Image processing in which polygon is divided

• US 6,246,414 B1
• Filed: 11/02/1998
• Issued: 06/12/2001
• Est. Priority Date: 11/17/1997
• Status: Expired due to Fees

• Current Assignee: NEC Electronics Corporation (Renesas Electronics Corporation)
• Original Assignee: NEC Corporation
• Inventors: Kawasaki, Tomoyuki
• Primary Examiner(s): Vo, Cliff N.
• Application Number:
  US09/184,725
• Time in Patent Office: 953 Days
• Field of Search: 345/418, 345/419, 345/425, 345/426, 345/427, 345/428, 345/429, 345/430
• US Class Current: 345/419
• CPC Class Codes: G06T 15/005 General purpose rendering architectures

Abstract

In an image processing apparatus, a polygon dividing section selectively divides each of a set of polygons approximately representing a three-dimensional object based on a geometric data of the polygon and a reference data to convert the set of polygons into a new set of polygons. A brightness calculating section calculates a brightness of each of apexes of each of the new set of polygons to represent the three-dimensional object when a light is irradiated to the three-dimensional object. A display control section displays a three-dimensional image corresponding to the three-dimensional object viewed from a viewpoint on a display unit with the calculated brightnesses.

Claims

1. An image processing apparatus comprising:

a display unit;

polygon dividing means for selectively dividing each of a set of polygons approximately representing a three-dimensional object based on a geometric data of said polygon and a reference data to convert said set of polygons into a new set of polygons, wherein said polygon dividing means divides each of said set of polygons into new polygons based on lengths of sides of each of said set of polygons and said reference data;

brightness calculating means for calculating a brightness of each of apexes of each of said new set of polygons to represent said three-dimensional object when a light is irradiated to said three-dimensional object; and

display control means for displaying a three-dimensional image corresponding to said three-dimensional object viewed from a viewpoint on said display unit with the calculated brightnesses.

2. An image processing apparatus according to claim 1, further comprising coordinate converting means for coordinate-converting polygon data representing each of a plurality of polygons approximately representing said three-dimensional object based on at least one of a rotation instruction, an expansion instruction, a contraction instruction and a shift instruction to produce said set of polygons.

3. An image processing apparatus according to claim 1, wherein said display control means comprises:

hidden surface deleting means for removing the whole portion or a portion of each of said new set of polygons which is not viewed from the viewpoint.

4. An image processing apparatus according to claim 1, wherein said display control means comprises:

texture mapping means for mapping a texture data to a pixel associated with each of said new set of polygons which is viewed from the viewpoint.

5. An image processing apparatus according to claim 1, wherein said display control means comprises:

a bump mapping section for calculating expansion or contraction of a bump to produce a bump data, and for mapping the bump data to a pixel associated with each of said new set of polygons which is viewed from the viewpoint.

6. An image processing apparatus according to claim 1, wherein each of said set of polygons has a triangle shape, and

wherein said polygon dividing means compares the length of each of said sides of each of said set of polygons with said reference data and divides each of said set of polygons into said new polygons when the length of at least one of said sides is longer than said reference data.

7. An image processing apparatus according to claim 6, wherein said polygon dividing means divides each of said set of polygons into said four new polygons when the lengths of said three sides are all longer than said reference data, divides each of said set of polygons into said three new polygons when the lengths of two of said three sides are all longer than said reference data, and divides each of said set of polygons into said two new polygons when the length of one of said three sides is all longer than said reference data.

8. An image processing apparatus according to claim 1, wherein said polygon dividing means divides each of said set of polygons into new polygons based on said reference data and average unit normal vectors which are obtained by averaging normal vectors of planes contacting each of apexes of each of said set of polygons to have a unit magnitude.

9. An image processing apparatus according to claim 8, wherein said polygon dividing means calculates angles between every two of said average unit normal vectors, and divides each of said set of polygons into new polygons when at least one of said angles is larger than said reference data.

10. An image processing apparatus according to claim 8, wherein said polygon dividing means calculates component angles between every two of said average unit normal vectors in units of components, and divides each of said set of polygons into new polygons when at least one of said components angles is larger than said reference data.

11. A method of displaying a three-dimensional image corresponding to a three-dimensional object, comprising the steps of:

selectively dividing each of a set of polygons approximately representing a three-dimensional object based on a geometric data of said polygon and a reference data to convert said set of polygons into a new set of polygons, wherein said dividing step includes dividing each of said set of polygons into new polygons based on lengths of sides of each set of polygons and said reference data;

calculating a brightness of each of apexes of each of said new set of polygons to represent said three-dimensional object when a light is irradiated to said three-dimensional object; and

displaying a three-dimensional image corresponding to said three-dimensional object viewed from a viewpoint on a display unit with the calculated brightnesses.

12. A method according to claim 11, further comprising the step of coordinate-converting polygon data representing each of a plurality of polygons approximately representing said three-dimensional object based on at least one of a rotation instruction, an expansion instruction, a contraction instruction and a shift instruction to produce said set of polygons.

13. A method according to claim 11, wherein said displaying step includes deleting the whole portion or a portion of each of said new set of polygons which is not viewed from the viewpoint.

14. A method according to claim 11, wherein said displaying step includes mapping a texture data to a pixel associated with each of said new set of polygons which is viewed from the viewpoint.

15. A method according to claim 11, wherein said displaying step includes:

calculating expansion or contraction of a bump to produce a bump data, and

mapping the bump data to a pixel associated with each of said new set of polygons which is viewed from the viewpoint.

16. A method according to claim 11, wherein each of said set of polygons has a triangle shape, and

wherein said dividing step includes:

comparing the length of each of said sides of each of said set of polygons with said reference data; and

dividing each of said set of polygons into said new polygons when the length of at least one of said sides is longer than said reference data.

17. A method according to claim 16, wherein said dividing step includes:

dividing each of said set of polygons into said four new polygons when the lengths of said three sides are all longer than said reference data;

dividing each of said set of polygons into said three new polygons when the lengths of two of said three sides are all longer than said reference data; and

dividing each of said set of polygons into said two new polygons when the length of one of said three sides is all longer than said reference data.

18. A method according to claim 11, wherein said dividing step includes:

dividing each of said set of polygons into new polygons based on said reference data and average unit normal vectors which are obtained by averaging normal vectors of planes contacting each of apexes of each of said set of polygons to have a unit magnitude.

19. A method according to claim 18, wherein said dividing step includes:

calculating angles between every two of said average unit normal vectors; and

dividing each of said set of polygons into new polygons when at least one of said angles is larger than said reference data.

20. A method according to claim 18, wherein said dividing step includes:

calculating component angles between every two of said average unit normal vectors in units of components; and

dividing each of said set of polygons into new polygons when at least one of said components angles is larger than said reference data.

21. An image processing apparatus comprising:

a display unit;

polygon dividing means for selectively dividing each of a set of polygons approximately representing a three-dimensional object based on a geometric data of said polygon and a reference data to convert said set of polygons into a new set of polygons, wherein said polygons are triangles and the number of polygons each triangle is divided into is based upon the number of sides of the triangle whose length is greater than the reference data;

brightness calculating means for calculating a brightness of each of apexes of each of said new set of polygons to represent said three-dimensional object when a light is irradiated to said three-dimensional object; and

display control means for displaying a three-dimensional image corresponding to said three-dimensional object viewed from a viewpoint on said display unit with the calculated brightnesses.

22. A method of displaying a three-dimensional image corresponding to a three-dimensional object, comprising the steps of:

selectively dividing each of a set of polygons approximately representing a three-dimensional object based on a geometric data of said polygon and a reference data to convert said set of polygons into a new set of polygons, wherein said polygons are triangles and the number of polygons each triangle is divided into is based upon the number of sides of the triangle whose length is greater than the reference data;

calculating a brightness of each of apexes of each of said new set of polygons to represent said three-dimensional object when a light is irradiated to said three-dimensional object; and

displaying a three-dimensional image corresponding to said three-dimensional object viewed from a viewpoint on a display unit with the calculated brightnesses.

23. An image processing apparatus comprising:

a display unit;

polygon dividing means for selectively dividing each of a set of polygons approximately representing a three-dimensional object based on a geometric data of said polygon and a reference data to convert said set of polygons into a new set of polygons, wherein said polygon dividing means divides each of said set of polygons into new polygons based on said reference data and average unit normal vectors which are obtained by averaging normal vectors of planes contacting each of apexes of each of said set of polygons to have a unit magnitude;

brightness calculating means for calculating a brightness of each of apexes of each of said new set of polygons to represent said three-dimensional object when a light is irradiated to said three-dimensional object; and

display control means for displaying a three-dimensional image corresponding to said three-dimensional object viewed from a viewpoint on said display unit with the calculated brightnesses.

24. A method of displaying a three-dimensional image corresponding to a three-dimensional object, comprising the steps of:

selectively dividing each of a set of polygons approximately representing a three-dimensional object based on a geometric data of said polygon and a reference data to convert said set of polygons into a new set of polygons, wherein said dividing step includes dividing each of said set of polygons into new polygons based on said reference data and average unit normal vectors which are obtained by averaging normal vectors of planes contacting each of apexes of each of said set of polygons to have a unit magnitude;

calculating a brightness of each of apexes of each of said new set of polygons to represent said three-dimensional object when a light is irradiated to said three-dimensional object; and

displaying a three-dimensional image corresponding to said three-dimensional object viewed from a viewpoint on a display unit with the calculated brightnesses.