequency portion of a spatial frequency that has a substantial effect on the resolution of the human eye, a filter characteristic that matches the resolution of the acquired two-dimensional image with the resolution of the human eye is selected. With respect to the low-frequency portion where the brightness unevenness due to the unevenness exists, it is possible to set a filter characteristic (high-pass filter characteristic) that blocks this.

  In addition, it is desirable that the filter characteristic setting means can set a filter characteristic associated with the observation distance of the metallic paint surface. The contrast sensitivity of the human eye shown in FIG. 1 varies depending on the observation distance. This is because the number of stripe patterns that fall within the 1 ° field of view varies. According to this configuration, by appropriately applying the contrast sensitivity of the human eye associated with the observation distance, filter images (human eyes) corresponding to a plurality of observation distances can be obtained from one two-dimensional image acquired by the imaging unit. Image that matches the resolution of the image can be acquired.

  In the configuration according to any one of claims 17 to 19, the filter characteristic designating unit is capable of designating a through process that does not execute the filter process by the spatial digital filter, and when the through process is designated, It is desirable that the apparatus includes a glitter material evaluation unit that extracts an evaluation parameter relating to the glitter material itself based on the two-dimensional image acquired by the imaging unit. A so-called raw image that has not been subjected to filter processing is generally a high-resolution image, which is advantageous for measuring the brightness (reflectance), size, density, and the like of the glitter material itself. According to this configuration, based on the raw image, the evaluation parameter relating to the glitter material itself can be extracted by the glitter material evaluation means.

  In the configuration of any one of claims 16 to 20, it is desirable to include a particle sensation index calculation unit that obtains an evaluation index related to the particle sensation based on the evaluation parameter extracted by the calculation unit. 21). According to this configuration, it is possible to automatically and quantitatively automatically calculate the particle sensation on the metallic painted surface as a predetermined evaluation index by the particle sensation index calculation unit based on the evaluation parameter extracted by the calculation unit.

  The operation program of the metallic paint surface evaluation apparatus concerning Claim 22 of this invention is a program for operating the metallic paint surface evaluation apparatus provided with a predetermined image processing means and a calculating means, Comprising: The metallic paint surface used as a measuring object An image input step for receiving an input of a two-dimensional image obtained by photoelectrically converting a light image of a predetermined measurement area in the image processing unit, and image processing for adjusting at least the resolution of the image to the resolution of the human eye in the image processing means. An image processing step for generating a predetermined processed image, and a calculation step for causing the calculation means to extract an evaluation parameter related to a human visual sense based on a feature amount of the processed image. .

  An operation program for a metallic painted surface evaluation apparatus according to a twenty-third aspect of the present invention is a program for operating a metallic painted surface evaluation apparatus including predetermined imaging means, image processing means, and arithmetic means, An imaging step of irradiating a predetermined measurement area of the metallic painted surface to be measured with illumination light, photoelectrically converting the reflected light to obtain a two-dimensional image of the measurement area, and receiving an input of the two-dimensional image An image input step; an image processing step for causing the image processing means to perform image processing for adjusting at least the resolution of the image to a resolution of a human eye; and generating a predetermined processed image; and And a calculation step for extracting an evaluation parameter related to human visual perception based on the feature amount.

According to a twenty-fourth aspect of the present invention, there is provided a method for evaluating a visual feeling of a metallic coating surface, wherein the metallic coating is based on a two-dimensional image obtained by photoelectrically converting a light image of a predetermined measurement area on a metallic coating surface to be measured. A method for evaluating the visual perception of a surface, wherein the two-dimensional image is binarized with a predetermined luminance threshold value to generate a binarized image, and the high-luminance portion in the binarized image is described in the following (4) to (4) to A predetermined evaluation value related to visual feeling is obtained from an average value of at least one or more feature values selected from the group consisting of (6) and variations in the measurement area.
(4) Brightness in a region of the high luminance portion above the threshold (5) Area of the high luminance portion (6) Integral value of brightness in the region of the high luminance portion above the threshold and the area of the high luminance portion

  According to this configuration, the feature values of (4) to (6) acquired from the binarized image are not simply evaluated based on the average value, but a predetermined evaluation regarding the visual feeling is performed by incorporating the variation element. Since the value is obtained, a fine analysis of the high-luminance portion generated by the glitter material can be performed, and this can be reflected in the visual evaluation value.

  According to the visual evaluation method according to claim 1, image processing for matching the resolution of the two-dimensional image acquired from the measurement object with the resolution of the human eye is performed, and the evaluation parameter is calculated from the image matched with the resolution of the human eye. Therefore, the correlation between the visually evaluated value and the measured value can be increased. Therefore, the visual feeling of the measurement object can be quantitatively evaluated by matching the visual feeling of the human eye.

  According to the visual evaluation method according to the second aspect, since the batch image processing can be performed by the filter processing, the image processing can be simplified.

  According to the visual evaluation method according to the third and fourth aspects, the resolution of the two-dimensional image that is efficiently acquired can be matched with the resolution of the human eye for a required spatial frequency region.

  According to the visual evaluation method according to the fifth aspect, since the feature quantity that is relatively easy to digitally characterization is used, the extraction process of the evaluation parameter can be simplified.

  According to the visual evaluation method according to the sixth aspect, the contribution degree of the particles to the light reflection characteristics of the measurement object including various light reflective particles can be quantitatively evaluated while matching the visual feeling.

  According to the visual feeling evaluation method according to claim 7 and claim 8, since a predetermined evaluation parameter can be acquired from an image matched with human perception with respect to the visual feeling related to brightness, more accurate visual feeling evaluation is performed. be able to.

  According to the visual feeling evaluation method according to the ninth aspect, the particle feeling, which can be said to be the degree of contribution of the glittering material to the light reflection characteristics of the metallic coating surface, can be quantitatively evaluated while matching the visual feeling.

  According to the visual evaluation method according to the tenth aspect, it is possible to remove the influence of the uneven brightness due to the uneven coating from the acquired two-dimensional image, so that it is possible to perform a more accurate visual evaluation.

  According to the visual evaluation system according to the eleventh aspect, image processing is performed by the image processing unit to match the resolution of the two-dimensional image acquired from the measurement object by the imaging unit with the resolution of the human eye. Since the evaluation parameter is extracted from the image that matches the resolution of the human eye, the correlation between the visual evaluation value and the measurement value can be increased. Therefore, the visual feeling of the measurement object can be quantitatively evaluated by matching the visual feeling of the human eye.

  According to the visual evaluation system according to the twelfth aspect, since the batch image processing by the spatial digital filter can be performed, the image processing can be simplified.

  According to the visual evaluation system according to the thirteenth aspect, the user can set the characteristic of the spatial digital filter to an arbitrary characteristic by the filter characteristic specifying means, so that an image matched with various purposes can be generated. Therefore, various evaluation parameters can be acquired from one two-dimensional image acquired by the imaging means, and various visual feeling evaluations can be efficiently performed.

  According to the visual evaluation system according to the fourteenth aspect, since the gamma correction processing means can acquire the predetermined evaluation parameter from the image matched with the human perception with respect to the visual feeling relating to the brightness, more accurate visual evaluation. It can be performed.

  According to the visual evaluation system according to the fifteenth aspect, the visual evaluation by the human eye can be quantitatively automatically calculated as the predetermined evaluation index, so that objective evaluation data relating to the visual observation of the measurement target surface can be quickly obtained. It becomes possible.

  According to the metallic paint surface evaluation apparatus according to claim 16, the image processing unit performs image processing so as to match the resolution of the human eye, and the arithmetic unit uses the feature amount of the image after the image processing to form the metallic paint surface. Therefore, the correlation between the visual evaluation value and the measurement value can be increased. Therefore, it is possible to quantitatively evaluate the particle feeling of the metallic painted surface by matching the particle feeling with the human eye.

  According to the metallic painted surface evaluation apparatus of the seventeenth aspect, since the user can set the characteristics of the spatial digital filter to an arbitrary characteristic by the filter characteristic specifying means, it is possible to generate images that match various purposes. . Accordingly, various evaluation parameters can be acquired from one metallic painted surface image acquired by the imaging means, and various particle feeling evaluations can be performed efficiently.

  According to the metallic painted surface evaluation apparatus of the eighteenth aspect, since the influence of uneven brightness due to uneven coating can be removed, more accurate particle feeling evaluation can be performed.

  According to the metallic paint surface evaluation apparatus according to claim 19, from one metallic paint surface image acquired by the imaging means, filter images corresponding to a plurality of observation distances (images matched with the resolution of the human eye) are obtained. Since it can be acquired, it becomes possible to efficiently evaluate a multi-faceted particle feeling.

  According to the metallic painted surface evaluation apparatus according to claim 20, the evaluation parameter relating to the glittering material itself can be extracted by the glittering material evaluation means, and two types of particles, that is, the particle feeling perceived by the eye and the evaluation parameter of the glittering material itself, can be obtained with one piece of hardware. Information can be acquired. Since these two types of information are necessary information in the field of development of paints and repair of automobile bodies, an evaluation device suitable for such applications can be provided.

  According to the metallic painted surface evaluation apparatus according to claim 21, since the particle feeling by the human eye can be automatically calculated quantitatively as a predetermined evaluation index, objective evaluation data relating to the particle feeling of the measurement target surface can be obtained quickly. Is possible.

  According to the operation program of the metallic paint surface evaluation apparatus concerning Claim 22 and Claim 23, using the metallic paint surface evaluation apparatus which has a predetermined composition, the particle feeling of a metallic paint surface is changed into the particle feeling by human eyes. Match and be able to evaluate quantitatively.

  According to the visual feeling evaluation method for a metallic paint surface according to claim 24, it is possible to perform a fine analysis of a high-luminance portion generated by the glitter material, and to reflect this in the visual evaluation value. The visual feeling can be evaluated more accurately.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
(Description of hardware configuration)
FIG. 2 is a block diagram schematically showing the overall configuration of the visual evaluation system according to the embodiment of the present invention. This visual feeling evaluation system can be applied as a system for objectively evaluating the visual feeling of various measurement objects, such as the feeling of painting, profound feeling, and surface condition. That is, the metallic paint surface evaluation apparatus S for quantitatively evaluating the feeling of particles, which is the influence that the reflected light from the glittering material contained in the metallic paint surface has on the human visual feeling on the metallic paint surface, explain. The metallic painted surface evaluation apparatus S includes an imaging unit 1, a measurement control unit 2, an image processing unit 3, a calculation unit 4, an operation unit 5, an output unit 61, and a display unit 62.

  The imaging means 1 irradiates a predetermined measurement area on the metallic paint surface to be measured with illumination light, and photoelectrically converts the reflected light to obtain a two-dimensional image of the measurement area. The measurement control unit 2 performs control for causing the imaging unit 1 to acquire the two-dimensional image in a predetermined procedure. The image processing means 3 generates a predetermined processed image by performing image processing that matches the resolution of the acquired image with the resolution of the human eye. The calculation means 4 extracts an evaluation parameter related to human visual feeling based on the feature amount of the processed image and performs calculation for obtaining a predetermined particle feeling index for quantitatively evaluating the particle feeling. The operation unit 5 is used by the user to give predetermined processing commands, setting commands, and the like to the measurement control unit 2, the image processing unit 3, and the calculation unit 4. The output unit 61 comprises a printer or the like, and outputs the particle sensation index obtained by the calculation means 4 as numerical data. The display unit 62 includes an LCD, a CRT, or the like, and displays the particle sensation index and the like to the user.

The hardware configuration of the metallic paint surface evaluation apparatus S can be set as appropriate. For example,
(A) The imaging means 1 is composed of a unidirectional illumination type reflected light measurement device or a multi-angle illumination type reflected light measurement device, and includes a measurement control means 2, an image processing means 3, an arithmetic means 4, an operation section 5 and a display section. 62 is configured with a personal computer or the like, and a hardware configuration in which both are connected by a USB cable,
(B) In the configuration of (a) above, a hardware configuration in which the reflected light measuring device has the measurement control means 2,
(C) A hardware configuration in which the reflected light measurement device as the imaging unit 1 is integrated with the measurement control unit 2, the image processing unit 3, the calculation unit 4, the operation unit 5, and the display unit 62,
Etc. can be illustrated.

  An operation program that takes in a two-dimensional image of a metallic painted surface previously captured by another imaging unit and causes a personal computer or the like to execute processing corresponding to the image processing unit 3 and the calculation unit 4, or the above (a) to (a) to The present invention can also be implemented by providing an operation program for operating the metallic paint surface evaluation apparatus S having the hardware configuration (c).

  FIG. 3 is a configuration diagram showing an example of the metallic painted surface evaluation apparatus S having the hardware configuration (a). This metallic painted surface evaluation apparatus S is configured by connecting a multi-angle illumination type reflected light measuring apparatus 10 and a personal computer PC with a USB cable 103. The reflected light measuring device 10 includes a box-shaped outer body 101, an illumination optical system 11, a light receiving optical system 14, an image sensor 15, and a signal processing circuit 16 housed in the outer body 101.

  A measurement opening 102 is provided in the bottom surface of the outer body 101, and the metallic coating surface 71 of the metallic coating plate 7, which is a measurement object, is closely opposed to the measurement opening 102. The metallic paint plate 7 is made of, for example, a metallic paint surface of an automobile body. FIG. 4 is a perspective view of the metallic paint plate 7. As shown in the partially enlarged view, the metallic paint plate 7 is composed of a base material 701 serving as a coating base and a metallic paint applied thereon. And a film 702. In the metallic coating film 702, a glitter material 703 made of flaky aluminum pieces, mica pieces, or the like is dispersed and blended. By containing this glittering material 703, when the metallic coating surface 71 is irradiated with light, a so-called metallic effect is generated, and the observer of the metallic coating surface 71 is given a particle feeling. A portion of the metallic coating surface 71 corresponding to the size of the measurement opening 102 is a measurement area 72 for measuring particle feeling.

  The illumination optical system 11 includes a first illumination system 11a, a second illumination system 11b, and a second illumination system arranged in directions of 15 °, 45 °, and 75 ° from the normal direction of the sample surface (metallic coating surface 71), respectively. 3 illumination systems 11c. The first illumination system 11a includes a light source 12a made of a tungsten lamp or the like, and a collimator lens 13a disposed in front of the light source 12a. The light emitted from the light source 12a is collimated by the collimating lens 13a into a parallel light beam, and illuminates the metallic coating surface 71 from a direction with a normal angle of 15 °. Similarly, the second illumination system 11b and the third illumination system 11c have light sources 12b and 12c and collimating lenses 13b and 13c, respectively, and the metallic coating surface 71 has directions of normal angles of 45 ° and 75 °, respectively. Illuminate from. Thereby, it is possible to individually irradiate illumination light from the directions of normal line angles of 15 °, 45 °, and 75 ° with respect to the metallic coating surface 71 with a parallel light beam similar to sunlight. The configuration of the illumination optical system 11 may be set as appropriate. For example, the configuration including only the first illumination system 11a, the configuration including the first illumination system 11a and the third illumination system 11c, or four or more configurations. It is good also as a structure which consists of an illumination system.

  On the other hand, the light receiving optical system 14 is arranged in the normal direction of the sample surface (metallic coating surface 71), and forms an optical image of the reflected light reflected from the metallic coating surface 71 on the imaging element 15 arranged in the subsequent stage. Let Such an arrangement of the illumination optical system 11 and the light receiving optical system 14 is intended to approximate a condition for a human to visually observe the metallic coating plate 7. That is, when illuminated from a direction with a normal angle of 15 °, reflected light close to regular reflected light from the metallic coating surface 71 can be imaged by the imaging element 15. In addition, when illuminated from a direction with a normal angle of 75 °, it is possible to image reflected light close to diffused light away from regular reflection, and when illuminated from a direction with a normal angle of 45 °, Intermediate reflected light can be imaged.

  The image sensor 15 photoelectrically converts an optical image of reflected light reflected from the metallic coating surface 71, and for example, a CCD two-dimensional sensor can be applied. The image sensor 15 is also arranged in the normal direction as in the light receiving optical system 14. FIG. 3 shows an example in which the imaging element 15 is attached to the optical axis position of the fixed plate 130 arranged in parallel with the sample surface.

  The imaging element 15 including the light receiving optical system 14 preferably has a resolution higher than the resolution of the human eye. For example, a monochrome CCD (imaging resolution = 8.4 × 8. 4 μm) can be used. Instead of the CCD two-dimensional sensor, other elements that can convert a two-dimensional image into an electrical signal, such as a CMOS sensor or a device that scans a photodiode, can be used.

  The signal processing circuit 16 is a circuit that amplifies the analog signal output from the image sensor 15 and converts it into a digital signal, and further performs brightness correction according to the shutter speed. The signal processing circuit 16 will be described in detail later. A signal (two-dimensional image data) output from the signal processing circuit 16 is transmitted to the personal computer PC via an unillustrated interface unit and the USB cable 103.

(Explanation of electrical configuration)
FIG. 5 is a block diagram showing the electrical functional configuration of the imaging means 1 and the measurement control means 2. The signal processing circuit 16 of the imaging unit 1 includes an amplification circuit 161, an A / D conversion unit 162, and a brightness correction unit 163. A shutter 17 for adjusting the exposure amount of the image sensor 15 and a shutter drive unit 171 for opening and closing the shutter 7 are provided.

  The amplifier circuit 161 includes a current-voltage conversion circuit, a variable gain amplifier, and the like, converts the current generated by the photoelectric conversion by the image sensor 15 into a voltage, and amplifies the voltage to a predetermined voltage signal. The A / D converter 162 converts the analog voltage signal output from the amplifier circuit 161 into a digital signal.

  The brightness correction unit 163 corrects the brightness of the captured image in accordance with the shutter speed of the shutter 17 that adjusts the exposure amount of the image sensor 15. Metallic paints vary from bright silver to nearly black, and the reflectance varies greatly depending on the color of the metallic paint. On the other hand, the dynamic range of an image sensor such as a CCD is not wide enough to cover all the colors of these metallic paints. Therefore, in order to suppress the ratio of saturated pixels and low luminance pixels, the reflectance of the metallic paint surface to be measured Accordingly, it is necessary to switch the shutter speed and perform imaging with an appropriate exposure amount. However, the image captured in this way depends on the shutter speed, and does not reflect the actual reflectance of the metallic paint surface as it is. Therefore, the brightness correction unit 163 performs brightness correction according to the shutter speed in order to smooth such shutter speed dependency. The brightness correction unit 163 may be included in the image processing unit 3 at the subsequent stage.

  The shutter 17 is always “open” for a predetermined time when the light receiving surface of the image sensor 15 is shielded, and the light sources 12a to 12c are operated to cause the image sensor 15 to receive the reflected light from the metallic coating surface 71. The image sensor 15 is exposed. The shutter driving unit 171 receives a control signal and a shutter speed setting from a shutter control unit 22 to be described later, and performs opening / closing driving of the shutter 17 at the shutter speed. Instead of the shutter 17, an electronic shutter function built in the CCD or the like can be used. If such an electronic shutter function is used, the shutter 17 and the shutter driving unit 171 can be omitted.

  Next, the measurement control unit 2 includes a lighting control unit 21, a shutter control unit 22, a timing generator (TG) 23, a shutter speed determination unit 24, and a measurement control unit 25. The lighting control unit 21 is a functional unit that controls the lighting operation of the light sources 12 a to 12 c provided in the illumination optical system 11, and any one of the light sources 12 a to 12 c according to the measurement routine given from the measurement control unit 25. Alternatively, lighting control is performed such that the lamps are sequentially turned on starting from the one with the smaller normal angle.

  The shutter control unit 22 generates an opening / closing control signal for the shutter 17 and a setting signal for the shutter speed, and outputs them to the shutter drive unit 171.

  The timing generator 23 controls a photographing operation (charge accumulation based on exposure, reading of accumulated charge, etc.) by the image sensor 15, and a predetermined timing pulse (pixel drive signal) based on a photographing control signal from the measurement control unit 25. , A horizontal synchronizing signal, a vertical synchronizing signal, a horizontal scanning circuit driving signal, a vertical scanning circuit driving signal, etc.) are generated and output to the image sensor 15.

  When imaging the metallic paint surface 71, the shutter speed determination unit 24 sets the shutter speed so that the output of the image sensor 15 does not saturate based on the provisional captured image for setting the exposure amount of the image sensor 15. . Specifically, an average amount of reflected light is obtained from the provisional captured image, and a shutter speed is set based on the amount of reflected light so that appropriate exposure according to the dynamic range of the image sensor 15 can be performed. The shutter speed set by the shutter speed determination unit 24 is output to the shutter control unit 22 via the measurement control unit 25. The shutter speed information is also output to the brightness correction unit 163 of the signal processing circuit 16 and is used as a parameter for the brightness correction process according to the shutter speed by the brightness correction unit 163.

  The measurement control unit 25 receives an operation signal from the operation unit 5, gives a control signal to each functional unit, and controls the overall measurement operation by the measurement control unit 2. That is, in order to capture a two-dimensional image of the metallic paint surface 71, control signals for operating the functional units such as the lighting control unit 21, the shutter control unit 22, and the timing generator 23 are generated. In addition, the provisional photographing operation for setting the exposure amount of the image sensor 15 is also controlled. In this case, the shutter control unit 22 is set with a predetermined fixed shutter speed, and the shutter speed determination unit 24 performs an operation for obtaining an appropriate shutter speed based on the provisional captured image obtained thereby. Make it.

  FIG. 6 is a block diagram showing the electrical functional configuration of the image processing means 3 and the calculation means 4. The image processing means 3 includes an image memory 31, a spatial digital filter 32, a filter characteristic setting unit 33, a filter characteristic storage unit 34, and a gamma correction unit 35. The image memory 31 is composed of a RAM or the like, and temporarily stores the two-dimensional image data sent from the imaging unit 1 or temporarily stores the image filtered by the spatial digital filter 32.

  The spatial digital filter 32 performs a filter process for matching the resolution of the two-dimensional image acquired by the imaging unit 1 with the resolution of the human eye, and has a predetermined filter characteristic such as a moving average filter or a Laplacian filter. , FIR filter, two-dimensional FFT filter, and the like.

  FIG. 7A is a photograph showing an example of an output image of the imaging unit 1 (a two-dimensional image output from the brightness correction unit 163). When the resolution of the light receiving optical system 14 and the imaging element 15 is high, as shown in FIG. 7A, even the contrast (particle property) generated by each of the glittering materials that cannot be perceived by the human eye is imaged. Become so. The spatial digital filter 32 performs a filtering process that degrades such a high-resolution two-dimensional image into a two-dimensional image actually perceived by the human eye. FIG. 7B is a photograph showing an example of an image (output of the spatial digital filter 32) on which such filter processing has been performed. As is clear from the photograph in FIG. 7A, the image has degraded particle properties, and it can be said that there is a great difference in the visual feeling between the two.

  As described above with reference to FIG. 1, this is because human contrast sensitivity has characteristics as shown in FIG. 8A with respect to an observation object having contrast. As shown in the characteristics, the human eye has a contrast = 1 (maximum) pattern at a spatial frequency of 60 cycles / 1 ° (the above-described stripe pattern) and a contrast at a spatial frequency of 5 cycles / 1 ° = 1 /. The 500 patterns are perceived as almost the same contrast. However, if the contrast is calculated numerically based on the luminance value extracted from the image, the two do not have the same contrast.

  However, by applying a filter having a transfer function (output amplitude / input amplitude) as shown in FIG. 8B to the original high-resolution image, the contrast that can be visually perceived and the calculated contrast are equivalent. Can be handled. That is, the transfer function is lowered in a region where the perception ability is reduced in the human eye and the spatial frequency is high, and the resolution of the original image is matched with the resolution of the human eye. Such a transfer function is obtained from the contrast ratio with the point having the highest contrast sensitivity, assuming that the point (5 cycles / 1 °) having the highest contrast sensitivity on the spatial frequency is “1”.

  Furthermore, in order to evaluate the visual feeling, it is necessary to fix the observation distance from the measurement target surface. For example, when a pattern of 60 cycles / 1 ° is observed from a distance of 25 cm, the pattern cycle width is about 73 μm / cycle. In order to evaluate the contrast in accordance with the sensitivity of the human eye when observing the metallic paint surface 71 as the sample surface under such conditions, for example, the filter characteristics shown in FIG. become. In FIG. 8C, the transfer function is displayed by converting the horizontal axis into the observation distance. Such a transfer function shifts in the left-right direction according to the observation distance.

  Accordingly, the spatial digital filter 32 has a filter characteristic as shown in FIG. 8C, for example. By applying such a spatial digital filter 32, the two-dimensional image input from the imaging means 1 is shown in FIG. An image such as a photograph in FIG. 7A is converted into an image that matches the resolution of the human eye as in the photograph in FIG. 7B.

  The filter characteristics set in the spatial digital filter 32 are the resolution of the acquired two-dimensional image over the entire perceived spatial frequency as shown in FIGS. 8B and 8C. However, it may be a low-pass filter that approximates the characteristics of the high-frequency part in the contrast sensitivity of the human eye with respect to the spatial frequency. Even with such a low-pass filter, it is possible to match the resolution of the acquired two-dimensional image with the resolution of the human eye for at least the high-frequency part that substantially affects the resolution of the human eye.

  The filter characteristic setting unit 33 (filter characteristic setting unit) sets the filter characteristic of the spatial digital filter 32 to an arbitrary characteristic based on designation (or automatic setting) from the operation unit 5 (filter characteristic designation unit). Part. The filter characteristic setting unit 33 extracts various filter characteristic information stored in the filter characteristic storage unit 34 in accordance with the designation information from the operation unit 5, performs an operation of combining a plurality of filter characteristics as necessary, and performs spatial digital A predetermined filter characteristic to be given to the filter 32 is specified.

  The filter characteristic storage unit 34 stores data in various filter characteristics to be set in the spatial digital filter 32, and includes at least an observation distance-by-observation pattern storage unit 341 and a low-frequency unevenness removal pattern storage unit 342. In the pattern storage unit 341 for each observation distance, for example, the filter characteristics as shown in FIG. 8C correspond to the observation distances from the measurement target surface (for example, the filter characteristics for each of the observation distances 25 cm, 50 cm, 75 cm, and 1 m). Stored. For example, when measuring the visual feeling at an observation distance of 25 cm, the filter characteristic setting unit 33 extracts a filter characteristic corresponding to the observation distance of 25 cm from the observation distance-specific pattern storage unit 341, and sets the filter characteristic in the spatial digital filter 32. To do. In the observation distance-specific pattern storage unit 341, for example, only filter characteristics at an observation distance of 25 cm are stored. For example, when obtaining a particle feeling at an observation distance of 50 cm, the observation is performed based on the filter characteristics at the observation distance of 25 cm. A filter characteristic at a distance of 50 cm may be obtained by calculation, and the filter characteristic may be set in the spatial digital filter 32.

  The low frequency unevenness removal pattern storage unit 342 stores predetermined filter characteristics for removing paint unevenness on the metallic paint surface. On the metallic coating surface, uneven brightness may occur due to uneven coating. Such brightness unevenness occurs in a low frequency region lower than the particulate spatial frequency (1 cycle / mm) normally generated by the bright material, as shown in FIG. 9A. Therefore, for example, by applying a so-called high-pass filter that cuts a low frequency region as shown in FIG. 9A, the image acquired by the imaging means 1 includes brightness unevenness due to paint unevenness. However, the influence of the unevenness of brightness can be removed. When there is a command to remove unevenness of brightness from the operation unit 5, the filter property setting unit 33 extracts the filter property extracted from the observation distance-specific pattern storage unit 341 and the high pass extracted from the low frequency unevenness removal pattern storage unit 342. For example, a filter characteristic as shown in FIG. 9B combined with the filter is generated, and the filter characteristic is set in the spatial digital filter 32.

  The operation unit 5 can designate a through process that does not cause the filter characteristic setting unit 33 to execute the filter process by the spatial digital filter 32. This through process is a process for acquiring the evaluation parameter of the glitter material itself based on the high-resolution image that has not been subjected to the filter process in the glitter material evaluation calculation unit 44 described later. When such a through process is designated, the filter characteristic setting unit 33 sets the transfer function of the spatial digital filter 32 to 1/1.

  The gamma correction unit 35 (gamma correction processing unit) is a functional unit that performs image processing for converting the brightness of the two-dimensional image acquired by the imaging unit 1 into brightness perceived by humans. The gamma correction unit 35 adjusts the brightness scale of the image to the sensitivity of the human eye by, for example, logarithmically converting the level of the output image signal of the spatial digital filter 32 using a predetermined gamma characteristic. .

According to Weber-Fechner's law, the relationship between the intensity of a stimulus given to a person and the perception felt by the person increases as the intensity of the stimulus increases geometrically, the magnitude of the sense increases geometrically. Have a relationship. This is also valid for the perception of brightness, and even if the brightness increases linearly, the brightness perceived by humans only increases logarithmically. For example, in the L ^* a ^* b ^* color system known as a general color system of a color space, the brightness L ^* (Elster), which is the brightness perceived by humans, is expressed by the following equation (1): Is represented by
L ^* = 116 × (Y / Yn) ^1/3 −16 (1)
However, Y / Yn> 0.008856
Y: Stimulus value by standard visual sensitivity characteristic Yn: Stimulus value of perfect diffuse reflection surface Here, the above “logarithmic increase” is not limited to a logarithmic increase in a strict mathematical sense, This means that the larger the input is, the wider the increase is such that the output is nonlinearly compressed. The lightness L ^* in the L ^* a ^* b ^* color system is defined by the exponential power of the stimulus value Y to the (1/3) th power, and such definition is also included in the concept of “logarithmic”.

  The gamma correction unit 35 converts the output of each pixel so as to logarithmically convert the brightness of the two-dimensional image acquired by the imaging unit 1 to the brightness perceived by the human eye according to the above equation (1), for example. Perform image processing. FIG. 7C is a photograph showing the image after the brightness conversion of the image of FIG. 7B (the output of the spatial digital filter 32) is performed by the gamma correction unit 35. After the above image processing is performed, the image data is sent to the calculation means 4, the feature amount is extracted from the image after the image processing, and the evaluation parameter regarding the particle feeling (visual feeling) of the metallic painted surface is extracted. The Rukoto.

  The calculation means 4 includes a feature amount calculation unit 41, a particle sensation index calculation unit 42 (particle sensation index calculation unit; psychophysical quantity calculation unit), an angle characteristic calculation unit 43, a brilliant material evaluation calculation unit 44 (bright material evaluation unit), a memory A unit 45 and an output / display control unit 46 are provided.

The feature amount calculation unit 41 is a predetermined feature amount related to the particle feeling on the metallic paint surface, for example, (1) image brightness and brightness distribution, from the image subjected to image processing by the image processing unit.
(2) The area of the black portion and / or the white portion when the image is binarized with a predetermined threshold,
(3) When the image is binarized with a predetermined threshold value, the particle sensation is obtained by either the number of independent black portions and / or white portions, or the combination of the feature values of (1) to (3) above. It is a function part which calculates | requires the evaluation parameter for evaluating this quantitatively by calculation.

  The feature amount extracted by the feature amount calculation unit 41 will be described with reference to FIGS. FIG. 10 is a diagram schematically showing an image obtained by photographing the metallic paint surface 71 shown in FIG. In FIG. 10, a surface P1 indicates a measurement area 72, and the vertical direction of the surface P1 indicates the degree of brightness, and is drawn with an indicator that the higher the position is, the brighter. The cones C <b> 1 to C <b> 3 indicate portions where the reflectance is high, and the surface P <b> 2 is a plane that represents an average value (predetermined threshold value) of the brightness of the entire measurement area 72. The part above the surface P2 is binarized as a high luminance part, and the part below the surface P2 is binarized as a low luminance part.

  Here, as described above, as the characteristic amount related to the metallic characteristic of the metallic coating surface 71, the brightness a of the high luminance part (the protruding height of each of the cones C1 to C3 from the surface P2) and the area of the high luminance part b (the area occupied by each of the cones C1 to C3 on the surface P2), the number of high brightness portions (the number of the cones C1 to C3 protruding from the surface P2; three in FIG. 10), and the like.

  Now, in the captured image of the measurement area 72, a group of connected pixels having brightness in a high-luminance part exceeding the plane P2 is defined as “particle”. In the schematic diagram shown in FIG. 10, each of the cones C1 to C3 is a “particle”. Then, in each of these particles, the value of the brightness a and the value of the area b of the high luminance part can be obtained, but the brightness a and the area b can be handled as evaluation parameters for evaluating the particle feeling.

  FIG. 11 is a schematic diagram in which the schematic diagram of FIG. 10 is replaced with a two-dimensional plane. FIG. 11 shows a case where there are five “particles” (cones C1 to C5). Based on FIG. 11, the above points will be described in detail. In this case, for each of the cones C1 to C5, the values of the brightness a1 to a5 and the areas b1 to b5 of the high luminance part can be acquired as evaluation parameters. it can. And it becomes possible by calculating | requiring statistical processing about the brightness a1-a5 of the high-intensity part of each particle | grain, the average value of high-intensity part brightness, the standard deviation of high-intensity part brightness, etc. can be calculated | required.

  Similarly, by performing statistical processing on the areas b1 to b5 of the high luminance part of each particle, it is possible to obtain the average value of the high luminance part area, the standard deviation of the high luminance part brightness, and the like. Furthermore, by counting the number of particles present in the measurement area 72, the total number of particles in the high luminance part and the number of particles per unit area can be obtained. Such a statistical processing value can be handled as an evaluation parameter for evaluating particle feeling more simply.

  As described above, if statistical processing is performed on the brightness of the high-luminance portion, the area of the high-luminance portion, and the like, and not only the average value but also the standard deviation, it is advantageous in evaluating the particle feeling. That is, if an image in a predetermined region is evaluated only by the average value of the brightness and area of the high-luminance part, it is impossible to quantitatively measure the difference in particle feeling due to the variation in brightness and area of individual particles. FIGS. 12A and 12B are plan views showing the above-defined “particles” binarized on the plane P2, and the black portion is a high-intensity cone Cn or cone Cm portion. .

  Comparing FIGS. 12 (a) and 12 (b), the number of particles and the average value of the particle areas are the same, but the area of each particle is different, so it is clear as a visual feeling (particle feeling). It will be different. That is, in FIG. 12 (a), since the area of each particle is almost constant, a high-brightness portion having substantially the same luminance is uniformly dispersed. In FIG. It is clear that there is a large variation in the area of the particles, resulting in a considerably different particle feeling. In a metallic coated plate, a large amount of fine glittering material is dispersed and blended, so the number of the “particles” is very large, and the brightness and area of each particle have a distribution close to a normal distribution. Therefore, by obtaining the average value and the standard deviation (variation), it is possible to accurately grasp the state of “particles” in the metallic paint plate.

  As described above, the visual feeling (particle feeling) of the metallic painted surface is binarized by binarizing a two-dimensional image of a predetermined measurement area acquired by the imaging unit 1 with a predetermined luminance threshold (average brightness). An image can be generated and quantitatively evaluated from the brightness of the high-luminance portion or the average value of the area of the high-luminance portion in the binarized image and the variation in the measurement area. In addition, for example, the particle feeling can be quantitatively evaluated from the average value and variation of the integrated values of the brightness of the high-luminance portion and the area of the high-luminance portion. In addition, when not sticking to the particle sensation seen by human eyes, the above-described average value is obtained for the two-dimensional image acquired by the imaging means 1 for the image that is not subjected to the filter processing by the spatial digital filter 32 (through processing). The surface reflection characteristics of the metallic paint surface can also be evaluated by a method for obtaining variation.

  Returning to FIG. 6, the feature amount calculation unit 41 is configured to extract an evaluation parameter by the above-described method, and an average brightness calculation unit 411, a binarization processing unit 412, an evaluation parameter extraction unit 413, and a statistical processing unit. 414.

  The average brightness calculation unit 411 calculates the average brightness of the image processed image input from the image processing unit 3. For example, a calculation process is performed to create a luminance histogram for the image and obtain an average value thereof. This is a process for obtaining the brightness level (threshold level for binarization) of the surface P2 in the above description.

  The binarization processing unit 412 performs a process of dividing the image-processed image into white / black binary regions using the average brightness obtained by the average brightness calculation unit 411 as a threshold value. Thereby, in the image, as shown in FIG. 12, the high-luminance portion and the low-luminance portion are partitioned, and the “particles” are detected.

  The evaluation parameter extraction unit 413 extracts a predetermined evaluation parameter for evaluating the particle feeling in the high luminance portion detected by the binarization processing unit 412. That is, as described above based on FIG. 11, for each of the cones C1 to C5, for example, the values of brightness a1 to a5 of the high luminance part, the values of areas b1 to b5, the number of particles in the measurement area, and the like. Each is obtained as an evaluation parameter.

  The statistical processing unit 414 is a functional unit that performs predetermined statistical processing using the evaluation parameter obtained by the evaluation parameter extraction unit 413 and obtains an evaluation parameter for quantitatively evaluating the particle feeling by calculation. For example, the average value and the standard deviation are obtained by calculation using the values of the brightness a1 to a5 and the areas b1 to b5 of the high luminance part obtained by the evaluation parameter extraction unit 413. The evaluation parameter obtained by the statistical processing unit 414 is based on the feature amount extracted from the image matched to the resolution of the human eye, and the visual feeling (particle feeling) of the metallic coating surface 71 to be measured. Is quantitatively expressed.

  The particle sensation index calculating unit 42 performs an operation for obtaining an evaluation index related to the particle sensation based on the evaluation parameter extracted by the feature amount calculating unit 41. That is, the particle sensation index calculation unit 42 is the evaluation parameter obtained by the statistical processing unit 414 and / or the brightness a1 to a5 value of the high luminance part and the area b1 to b5 value obtained by the evaluation parameter extraction unit 413. Is used to automatically calculate an evaluation index for numerically evaluating the particle feeling.

FIG. 13 is a graph showing the correlation between the average value of the brightness of the high-intensity portion extracted from the images actually taken for 37 sheets of the metallic paint plate and the particle feeling evaluated by visually evaluating the metal paint plate. is there. As is apparent from this graph, it can be seen that the visual feeling of particles and the average value of the brightness of the high luminance portion have a high correlation. Therefore, in the particle sensation index calculation unit 42, for example, the linear function y = 0.9011x + 0.1388 shown in FIG.
(However, x is visual particle sensation index, y is average brightness of peak part)
Can be stored in advance, and using this function, an evaluation index related to visual feeling can be derived from the average value of the brightness of the high-luminance part obtained by the statistical processing unit 414.

  Further, by combining evaluation parameters for the average value and standard deviation of the high-luminance part brightness and the average value and standard deviation of the high-luminance part area, an evaluation index that is more highly correlated with visual observation is obtained. It is also possible. Further, with respect to other visual feelings about the metallic paint plate, for example, a glittering feeling or a deep feeling, an evaluation function is obtained in advance or a predetermined look-up table is set so that the feature amount calculating unit 41 An evaluation index can be derived quantitatively based on the extracted evaluation parameters.

  The angle characteristic calculation unit 43 is a functional unit for quantifying and evaluating the change in the angle of the particle feeling when evaluating the particle feeling of the metallic paint surface. The angle characteristic calculation unit 43 and the comprehensive evaluation index calculation unit 432 And.

  The particle feeling on the metallic coating surface varies depending on the observation angle. In general, when illuminating the metallic paint surface with illumination light, the particle feel is high when observed from the direction near the regular reflection direction (the bright material appears to shine well), and as the distance from the regular reflection direction increases. , The feeling of particles is low (the brightness of the glittering material becomes inconspicuous). That is, as shown in FIG. 14, when the observation angle is the normal direction of the sample, when the illumination direction is changed based on the reference, the particle feeling felt by humans changes as shown in the graph. Such an angle change tendency of particle feeling is generally common to any metallic coating surface containing any glittering material, but is shown by the curves of Sample 1 and Sample 2 in FIG. As described above, the degree of change in the particle feeling varies depending on the shape and type of the glitter material, the type of base paint, and the like. For example, there are metallic painted surfaces in which the particle feeling does not change much even if they are far away from the regular reflection direction, and conversely metallic coating surfaces in which the particle feeling changes greatly only by leaving a little from the regular reflection direction.

  In view of such circumstances, the angle characteristic calculation unit 43 performs a calculation for quantitatively evaluating the change in the particle feeling accompanying the change in the observation angle with respect to the metallic coating surface. Therefore, when the angle characteristic calculation unit 43 is caused to function, it is necessary for the imaging unit 1 to acquire at least two two-dimensional images with different illumination angles. That is, at least in the reflected light measurement device 10 shown in FIG. 3, the first illumination angle (for example, the normal angle 15 is set to any one of the illumination optical systems 11 in the measurement area 72 of the metallic coating surface 71 to be measured. The first illumination system 11a is used to irradiate illumination light, and the reflected light is imaged by the image sensor 15 to obtain a first two-dimensional image, and the first illumination angle is different from the first illumination angle. Illumination light is irradiated to the same measurement area 72 at an illumination angle of 2 (for example, using the third illumination system 11c having a normal angle of 75 °), and the reflected light is imaged by the imaging device 15 to obtain the measurement area 72. It is necessary to acquire the second two-dimensional image.

  Then, each of the first two-dimensional image and the second two-dimensional image is subjected to image processing according to the resolution of the human eye by the image processing unit 3, and a predetermined evaluation parameter is extracted by the feature amount calculation unit 41. . After that, the particle feeling of the first two-dimensional image and the second two-dimensional image is obtained as a first evaluation index and a second evaluation index by the particle feeling index calculation unit 42, respectively.

  The angle characteristic parameter calculation unit 431 obtains, for example, a change amount from the first evaluation index to the second evaluation index, or obtains a change rate from the first evaluation index to the second evaluation index. Thus, an angle characteristic parameter for quantitatively evaluating the change in the feeling of particles accompanying the change in the observation angle is obtained. In the case of the former change amount, the change in the angle of particle feeling is quantitatively evaluated as the difference between the absolute amounts of the first and second evaluation indexes that are the basis of particle feeling evaluation. In the case of the latter change rate, the change in the angle of the particle feeling is quantitatively evaluated as the change rate indicating how much the evaluation index of the particle feeling is changed by changing the regular reflection direction.

In addition, the first illumination angle (first illumination system 11a having a normal angle of 15 °) and the second illumination angle (third illumination system 11c having a normal angle of 75 °) and the intermediate between them. The illumination area is irradiated with 3 illumination angles (second illumination system 11b having a normal angle of 45 °) to the measurement area 72, and the reflected light is imaged by the image sensor 15, respectively. It is also possible to acquire the first to third two-dimensional images and obtain the angle characteristic parameter based on the feature amounts of these three two-dimensional images. In this case, for example, the change rate of the particle sensitivity index with respect to the observation angle is obtained by the angle characteristic parameter calculation unit 431. That is, the angle characteristic parameter can be obtained based on the following equation (2).
(First evaluation index [15 °] −second evaluation index [75 °]) / third evaluation index [45 °]
... (2)

Alternatively, when the constants a and b for matching the angle change characteristic of the particle feeling visually felt with the calculated value are obtained in advance, the angle characteristic parameter is obtained based on the following equation (3). Can do.
(First evaluation index [15 °] −second evaluation index [75 °]) ^a / (third evaluation index [45 °]) ^b
... (3)
In this case, since the constants a and b for matching the angle change characteristic of the particle feeling visually felt and the calculated value are used, the particle feeling is directly calculated based on the first to third evaluation indexes. Can do. The constants a and b are constants that are experimentally obtained so that the angle change characteristic of the particle feeling visually felt matches the calculated value.

  The comprehensive evaluation index calculation unit 432 uses all or any two of the first evaluation index to the third evaluation index and synthesizes them to obtain the angle characteristic of particle feeling as an integrated evaluation index. Part. As described above, the particle sensation varies depending on the observation angle, but a human being has a visual ability to comprehensively determine the particle sensation due to the difference in the observation angle and derive one comprehensive particle sensation. This is considered to be that the particle feeling that changes depending on the observation angle is averaged by some kind of brain processing to comprehensively determine the particle feeling. The comprehensive evaluation index calculation unit 432 calculates an integrated evaluation index obtained by synthesizing a plurality of evaluation indexes obtained by the particle sensation index calculation unit 42, so that the total particle sensation approximated to the in-brain processing is obtained as a quantitative index. It becomes possible.

When the first evaluation index to the third evaluation index are obtained, the calculation process for obtaining the integrated evaluation index by the comprehensive evaluation index calculation unit 432 can be calculated based on, for example, the following equation (4). . The constants c, d, and e are constants that are experimentally obtained so that the angle change characteristic of the particle feeling visually felt matches the calculated value.
c × first evaluation index [15 °] + d × second evaluation index [75 °] + e × third evaluation index [45 °]
... (4)

  By providing such an angle characteristic calculation unit 43, the change in the angle of the particle feeling can be quantified and evaluated when evaluating the particle feeling on the metallic coating surface. In other words, the degree of change in the angle of particle feeling on the metallic coating surface, which varies depending on the shape and type of the glitter material, the type of base paint, etc., can be acquired as quantitative data, so that quality control of the metallic coating surface can be performed with high accuracy. become. In addition, since it is possible to manage the angle-dependent particle feeling with one evaluation index (the evaluation index obtained by the angle characteristic parameter calculation unit 431 or the comprehensive evaluation index calculation unit 432), data management is simplified. can do.

  When the through process is designated by the operation unit 5, the glitter material evaluation calculation unit 44 is based on the two-dimensional image acquired by the imaging unit 1, and the glitter material 703 contained in the metallic coating film 702. (See FIG. 4) Extract the evaluation parameters for itself. The glitter material evaluation calculation unit 44 calculates the brightness (reflectance), size, density, and the like of the glitter material itself based on the feature amount extracted from the high-resolution image that has not been filtered. Various image processing techniques can be applied to such an evaluation parameter derivation method. For example, a processing method similar to the binarization processing performed by the feature amount calculation unit 41 can be applied. In this case, the function of the glitter material evaluation calculation unit 44 may be shared by the feature amount calculation unit 41.

  The memory unit 45 includes a RAM or the like, and includes evaluation parameters obtained by each unit of the calculation unit 4, that is, the feature amount calculation unit 41, the particle sensation index calculation unit 42, the angle characteristic calculation unit 43, and the glitter material evaluation calculation unit 44 The evaluation index is temporarily stored.

  The output / display control unit 46 converts the evaluation parameter, the evaluation index, the shape information of the glitter material, and the like related to the particle feeling obtained by the calculation unit 4 into a predetermined format and outputs the converted information to the output unit 61 or the display unit 62. Control to display the screen.

(Explanation of operation flow)
The operation of the metallic painted surface evaluation apparatus S configured as described above will be described based on the flowcharts shown in FIGS. 15 to 19 with reference to the block diagrams of FIGS. FIG. 15 is a flowchart showing an overall operation flow of the metallic painted surface evaluation apparatus S. First, a two-dimensional image of a predetermined measurement area 72 (see FIG. 4) of the metallic paint surface 71 to be measured is acquired by the imaging unit 1 (step S1).

  Then, using the two-dimensional image acquired by the imaging means 1, it is selected whether to perform particle feeling (visual feeling) measurement or to perform glitter material measurement for evaluating the glitter material itself (step S2). This selection depends on which process the user desires, and is performed by a predetermined command process by the operation unit 5, for example. When the particle sensation measurement is selected in step S2, image processing is performed by the image processing unit 3 so that the resolution of the image matches the resolution of the human eye, and the feature amount calculation unit 41 of the calculation unit 4 performs the feature of the processed image. Based on the quantity, an evaluation parameter related to the particle feeling (visual feeling) is extracted, and a calculation process for obtaining a particle feeling index for quantitatively evaluating the particle feeling is executed by the particle feeling index calculation unit 42 (step S3). ).

  Subsequently, it is confirmed whether or not the angular characteristic of the particle feeling is to be measured using a plurality of particle feeling indexes obtained in step S3 (step S4). When the angle characteristic is measured (Yes in step S4), the angle characteristic calculation unit 43 of the calculation means executes a calculation process for quantifying and evaluating the angle change of the particle feeling. When this angle measurement process is performed, the imaging unit 1 acquires at least two two-dimensional images with different illumination angles for the same sample. On the other hand, when the angle characteristic is not measured (No in step S4), the measurement result is output or displayed on the output unit 61 or the display unit 62 as necessary, and the process ends.

  When the glitter material measurement is selected in step S2, the image processing means 3 does not execute a predetermined filter process (through process), and the glitter material is based on the two-dimensional image itself acquired by the imaging means 1. An evaluation parameter of the glitter material itself is obtained by the evaluation calculation unit 44 (step S6). Thereafter, the result of the bright material measurement is output or displayed on the output unit 61 or the display unit 62 as necessary, and the process ends.

  FIG. 16 is a flowchart showing details of the two-dimensional image acquisition step (step S1) in the flowchart of FIG. As a preparatory work, for example, using a reflected light measuring device 10 as shown in FIG. 3, a work of setting the metallic coating plate 7 to be measured in the measurement opening 102 is performed in advance. Then, which one of the first to third illumination systems 11a to 11c included in the illumination optical system 11 of the reflected light measurement device 10 is to be used is selected (step S11).

  Normally, the particle feeling is evaluated by visual observation in the regular reflection direction. Therefore, when relatively evaluating the particle feeling for a plurality of metallic paint plate samples, only the first illumination system 11a having a normal angle of 15 ° is used. This will be used and will be selected. On the other hand, when the angular characteristic of particle feeling is evaluated for one metallic paint plate sample (when the step S5 is executed), all or any two of the first to third illumination systems 11a to 11c are used. One of the illumination systems is selected. This selection is made from the operation unit 5 to the measurement control unit 25 by the user.

  Subsequent steps S12 to S14 are processes for obtaining a shutter speed corresponding to the reflectance of the metallic paint surface to be measured and setting an appropriate exposure amount of the image sensor. The light source of the illumination system selected in step S11 is turned on (step S12), and provisional imaging is performed in which the image sensor 15 captures the surface reflected light from the metallic paint plate as the measurement target (step S13). At this time, the shutter control unit 22 (see FIG. 5) sets the shutter speed of the shutter 17 to a default fixed shutter speed.

  Then, based on the amount of reflected light obtained from the image obtained by the provisional imaging in step S13, the shutter speed determination unit 24 does not saturate the output of the image sensor 15 when imaging the metallic coated plate as the measurement target. A correct shutter speed is calculated (step S14). The shutter speed calculated in this way is set to the shutter control unit 22 via the measurement control unit 25.

  Thereafter, using the illumination system selected in step S11, the actual imaging of the metallic coated plate to be measured is performed at the shutter speed calculated in step S14 (step S15). With this operation, a two-dimensional image of the measurement area 72 (see FIG. 4) of the metallic paint surface 71 is captured by the image sensor 15. Analog data output from the image sensor 15 is sent to the signal processing circuit 16, where amplification and digital conversion processing are performed, and the brightness correction unit 163 smoothes the shutter speed dependency. Therefore, brightness correction according to the shutter speed is performed (step S16). The two-dimensional image data after the brightness correction is output to the image processing means 3. Thereafter, the light source of the illumination system is turned off (step S17).

  Then, it is confirmed whether or not the same metallic coated plate sample is imaged at different illumination angles (step S18). For example, when measuring the angular characteristics of particle feeling, when simply obtaining the particle feeling index with different illumination angles. (Yes in step S18), the process returns to step S11 and the same processing is executed for another illumination system. On the other hand, when imaging is not performed at a different illumination angle (No in step S18), the process is completed.

  Next, FIG. 17 is a flowchart showing details of the step (step S3) of the particle sensation index calculation process in the flowchart of FIG. Here, first, the filter characteristic of the spatial digital filter 32 is set by the filter characteristic setting unit 33 of the image processing means 3 (step S31). This filter characteristic is set by using the filter characteristic storage unit 34 in accordance with the order of the observation distance from the measurement target surface where the particle feeling should be obtained and the removal of coating unevenness (command signal from the operation unit 5 by the user). Is set. When the filter characteristics of the spatial digital filter 32 are fixed, this step 31 is skipped.

  Then, the spatial digital filter 32 in which the predetermined filter characteristics are set performs a filtering process for matching the (high resolution) two-dimensional image output from the imaging unit 1 with the resolution of the human eye (step S32). . Subsequently, the gamma correction unit 35 performs image processing for converting the brightness of the two-dimensional image output from the spatial digital filter 32 into the brightness perceived by humans (step S33). The above is the processing in the image processing means 3. The image data subjected to such processing is output to the calculation means 4.

  In the calculating means 4, first, the average brightness of the image processed image given from the image processing means 3 is calculated by the average brightness calculating section 411 of the feature amount calculating section 41 (step S34). Then, the binarization processing unit 412 performs binarization processing for dividing the image into binary regions of a high luminance region and a low luminance region, using the average brightness obtained by the average brightness calculation unit 411 as a threshold value. Performed (step S35). This is also a process for grasping the feature amount of the image.

  Further, the evaluation parameter extraction unit 413 extracts a predetermined evaluation parameter for evaluating the particle feeling in the high luminance portion detected by the binarization processing unit 412 (step S36). As described above, this evaluation parameter includes, for example, the brightness value, the area value, and the number of particles in the measurement area of the high luminance part.

  Then, the statistical processing unit 414 performs predetermined statistical processing using the evaluation parameter obtained in step S36, and an evaluation parameter for quantitatively evaluating the particle feeling is obtained by calculation (step S37). The evaluation parameters here are, for example, the average value of the brightness value and the area value of the high-luminance part, and the variation (standard deviation) thereof.

  Although the evaluation parameter for indirectly evaluating the particle feeling is obtained by the processing of step S37, the particle amount index calculating unit 42 uses the feature amount calculating unit to directly evaluate the particle feeling. Based on the various evaluation parameters extracted in 41, an operation for obtaining an evaluation index related to particle feeling is performed (step S38). As a result, an evaluation index for quantitatively evaluating the optical characteristics of the metallic paint surface 71 to be measured, particularly the particle feeling, can be obtained.

  Further, FIG. 18 is a flowchart showing details of the step (step S5) of the angle characteristic calculation process in the flowchart of FIG. In this case, at least two two-dimensional images with different illumination angles are acquired for the same sample by the imaging means 1, and a particle sensation index based on each image is obtained by the particle sensation index calculation unit 42. Is the premise.

  First, in the angle characteristic parameter calculation unit 431 of the angle characteristic calculation unit 43, an angle characteristic evaluation formula for quantitatively evaluating the angle change of the particle feeling is set using the particle feeling index (step S51). For example, when two images with different illumination angles are used, the angle characteristic evaluation formula obtains the first evaluation index and the second evaluation index by the particle sensation index calculation unit 42 for each image, This is an arithmetic expression for obtaining the amount of change from the evaluation index to the second evaluation index or obtaining the rate of change from the first evaluation index to the second evaluation index. Further, when the first evaluation index to the third evaluation index are obtained by the particle feeling index calculation unit 42 for three images with different illumination angles, for example, the rate of change of the particle feeling index with respect to the observation angle is set. Either the above expression (2) or (3) for obtaining is set.

  Thereafter, a plurality of particle sensation indices obtained by the particle sensation index calculating unit 42 are acquired by the angle characteristic parameter calculating unit 431 (step S52), and the angle characteristic parameter is determined based on the angle characteristic evaluation formula set in step S51. Calculated (step S53). Thereby, the parameter which quantifies and evaluates the angle change of the particle feeling of a metallic coating surface is calculated | required.

  Subsequently, the comprehensive evaluation index calculation unit 432 confirms whether or not to obtain the angle characteristic of the particle feeling as an integrated evaluation index using the plurality of particle feeling indexes calculated by the particle feeling index calculation unit 42. (Step S54). If the integrated evaluation index is not obtained (No in step S54), the angle characteristic calculation process ends. On the other hand, when obtaining the integrated evaluation index, a predetermined comprehensive evaluation formula is set in the comprehensive evaluation index calculating unit 432 (step S56). This comprehensive evaluation formula is an arithmetic expression such as the above-described formula (4).

  Then, by applying the plurality of particle sensation indexes acquired in step S52 to the comprehensive evaluation formula set in step S56, the comprehensive evaluation index calculation unit 432 combines the plurality of particle sensation indexes with the angular characteristics. An integrated evaluation index is obtained (step S57). Thereby, the total particle feeling approximated to human brain processing is obtained as a quantitative index.

  FIG. 19 is a flowchart showing details of the step (step S6) of the glitter material evaluation calculation process in the flowchart of FIG. In this case, since it is not necessary to perform image processing that matches the resolution of the human eye with respect to the two-dimensional image acquired by the imaging unit 1 first, the operation unit 5 prevents the spatial digital filter 32 from performing filtering processing. A through process is designated in the filter characteristic setting unit 33 (step S61).

  This unfiltered image is taken into the glitter material evaluation calculation unit 44 of the calculation means 4. Then, the feature value is extracted from the high-resolution image that has not been filtered by the glitter material evaluation calculation unit 44 (step S62). Based on the feature value, the brightness (reflectance) and size of the glitter material itself are extracted. Evaluation parameters of the glitter material itself, such as density, are obtained by calculation (step S63). The above is the operation flow of the metallic painted surface evaluation apparatus S according to the present embodiment.

  As mentioned above, although embodiment of this invention was illustrated exemplifying the metallic paint surface evaluation apparatus S which mainly evaluates the particle feeling in a metallic paint surface, this invention is not limited to this. For example, the present invention can be applied to visual evaluation of a painted surface that does not include a glittering material, and visual evaluation of a building material, a decorative board, and other various articles.

  Moreover, it can also provide as an operation | movement program which performs the process which this metallic paint surface evaluation apparatus S performs instead of the above-mentioned metallic paint surface evaluation apparatus S. Such a program can be recorded on a computer-readable recording medium such as a flexible disk, a CD-ROM, a ROM, a RAM, and a memory card attached to the computer and provided as a program product. Alternatively, the program can be provided by being recorded on a recording medium such as a hard disk of the personal computer PC shown in FIG. A program can also be provided by downloading via a network.

It is a graph which shows the contrast sensitivity with respect to the spatial frequency of a human eye. It is a block diagram showing roughly the whole composition of metallic paint surface evaluation device S concerning the embodiment of the present invention. It is a block diagram which shows an example of the hardware constitutions of the metallic paint surface evaluation apparatus S concerning embodiment. It is the perspective view of the metallic coating board used as a measuring object, and its partial enlarged view. It is a block diagram which shows the electrical function structure of an imaging means and a measurement control means. It is a block diagram which shows the electrical function structure of an image processing means and a calculating means. It is a figure of the photograph format which shows the image made into a process handling in the metallic paint surface evaluation apparatus S concerning embodiment, (a) is the output image from an imaging means, (b) is the image after a filter process, (c) Indicates images after gamma correction. It is explanatory drawing about the filter characteristic set to a spatial digital filter, (a) is a graph figure about the contrast sensitivity of a human eye, (b) is a graph figure which shows a basic filter characteristic, (c) is observation It is a graph which shows the filter characteristic which considered distance. It is explanatory drawing about the filter characteristic for removing the coating nonuniformity. It is a figure which shows typically the image which image | photographed the metallic coating surface 71 shown in FIG. It is the schematic diagram which replaced the schematic diagram of FIG. 10 with the two-dimensional plane. It is the top view which binarized and showed the defined "particle" on the surface P2. It is a graph which shows the correlation with the average value of the high-intensity part brightness extracted from the image actually image | photographed about the some metallic coating board, and the particle feeling evaluated by evaluating the said metallic coating board visually. It is a graph which shows the angle dependence of a particle feeling. It is a flowchart which shows the whole operation | movement flow of the metallic paint surface evaluation apparatus S concerning embodiment. It is a flowchart which shows the detail of the acquisition step (step S1) of a two-dimensional image in the flowchart of FIG. It is a flowchart which shows the detail of the step (step S3) of a particle | grain sensitivity index calculation process in the flowchart of FIG. It is a flowchart which shows the detail of the step (step S5) of an angle characteristic calculation process in the flowchart of FIG. It is a flowchart which shows the detail of the step (step S6) of the luster material evaluation calculation process in the flowchart of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Imaging means 10 Reflected light measuring apparatus 11 Illumination optical system 14 Light receiving optical system 15 Imaging element (Means which photoelectrically convert the optical image of a measuring object)
163 Brightness Correction Unit 2 Measurement Control Unit 25 Measurement Control Unit 3 Image Processing Unit 32 Spatial Digital Filter (Means for Filtering)
33 Filter characteristic setting section (filter characteristic setting means)
34 Filter characteristic storage unit 35 Gamma correction unit (gamma correction processing means)
4 calculating means 41 feature amount calculating section (calculating means)
42 Particle Sensation Index Calculation Unit (Particle Sensitivity Index Calculation Unit; Psychophysical Quantity Calculation Unit)
43 Angle Characteristic Calculation Unit 44 Luminous Material Evaluation Calculation Unit (Luminous Material Evaluation Means)
5 Operation part (filter characteristic designation means)
7 Metallic paint plate 71 Metallic paint surface (object to be measured)
72 Measurement Area 702 Metallic Coating Film 703 Bright Material S Metallic Paint Surface Evaluation Device

Claims (24)

Photoelectrically converting the optical image of the measurement object to obtain a two-dimensional image of the measurement object;
Perform image processing to match the resolution of the image with the resolution of the human eye,
A visual feeling evaluation method, wherein an evaluation parameter relating to human visual feeling is extracted based on a feature amount of the image after the image processing.   The visual evaluation method according to claim 1, wherein the image processing is a filter processing that matches the resolution of the acquired two-dimensional image with the resolution of a human eye.   The visual feeling evaluation method according to claim 2, wherein the filtering process is a process of applying a band pass filter approximated to a human eye contrast sensitivity to a spatial frequency to the acquired two-dimensional image.   3. The visual inspection according to claim 2, wherein the filtering process is a process of applying a low-pass filter approximated to a characteristic of a high-frequency part in contrast sensitivity of human eyes with respect to a spatial frequency to the acquired two-dimensional image. Feeling evaluation method. The visual evaluation method according to claim 1, wherein the feature amount of the image is at least one feature amount selected from the group consisting of the following (1) to (3) in the image after the image processing. .
(1) Image brightness and brightness distribution (2) Black and / or white area when the image is binarized with a predetermined threshold (3) The image is binarized with a predetermined threshold Number of independent black and / or white parts   The visual evaluation method according to claim 1, wherein the evaluation parameter is an evaluation parameter for evaluating an influence of reflected light from particles contained in the measurement object on human visual feeling.   The image processing is characterized in that, as the image processing, image processing for matching the resolution of the acquired image with the resolution of a human eye and image processing for converting the brightness of the image into brightness perceived by a human being are performed. The visual evaluation method according to 1.   The image processing for converting the brightness is an image processing that adjusts the brightness scale to human sensitivity so that the brightness of the acquired image is nonlinearly compressed as the brightness increases. The visual evaluation method according to claim 7, wherein:   The visual feeling evaluation method according to claim 1, wherein the measurement object is a metallic paint surface.   The visual evaluation method according to claim 9, wherein in the image processing, image processing for removing coating unevenness on the metallic coating surface is further performed. Imaging means for photoelectrically converting a light image of the measurement object to obtain a two-dimensional image of the measurement object;
Image processing means for generating a predetermined processed image by performing image processing that matches at least the resolution of the image with the resolution of the human eye;
A visual sensation evaluation system comprising: calculation means for extracting an evaluation parameter related to human visual sensation based on the feature amount of the processed image.   12. The visual evaluation system according to claim 11, wherein the image processing unit includes a spatial digital filter for adjusting the resolution of the two-dimensional image acquired by the imaging unit to the resolution of a human eye. Filter characteristic specifying means for specifying the characteristic of the spatial digital filter as an arbitrary characteristic;
13. The visual evaluation system according to claim 12, further comprising filter characteristic setting means for setting the characteristics of the spatial digital filter to the filter characteristics designated by the filter characteristic designation means.   12. The visual feeling evaluation according to claim 11, wherein the image processing means further comprises gamma correction processing means for converting the brightness of the two-dimensional image acquired by the imaging means into brightness perceived by a human. system.   The visual feeling evaluation system according to claim 11, further comprising psychophysical quantity calculation means for obtaining an evaluation index related to human visual feeling based on the evaluation parameter extracted by the calculation means. A metallic paint surface evaluation apparatus for quantitatively evaluating a particle feeling, which is an effect of reflected light from a glitter material contained in a metallic paint surface on human visual perception of the metallic paint surface,
Imaging means for irradiating a predetermined measurement area of a metallic coating surface to be measured with illumination light, photoelectrically converting the reflected light to obtain a two-dimensional image of the measurement area,
Image processing means for generating a predetermined processed image by performing image processing that matches at least the resolution of the image with the resolution of the human eye;
An apparatus for evaluating a metallic painted surface, comprising: an arithmetic unit that extracts an evaluation parameter relating to human visual perception based on a feature amount of the processed image. The image processing means includes a spatial digital filter for adjusting the resolution of the two-dimensional image acquired by the imaging means to the resolution of the human eye, and further a filter for designating the characteristics of the spatial digital filter as an arbitrary characteristic Characteristic specifying means;
17. The metallic paint surface evaluation apparatus according to claim 16, further comprising filter characteristic setting means for setting the characteristic of the spatial digital filter to the filter characteristic designated by the filter characteristic designation means.   The metallic paint surface evaluation apparatus according to claim 17, wherein the filter property setting means is capable of setting a filter property capable of removing low frequency unevenness due to paint unevenness of the metallic paint surface.   The metallic paint surface evaluation apparatus according to claim 17, wherein the filter property setting means is capable of setting a filter property associated with an observation distance of the metallic paint surface. The filter characteristic designating means is capable of designating a through process that does not execute the filter process by the spatial digital filter,
20. A bright material evaluation unit that extracts an evaluation parameter related to the bright material itself based on a two-dimensional image acquired by the imaging unit when the through process is designated. The metallic paint surface evaluation apparatus in any one of.   The metallic paint surface evaluation apparatus according to any one of claims 16 to 20, further comprising a particle feeling index calculating means for obtaining an evaluation index related to the particle feeling based on the evaluation parameter extracted by the calculating means. A program for operating a metallic paint surface evaluation apparatus comprising predetermined image processing means and calculation means,
An image input step for receiving an input of a two-dimensional image obtained by photoelectrically converting a light image of a predetermined measurement area on the metallic coating surface to be measured;
An image processing step of causing the image processing means to perform image processing that matches at least the resolution of the image with the resolution of a human eye and to generate a predetermined processed image;
An operation program for a metallic paint surface evaluation apparatus, characterized in that the calculation means executes a calculation step of extracting an evaluation parameter related to human visual perception based on a feature amount of the processed image. A program for operating a metallic paint surface evaluation apparatus comprising predetermined imaging means, image processing means and calculation means,
An imaging step of causing the imaging means to irradiate a predetermined measurement area of the metallic paint surface to be measured, and photoelectrically converting the reflected light to obtain a two-dimensional image of the measurement area;
An image input step for receiving input of the two-dimensional image;
An image processing step of causing the image processing means to perform image processing that matches at least the resolution of the image with the resolution of a human eye and to generate a predetermined processed image;
An operation program for a metallic paint surface evaluation apparatus, characterized in that the calculation means executes a calculation step of extracting an evaluation parameter related to human visual perception based on a feature amount of the processed image. A method for evaluating the visual feeling of the metallic coating surface based on a two-dimensional image obtained by photoelectrically converting a light image of a predetermined measurement area on the metallic coating surface to be measured,
Binarizing the two-dimensional image with a predetermined luminance threshold value to generate a binarized image;
About the high-intensity part in the said binarized image, the predetermined value regarding visual feeling is obtained from the average value of at least one or more feature values selected from the group consisting of the following (4) to (6) and the variation in the measurement area. A visual evaluation method for a metallic painted surface, characterized in that an evaluation value is obtained.
(4) Brightness in a region of the high luminance portion above the threshold (5) Area of the high luminance portion (6) Integral value of brightness in the region of the high luminance portion above the threshold and the area of the high luminance portion