JP2005190261A - Image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily create a virtual texture image of a target surface using a small amount of data. <P>SOLUTION: A spectral reflection data accepting part 11 accepts spectral reflection data that show the spectral reflection characteristic of the entire target surface under a plurality of observing conditions which differ at least in illuminating positions or viewing positions. A brightness distribution data accepting part 12 accepts the target surface's brightness distribution data at a predetermined illuminating position and viewing position. An observing condition information accepting part 13 accepts the observing conditions employed during the formation of the texture image. Based on the spectral reflection data and the brightness distribution data, a texture image forming part 14 creates a virtual texture image of the target surface under the observing conditions shown in observing condition information. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an image creating apparatus that creates a virtual texture image of a target surface.

  As paints for automobile bodies, mobile phones, home appliances, etc., metallic paints mainly composed of color pigments and glittering materials are known. The painted surface to which the metallic paint is applied has properties different from those of the solid paint mainly composed of a color pigment. That is, the color changes depending on the change in the illumination position (light source position) and the viewpoint position. In addition, since a bright material is included, the luminance distribution in a predetermined region of the painted surface is not uniform. For this reason, when trying to virtually express a metallic painted automobile or the like with three-dimensional computer graphics, even if the polygon model is simply subjected to shading, a texture unique to metallic painting cannot be obtained.

  In order to virtually express such a metallic painted surface with high quality, the following method may be adopted.

  There is a technique called texture mapping in which a photographed image (texture image) acquired from the real world is pasted on the polygon model surface.

  As one method of this texture mapping, a plurality of captured images obtained by capturing the target object with different viewpoints or illumination conditions are prepared as texture images. When rendering a three-dimensional object, the normal and viewpoint of the object surface, the illumination position, etc. There is a method of mapping by switching texture images prepared in advance from information. However, when a large number of texture images are prepared in accordance with a plurality of imaging environments as described above, a huge amount of texture memory is required. Thus, a technique for compressing the above-described many texture images has been proposed (see, for example, Patent Document 1).

  On the other hand, as a method of texture mapping, there is a technique of mapping basic texture map data on the surface of a three-dimensional object and then mapping optical attribute map data (see, for example, Patent Document 2). Here, the basic texture map data is created based on information on the type, color, thickness, and shape of the yarn, and the optical attribute map data includes diffuse reflectance (reflectance for each color of RGB), specular reflectance (RGB). It is created based on information such as reflectance for each color) and reflectance directivity.

JP 2003-223650 A JP 2003-36449 A

  However, the techniques described in the above patent documents have the following problems. That is, in the technique described in Patent Document 1, since the texture image data before compression is enormous, the amount of data is still very large even after compression. According to the technique described in Patent Document 2, since object configuration information (thread type, thickness, shape, etc.) is required for creating a texture pattern, preparation for creating a texture image is not easy.

  The present invention provides an image creation apparatus that can easily create a texture image based on a small amount of data.

  The present invention is an image creation device for creating a virtual texture image of a target surface, and spectral reflection data indicating spectral reflection characteristics of the entire target surface at least under a plurality of observation conditions with different illumination positions or viewpoint positions. A spectral reflection data reception unit for receiving, a luminance distribution data reception unit for receiving luminance distribution data of the target surface at a predetermined illumination position and viewpoint position, an observation condition information reception unit for receiving observation condition information at the time of texture image creation, A texture image creating unit that creates a virtual texture image of the target surface under the viewing condition indicated by the viewing condition information based on the spectral reflection data and the luminance distribution data.

  On the metallic coating surface, the spatial distribution of colors is substantially uniform, and the luminance distribution hardly changes even if the illumination position or the viewpoint position changes. Therefore, in the present invention, the luminance distribution data indicating the luminance distribution of the target surface at the predetermined illumination position and viewpoint position is used as the original data for creating the texture image. Further, the metallic painted surface has a characteristic that the color changes depending on the change of the illumination position or the viewpoint position. Therefore, in the present invention, in order to express a color change due to a change in the illumination position or the viewpoint position, spectral reflection data indicating spectral reflection characteristics of the entire target surface under a plurality of observation conditions having at least different illumination positions or viewpoint positions is used as a texture image. The original data for creation. Based on the spectral reflection data and the luminance distribution data, a virtual texture image of the target surface under a desired observation condition is created. For this reason, the amount of data can be reduced compared with the case where texture images under a plurality of observation conditions are prepared in advance. Moreover, since the configuration information of the target surface is unnecessary, a texture image can be easily created.

  Note that the image creating apparatus of the present invention is not limited to a metallic paint surface, but can be used for other surfaces such as an automobile interior surface and a monochromatic textile (monochromatic post-dyed fabric, monochromatic knit).

  In addition, the present invention is an image creation device that creates a virtual three-dimensional image of a target object, and a three-dimensional shape data receiving unit that receives three-dimensional shape data of the target object including one or more target surfaces; Spectral reflection data receiving unit for receiving spectral reflection data indicating spectral reflection characteristics of the entire target surface under a plurality of observation conditions having at least different illumination positions or viewpoint positions, and luminance of the target surface at a predetermined illumination position and viewpoint position A luminance distribution data receiving unit that receives distribution data, an observation condition information receiving unit that receives observation condition information indicating an illumination position and a viewpoint position with respect to the target object at the time of creating a three-dimensional image, the three-dimensional shape data, and the observation condition information An observation condition specifying unit for obtaining an observation condition for each of the target surfaces at the time of creating a three-dimensional image, and the spectrum Based on the projection data and the luminance distribution data, a virtual texture image of each target surface in each observation condition obtained by the observation condition specifying unit is pasted on each target surface included in the three-dimensional shape data, A texture image pasting unit that creates a virtual three-dimensional image of the target object.

  In the image creating apparatus of the present invention, it is preferable that at least one of the spectral reflection data and the luminance distribution data is actual measurement data obtained by measuring an actual surface.

  The present invention is also an image creation method for creating a virtual texture image of a target surface, wherein the spectral reflection indicates spectral reflection characteristics of the entire target surface under a plurality of observation conditions having at least different illumination positions or viewpoint positions. Spectral reflection data reception step for receiving data, luminance distribution data reception step for receiving luminance distribution data of the target surface at a predetermined illumination position and viewpoint position, and observation condition information reception step for receiving observation condition information when creating a texture image And a texture image creation step of creating a virtual texture image of the target surface under the observation conditions indicated by the observation condition information based on the spectral reflection data and the luminance distribution data. .

  In addition, the present invention is an image creation device for creating a virtual three-dimensional image of a target object, the three-dimensional shape data receiving step for receiving three-dimensional shape data of the target object including one or more target surfaces; Spectral reflection data receiving step for receiving spectral reflection data indicating spectral reflection characteristics of the entire target surface under a plurality of observation conditions having at least different illumination positions or viewpoint positions, and luminance of the target surface at a predetermined illumination position and viewpoint position A luminance distribution data receiving step for receiving distribution data, an observation condition information receiving step for receiving observation condition information indicating an illumination position and a viewpoint position for the target object at the time of creating a three-dimensional image, the three-dimensional shape data, and the observation condition information To obtain the observation condition for each target surface at the time of creating a three-dimensional image Based on the condition specifying step and each target surface included in the three-dimensional shape data based on the spectral reflection data and the luminance distribution data, the virtual surface of each target surface in each observation condition obtained in the observation condition specifying step A texture image pasting step for pasting a simple texture image and creating a virtual three-dimensional image of the target object.

  In the image creation method of the present invention, it is preferable that at least one of the spectral reflection data and the luminance distribution data is actual measurement data obtained by measuring an actual surface.

  The present invention is also an image creation program for causing a computer to create a virtual texture image of a target surface, wherein the computer reflects spectral reflection of the entire target surface under a plurality of observation conditions with at least different illumination positions or viewpoint positions. Spectral reflection data reception step for receiving spectral reflection data indicating characteristics, luminance distribution data reception step for receiving luminance distribution data of the target surface at a predetermined illumination position and viewpoint position, and observation condition information at the time of texture image creation An observation condition information receiving step, and a texture image creation step of creating a virtual texture image of the target surface under the observation conditions indicated by the observation condition information based on the spectral reflection data and the luminance distribution data. It is characterized by making it.

  Further, the present invention is an image creation program for causing a computer to create a virtual three-dimensional image of a target object, wherein the computer receives three-dimensional shape data of the target object including one or more target surfaces. A data reception step, a spectral reflection data reception step for receiving spectral reflection data indicating spectral reflection characteristics of the entire target surface under a plurality of observation conditions with at least different illumination positions or viewpoint positions, and a predetermined illumination position and viewpoint position, A luminance distribution data receiving step for receiving luminance distribution data of the target surface, an observation condition information receiving step for receiving observation condition information indicating an illumination position and a viewpoint position of the target object at the time of creating a three-dimensional image, and the three-dimensional shape data And based on the observation condition information An observation condition specifying step for obtaining an observation condition for each target surface, and each of the target surfaces included in the three-dimensional shape data based on the spectral reflection data and the luminance distribution data. A texture image pasting step of pasting a virtual texture image of each target surface under observation conditions and creating a virtual three-dimensional image of the target object is performed.

  In the image creation program of the present invention, it is preferable that at least one of the spectral reflection data and the luminance distribution data is actual measurement data obtained by measuring an actual surface.

  According to the present invention, a virtual texture image of a target surface under a desired observation condition is obtained based on spectral reflection data of the entire target surface under a plurality of observation conditions and luminance distribution data of the target surface under a predetermined observation condition. create. For this reason, the amount of data can be reduced compared with the case where texture images under a plurality of observation conditions are prepared in advance. Moreover, since the configuration information of the target surface is unnecessary, a texture image can be easily created.

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

  FIG. 1 is a block diagram showing a configuration of an image creating apparatus 10 according to the present embodiment. The image creating apparatus 10 creates virtual texture image data (hereinafter referred to as a texture image) of a painted surface or the like (hereinafter referred to as a target surface) of a predetermined area (for example, a 10 mm × 10 mm area) of an automobile body. Is. The image creating apparatus 10 is particularly preferably used for virtual expression of the texture of a painted surface of an automobile body, a mobile phone, a home appliance, or the like to which a metallic paint is applied.

  In FIG. 1, the image creating apparatus 10 includes a spectral reflection data receiving unit 11, a luminance distribution data receiving unit 12, an observation condition information receiving unit 13, and a texture image creating unit 14. In the present embodiment, the image creating apparatus 10 is realized by a computer, and each of the units 11 to 14 is realized by executing an image creating program stored in a recording medium such as a ROM by a CPU and a RAM. However, it goes without saying that the realization mode of the image creating apparatus 10 is not particularly limited.

  FIG. 2 is a flowchart showing an operation procedure of the image creating apparatus 10 according to the present embodiment. Hereinafter, the operation of the image creating apparatus 10 will be specifically described with reference to FIGS. 1 and 2.

  The spectral reflection data receiving unit 11 receives spectral reflection data indicating spectral reflection characteristics of the entire target surface under a plurality of observation conditions having at least different illumination positions or viewpoint positions (S11). Here, as the spectral reflection data, for example, reflectance data for each wavelength of 10 nm in the visible light region (wavelength 400 to 800 nm) can be mentioned, but any other data is adopted as long as it exhibits spectral reflection characteristics. can do. As an example, there are three light primary colors RGB. The spectral reflection data may be actually measured data or virtually created data.

  In the present embodiment, the spectral reflection data is actual measurement data obtained by measuring a metallic-coated test piece as follows. FIG. 3 is a diagram showing a measurement environment for spectral reflection data. In FIG. 3, the illumination position and the viewpoint position are represented by spherical coordinates (θi, φi) and (θe, φe), respectively, with the center of the test piece as the origin. A light source is arranged at the illumination position, and a light receiver for measuring the luminance value of each color of R (red), G (green), and B (blue) is arranged at the viewpoint position. In such a measurement system, θi, φi, θe, and φe are changed, and the reflected light from the test piece is received by the light receiver, and the luminance values r (θi, φi, θe, φe), g of the RGB colors are received. (Θi, φi, θe, φe), b (θi, φi, θe, φe) are measured. Here, θi and θe are changed at 10 ° intervals in the range of 0 ° to 180 °, and φi and φe are changed at 10 ° intervals in the range of 0 ° to 90 °.

  The spectral reflection data receiving unit 11 is a luminance value r (θi, φi, θe, φe), g (θi, φi, θe, φe), b (θi, φi, θe,) measured as described above. φe) is received as spectral reflection data and passed to the texture image creation unit 14.

  The luminance distribution data receiving unit 12 receives luminance distribution data indicating the luminance distribution of the target surface at the predetermined illumination position and viewpoint position (S12). Here, the luminance distribution data may be actually measured data or may be virtually created data.

  In the present embodiment, the luminance distribution data is actual measurement data obtained by measuring a metallic-coated test piece as follows. FIG. 4 is a diagram showing a measurement environment for luminance distribution data. In FIG. 4, a light source and a monochromatic CCD are fixedly arranged in a plane perpendicular to the test piece including the center of the test piece, and an optical system with 25 ° incidence and 10 ° light reception is obtained. Here, the spectral distribution characteristics of the light source and the monochromatic CCD are flat in the visible light region, but may be set as appropriate. In this measurement system, light reflected from a test piece of light from a light source is received by a monochromatic CCD, and the luminance distribution of the reflected light is measured. Here, it is assumed that the measurement result shown in FIG. 5 is obtained. Each value BL (u, v) shown in FIG. 5 is a luminance value detected by each light receiving element of the single color CCD, and is arranged in a matrix corresponding to the arrangement of the light receiving elements of the single color CCD. Here, the variables u and v indicate the horizontal and vertical positions of the matrix of FIG. In FIG. 5, the luminance value is expressed by 16 gradations of levels 0 to 15.

  The luminance distribution data receiving unit 12 receives the luminance distribution BL (u, v) measured as described above as luminance distribution data and passes it to the texture image creating unit 14.

  The observation condition information accepting unit 13 accepts observation condition information indicating an observation condition for the target surface at the time of creating the texture image (S13). Specifically, when an attempt is made to create a texture image when the illumination position with respect to the target surface is (θi ′, φi ′) and the viewpoint position with respect to the target surface is (θe ′, φe ′), (θi ′ , Φi ′, θe ′, φe ′) is given to the observation condition information receiving unit 13 as observation condition information. Then, the observation condition information reception unit 13 passes the received observation conditions (θi ′, φi ′, θe ′, φe ′) to the texture image creation unit 14.

  Next, the texture image creating unit 14 receives the observation condition received from the observation condition information receiving unit 13 based on the spectral reflection data received from the spectral reflection data receiving unit 11 and the luminance distribution data received from the luminance distribution data receiving unit 12. A virtual texture image of the target surface under the observation condition indicated by the information is created (S14, S15).

  Hereinafter, a procedure for creating a texture image will be described. First, the texture image creating unit 14 has luminance values r (θi, φi, θe, φe), g (θi, φi, θe, φe), b (θi, φi, θe, φe) that are spectral reflection data. ), The observation conditions (θi, φi, θe, φe) coincide with the observation conditions (θi ′, φi ′, θe ′, φe ′) at the time of creating the texture image, that is, r (θi ′, φi ′). , Θe ′, φe ′) (hereinafter referred to as r ′), g (θi ′, φi ′, θe ′, φe ′) (hereinafter referred to as g ′), b (θi ′, φi ′, θe ′), φe ′) (hereinafter referred to as b ′) is selected (S14). Then, by multiplying each of the luminance values r ′, g ′, b ′ of the RGB colors by the luminance distribution BL (u, v), the luminance distributions R (u, v), G of the RGB colors constituting the texture image. (U, v) and B (u, v) are calculated (S15). That is, the luminance distribution of each color of RGB constituting the texture image is R (u, v) = r ′ · BL (u, v), G (u, v) = g ′ · BL (u, v), B (u, v) = b ′ · BL (u, v). Specifically, when r ′ = 15, g ′ = 7, and b ′ = 2, R (u, v), G (u, v), and B (u, v) are as shown in FIG. 7, 8 as shown.

  The texture image created by the texture image creation unit 14 is displayed on a display or output to another device or program.

  In the above description, some of (θi, φi, θe, φe) matches the observation condition information (θi ′, φi ′, θe ′, φe ′), but they always match. May not be present. In this case, r ′, g ′, and b ′ are calculated from the spectral reflection data r, g, and b by various interpolation methods such as a nearest neighbor method and a linear interpolation method.

  Steps S11 to S13 may be executed in any order. Further, the spectral reflection data, the luminance distribution data, and the observation condition information may be input by the user via a user interface, or may be input from another device or program.

  As described above, according to the image creating apparatus 10 according to the present embodiment, a texture image is generated based on the spectral reflection data of the entire target surface under a plurality of observation conditions and the luminance distribution data of the target surface under a predetermined observation condition. Since it is created, the amount of data necessary for creating a texture image under a desired viewing condition can be reduced as compared with a case where texture images under a plurality of viewing conditions are stored in advance. For this reason, efficient virtual representation of texture is possible with limited resources (memory capacity, data transfer rate).

  Here, in the present embodiment, the spatial distribution of the color within the target surface and the change in the luminance distribution accompanying the change in the illumination position or the viewpoint position are not considered. For this reason, the image creating apparatus 10 according to the present embodiment is preferably used for a target surface that has a substantially uniform color spatial distribution and a small change in luminance distribution due to a change in observation conditions. Examples of such target surfaces include painted surfaces of automobile bodies, mobile phones, home appliances, etc., automobile interior surfaces, monochromatic textiles (monochromatic post-dyed fabrics, monochromatic knits), and the like. In addition, since spectral reflection data indicating the spectral reflection characteristics of the entire target surface under a plurality of observation conditions is used, it is particularly preferably used for the target surface whose color changes as the illumination position or viewpoint position changes. Therefore, the image creating apparatus 10 according to the present embodiment is preferably used particularly for a painted surface to which a metallic paint containing a glittering material is applied.

  In addition, when the texture image data is compressed, data expansion processing is required at the time of texture mapping, but according to the present embodiment, the expansion processing is not necessary. For this reason, compared with the case where texture image data is compressed, the amount of calculation at the time of texture image creation can be reduced, and high quality texture expression can be performed at a limited CPU speed.

  Further, since the texture image is created based on the spectral reflection data and the luminance distribution data, the object configuration information is not required. For example, in the case of a metallic paint, information such as the type of color pigment, the type, diameter, and content of glittering fine particles is not required. For this reason, the virtual expression of a texture can be performed easily. If there is a test piece such as a painted surface of an automobile, a virtual representation of the target surface is possible only by measuring the spectral reflection characteristics and the luminance distribution of the painted surface of the test piece.

  In addition, when actual measurement data is used as spectral reflection data and luminance distribution data, the actual texture of the object surface can be easily and realistically reproduced.

  FIG. 9 is a block diagram illustrating a configuration of an image creating apparatus 20 according to another embodiment. The image creation device 20 performs texture mapping on the 3D shape data to create virtual 3D image data (hereinafter referred to as a 3D image) of the target object. In FIG. 9, an image creating apparatus 20 includes a three-dimensional shape data receiving unit 21, a spectral reflection data receiving unit 22, a luminance distribution data receiving unit 23, an observation condition information receiving unit 24, an observation condition specifying unit 25, and a texture image pasting. Part 26. Hereinafter, the image creating apparatus 20 will be described, but the description of the same parts as the image creating apparatus 10 will be omitted.

  FIG. 10 is a flowchart showing an operation procedure of the image creating apparatus 20 according to the present embodiment. Hereinafter, the operation of the image creating apparatus 20 will be specifically described with reference to FIG.

  The three-dimensional shape data receiving unit 21 receives three-dimensional shape data including one or more target surfaces representing the three-dimensional shape of the target object (S21). In the present embodiment, the three-dimensional shape data includes a plurality of polygonal surfaces Sj (j = 1, 2, 3,...) Representing the shape of the automobile body that is the target object B, as shown in FIG. It is data. The plurality of polygonal surfaces Sj correspond to the painted surface of the automobile body, and are target surfaces Sj on which texture images are to be pasted. Here, each polygon surface Sj is a polygon and is defined by the coordinates of each vertex. The three-dimensional shape data receiving unit 21 passes the three-dimensional shape data to the texture image pasting unit 26.

  The spectral reflection data receiving unit 22 receives spectral reflection data (S22). Here, the spectral reflection data is measured on the test piece on the painted surface of the automobile body in the same manner as in the image creating apparatus 10. Therefore, the spectral reflection data are the luminance values r (θi, φi, θe, φe), g (θi, φi, θe, φe), b (θi, φi, θe, φe) of each color of RGB. The spectral reflection data receiving unit 22 passes the spectral reflection data to the texture image pasting unit 26.

  The luminance distribution data receiving unit 23 receives luminance distribution data (S23). Here, the luminance distribution data is measured on the test piece on the painted surface of the automobile body in the same manner as in the image creating apparatus 10. Therefore, the luminance distribution data is the luminance distribution BL (u, v). The luminance distribution data receiving unit 23 passes the luminance distribution data to the texture image pasting unit 26.

  The observation condition information receiving unit 24 receives observation condition information indicating an illumination position and a viewpoint position with respect to the target object at the time of creating a three-dimensional image (S24).

  Specifically, as shown in FIG. 11, when the illumination position is the coordinate (xi, yi, zi) and the viewpoint position is the coordinate (xe, ye, ze) in the coordinate system where the target object B is placed. When the three-dimensional image is to be created, the illumination coordinates (xi, yi, zi) and the viewpoint coordinates (xe, ye, ze) are given to the observation condition information receiving unit 24 as observation condition information. The observation condition information receiving unit 24 passes this observation condition information to the observation condition specifying unit 25.

  Next, the observation condition specifying unit 25 obtains an observation condition for each target surface Sj when creating a three-dimensional image based on the three-dimensional shape data and the observation condition information (S25). Specifically, for each target surface Sj, the target surface Sj is determined from a plurality of vertex coordinates defining the target surface Sj, illumination coordinates (xi, yi, zi), and viewpoint coordinates (xe, ye, ze). An illumination position (θij, φij) and a viewpoint position (θej, φej) are calculated. Then, the calculated observation conditions (θij, φij, θej, φej) are passed to the texture image pasting unit 26.

  Next, the texture image pasting unit 26 received from the three-dimensional shape data receiving unit 21 based on the spectral reflection data received from the spectral reflection data receiving unit 22 and the luminance distribution data received from the luminance distribution data receiving unit 23. A virtual texture image of each target surface Sj under each observation condition obtained by the observation condition specifying unit 25 is pasted on each target surface Sj included in the three-dimensional shape data, and a virtual three-dimensional image of the target object B is attached. Is created (S26-28). Here, the texture image pasting unit 26 may create the color texture image based on the spectral reflection data and the luminance distribution data, and then paste the color texture image on the target surface, or based on the luminance distribution data. After the monochrome texture image is pasted on the target surface, color rendering may be performed on the target surface based on the spectral reflection data. If the shape of the target surface Sj and the luminance arrangement shape of the luminance distribution data are different, the luminance arrangement shape of the luminance distribution data may be aligned with the shape of the target surface Sj by an appropriate method.

  In the present embodiment, the texture image pasting unit 26 pastes a texture image in the following procedure. First, the luminance distribution BL (u, v) is pasted as a texture pattern to each of the plurality of target surfaces Sj included in the three-dimensional shape data (S26). Next, color rendering is performed on each of the target surfaces Sj. That is, the observation conditions are selected from the luminance values r (θi, φi, θe, φe), g (θi, φi, θe, φe), b (θi, φi, θe, φe) of the RGB colors that are spectral reflection data. (Θi, φi, θe, φe) coincides with the observation condition (θij, φij, θej, φej) for the target surface Sj at the time of creating a three-dimensional image, that is, r (θij, φij, θej, φej) (hereinafter, rj), g (θij, φij, θej, φej) (hereinafter referred to as gj), b (θij, φij, θej, φej) (hereinafter referred to as bj) are selected (S27). Then, by multiplying the luminance values rj, gj, bj of the respective RGB colors by the luminance distribution BL (u, v) pasted on the target surface Sj, the luminance distribution of the respective RGB colors is given to the target surface Sj (S28). ). Thereby, the luminance distribution of each RGB color of the target surface Sj is Rj (u, v) = rj · BL (u, v), Gj (u, v) = gj · BL (u, v), Bj (u, v) = bj · BL (u, v). When reflectance data ref (θi, φi, θe, φe, λ) (where λ = 400 to 800 nm, 10 nm interval) is used as spectral reflection data, the luminance distribution of the target surface Sj is Refj (u, v, λ) = refj · BL (u, v). Here, refj = ref (θij, φij, θej, φej, λ).

  The three-dimensional image created by the texture image pasting unit 26 is displayed on a display or output to another device or program.

  In addition, said step S21-24 may be performed in what order. Further, the three-dimensional shape data, spectral reflection data, luminance distribution data, and observation condition information may be input by a user via a user interface, or may be input from another device or program.

  As described above, according to the image creating apparatus 20 according to the present embodiment, in addition to the same effects as the image creating apparatus 10, the following effects can be obtained. That is, if there is spectral reflection data and luminance distribution data of a part of the surface of a target object such as an automobile body, a virtual appearance image of the entire target object at an arbitrary illumination position and viewpoint position can be created.

  As mentioned above, although embodiment of the image preparation apparatus concerning this invention was shown, it cannot be overemphasized that this invention is not limited to said embodiment. For example, in the above embodiment, the luminance distribution BL (u, v) shown in FIG. 5 is used as luminance distribution data as it is, but binarized luminance values may be used as luminance distribution data. In this case, the data amount can be further reduced. Here, the binarization of the luminance value is performed by the following procedure, for example. First, the average value AB of the luminance values shown in FIG. 5 is calculated. Next, an average value BB of luminance values less than the average value AB and an average value LB of luminance values equal to or higher than the average value AB are calculated. Then, the luminance value less than the average value AB is replaced with BB / AB, and the luminance value equal to or higher than the average value AB is replaced with LB / AB.

  Further, when the reflection from the target surface is isotropic reflection or close to it, spectral reflection data can be measured by the following measurement method. FIG. 12 shows a measurement environment for spectral reflection data in isotropic reflection. In FIG. 12, the light source and the light receiver are arranged in a plane perpendicular to the test piece including the center of the test piece. The position of the light source is fixed, and the incident angle of the light of the light source with respect to the test piece is 60 °. In this measurement system, the light receiving angle is changed by a predetermined angle within a range of −30 to 60 °, and the spectral reflectance is measured by the light receiver. In this case, spectral reflection data under observation conditions other than the actually measured observation conditions are calculated from the measured spectral reflection data. Therefore, when the reflection by the target surface is isotropic reflection or close to it, the amount of data can be further reduced. In this case, information indicating the difference between the regular reflection angle and the light receiving angle can be used as observation condition information. Here, the regular reflection angle is obtained from the illumination position with respect to the target surface, and the light reception angle is obtained from the viewpoint position with respect to the target surface.

1 is a block diagram showing a configuration of an image creation device 10. FIG. 3 is a flowchart showing an operation procedure of the image creating apparatus 10. It is a figure which shows the measurement environment of spectral reflection data. It is a figure which shows the measurement environment of luminance distribution data. It is a figure which shows luminance distribution data. It is a figure which shows the luminance distribution of R color which comprises a texture image. It is a figure which shows the luminance distribution of G color which comprises a texture image. It is a figure which shows the luminance distribution of B color which comprises a texture image. 2 is a block diagram illustrating a configuration of an image creation device 20. FIG. 4 is a flowchart showing an operation procedure of the image creating apparatus 20. FIG. 4 is a diagram showing three-dimensional shape data of a target object B. It is a figure which shows the measurement environment of the spectral reflection data in isotropic reflection.

Explanation of symbols

  10, 20 Image creation device, 11, 22 Spectral reflection data reception unit, 12, 23 Luminance distribution data reception unit, 13, 24 Observation condition information reception unit, 14 Texture image creation unit, 21 3D shape data reception unit, 25 Observation Condition specifying unit, 26 texture image pasting unit, Sj target surface, B target object.

Claims (9)

An image creation device for creating a virtual texture image of a target surface,
A spectral reflection data receiving unit that receives spectral reflection data indicating spectral reflection characteristics of the entire target surface under a plurality of observation conditions with at least different illumination positions or viewpoint positions;
A luminance distribution data receiving unit for receiving luminance distribution data of the target surface at a predetermined illumination position and viewpoint position;
An observation condition information receiving unit for receiving observation condition information when creating a texture image;
Based on the spectral reflection data and the luminance distribution data, a texture image creation unit that creates a virtual texture image of the target surface under the observation conditions indicated by the observation condition information;
An image creating apparatus comprising: An image creation device for creating a virtual three-dimensional image of a target object,
A three-dimensional shape data receiving unit for receiving three-dimensional shape data of the target object including one or more target surfaces;
A spectral reflection data receiving unit that receives spectral reflection data indicating spectral reflection characteristics of the entire target surface under a plurality of observation conditions with at least different illumination positions or viewpoint positions;
A luminance distribution data receiving unit for receiving luminance distribution data of the target surface at a predetermined illumination position and viewpoint position;
An observation condition information receiving unit for receiving observation condition information indicating an illumination position and a viewpoint position with respect to the target object at the time of creating a three-dimensional image;
An observation condition specifying unit for obtaining an observation condition for each target surface at the time of creating a three-dimensional image based on the three-dimensional shape data and the observation condition information;
Based on the spectral reflection data and the luminance distribution data, a virtual texture image of each target surface under each observation condition obtained by the observation condition specifying unit is pasted on each target surface included in the three-dimensional shape data. A texture image pasting unit for creating a virtual three-dimensional image of the target object;
An image creating apparatus comprising:   The image creating apparatus according to claim 1, wherein at least one of the spectral reflection data and the luminance distribution data is actual measurement data obtained by measuring an actual surface. An image creation method for creating a virtual texture image of a target surface,
Spectral reflection data receiving step for receiving spectral reflection data indicating spectral reflection characteristics of the entire target surface under a plurality of observation conditions with at least different illumination positions or viewpoint positions;
A luminance distribution data receiving step for receiving luminance distribution data of the target surface at a predetermined illumination position and viewpoint position;
An observation condition information receiving step for receiving observation condition information at the time of creating the texture image;
Based on the spectral reflection data and the luminance distribution data, a texture image creation step of creating a virtual texture image of the target surface under the observation conditions indicated by the observation condition information;
An image creating method characterized by comprising: An image creation device for creating a virtual three-dimensional image of a target object,
3D shape data receiving step for receiving 3D shape data of the target object including one or more target surfaces;
Spectral reflection data receiving step for receiving spectral reflection data indicating spectral reflection characteristics of the entire target surface under a plurality of observation conditions with at least different illumination positions or viewpoint positions;
A luminance distribution data receiving step for receiving luminance distribution data of the target surface at a predetermined illumination position and viewpoint position;
An observation condition information receiving step for receiving observation condition information indicating an illumination position and a viewpoint position with respect to the target object at the time of creating a three-dimensional image;
An observation condition specifying step for obtaining an observation condition for each of the target surfaces at the time of creating a three-dimensional image based on the three-dimensional shape data and the observation condition information;
Based on the spectral reflection data and the luminance distribution data, a virtual texture image of each target surface under each observation condition obtained in the observation condition specifying step is pasted on each target surface included in the three-dimensional shape data. A texture image pasting step for creating a virtual three-dimensional image of the target object;
An image creation method characterized by comprising:   6. The image creation method according to claim 4, wherein at least one of the spectral reflection data and the luminance distribution data is actual measurement data obtained by measuring an actual surface. An image creation program for causing a computer to create a virtual texture image of a target surface.
Spectral reflection data receiving step for receiving spectral reflection data indicating spectral reflection characteristics of the entire target surface under a plurality of observation conditions with at least different illumination positions or viewpoint positions;
A luminance distribution data receiving step for receiving luminance distribution data of the target surface at a predetermined illumination position and viewpoint position;
An observation condition information receiving step for receiving observation condition information at the time of creating the texture image;
Based on the spectral reflection data and the luminance distribution data, a texture image creation step of creating a virtual texture image of the target surface under the observation conditions indicated by the observation condition information;
An image creation program characterized by causing An image creation program for causing a computer to create a virtual three-dimensional image of a target object.
3D shape data receiving step for receiving 3D shape data of the target object including one or more target surfaces;
Spectral reflection data receiving step for receiving spectral reflection data indicating spectral reflection characteristics of the entire target surface under a plurality of observation conditions with at least different illumination positions or viewpoint positions;
A luminance distribution data receiving step for receiving luminance distribution data of the target surface at a predetermined illumination position and viewpoint position;
An observation condition information receiving step for receiving observation condition information indicating an illumination position and a viewpoint position with respect to the target object at the time of creating a three-dimensional image;
An observation condition specifying step for obtaining an observation condition for each of the target surfaces at the time of creating a three-dimensional image based on the three-dimensional shape data and the observation condition information;
Based on the spectral reflection data and the luminance distribution data, a virtual texture image of each target surface under each observation condition obtained in the observation condition specifying step is pasted on each target surface included in the three-dimensional shape data. A texture image pasting step for creating a virtual three-dimensional image of the target object;
An image creation program characterized by causing   9. The image creation program according to claim 7, wherein at least one of the spectral reflection data and the luminance distribution data is actual measurement data obtained by measuring an actual surface.

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