Image processing apparatus and method therefor

• US 9,076,266 B2
• Filed: 01/30/2012
• Issued: 07/07/2015
• Est. Priority Date: 02/09/2011
• Status: Active Grant

• Current Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Original Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Inventors: Hanamoto, Takashi
• Primary Examiner(s): Repko, Jason M
• Assistant Examiner(s): Patel, Jitesh
• Application Number:
  US13/361,105
• Publication Number:
  US 20120200570A1
• Time in Patent Office: 1,254 Days
• Field of Search: 345/418, 345/426, 345/427, 345/428, 345/589, 345/619
• US Class Current: 1/1
• CPC Class Codes: G06T 15/506 Illumination models

Abstract

Based on the refractive property and/or reflectance property of an object, it is determined which one of light, spectra, and channels is to be used as a target for tracing by the ray-tracing method. A pixel value of image data representing the object is determined by tracing at least one entity of the determined target for tracing from a view point in the virtual three-dimensional space to a light source.

Claims

1. An image processing apparatus for generating image data representing at least one object in a virtual three-dimensional space using a ray-tracing method, the apparatus comprising:

a first determiner configured to determine whether or not light to be traced strikes an object;

a second determiner configured to determine, in a case where it is determined that the light strikes the object, a distance between the object and a view point in the virtual three-dimensional space so as to determine whether light or a plurality of entities of spectral light are to be used as a target for tracing by the ray-tracing method; and

a third determiner configured to determine a pixel value of image data representing the object by tracing the target for tracing, determined by the second determiner, from the view point to a light source in the virtual three-dimensional space,

wherein the second determiner determines the plurality of entities of spectral light as the target for tracing between the object and the view point, in a case where the distance is less than a first distance, (a) the target for tracing comprises a ray of one of a plurality of channels based on visual perception properties in a first case where the distance is less than the first distance and not less than a second distance, (b) the target for tracing comprises a ray of a single wavelength in a second case where the distance is less than the second distance, and (c) the second determiner determines the light as the target for tracing between the object and the view point, in a third case where the distance is not less than the first distance,

wherein the third determiner calculates an attenuation factor of light in a path of the tracing in the third case, calculates a spectral attenuation factor in a path of the tracing in the second case, calculates a channel attenuation factor in a path of the tracing in the first case, and determines a pixel value of image data representing the object using those attenuation factors, and

wherein the first to third determiners are implemented using a processor.

2. An image processing apparatus for generating image data representing at least one object in a virtual three-dimensional space using a ray-tracing method, the apparatus comprising:

a first determiner configured to determine light to be traced strikes an object;

a second determiner configured to determine, in a case where it is determined that the light strikes the object, whether or not the object diffuses light;

a counter configured to count a number of times the light has consecutively struck another object which diffuses light;

a third determiner configured to determine whether the light or a plurality of entities of spectral light are to be used as a target of tracing between a view point and an object which has a spectral singularity, based on the number of times counted by the counter;

a fourth determiner configured to determine a pixel value of image data representing the object by tracing the target for tracing, determined by the third determiner, from the view point to a light source in the virtual three-dimensional space; and

a calculator configured to calculate, in a case where the light strikes the object which diffuses light, a distance between the object and the other object, which diffuses light, struck by the light before the light reaches the object,

wherein the third determiner determines the light as the target for tracing in a case where the count value is not less than 2 and the distance is not less than a predetermined distance, and

wherein the first to fourth determiners, the counter, and the calculator are implemented using a processor.

3. An image processing method of generating image data representing at least one object in a virtual three-dimensional space using a ray-tracing method, the method comprising:

using a processor to perform;

a first determination step of determining whether or not light to be traced strikes an object;

a second determination step of determining, in a case where it is determined that the light strikes the object, a distance between the object and a view point in the virtual three-dimensional space so as to determine whether the light or a plurality of entities of spectral light are to be used as a target for tracing by the ray-tracing method; and

a third determination step of determining a pixel value of image data representing the object by tracing the target for tracing, determined in the second determination step, from the view point to a light source in the virtual three-dimensional space,

wherein, in the second determination step, the plurality of entities of spectral light are determined as the target for tracing between the object and the view point, in a case where the distance is less than a first distance, (a) the target for tracing comprises a ray of one of a plurality of channels based on visual perception properties in a first case where the distance is less than the first distance and not less than a second distance, (b) the target for tracing comprises a ray of a single wavelength in a second case where the distance is less than the second distance, and (c) the light is determined as the target for tracing between the object and the view point, in a third case where the distance is not less than the first distance, and

wherein, in the third determination step, an attenuation factor of light in a path of the tracing is calculated in the third case, a spectral attenuation factor in a path of the tracing is calculated in the second case, a channel attenuation factor in a path of the tracing is calculated in the first case, and a pixel value of image data representing the object is determined using those attenuation factors.

4. An image processing method of generating image data representing at least one object in a virtual three-dimensional space using a ray-tracing method, the method comprising:

using a processor to perform;

a first determination step of determining light to be traced strikes an object;

a second determination step of determining, in a case where it is determined that the light strikes the object, whether or not the object diffuses light;

a counting step of counting a number of times the light has consecutively struck another object which diffuses light;

a third determination step of determining whether the light or a plurality of entities of spectral light are to be used as a target of tracing between a view point and an object which has a spectral singularity, based on the number of times counted in the counting step;

a fourth determination step of determining a pixel value of image data representing the object by tracing the target for tracing, determined in the third determination step, from the view point to a light source in the virtual three-dimensional space; and

a calculation step of calculating, in a case where the light strikes the object which diffuses light, a distance between the object and the other object, which diffuses light, struck by the light before the light reaches the object,

wherein, in the third determination step, the light is determined as the target for tracing in a case where the count value is not less than 2 and the distance is not less than a predetermined distance.

5. A non-transitory computer readable medium storing a computer-executable program for causing a computer to perform a method of generating image data representing at least one object in a virtual three-dimensional space using a ray-tracing method, the method comprising:

a first determination step of determining whether or not light to be traced strikes an object;

a second determination step of determining, in a case where it is determined that the light strikes the object, a distance between the object and a view point in the virtual three-dimensional space so as to determine whether the light or a plurality of entities of spectral light are to be used as a target for tracing by the ray-tracing method; and

a third determination step of determining a pixel value of image data representing the object by tracing the target for tracing, determined in the second determination step, from the view point to a light source in the virtual three-dimensional space,

wherein, in the second determination step, the plurality of entities of spectral light are determined as the target for tracing between the object and the view point, in a case where the distance is less than a first distance, (a) the target for tracing comprises a ray of one of a plurality of channels based on visual perception properties in a first case where the distance is less than the first distance and not less than a second distance, (b) the target for tracing comprises a ray of a single wavelength in a second case where the distance is less than the second distance, and (c) the light is determined as the target for tracing between the object and the view point, in a third case where the distance is not less than the first distance, and

wherein, in the third determination step, an attenuation factor of light in a path of the tracing is calculated in the third case, a spectral attenuation factor in a path of the tracing is calculated in the second case, a channel attenuation factor in a path of the tracing is calculated in the first case, and a pixel value of image data representing the object is determined using those attenuation factors.

6. A non-transitory computer readable medium storing a computer-executable program for causing a computer to perform a method of generating image data representing at least one object in a virtual three-dimensional space using a ray-tracing method, the method comprising:

a first determination step of determining light to be traced strikes an object;

a second determination step of determining, in a case where it is determined that the light strikes the object, whether or not the object diffuses light;

a counting step of counting a number of times the light has consecutively struck another object which diffuses light;

a third determination step of determining whether the light or a plurality of entities of spectral light are to be used as a target of tracing between a view point and an object which has a spectral singularity, based on the number of times counted in the counting step;

a fourth determination step of determining a pixel value of image data representing the object by tracing the target for tracing, determined in the third determination step, from the view point to a light source in the virtual three-dimensional space; and

a calculation step of calculating, in a case where the light strikes the object which diffuses light, a distance between the object and the other object, which diffuses light, struck by the light before the light reaches the object,

wherein, in the third determination step, the light is determined as the target for tracing in a case where the count value is not less than 2 and the distance is not less than a predetermined distance.