JP2006275955A - Optical characteristic measuring apparatus and image processing system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical characteristic measuring apparatus and an image processing system capable of achieving a function such as BRDF corresponding to multi-band. <P>SOLUTION: The optical characteristic measuring apparatus is provided with a table 20 mounted rotatably to θ1 direction and θ2 direction, an irradiation section 40 for irradiating light to a sample S placed on the table 20, and a camera 50 for taking a photograph of the sample S. The irradiation section 40 is provided with a horizontal arm 41 mounted rotatably to the θ1 direction, an arch arm 43 mounted rotatably to θ3 direction, and a light source section 44 wherein two rotatable turrets having eight color filters respectively are arranged. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical property measuring apparatus and an image processing system for measuring optical properties of an object.

  In recent years, a technique for estimating the color and reflectance of a subject from a multiband image photographed using four or more color filters in order to reproduce an image having a color, gloss, and texture that is as close as possible to an actual object Research is underway.

On the other hand, in recent years, in the world of computer graphics, optical characteristics of objects such as reflection characteristics are measured, and based on the measurement results, a bi-directional reflectance distribution function (BRDF) and a bi-directional texture function are used. There is known a technique for obtaining a function indicating optical characteristics such as (BTF: Bi-directional Texture Function) and rendering using the obtained function. This technique is known to be particularly effective when rendering an object having optical anisotropy such as cloth. Non-Patent Documents 1 and 2 are known as techniques for measuring the optical characteristics and obtaining BRDF. Non-patent documents 3 to 5 are known as methods for obtaining BTF by measuring optical characteristics.
G. Borshukov, “Measured BRDF in Film Production-Realistic Cloth Appearance for“ The Matrix Reloaded ”, ACM SIGGRAPH2003 on Sketches and Applications, 1-1 (2003) (Measurement of BRDF in the Film Industry-“ The Matrix Reloaded ” Realistic clothing composition) Murakami Color Research Laboratory http://www.mcrl.co.jp/keisoku/optics/optics02/optics-02.html#GP-200 KJDana, B.van Ginneken, SKNayar, JJKoenderink, “Reflectance and Texture of Real-Surface”, Colombia University Technical Report, No. CUCS-048-96, 1996 (Reflectance and texture of the surface of real objects) MLKoudelka, S. Magada, PNBelhumeur, and DJKriegman, “Acquisition, Compression, and Synthesis of Bidirectional Texture Functions”, Proc. Of 3rd International Workshop on Texture Analysis and Synthesis (Texture 2003) ) Y. Yamaguchi, M. sekine, S. Yanagawa, “Bidirectional Texture Mapping for Realistic Cloth Rendering”, ACM SIGGRAPH2003 on Sketches and Application (2003) (Bidirectional Texture Mapping for Realistic Rendering)

  However, none of the above-mentioned non-patent documents obtains BRDF or BTF corresponding to a multiband composed of four or more color components.

  An object of the present invention is to provide an optical characteristic measuring apparatus and an image processing system capable of obtaining a function indicating optical characteristics corresponding to multiband.

  An optical characteristic measurement apparatus according to the present invention is an optical characteristic measurement apparatus that measures the optical characteristics of an actual object in order to obtain a function indicating the optical characteristics used when rendering a virtual three-dimensional model. The table is placed and the color of the light irradiated to the object is switched to at least one of the four colors, and the irradiation direction of the light to the object is switched to irradiate the object with light. Means, a monochrome camera for photographing the object placed on the table, and a photographing direction switching means for switching a photographing direction with respect to the object of the monochrome camera.

  Further, in the above configuration, the irradiating means is disposed so as to be movable on a celestial sphere centered on the object, and at least an emission unit that emits light output from the light source to the object, A light guide unit that switches four color filters to transmit light from the light source and guides the light to the emitting unit; and a positioning unit that positions the emitting unit at an arbitrary position on the celestial sphere. preferable.

  In the above configuration, the light guide unit includes an optical fiber that guides light from the light source to the emission unit, and at least four color filters, and any one of the color filters is an optical input end of the optical fiber. It is preferable to provide a rotating body that is rotatably disposed between the light source and the optical fiber so as to be positioned with respect to the optical fiber.

  Further, in the above configuration, there are two rotating bodies, and the optical fiber includes two branch fibers corresponding to each rotating body, and a trunk that multiplexes light from each branch fiber and guides the light to the emitting unit. Preferably, the branch fiber guides light transmitted through a color filter included in a corresponding rotating body to the trunk fiber.

  In the above configuration, the irradiation unit preferably switches 16 colors.

  In the above configuration, the positioning means extends in the horizontal direction from the center of the table, and is attached to the horizontal arm so as to be rotatable with respect to the center of the table with the vertical direction as the first axis. And an arch-shaped arch arm attached to the front end side of the horizontal arm and rotatably attached with the longitudinal direction of the horizontal arm as a second axis. .

  Further, in the above configuration, the measurement direction switching unit rotates the table by a predetermined angle with a direction orthogonal to the object placement surface as a third axis, and a direction orthogonal to the third axis. It is preferable to switch the measurement direction by rotating the shaft 4 by a predetermined angle.

  In the above configuration, the photographing direction switching means rotates the table by a predetermined angle with a direction orthogonal to the object placement surface as a third axis, and a direction orthogonal to the third axis. It is preferable to switch the photographing direction by rotating it by a predetermined angle as the axis 4.

  In the above configuration, the monochrome camera captures an object every time the measurement condition defined by the irradiation direction and the imaging direction is switched, and the monochrome camera captures an image for each color under the same measurement condition. Generating means for generating a texture image composed of at least four color components by associating the generated image of the object, and generating a bidirectional texture function of the object by associating the generated texture image with its measurement condition Is preferably further provided.

  In the above configuration, it is preferable that the function generation unit generates a bidirectional reflectance distribution function of an object by calculating a representative value of the texture image and associating the calculated representative value with the measurement condition.

  Further, in the above-described configuration, both the camera characteristic storage means for storing the camera characteristics of the black and white camera, the spectrum storage means for storing the illumination light spectrum of the light irradiated by the irradiation means, and both generated by the function generation means It is preferable to further include estimation means for estimating the spectral reflectance of the object based on the directional reflectance distribution function, the camera characteristics, and the illumination light spectrum.

  An image processing system according to the present invention is an optical characteristic measuring apparatus for measuring an optical characteristic of an actual object in order to obtain a function indicating the optical characteristic used when rendering a virtual three-dimensional model, and the object is placed And an irradiation means for irradiating the object with light by switching the color of light irradiating the object to one of at least two colors and switching the direction of light irradiation to the object And an RGB camera for photographing an object placed on the table, and photographing direction switching means for switching a photographing direction for the object of the RGB camera.

  Further, in the above configuration, the irradiating means is disposed so as to be movable on a celestial sphere centered on the object, and at least an emission unit that emits light output from the light source to the object, A light guide unit that switches two color filters to transmit light from the light source and guides the light to the emitting unit; and a positioning unit that positions the emitting unit at an arbitrary position on the celestial sphere. preferable.

  In the above configuration, the light guide unit includes an optical fiber that guides light from the light source to the emission unit, and at least two color filters, and one of the color filters is an optical input end of the optical fiber. It is preferable to provide a rotating body that is rotatably disposed between the light source and the optical fiber so as to be positioned with respect to the optical fiber.

  In the above configuration, the rotator is three rotators: an R rotator, a G rotator, and a B rotator, and the R rotator is within the red band of the spectral sensitivity characteristics of the RGB camera. In which at least two types of color filters that transmit different wavelength components are arranged, and the G rotating body transmits at least two types of different wavelength components within the green band of the spectral sensitivity characteristics of the RGB camera. The B rotator is composed of at least two types of color filters that transmit different wavelength components within the blue band of the spectral sensitivity characteristics of the RGB camera, and the optical fiber is configured to rotate each color. Three branch fibers corresponding to the body, and a trunk fiber that multiplexes the light from each branch fiber and guides it to the emission part, and the branch fibers correspond to each other Directing the light transmitted through the color filter rotating body provided on the stem fiber is preferred.

  In the above configuration, the positioning means extends in the horizontal direction from the center of the table, and is attached to the horizontal arm so as to be rotatable with respect to the center of the table with the vertical direction as the first axis. And an arch-shaped arch arm attached to the front end side of the horizontal arm and rotatably attached with the longitudinal direction of the horizontal arm as a second axis. .

  In the above configuration, the photographing direction switching means rotates the table by a predetermined angle with a direction orthogonal to the object placement surface as a third axis, and a direction orthogonal to the third axis. It is preferable to switch the photographing direction by rotating it by a predetermined angle as the axis 4.

  In the above configuration, the RGB camera captures an object every time the measurement conditions defined by the irradiation direction and the imaging direction are switched, and the color components captured by the RGB camera under the same measurement conditions A function generating unit that generates a texture image composed of at least four color components by associating images of different objects with each other, and generates a bidirectional texture function of the object by associating the generated texture image with its measurement condition It is preferable.

  In the above configuration, it is preferable that the function generation unit generates a bidirectional reflectance distribution function of an object by calculating a representative value of the texture image and associating the calculated representative value with the measurement condition.

  An optical characteristic measurement apparatus according to the present invention is an optical characteristic measurement apparatus that measures the optical characteristics of an actual object in order to obtain a function indicating the optical characteristics used when rendering a virtual three-dimensional model. The table is placed and the color of the light irradiated to the object is switched to at least one of the four colors, and the irradiation direction of the light to the object is switched to irradiate the object with light. Means, a spectral luminance meter for measuring fluorescence characteristics and reflection characteristics of the object placed on the table, a measurement direction switching means for switching a measurement direction with respect to the object of the spectral luminance meter, the irradiation direction and the imaging direction The bi-directional reflectance distribution function including fluorescence characteristics based on the fluorescence characteristics and reflection characteristics of the object measured by the spectral luminance meter each time the measurement conditions defined by Characterized in that it comprises a product to function generating means.

  Further, in the above configuration, both the camera characteristic storage means for storing the camera characteristics of the RGB camera, the spectrum storage means for storing the illumination light spectrum of the light irradiated by the irradiation means, and both generated by the function generation means It is preferable to further include estimation means for estimating the spectral reflectance based on the directional reflectance distribution function, the camera characteristics, and the illumination light spectrum.

  An optical characteristic measurement apparatus according to the present invention is an optical characteristic measurement apparatus that measures the optical characteristics of an actual object in order to obtain a function indicating the optical characteristics used when rendering a virtual three-dimensional model. The table is placed and the color of the light irradiated to the object is switched to at least one of the four colors, and the irradiation direction of the light to the object is switched to irradiate the object with light. And the measurement means is a multispectral camera, each time the measurement conditions defined by the measurement direction switching means for switching the measurement direction with respect to the object of the multispectral camera and the irradiation direction and the imaging direction are switched. Based on the fluorescence characteristics and reflection characteristics of the object measured by the multispectral camera, a bidirectional reflectance distribution function including the fluorescence characteristics is generated. Characterized in that it comprises a function generating means for.

  An image processing system according to the present invention is an image processing system including an optical characteristic measuring device and an image processing device, and the optical characteristic measuring device irradiates the table on which an actual object is placed and the object. The light color is switched to at least one of four colors, and the irradiation direction of the light to the object is switched to irradiate the object with light, and the object placed on the table is photographed When the measurement conditions defined by the irradiation direction and the shooting direction are switched, the monochrome camera is switched under the same measurement condition each time the monochrome camera, the shooting direction switching means for switching the shooting direction with respect to the object of the monochrome camera are switched In addition to generating a texture image composed of at least four color components by associating images captured for each color with the generated texture image A function generating unit that generates a function indicating the optical characteristic of the object by associating the measurement condition, and the image processing apparatus stores a function indicating the optical characteristic generated by the function generating unit Storage means; model storage means for storing a virtual three-dimensional model generated in advance in the virtual three-dimensional space; and rendering means for rendering the virtual three-dimensional model using a function indicating the optical characteristics. Features.

  In the above configuration, it is preferable that the image forming apparatus further includes a multi-primary color display device that displays the virtual three-dimensional model rendered by the rendering unit.

  An image processing system according to the present invention is an image processing system including an optical characteristic measuring device and an image processing device, and the optical characteristic measuring device irradiates the table on which an actual object is placed and the object. The light color is switched to one of at least two colors, and the irradiation direction of the light to the object is switched to irradiate the object with light, and the object placed on the table is photographed When the measurement conditions defined by the RGB camera, the shooting direction switching means for switching the shooting direction of the object of the RGB camera, and the irradiation direction and the shooting direction are switched, the RGB camera A texture image composed of at least four color components is generated by associating images of objects with different color components captured by Function generating means for generating a function indicating the optical characteristic of the object by associating the texture image with its measurement condition, and the image processing apparatus stores the function indicating the optical characteristic generated by the function generating means Function storage means, model storage means for storing a virtual three-dimensional model generated in advance in the virtual three-dimensional space, and rendering means for rendering the virtual three-dimensional model using the function indicating the optical characteristics. It is characterized by that.

  In the above configuration, it is preferable that the image forming apparatus further includes a multi-primary color display device that displays the virtual three-dimensional model rendered by the rendering unit.

  According to the first aspect of the present invention, at least four colors of light are sequentially switched and irradiated to an object placed on the table by sequentially switching the irradiation direction, and is defined by the irradiation direction and the photographing direction. Since the measurement conditions are sequentially switched and the image of the object is taken by the monochrome camera, a texture image composed of four color components can be easily obtained for each measurement condition. Therefore, a function indicating optical characteristics having multiband color components can be easily obtained using a relatively inexpensive black and white camera without using a special camera.

  According to the second aspect of the present invention, the light source itself is moved onto the celestial sphere because it is arranged so as to be movable on the celestial sphere centered on the object and has an emission part for emitting light from the light source to the object. The irradiation direction can be changed with a weak force as compared with the case where the arrangement is possible.

  According to the third aspect of the present invention, the color of the light irradiating the object can be switched by rotating the rotating body in which the color filters of at least four colors are arranged and positioning the color filter at the input end of the optical fiber. Therefore, such color switching can be performed by a simple operation.

  According to the fourth aspect of the present invention, since the optical fiber is constituted by two rotating bodies, branch fibers corresponding to the respective rotating bodies, and a trunk fiber that combines light from the branch fibers, two types of light It is possible to irradiate an object with light of a color obtained by combining the two, and a two-band image can be obtained by one photographing.

  According to the fifth aspect of the present invention, it is possible to obtain a function indicating optical characteristics having 16 multiband color components using a known black and white camera without using a special camera.

  According to the invention described in claim 6, since the horizontal arm and the arch arm are provided, the light irradiation direction can be adjusted with two degrees of freedom.

  According to the seventh aspect of the present invention, the table is rotated with the direction orthogonal to the object placement surface as the third axis, and rotated with the direction orthogonal to the third axis as the fourth axis. Therefore, the measurement direction can be adjusted with two degrees of freedom.

  According to the eighth aspect of the present invention, a bidirectional texture function of an object can be automatically generated from an image taken by a black and white camera.

  According to the ninth aspect of the present invention, a bidirectional reflectance distribution function of an object can be automatically generated from an image photographed by a monochrome camera.

  According to the invention of claim 10, it is possible to obtain a highly accurate estimation result of the spectral reflectance using the multiband bidirectional reflectance distribution function.

  According to the invention of claim 11, at least two colors of light are sequentially switched and irradiated to the object placed on the table by sequentially switching the irradiation direction, and is defined by the irradiation direction and the photographing direction. Since the measurement conditions are sequentially switched and the image of the object is captured by the RGB camera, a texture image composed of four color components can be easily obtained for each measurement condition. Therefore, a function indicating optical characteristics having multiband color components can be easily obtained using a relatively inexpensive RGB camera without using a special camera.

  According to the twelfth aspect of the present invention, the light source itself is moved on the celestial sphere because the illuminating unit is provided so as to be movable on the celestial sphere centered on the object and emits light from the light source to the object. The irradiation direction can be changed with a weak force as compared with the case where the arrangement is possible.

  According to the thirteenth aspect of the present invention, the color of the light irradiating the object can be switched by rotating the rotating body in which at least two color filters are arranged and positioning the color filter at the input end of the optical fiber. Therefore, such color switching can be performed by a simple operation.

  According to the fourteenth aspect of the present invention, since a three-band image can be obtained by one photographing, the number of photographing can be reduced. In addition, since each of the R rotating body to the B rotating body includes at least two types of color filters, an image of at least 6 bands can be obtained.

  According to the invention described in claim 15, since the horizontal arm and the arch arm are provided, the light irradiation direction can be adjusted with two degrees of freedom.

  According to the sixteenth aspect of the present invention, the table is rotated with the direction orthogonal to the object placement surface as the third axis, and rotated with the direction orthogonal to the third axis as the fourth axis. Therefore, the measurement direction can be adjusted with two degrees of freedom.

  According to the seventeenth aspect, a bidirectional texture function of an object can be automatically generated from an image photographed by an RGB camera.

  According to the invention described in claim 18, the bidirectional reflectance distribution function of the object can be automatically generated from the image photographed by the RGB camera.

  According to the nineteenth aspect of the invention, it is possible to obtain a highly accurate estimation result of the spectral reflectance using the multiband bidirectional reflectance distribution function.

  According to the twentieth aspect of the invention, since the object is measured using the spectral radiance meter, the reflection characteristic function including the fluorescence characteristic of the object can be obtained.

  Since the object is measured using the multispectral camera, the bidirectional reflectance distribution function including the fluorescence characteristic of the object can be obtained with high accuracy.

  According to the inventions of claims 22 and 24, it is possible to provide an image processing system capable of performing rendering using a function indicating multiband optical characteristics.

  According to the twenty-third and twenty-fifth aspects of the present invention, since an image rendered using a function indicating multiband optical characteristics is displayed by the multi-primary color display device, a more realistic CG image can be expressed.

  Hereinafter, an image processing system according to an embodiment of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1A shows an overall configuration diagram of an image processing system according to Embodiment 1 of the present invention, and FIG. 1B shows details of a light source unit. The image processing system includes an optical characteristic measuring device 1 and an image processing device 2. The optical characteristic measuring apparatus 1 includes an imaging device 3 that images a substance and a control device 4 that controls the imaging device 3.

  The imaging apparatus 3 includes a base 10, a table 20 disposed on the upper side (+ N direction) of the base 10, a switching unit 30 that switches the orientation of the material placement surface of the table 20, and a substance from above the table 20. On the other hand, an irradiation unit 40 for irradiating light, a camera 50 for photographing a sample, a pedestal 60 disposed below (−N direction) the base 10, and a dark box 70 covering the entire apparatus are provided.

  The base 10 has a disk shape, and a cylindrical shaft 11 is erected from the center thereof. The table 20 is a disk-shaped member having a substance placement surface on which a substance is placed. The table 20 is supported with respect to the switching unit 30 and the shaft 11, and a long support plate 21 is provided in the horizontal direction. The support plate 21 is pivotally supported by the upper end of the shaft 11 and is disposed so as to be rotatable in the θ1 direction on a horizontal plane (U-V plane). The shaft 11 incorporates a motor M1 (not shown in FIG. 1), and the support plate 21 receives the driving force of the motor M1 and is rotated and positioned in the θ1 direction. As a result, the table 20 is rotated in the θ1 direction with the longitudinal direction of the shaft 11 as the rotation axis (axial center) Z1.

  On one end side of the support plate 21, plate-like standing plates 22 and 23 are erected. A shaft 24 penetrates the standing plates 22 and 23 in the horizontal direction. The table 20 is connected to one end of the shaft 24, and the motor M2 is connected to the other end. For example, a stepping motor is employed as the motor M2. The motor M2 and the shaft 24 are connected via a coupling (not shown). The shaft 24 is rotated and positioned in the θ2 direction by the driving force of the motor M2. Accordingly, the table 20 rotates in the θ2 direction with respect to the switching unit 30 with the longitudinal direction of the shaft 24 as the rotation axis (axial center) Z2.

  The irradiation unit 40 includes a horizontal arm 41 that is long in the horizontal direction through which the shaft 11 is penetrated at one end, a connecting plate 42 that is erected in the vertical direction (+ N direction) at the other end of the horizontal arm 41, and a connecting plate 42. An arch arm 43 rotatably connected to the rotation axis Z3 at one end thereof, a light source unit 44 disposed outside the dark box 70, a motor M3 for rotating the arch arm 43, and a light source unit 44. ing.

  For example, a stepping motor is employed as the motor M3, and the arch arm 43 is rotated in the θ3 direction about the rotation axis Z3. The arch arm 43 has an arch shape in which the optical axis L1 irradiates the central portion 21a when the longitudinal direction is positioned parallel to the longitudinal direction of the connecting plate 42. Further, the arch arm 43 has an injection port 45 formed at the tip. The shaft 11 incorporates a motor M4 (not shown in FIG. 1, refer to FIG. 3), and the horizontal arm 41 receives the driving force of the motor M4 and is rotated and positioned in the θ1 direction.

  The light source unit 44 includes a box 443 that covers two light sources 441 and 442 and light sources 441 and 442 (not shown). Holes 441a and 442a for emitting light from each of the light sources 441 and 442 to the outside are formed in the front surface 443a of the box 443. As the light sources 441 and 442, a xenon light source, a metal halide lamp, a light emitting diode, a laser diode, or the like is employed. However, a xenon light source is preferable as the light sources 441 and 442 because it has a continuous intensity distribution in the visible range.

  Rotating turrets (rotating bodies) 444 and 445 corresponding to the light sources 441 and 442 are disposed on the front surface 443a. The rotating turrets 444 and 445 have a disk shape, and eight holes 444a and 445a are formed along the outer periphery. The rotating turrets 444 and 445 are attached to the front surface 443a so as to be rotatable in directions θ4 and θ5 indicated by arrow signs. The rotating turrets 444 and 445 receive driving force from the motors M5 and M6 (see FIG. 3), rotate in the θ4 and θ5 directions, and are positioned.

  Bandpass filters (color filters) 471 to 4716 that transmit light of different wavelengths are attached to the eight holes 444a and 445a of the rotating turrets 444 and 445, respectively. FIG. 2 is a graph showing the spectral transmittance of the bandpass filters 471 to 4716, in which the horizontal axis indicates the wavelength (nm) and the vertical axis indicates the transmittance. This graph has 16 mountain-shaped curves G1 to G16. As the curve G1 moves toward the curve G16, each curve has a larger wavelength with respect to the peak. Curves G1 to G16 indicate the spectral transmittances of the bandpass filters 471 to 4716, respectively. In the present embodiment, the rotating turret 444 includes bandpass filters 471 to 478, and the rotating turret 445 includes bandpass filters 479 to 4716. However, this is only an example, and there is no particular limitation as to which rotating turret the bandpass filters 471 to 4716 are arranged. When the bandpass filters 471 to 4716 are collectively called, the reference numeral 47 is attached to the bandpass filter.

  An optical fiber 46 is disposed between the light source unit 44 and the emission port 45. The optical fiber 46 includes branch fibers 462 and 463 that receive light from the light sources 441 and 442, and a trunk fiber 461 that combines the light from the branch fibers 462 and 463 and guides the light to the exit 45.

  The branch fibers 462 and 463 are arranged so that the input ends thereof face the holes 441a and 442a of the front surface 443a.

  A distal end 461 a of the trunk fiber 461 on the exit port 45 side is attached to the arch arm 43 by a fiber folder 48. A reflection mirror 49 is attached in front of the tip 461a to reflect light output from the tip 461a in the horizontal direction by 90 degrees and guide it to the table 20 side.

  Accordingly, if any one of the bandpass filters 47 is positioned so as to face the holes 441a and 442a, the light of the color transmitted through the positioned bandpass filter is emitted from the emission port 45 through the optical fiber 46. Therefore, it is possible to irradiate an object placed on the table 20 with light of a desired color. Note that the light sources 441 and 442 may be turned on simultaneously, or one of them may be turned off. When the lights are turned on at the same time, light of a color obtained by combining the light of the color transmitted through the band-pass filter 47 of the rotating turret 444 and the light of the color transmitted through the band-pass filter 47 of the rotating turret 445 is emitted from the emission port 45. Can be made. Thereby, the kind of color of the light irradiated with respect to a substance can be increased.

  The dark box 70 shown in FIG. 1 has a rectangular parallelepiped shape, and a shooting hole 71 for shooting an object placed on the table 20 with the camera 50 is formed on the side surface. The camera 50 is a black and white camera, and in this embodiment, “ORCA ER-1384” manufactured by Hamamatsu Photonics Co., Ltd. can be adopted. The dark box 70 is not limited to a rectangular parallelepiped shape, and may have any shape as long as the shape can cover the entire apparatus, for example, a dome shape.

  FIG. 3 is a block diagram showing an electrical configuration of the image processing system shown in FIG. The photographing apparatus 3 includes motors M1 to M6 and light sources 441 and 442 shown in FIG. The control device 4 includes a motor controller 401, motor drivers 402 to 407, and light source drivers 408 and 409.

  The motor driver 402 generates a drive current for the motor M1 under the control of the motor controller 401, and rotates the table 20 in the θ1 direction shown in FIG. The motor driver 403 generates a drive current for the motor M2 under the control of the motor controller 401, and rotates the table 20 in the θ2 direction shown in FIG. The motor driver 404 generates a drive current for the motor M3 under the control of the motor controller 401, and rotates the arch arm 43 in the θ3 direction shown in FIG. The motor driver 405 generates a drive current for the motor M4 under the control of the motor controller 401, and rotates the horizontal arm 41 in the θ1 direction shown in FIG. The motor driver 406 generates a driving current for the motor M5 under the control of the motor controller 401, and rotates the rotating turret 444 in the θ4 direction shown in FIG. The motor driver 407 generates a driving current for the motor M6 under the control of the motor controller 401, and rotates the rotating turret 445 in the θ5 direction shown in FIG.

  The motor controller 401 receives various control signals from the image processing apparatus 2 and controls the motor drivers 402 to 407 according to the signals.

  The light source driver 408 generates a drive current based on the control signal from the image processing apparatus 2 and turns on the light source 441. The light source driver 409 generates a drive current based on the control signal from the image processing apparatus 2 and turns on the light source 442.

  The image processing apparatus 2 includes a CPU (Central Processing Unit) 201, a RAM (Random Access Memory) 202, a ROM (Read Only Memory) 203, an input device 204, a video capture board 205, a display device 206, a recording medium driving device 207, It is composed of a normal computer having an external storage device 208 and an input / output interface (I / F) 209.

  The CPUs 201 to I / F 209 are connected to each other through a bus line including a control bus, an address bus, and a data bus so that various data can be transmitted and received. The video capture board 205 acquires an image of an object photographed by the camera 50 via, for example, an IEEE 1394 standard cable.

  The input device 204 includes a keyboard and a mouse. The display device 206 is composed of a multi-primary color display device. Note that a CRT (cathode ray tube), a plasma display, a liquid crystal panel, or the like may be employed instead of the multi-primary color display device.

  The recording medium driving device 207 is composed of a hard disk and stores a program such as an operating system. The recording medium driving device 207 is a device that reads data from a recording medium such as a flexible disk, a CD-ROM, and a DVD-ROM and writes data to the recording medium.

  The I / F 209 is, for example, an RS-232C serial interface, and connects the image processing apparatus 2 to the control apparatus 4 via an RS-232C cable.

  FIG. 4A is a simplified view of the photographing apparatus 3, and FIG. 4B is an enlarged schematic diagram of a portion of the table 20. In FIG. 4, it is assumed that a sample S made of fiber as a substance is placed on the table 20. FL indicates the fiber direction (warp or weft direction) of the sample S. The sample S is placed on the table 20 so that the fiber direction FL is parallel to the U axis when the rotation axis Z2 is V-shaped. Accordingly, the angle α indicates the rotation angle of the table 20 in the θ1 direction with respect to the U axis, and also indicates the angle formed by the U axis and the fiber direction FL. As shown in FIG. 4B, the angle β indicates the angle formed between the normal vector N1 of the table 20 and the N axis, that is, the rotation angle of the table 20 with respect to the θ2 direction.

  The angle m indicates an angle formed between the arch arm 43 and the U-V plane. An angle n indicates an angle formed between the U axis and the horizontal arm 41. The angle γ indicates an angle formed between the line segment R1 and the orthogonal projection R2 of the line segment R1 connecting the center O and the exit 45 to the U-V plane. The angle δ indicates an angle formed between the U axis and the orthogonal projection R2. Therefore, the angle γ and the angle δ are uniquely determined by the angle m and the angle n.

  The optical axis of the camera 50 is set on the U axis. However, the optical axis of the camera 50 is not limited to this, and may be set on the N axis or the V axis. In any case, one point on the celestial sphere B1 and the sample The camera 50 should just be installed so that an optical axis may be on the straight line which connects S. Note that the celestial sphere B1 is set for convenience of explanation, and does not actually exist.

  5 and 6 are flowcharts showing the operation of the image processing system when photographing the sample S made of a cloth as an object placed on the table 20. Hereinafter, the operation of the optical property measuring apparatus 1 will be described with reference to FIGS. 5 and 6.

  In step S <b> 1, the image processing apparatus 2 rotates the rotary turret 444 so that the bandpass filter 471 is positioned in the hole 441 a of the front surface 443 a of the light source unit 44. In the present embodiment, the image processing apparatus 2 rotates the rotating turret 444 so that the bandpass filters 471 to 478 are positioned in the holes 441a in this order, and then the bandpass filters 479 to 4716. However, the rotating turret 445 is rotated so that the holes 442a are positioned in this order.

  In step S2, the image processing apparatus 2 sets an angle α with respect to the θ1 direction of the table 20, drives the motor M1, and rotates the table 20 in the θ1 direction. In the present embodiment, the angle α is increased by 5 degrees, for example.

  In step S3, the image processing apparatus 2 drives the motor M2, sets an angle β with respect to the θ2 direction of the table 20, and rotates the table 20 in the θ2 direction. In the present embodiment, the angle β is increased by, for example, 15 degrees.

  In step S4, the image processing apparatus 2 drives the motor M3, sets the angle m with respect to the θ3 direction of the arch arm 43, and rotates the arch arm 43 in the θ3 direction. In the present embodiment, the angle m is increased by 5 degrees, for example.

  In step S5, the image processing apparatus 2 drives the motor M4, sets an angle n with respect to the θ1 direction of the horizontal arm 41, and rotates the horizontal arm 41 in the θ1 direction. In the present embodiment, the angle n is increased by 15 degrees, for example.

  In step S <b> 6, the image processing apparatus 2 turns on the light source 441 with a predetermined light amount, and causes the camera 50 to photograph the sample S placed on the table 20. When shooting is finished, the light source 441 is turned off. Although the light source 441 is turned on every time the table 20 is positioned, the light source 441 may be turned on at all times. Thereby, control of the light source 441 is simplified.

  In step S <b> 7, the image processing apparatus 2 acquires the object image captured by the camera 50, and the angle α and the angle β (measurement direction) when the image is captured, and the angle γ and the angle δ corresponding to the angle m and the angle n. (Irradiation direction) is associated and stored in the RAM 202 or the external storage device 208. Note that the measurement conditions shown in claim 8 are conditions defined by the angles α to δ.

  In step S8, the image processing apparatus 2 determines whether or not the angle δ has reached the final angle. If the angle δ has reached the final angle (YES in step S8), an initial value is set for the angle δ (step S9). ). On the other hand, if the angle δ has not reached the final angle (NO in step S8), the process returns to step S5 and the angle δ is set again. In the present embodiment, the angle δ is set to 0 degrees as an initial value and 360 degrees as a final angle, and is sequentially set from 0 degrees to 360 degrees in units of 15 degrees. The angle δ is assumed to increase counterclockwise with the U axis shown in FIG. 4A as a reference.

  In step S10, the image processing apparatus 2 determines whether or not the angle γ has reached the final angle. If the angle γ has reached the final angle (YES in step S10), the angle γ is set to an initial value (step S11). . On the other hand, if the angle γ has not reached the final angle in step S10 (NO in step S10), the process returns to step S4. In the present embodiment, the angle γ is set to −90 degrees as an initial value, 90 degrees is set as a final angle, and is sequentially set in units of 5 degrees from −90 degrees to 90 degrees. Further, the angle γ is set to 0 degrees when the line segment R1 is on the N axis.

  In step S12, the image processing apparatus 2 determines whether or not the angle β has reached the final angle. If the angle β has reached the final angle (YES in step S12), an initial value is set for the angle β (step S13). ). On the other hand, if the angle β has not reached the final angle (NO in step S12), the process returns to step S3 and the angle β is set again. In the present embodiment, the angle β is set to −90 degrees as an initial value, 90 degrees is set as a final angle, and is sequentially set in units of 5 degrees from −90 degrees to 90 degrees. The angle β is assumed to increase clockwise with the N axis shown in FIG. 4B as a reference.

  In step S14, the image processing apparatus 2 determines whether or not the angle α has reached the final angle. If the angle α has reached the final angle (YES in step S14), the process proceeds to step S15. On the other hand, if the angle α has not reached the final angle (NO in step S14), the process returns to step S2, and the angle α is set again. In the present embodiment, the angle α is set to 0 degrees as an initial value, 360 degrees is set as the final angle, and is sequentially set in units of 15 degrees from 0 degrees to 360 degrees. The angle α is assumed to increase clockwise with the U axis shown in FIG. 4A as a reference.

  7, 8, and 9 are diagrams illustrating a data structure of data acquired by the optical characteristic measurement apparatus 1 and stored by the image processing apparatus 2. In the first table shown in FIG. 7, the values expressed in increments of 15 degrees when the angle α is in the range of 0 to 360 degrees are set as items of each row, and the angles β are in increments of 5 degrees when the angle β is in the range of −90 degrees to 90 degrees. The represented value is an item in each column. In each field of the first table, an index for specifying the second table is stored. In FIG. 7, an index for specifying the second table is obtained by adding the row number and column number of each field to the alphabet T. For example, since index T00 is an index stored in the 0th row, 0th column field, “00” is described as a subscript.

  The second table shown in FIG. 8 is composed of a plurality of tables. Each table is assigned an index, and this index is associated with an index stored in each field of the first table. .

  In the second table, the values expressed in 5 degree increments in the range of the angle γ from −90 degrees to 90 degrees are set as items of each column, and the values expressed in 15 degree increments in the range of the angle δ from 0 degrees to 360 degrees. The value is an item on each line. In each field of the second table, data photographed by the optical characteristic measuring apparatus 1 is stored.

  FIG. 9 shows the data structure of the optical characteristic information. As shown in FIG. 9, the optical characteristic information has a total of 16 fields indicated by FI1 to FI16. In each of the fields FI1 to FI16, an image of the sample S photographed by the camera 50 when the sample S is irradiated with light transmitted through the bandpass filters 471 to 4716 is stored.

  For example, in the second table shown in FIG. 8, data stored in a field corresponding to an angle γ of −90 degrees and an angle δ of 0 degrees includes an angle α of 0 degrees, an angle β of 0 degrees, and an angle γ of An image of the sample S photographed by the camera 50 when -90 degrees and the angle δ are 0 degrees is stored.

  7 and 8, the step widths of the angle β and the angle γ are set every 5 degrees, and the step widths of the angle α and the angle γ are set every 15 degrees. However, the present invention is not limited to this. Depending on the resolution of the horizontal arm 41 or the like of the measuring apparatus 1, the step size may be finer, the step size may be larger, or, for example, in the range of 0 to 45 degrees in increments of 5 degrees. In the range of 45 degrees to 90 degrees, the step width may be appropriately changed according to the angle range, such as 10 degree increments.

  FIG. 10 shows a functional block diagram of the image processing apparatus 2. The image processing apparatus 2 includes a storage unit 100, a program execution unit 500, and a display unit 300. The storage unit 100 includes the RAM 202, the ROM 203, and the external storage device 208 shown in FIG. The program execution unit 500 includes the CPU 201 shown in FIG. The display unit 300 includes the display device 206 shown in FIG.

  The storage unit 100 includes an image storage unit 101, a function storage unit 102, and a model storage unit 103. The program execution unit 500 includes a calculation unit 201, a rendering processing unit 502, and an imaging mechanism control unit 503. These functions are realized by the CPU 201 executing an operating system and an image processing program stored in the external storage device 208.

  The image storage unit 101 stores a first table shown in FIG. 7 and a second table shown in FIG. The computing unit 201 creates a BTF using the data stored in the image storage unit 101 and stores the BTF in the function storage unit 102. Specifically, for each of the 16 types of images stored in the second table, an image composed of pixels in a predetermined row × predetermined column centered on the center of gravity of each image is extracted, and the extracted image is represented by a corresponding angle α˜. A BTF is created in association with the angle δ and stored in the function storage unit 102. The function storage unit 102 stores the BTF created by the calculation unit 201. As a result, a BTF having 16 color components, that is, a 16-band BTF can be created.

  The model storage unit 103 has various data for specifying the shape of a virtual 3D model created in advance in a virtual 3D space set on a computer, for example, a plurality of data set on the surface of the virtual 3D model The coordinates of the vertices of the polygons such as triangles or quadrangles, and the ridge lines connecting the vertices are stored, and the coordinates of the virtual light source and the virtual camera set in the virtual three-dimensional space are stored. The virtual three-dimensional space is represented by a coordinate system consisting of three orthogonal axes N ′, U ′, and V ′, respectively, and the N, U, and V axes shown in FIGS. 1 and 4A and 4B, respectively. It corresponds.

  The rendering processing unit 502 reads the BTF stored in the function storage unit 102, renders the virtual three-dimensional model on the virtual screen set in the three-dimensional space, and causes the display unit 300 to display the virtual three-dimensional model.

  The imaging mechanism control unit 503 outputs a control signal to the motor controller 401 to position the table 20 by rotating it by a predetermined angle with respect to the θ1 and θ2 directions. Further, the horizontal arm 41 is positioned by rotating a predetermined angle with respect to the θ1 direction, and the arch arm 43 is positioned by rotating a predetermined angle with respect to the θ3 direction. In addition, the imaging mechanism control unit 503 turns on the light sources 441 and 442 at a predetermined timing, for example, immediately before imaging the sample S, turns off the light sources 441 and 442 at the end of imaging, and turns off the light sources 441. , 442 is controlled. The display unit 300 includes a display device 206.

  FIG. 11 is a flowchart showing the processing of the rendering processing unit 502. In this flowchart, a dress DO worn by the virtual human body model TO shown in FIG. 13 is adopted as the virtual three-dimensional model, and a fabric of the dress DO is adopted as the sample S. In step S201, the rendering processing unit 502 sets a virtual screen in the virtual three-dimensional space. Here, the virtual screen is a rectangular area that is set at a predetermined position between the virtual camera VC and the virtual three-dimensional model in the virtual three-dimensional space and has a predetermined resolution.

  In step S202, the rendering processing unit 502 extracts one pixel from the virtual screen. In this case, for example, the rendering processing unit 502 extracts a pixel located at the upper left corner on the virtual screen when viewed from the line-of-sight direction of the virtual camera VC.

  In step S203, it is determined whether or not a virtual three-dimensional model exists on a straight line connecting a pixel set on the virtual screen and the virtual camera VC. If a virtual three-dimensional model exists (YES in step S203). Then, the intersection of the straight line and the virtual three-dimensional model is set as the point of interest CP ′ (step S204). On the other hand, when there is no intersection between the straight line and the virtual three-dimensional model (NO in step S203), the rendering processing unit 502 extracts the next pixel from the virtual screen. In this case, for example, the rendering processing unit 502 sequentially extracts pixels adjacent to the right as the next pixel. When all the pixels for one line are extracted, one rendering line below the one line is extracted. The pixel located on the far left is extracted as the next pixel.

  In step S205, the rendering processing unit 502 calculates angles α ′ to δ ′ at the point of interest CP ′ set on the surface of the virtual three-dimensional model.

  FIG. 12 is a diagram for explaining how the angles α ′ to δ ′ are calculated. The normal vector N1 ′ is a normal vector of the polygon P with respect to the polygon surface PS, and corresponds to N1 shown in FIGS. 4 (a) and 4 (b). The angles α ′ and β ′ correspond to the angles α and β shown in FIGS. 4A and 4B, and the angles γ ′ and δ ′ correspond to the angles γ and δ shown in FIG. The polygon surface PS of the polygon P corresponds to the surface of the actual sample S (that is, the sample placement surface).

  VC is a virtual camera, and VL is a virtual light source. The line of sight of the virtual camera VC is set on the U ′ axis and in the direction of interest CP ′. The vector L is a vector connecting the virtual light source VL and the target point CP ′, the vector L1 is an orthogonal projection vector of the vector L to the U′-V ′ plane, and the vector FL ′ is in the fiber direction FL. Correspondingly, the vector FLH is an orthogonal projection vector onto the U′-V ′ plane of the vector FL ′. Furthermore, the attention point CP ′ corresponds to the center O shown in FIG. 4A, and the U ′, V ′, and N ′ axes correspond to U, V, and N shown in FIGS. 4A and 4B, respectively. Corresponds to the axis.

  The rendering processing unit 502 sets a point of interest CP ′ on the surface of the virtual three-dimensional model, and based on the coordinates of the vertices P11, P12, and P13 of the polygon P including the point of interest CP ′, the normal vector N1 with respect to the polygon surface PS. 'Is calculated, and a vector L is calculated from the coordinates of the virtual light source VL and the coordinates of the point of interest CP'. The rendering processing unit 502 calculates an angle γ ′ between the vector L and the vector L1, calculates an angle δ ′ between the vector L1 and the U ′ axis, and calculates an angle α ′ between the vector FLH and the U ′ axis. Then, the angle β ′ between the normal vector N1 ′ and the N ′ axis is calculated, and the angles α ′ to δ ′ at the attention point CP ′ are calculated.

  In step S206, the rendering processing unit 502 determines whether the output value of the BTF corresponding to the angles α ′ to δ ′ calculated in step S205 exists in the function storage unit 102 (step S206), and the angle α ′. When the output value of BTF corresponding to ˜δ ′ is present in the function storage unit 102 (YES in step S206), the existing output value of BTF is read (step S207), and the read output value of BTF and designated by the user The RGB values of the pixels on the virtual screen set in step S202 or step S210 are calculated from the obtained colors (step S208).

  On the other hand, if the rendering processing unit 502 determines in step S206 that the BTF output values corresponding to the angles α ′ to δ ′ calculated in step S205 do not exist in the function storage unit 102 (NO in step S206), the calculation is performed. The BTF output values corresponding to the angles α ′ to δ ′ are calculated by interpolating the BTF output values corresponding to the angles close to the angles α ′ to δ ′ (step S209), and the calculated shading information and From the color set by the user, the RGB value of the pixel on the virtual screen set in step S202 or step S210 is calculated.

  In step S210, the rendering processing unit 502 determines whether or not pixel data has been set for all the pixels on the virtual screen, and if the RGB value is calculated for all the pixels (YES in step S210). ), The process proceeds to step S211.

  On the other hand, if the rendering processing unit 502 determines in step S210 that the calculation of the RGB values for all the pixels on the virtual screen has not been completed (NO in step S210), the next pixel data is extracted from the virtual screen. (Step S211), the process returns to Step S203.

  In step S212, the rendering processing unit 502 displays the virtual three-dimensional model rendered on the virtual screen on the display unit 300. In this case, an image as shown in FIG. 13 is displayed. Since the rendering processing unit 502 performs rendering using the BTF acquired by photographing the actual sample, the optical anisotropy of the cloth can be reproduced with high accuracy. Therefore, as shown in FIG. 13, it is possible to obtain an image in which shading is beautifully applied to the pleats of the tip portion and the chest portion of the dress DO.

  As described above, according to the image processing system according to the first embodiment, since the sample S is imaged by switching the bandpass filters 471 to 4716, a 16-band BTF can be obtained.

(Embodiment 2)
The image processing system according to the second embodiment is characterized in that BRDF is calculated instead of BTF, and rendering processing is performed using the calculated BRDF. FIG. 14 is a block diagram of an image processing system according to the second embodiment.

  The calculation unit 201 calculates the average value of the luminance of each pixel constituting each image stored in the fields FI1 to FI16 of the second table, and associates the calculated average value with the corresponding angle α to angle δ. A BRDF is created and stored in the function storage unit 102. This makes it possible to create a BRDF having 16 color components, that is, a 16-band BRDF.

  The rendering processing unit 502 renders the virtual three-dimensional model using the BRDF stored in the function storage unit 102.

  The camera characteristic storage unit 104 stores camera characteristics of the camera 50. As the camera characteristics, the spectral sensitivity of the camera 50 and the tone curve of the camera 50 can be used. FIG. 15A is a graph showing the spectral sensitivity of the camera 50, where the vertical axis shows the sensitivity and the horizontal axis shows the wavelength. FIG. 15B is a graph showing the tone curve of the camera 50, where the vertical axis indicates the gradation (0 to 250) output by the camera 50, and the horizontal axis indicates the amount of light received by the camera 50 (0 to 0. 1).

  The spectrum storage unit 105 illustrated in FIG. 14 stores the illumination light spectrum of the light sources 441 and 442. FIG. 16 is a graph showing an illumination light spectrum, where the vertical axis indicates the amount of light and the horizontal axis indicates the wavelength.

  The estimation unit 504 estimates the spectral reflectance of the sample S using the BRDF stored in the function storage unit 102, the camera characteristics stored in the camera characteristic storage unit 104, and the illumination light spectrum stored in the spectrum storage unit 105. To do. The estimation of the spectral reflectance is well known and will not be described.

  FIG. 17 is a graph showing the estimation result of the spectral reflectance. The thin line indicates the estimation result, and the thick line indicates the actual measurement value of the spectral reflectance by the spectrometer. The vertical axis indicates the reflectance, and the horizontal axis indicates the wavelength. As shown in FIG. 17, it can be seen that the spectral reflectance estimated using 16-band BRDF almost coincides with the actual measurement value, and an extremely accurate estimation result is obtained.

  FIG. 18 is a diagram showing BRDF calculated by the calculation unit 201 when red satin is used as the sample S. (A) shows an array of angles α to δ, and (b) shows an output value of BRDF when the angles α to δ are arranged by the squares shown in (a).

  In (a), the upper left vertex of the square is the origin. And the square shown to (a) is divided | segmented into the grid | lattice form by 16 squares, and these squares are further divided | segmented by 16 squares into the grid | lattice form. In the larger square, the angles α and δ are assigned constant values. The angle α is assigned values of 0, 90, 180, and 270 degrees in order from the left side to the right side, and the angle δ is assigned values of 0, 90, 180, and 270 degrees in order from the upper side to the lower side. Assigned.

  In the smaller square, the angles β and δ are assigned constant values. The smaller square in the larger square is assigned values of 0, 90/40, (90/4) · 2, (90/4) · 3 degrees in order from the left to the right, In order from the upper side to the lower side, values of 0, 90/4, (90/4) · 2, (90/4) · 3 degrees are assigned. When the output values of BRDF with respect to the angles α to δ arranged in this way are displayed in shades, a diagram shown in (b) is obtained.

  As described above, according to the image processing system according to the second embodiment, since the sample S is photographed by switching the bandpass filters 471 to 4716, a 16-band BRDF can be obtained. Furthermore, it is also possible to obtain a full spectrum BRDF from a 16-band BRDF using a known method.

(Embodiment 3)
The image processing system according to the third embodiment is characterized in that a spectral radiance meter is used instead of the camera 50. In the third embodiment, the same components as those in the first embodiment are denoted by the same reference numerals and the description thereof is omitted.

  In the present embodiment, the spectral radiance meter measures the reflection characteristics of the sample S placed on the table 20. Accordingly, in the fields FI1 to FI16 shown in FIG. 9, values of the reflection characteristics of the respective color components of the sample S obtained by the spectral radiance meter are stored. Then, the calculation unit 201 stores the reflection characteristics stored in each field of the second table in the function storage unit 102 in association with the corresponding angles α to δ. The rendering processing unit 502 reads the reflection characteristics corresponding to the angles α to δ stored in the function storage unit 102 and renders the virtual three-dimensional model.

  As described above, according to the image processing system according to the third embodiment, since the reflection characteristics of the sample S are measured using the spectral radiance meter, 16 pieces of the four input values of the angle α to the angle δ are obtained. It is possible to obtain a function that outputs a reflection characteristic composed of the color components.

(Embodiment 4)
The image processing system according to the fourth embodiment employs a spectral radiance meter instead of the camera 50, and is characterized by measuring not only the reflection characteristic but also the fluorescence characteristic. In the third embodiment, the same components as those in the first embodiment are denoted by the same reference numerals and the description thereof is omitted. In the present embodiment, the spectral radiance meter measures the reflection characteristics and fluorescence characteristics of the sample S. Accordingly, in the fields FI1 to FI16 shown in FIG. 9, values of the reflection characteristics and fluorescence characteristics of each color component of the sample S obtained by the spectral radiance meter are stored. Then, the calculation unit 201 stores the function storage unit 102 in association with the angles α to δ corresponding to the reflection characteristics and the fluorescence characteristics stored in each field of the second table. The rendering processing unit 502 reads the reflection characteristics and fluorescence characteristics corresponding to the angles α to δ stored in the function storage unit 102 and renders the virtual three-dimensional model.

  As described above, according to the image processing system according to the fourth embodiment, since the reflection characteristic and the fluorescence characteristic of the sample S are measured using the spectral radiance meter, the four input values of the angle α to the angle δ are obtained. On the other hand, it is possible to obtain a function that outputs reflection characteristics and fluorescence characteristics composed of 16 color components.

(Embodiment 5)
The fifth embodiment is characterized in that a multispectral camera is used instead of the camera 50 and the fluorescence characteristic and reflection characteristic of the sample S are measured by the multispectral camera. In the fifth embodiment, the same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted. In the present embodiment, the multispectral camera measures the reflection characteristics and fluorescence characteristics of the sample S. Accordingly, the fields FI1 to FI16 shown in FIG. 9 store the values of the reflection characteristics and fluorescence characteristics of each color component of the sample S obtained by the multispectral camera.

  The calculation unit 201 stores the information in the function storage unit 102 in association with the angles α to δ corresponding to the reflection characteristics and the fluorescence characteristics stored in each field of the second table. The rendering processing unit 502 reads the reflection characteristics and fluorescence characteristics corresponding to the angles α to δ stored in the function storage unit 102 and renders the virtual three-dimensional model.

  As described above, according to the image processing system according to the fifth embodiment, the reflection characteristic and the fluorescence characteristic of the sample S are measured using the multispectral camera. , A function that outputs reflection characteristics and fluorescence characteristics composed of 16 color components can be obtained.

(Embodiment 6)
The sixth embodiment is characterized in that the number of the light source sections 44 shown in FIG. 1 is three and an RGB camera is employed as the camera 50. FIG. 19 shows the light source unit 44 of the image processing system according to the sixth embodiment. The light source unit 44 includes three light source units 44R, 44G, and 44B. Each of the light source units 44R to 44B includes one light source (not shown) and one rotating turret 441R to 441B. Each of the rotating turrets 441R to 441B is provided with six color filters (not shown). The six color filters provided in the rotating turret 441R are red bands of the spectral sensitivity characteristics of the camera 50, and transmit different wavelength components. The six color filters included in the rotating turret 441G are each a green band of the spectral sensitivity characteristic of the camera 50 and transmit different wavelength components. The six color filters included in the rotating turret 441B are blue bands of the spectral sensitivity of the camera 50, and transmit different wavelength components.

  FIG. 20 is a graph showing the color filters of the light source units 44R to 44B and the spectral sensitivity characteristics of the camera 50. The dotted line shows the spectral sensitivity characteristics of the camera 50, and the solid line shows the spectral sensitivity characteristics of the light source units 44R to 44B. Show. In FIG. 20, since the horizontal axis indicates the wavelength, the peak located on the left in the dotted line indicates the blue band of the spectral sensitivity characteristic, the peak positioned at the center indicates the green band of the spectral sensitivity characteristic, and on the right The located mountain indicates the red band of the spectral sensitivity characteristic.

  When the color filter having the spectral sensitivity characteristic shown in (a) is selected by the light source units 44R to 44B, the camera 50 can capture a texture image of three bands at a time. Next, when a color filter having the spectral sensitivity characteristic shown in (b) is selected by the light sources 44R to 44B, the camera 50 captures a three-band texture image having a wavelength component different from that of (a) at a time. Can do. In this way, when the color filters of the light source units 441R to 441B are switched, an image of the three-band sample S can be taken by one photographing, so that the number of photographing can be greatly reduced.

(Embodiment 7)
The seventh embodiment is characterized in that the number of the light source sections 44 shown in FIG. 20 is one and an RGB camera is employed as the camera 50. FIG. 21 shows the light source unit 44 of the image processing system according to the seventh embodiment. The light source unit 44 includes one light source (not shown) and one rotating turret 44A. The rotating turret 44A includes two color filters (not shown). One of the two color filters included in the rotating turret 441A has a spectral sensitivity characteristic as indicated by a solid line in FIG. 22A, and the other color filter is in FIG. 22B. It has spectral sensitivity characteristics as shown by the solid line. The dotted line shown in FIG. 22 indicates the spectral sensitivity characteristic of the camera 50 as in FIG.

  The spectral sensitivity characteristic shown in FIG. 22A has two pulses, and the left pulse falls in the vicinity of the peak wavelength in the B band of the spectral sensitivity characteristic. The right pulse rises near the peak wavelength of the G band of the spectral sensitivity characteristic, and falls near the peak wavelength of the R band of the spectral sensitivity characteristic. On the other hand, the spectral sensitivity characteristic shown in (b) has a shape in which the unevenness is inverted with respect to (a).

  Therefore, according to the light source unit 44 shown in FIG. 21, an image of the 6-band sample S can be obtained by two photographings. As a result, it is possible to generate a 6-band BRDF.

  In the first to seventh embodiments, each function of the program execution unit 500 is configured by a CPU. However, the present invention is not limited to this, and may be configured by hardware such as an ASIC and mounted on a video camera or the like. In the first to fifth embodiments, the table 20 is rotatable with respect to the θ1 and θ2 directions to change the measurement direction. However, the present invention is not limited to this, and the camera 50 is arranged to be movable on the celestial sphere B1. By doing so, the measurement direction may be changed.

(A) is a diagram showing the overall configuration of an image processing system according to the present invention, and (b) is a drawing showing details of a light source unit. It is a graph which shows the spectral transmittance of a band pass filter, a horizontal axis shows a wavelength and a vertical axis shows a transmittance. FIG. 2 is a block diagram showing an electrical configuration of the image processing system shown in FIG. 1. (A) is drawing which simplified and showed the imaging device, (b) is an enlarged schematic diagram of a table. It is a flowchart which shows operation | movement when this image processing system image | photographs the sample which consists of cloth as an object mounted on the table. It is a flowchart which shows operation | movement when this image processing system image | photographs the sample which consists of cloth as an object mounted on the table. It is drawing which showed the data structure of the data acquired by the optical characteristic measuring apparatus and memorize | stored by the image processing apparatus. It is drawing which showed the data structure of the data acquired by the optical characteristic measuring apparatus and memorize | stored by the image processing apparatus. It is drawing which showed the data structure of the data acquired by the optical characteristic measuring apparatus and memorize | stored by the image processing apparatus. 2 shows a functional block diagram of the image processing apparatus 2. FIG. It is the flowchart which showed the process of the rendering process part. It is drawing for demonstrating a mode that angle (alpha) '-delta' is calculated. It is drawing which shows a rendering result. FIG. 3 shows a block diagram of an image processing system according to a second embodiment. (A) is a graph showing the spectral sensitivity of the camera, and (b) is a graph showing the tone curve of the camera. It is the graph which showed the illumination light spectrum, the vertical axis | shaft has shown the light quantity, and the horizontal axis has shown the wavelength. It is a graph which shows the estimation result of a spectral reflectance, a thin line shows an estimation result and the thick line has shown the measured value of the spectral reflectance by a spectrometer. It is drawing which represented BRDF calculated by the calculating part when using red satin as a sample. (A) shows an array of angles α to δ, and (b) shows an output value of BRDF when the angles α to δ are arranged by the squares shown in (a). 10 is a diagram illustrating a light source unit of an image processing system according to a sixth embodiment. It is the graph which showed the color filter of the light source parts 44R-44B, and the spectral sensitivity characteristic of a camera, a dotted line shows the spectral sensitivity characteristic of a camera, and the continuous line has shown the spectral sensitivity characteristic of the light source parts 44R-44B. FIG. 21 shows the light source unit 44 of the image processing system according to the seventh embodiment. It is the graph which showed the spectral sensitivity characteristic of the color filter with which the light source part shown in FIG. 21 is provided.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical characteristic measuring device 2 Image processing device 3 Image pick-up device 4 Control device 10 Base 11 Shaft 20 Table 21a Center part 21 Support plate 22 23 Standing plate 24 Shaft 30 Switching part 40 Irradiation part 41 Horizontal arm 42 Connection board 43 Arch arm 44 Light source unit 45 Outlet port 46 Optical fiber 47 Band pass filter 48 Fiber folder 49 Reflection mirror 50 Camera 60 Base 70 Dark box 71 Shooting hole 100 Storage unit 101 Image storage unit 102 Function storage unit 103 Model storage unit 500 Program execution unit 501 Calculation unit 502 Rendering processing unit 503 Imaging mechanism control unit

Claims (25)

An optical property measuring device for measuring an optical property of an actual object to obtain a function indicating an optical property used in rendering a virtual three-dimensional model,
A table on which an object is placed;
An illumination unit that irradiates the object with light by switching a color of light emitted to the object to any one of at least four colors and switching an irradiation direction of the light with respect to the object;
A black and white camera for photographing an object placed on the table;
An optical characteristic measuring apparatus comprising: a photographing direction switching means for switching a photographing direction with respect to an object of the monochrome camera. The irradiation means includes
A light source;
An emission unit that is arranged to be movable on a celestial sphere centered on the object, and that emits the light output from the light source to the object;
A light guide unit that switches color filters of at least four colors, transmits light from the light source, and guides the light to the emission unit;
2. The optical characteristic measuring apparatus according to claim 1, further comprising positioning means for positioning the emitting portion at an arbitrary position on the celestial sphere. The light guide is
An optical fiber that guides light from the light source to the emitting portion;
A rotating body that is arranged between the light source and the optical fiber so that at least four color filters are arranged and any one of the color filters is positioned with respect to the optical input end of the optical fiber. The optical characteristic measuring device according to claim 2, comprising: There are two rotating bodies,
The optical fiber is
Two branch fibers corresponding to each rotating body;
A trunk fiber that multiplexes the light from each branch fiber and guides it to the emission part,
4. The optical characteristic measuring apparatus according to claim 3, wherein the branch fiber guides light transmitted through a color filter included in a corresponding rotating body to the trunk fiber.   The optical property measuring apparatus according to claim 1, wherein the irradiating unit switches 16 colors. The positioning means extends in the horizontal direction from the center of the table, and is mounted so as to be rotatable with respect to the center of the table with the vertical direction as the first axis.
An arch-shaped arch arm that includes the ejection portion on the distal end, the other end is attached to the distal end of the horizontal arm, and is rotatably mounted with the longitudinal direction of the horizontal arm as a second axis. The optical property measuring apparatus according to claim 2, wherein:   The imaging direction switching means rotates the table at a predetermined angle with a direction orthogonal to the object placement surface as a third axis, and with a direction orthogonal to the third axis as a fourth axis. The optical characteristic measuring apparatus according to claim 1, wherein the photographing direction is switched by rotating the angle. The black and white camera captures an object every time the measurement conditions defined by the irradiation direction and the imaging direction are switched,
The monochrome camera generates a texture image composed of at least four color components by associating images of objects photographed for each color under the same measurement condition, and associates the generated texture image with the measurement condition. The optical measurement measurement device according to claim 1, further comprising a function generation unit that generates a bidirectional texture function of the object.   9. The function generating means generates a bidirectional reflectance distribution function of an object by calculating a representative value of the texture image and associating the calculated representative value with the measurement condition. Optical property measuring device. Camera characteristic storage means for storing camera characteristics of the monochrome camera;
Spectrum storage means for storing an illumination light spectrum of light irradiated by the irradiation means;
10. The apparatus according to claim 9, further comprising: an estimation unit that estimates a spectral reflectance of an object based on a bidirectional reflectance distribution function generated by the function generation unit, the camera characteristics, and the illumination light spectrum. The optical characteristic measuring apparatus as described. An optical property measuring device for measuring an optical property of an actual object to obtain a function indicating an optical property used in rendering a virtual three-dimensional model,
A table on which an object is placed;
An illumination unit that irradiates the object with light by switching a color of light emitted to the object to any one of at least two colors, and switching an irradiation direction of the light with respect to the object;
An RGB camera for photographing an object placed on the table;
An optical characteristic measuring apparatus comprising: a photographing direction switching means for switching a photographing direction with respect to an object of the RGB camera. The irradiation means includes
A light source;
An emission unit that is arranged to be movable on a celestial sphere centered on the object, and that emits the light output from the light source to the object;
A light guide unit that switches color filters of at least two colors, transmits light from the light source, and guides the light to the emission unit;
The optical characteristic measuring apparatus according to claim 11, further comprising positioning means for positioning the emitting portion at an arbitrary position on the celestial sphere. The light guide is
An optical fiber that guides light from the light source to the emitting portion;
A rotating body that is arranged between the light source and the optical fiber so that at least two color filters are arranged and any one of the color filters is positioned with respect to the light input end of the optical fiber. The optical characteristic measuring device according to claim 12, comprising: The rotating body is three rotating bodies of an R rotating body, a G rotating body, and a B rotating body,
In the R rotating body, at least two kinds of color filters that transmit different wavelength components are arranged in the red band of the spectral sensitivity characteristics of the RGB camera,
The G rotator is composed of at least two types of color filters that transmit different wavelength components in the green band of the spectral sensitivity characteristics of the RGB camera,
The B rotating body is composed of at least two kinds of color filters that transmit different wavelength components in the blue band of the spectral sensitivity characteristics of the RGB camera,
The optical fiber is
Three branch fibers corresponding to each rotating body;
A trunk fiber that multiplexes the light from each branch fiber and guides it to the emission part,
The optical characteristic measurement apparatus according to claim 13, wherein the branch fiber guides light transmitted through a color filter included in a corresponding rotating body to the trunk fiber. The positioning means extends in the horizontal direction from the center of the table, and is mounted so as to be rotatable with respect to the center of the table with the vertical direction as the first axis.
An arch-shaped arch arm that includes the ejection portion on the distal end, the other end is attached to the distal end of the horizontal arm, and is rotatably mounted with the longitudinal direction of the horizontal arm as a second axis. The optical characteristic measuring apparatus according to claim 12, wherein   The imaging direction switching means rotates the table at a predetermined angle with a direction orthogonal to the object placement surface as a third axis, and with a direction orthogonal to the third axis as a fourth axis. The optical characteristic measuring device according to claim 11, wherein the photographing direction is switched by rotating the angle. The RGB camera shoots an object every time the measurement conditions defined by the irradiation direction and the shooting direction are switched,
By associating images of objects with different color components captured by the RGB camera under the same measurement conditions to generate a texture image composed of at least four color components, and associating the generated texture image with the measurement conditions The optical measurement measurement device according to claim 11, further comprising a function generation unit configured to generate a bidirectional texture function of the object.   18. The function generation unit generates a bidirectional reflectance distribution function of an object by calculating a representative value of the texture image and associating the calculated representative value with the measurement condition. Optical property measuring device. An optical property measuring device for measuring an optical property of an actual object to obtain a function indicating an optical property used in rendering a virtual three-dimensional model,
A table on which an object is placed;
An illumination unit that irradiates the object with light by switching a color of light emitted to the object to any one of at least four colors and switching an irradiation direction of the light with respect to the object;
A spectral luminance meter for measuring the fluorescence characteristics and reflection characteristics of the object placed on the table;
Measurement direction switching means for switching the measurement direction with respect to the object of the spectral luminance meter;
Each time the measurement conditions defined by the irradiation direction and the imaging direction are switched, the bidirectional reflectance distribution function including the fluorescence characteristics based on the fluorescence characteristics and reflection characteristics of the object measured by the spectral luminance meter. An optical property measuring device comprising: function generating means for generating Camera characteristic storage means for storing camera characteristics of the RGB camera;
Spectrum storage means for storing an illumination light spectrum of light irradiated by the irradiation means;
20. The estimation device according to claim 19, further comprising: an estimation unit configured to estimate a spectral reflectance based on the bidirectional reflectance distribution function generated by the function generation unit, the camera characteristic, and the illumination light spectrum. Optical property measuring device. An optical property measuring device for measuring an optical property of an actual object to obtain a function indicating an optical property used in rendering a virtual three-dimensional model,
A table on which an object is placed;
An illumination unit that irradiates the object with light by switching a color of light emitted to the object to any one of at least four colors and switching an irradiation direction of the light with respect to the object;
The measuring means is a multispectral camera;
Measurement direction switching means for switching the measurement direction with respect to the object of the multispectral camera;
A bi-directional reflectance distribution function including fluorescence characteristics based on the fluorescence characteristics and reflection characteristics of the object measured by the multispectral camera each time the measurement conditions defined by the irradiation direction and the imaging direction are switched. An optical property measuring device comprising: function generating means for generating An image processing system including an optical characteristic measurement device and an image processing device,
The optical property measuring device is
A table on which the actual object is placed;
An illumination unit that irradiates the object with light by switching a color of light emitted to the object to any one of at least four colors and switching an irradiation direction of the light with respect to the object;
A black and white camera for photographing an object placed on the table;
Shooting direction switching means for switching the shooting direction with respect to the object of the monochrome camera;
Each time the measurement conditions defined by the irradiation direction and the shooting direction are switched, a texture image composed of at least four color components in association with images taken for each color by the monochrome camera under the same measurement conditions. And a function generation means for generating a function indicating the optical characteristics of the object by associating the generated texture image with the measurement condition,
The image processing apparatus includes:
Function storage means for storing a function indicating the optical characteristics generated by the function generation means;
Model storage means for storing a virtual three-dimensional model generated in advance in the virtual three-dimensional space;
An image processing system comprising: rendering means for rendering the virtual three-dimensional model using a function indicating the optical characteristic.   The image processing system according to claim 22, further comprising a multi-primary color display device that displays the virtual three-dimensional model rendered by the rendering means. An image processing system including an optical characteristic measurement device and an image processing device,
The optical property measuring device is
A table on which the actual object is placed;
An illumination unit that irradiates the object with light by switching a color of light emitted to the object to any one of at least two colors, and switching an irradiation direction of the light with respect to the object;
An RGB camera for photographing an object placed on the table;
Shooting direction switching means for switching the shooting direction with respect to the object of the RGB camera;
Each time the measurement conditions defined by the irradiation direction and the shooting direction are switched, the image of an object with a different color component captured by the RGB camera is associated with at least four color components under the same measurement condition. A function generation unit that generates a function indicating the optical characteristics of the object by associating the generated texture image with the measurement condition,
The image processing apparatus includes:
Function storage means for storing a function indicating the optical characteristics generated by the function generation means;
Model storage means for storing a virtual three-dimensional model generated in advance in the virtual three-dimensional space;
An image processing system comprising: rendering means for rendering the virtual three-dimensional model using a function indicating the optical characteristic.   The image processing system according to claim 24, further comprising a multi-primary color display device that displays the virtual three-dimensional model rendered by the rendering means.

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