IMAGE PROCESSING APPARATUS AND METHOD THEREFOR

• US 20120200570A1
• Filed: 01/30/2012
• Published: 08/09/2012
• 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
• Granted Patent: US 9,076,266 B2
• Time in Patent Office: Days
• US Class Current: 345/426
• 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 an object in a virtual three-dimensional space by using a ray-tracing method, the apparatus comprising:

a first determiner, configured to determine, based on a refractive property and/or reflectance property of the object, which one of light, spectra, and channels is to be used as a target for tracing by the ray-tracing method; and

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

wherein the first and second determiners are implemented using a processor.

2. The apparatus according to claim 1, wherein the light includes light itself as an entity, the spectra include a plurality of wavelength bands as entities, and the channels include a plurality of channels as entities.

3. The apparatus according to claim 1, wherein the first determiner determines the number of entities of the target for tracing in further consideration of an area in the virtual three-dimensional space.

4. The apparatus according to claim 1, further comprising a display section configured to display, on a monitor, an image represented by image data having a pixel value determined by the second determiner.

5. The apparatus according to claim 1, wherein the target for tracing is the light at a start of the ray-tracing method, and the first determiner determines the target for tracing if the light as the target for tracing strikes the object.

6. The apparatus according to claim 5, wherein the first determiner determines, based on the refractive property and/or reflectance property, whether the object has a spectral singularity, and determines the target for tracing if the object has the spectral singularity.

7. The apparatus according to claim 6, wherein the first determiner determines that the object has the spectral singularity, if the object transmits light and produces a structural color.

8. The apparatus according to claim 5, wherein the first determiner determines the target for tracing in further consideration of an area in the virtual three-dimensional space.

9. The apparatus according to claim 8, wherein the first determiner determines the spectrum as the target for tracing after the object, if a distance between the object and the view point is less than a first distance, and the object has a spectral singularity.

10. The apparatus according to claim 9, wherein the first determiner determines the channel as the target for tracing after the object, if a distance between the object and the view point is not less than the first distance and less than a second distance, and the object has the spectral singularity.

11. The apparatus according to claim 10, wherein the first determiner determines the light as the target for tracing after the object, if a distance between the object and the view point is not less than the second distance.

12. The apparatus according to claim 11, wherein the second determiner performs the tracing in consideration of an attenuation factor of light, and determines a pixel value of image data representing the object.

13. The apparatus according to claim 12, wherein the second determiner calculates an attenuation factor of light in a path of the tracing if the target for tracing is light, calculates a spectral attenuation factor in a path of the tracing if the target for tracing is a spectrum, calculates a channel attenuation factor in a path of tracing if the target for tracing is a channel, and determines a pixel value of image data representing the object by using the attenuation factors.

14. The apparatus according to claim 1, further comprising:

a third determiner, configured to determine in the tracing, based on the reflectance property, whether an object struck by the target for tracing is an object which diffuses light;

a counter, configured to count the number of times the target for tracing has consecutively struck an object which diffuses light; and

a calculator, configured to calculate a distance between the object and an object struck by the target for tracing before the object,

wherein the first determiner determines the target for tracing if the count value is less than 2 or the distance is less than a predetermined distance, and the object has a spectral singularity.

15. The apparatus according to claim 1, wherein the channels comprise three channels based on visual perception properties.

16. An image processing method of generating image data representing an object in a virtual three-dimensional space by using a ray-tracing method, the image processing method comprising:

using a processor to perform the steps of;

determining, based on a refractive property and/or reflectance property of the object, which one of light, spectra, and channels is to be used as a target for tracing by the ray-tracing method; and

determining a pixel value of image data representing the object by tracing at least one entity of a target for tracing determined by the first determiner from a view point in the virtual three-dimensional space to a light source.

17. A non-transitory computer readable medium storing a computer executable program for casing a computer to perform an image processing method of generating image data representing an object in a virtual three-dimensional space by using a ray-tracing method, the image processing method comprising the steps of:

determining, based on a refractive property and/or reflectance property of the object, which one of light, spectra, and channels is to be used as a target for tracing by the ray-tracing method; and

determining a pixel value of image data representing the object by tracing at least one entity of a target for tracing determined by the first determiner from a view point in the virtual three-dimensional space to a light source.