Image processing apparatus and method of same

• US 20050068333A1
• Filed: 09/23/2004
• Published: 03/31/2005
• Est. Priority Date: 09/25/2003
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Nagasaki, Tanio, Nakahashi, Teruyuki, Yamada, Hideshi, Watanabe, Osamu, Inada, Tetsugo, Moriyama, Yasuhiro
• Granted Patent: US 7,280,121 B2
• Time in Patent Office: Days
• US Class Current: 345/611
• CPC Class Codes: G06T 11/203 Drawing of straight lines or curves
• CPC Class Codes: G06T 15/503 Blending, e.g. for anti-aliasing
• CPC Class Codes: G06T 2200/12 involving antialiasing

Abstract

An image processing apparatus capable of realizing accurate anti-aliasing with a small memory, without being affected by the order of drawing, and without inducing a drop in the drawing speed, including an anti-aliasing system obtaining edge information from an image after drawing, determining a processing content necessary for the anti-aliasing, and performing the determined processing. Specifically, either of the information of a z-buffer and the information of the normal vector at each pixel obtained at the time of drawing, or both information, is scanned or by the information of normal vectors restored from the information of the z-buffer is used, a state machine for holding the state and a counter for measuring the continuity of an edge are prescribed, the value of which pixel adjacent in which direction to each pixel on each edge and what kind of ratio to use for blending are determined, and the determined values are used for blending. This is performed successively until the pixel values are updated.

Claims

1. An image processing apparatus generating pixel data inside a drawn area of a screen coordinate system to perform rendering with respect to a memory and generate an image drawn in said memory and, at that time, generating edge information and performing anti-aliasing, comprising

an edge information extracting means for extracting said edge information based on predetermined pixel data drawn in said memory and

an anti-aliasing means for determining the content of processing required for anti-aliasing based on the edge information obtained by said edge information extracting means and executing the determined processing.

2. An image processing apparatus as set forth in claim 1, wherein said anti-aliasing means determines adjoining pixels for blending with pixels on each edge and the blending ratio and performs blending based on the determined pixels and ratio.

3. An image processing apparatus as set forth in claim 2, wherein said anti-aliasing means includes a first means for detecting at which position of what shape of aliasing pattern a pixel being processed is at from said edge information and a second means for measuring a length from a start point of the detected aliasing pattern to the change point where the edge reverses and a length from the change point to where the aliasing pattern ends and calculating a position of a pixel to be blended with and a coefficient of blending based on information obtained from said first means and second means.

4. An image processing apparatus as set forth in claim 3, wherein

the pixel data drawn in said memory includes depth information, and

said edge information extracting means finds a second differentiation of the depth information obtained as a result of scanning a depth information buffer of said memory storing said depth information and extracts edge information based on the second differentiation.

5. An image processing apparatus as set forth in claim 3, wherein

the data generated at the time of drawing to said memory includes a normal vector for every pixel,

a normal vector buffer storing the normal vectors is formed in said memory, and

said edge information extracting means extracts the edge information based on normal vectors obtained as a result of scanning the normal vectors for the pixels stored in said normal vector buffer.

6. An image processing apparatus as set forth in claim 3, wherein

the pixel data drawn in said memory includes depth information, and

said edge information extracting means restores the normal vector for each pixel from the depth information obtained as a result of scanning the depth information buffer of said memory storing said depth information and the screen coordinates and extracts the edge information based on the restored normal vectors.

7. An image processing apparatus as set forth in claim 4, wherein said edge information extracting means extracts edge information of a plurality of lines near a line being examined.

8. An image processing apparatus as set forth in claim 6, wherein said edge information extracting means extracts edge information of a plurality of lines near a line being examined.

9. An image processing apparatus as set forth in claim 6, wherein said edge information extracting means extracts edge information of a plurality of lines near a line being examined.

10. An image processing method generating pixel data in a drawn area of a screen coordinate system to perform rendering with respect to a memory and generate an image drawn in said memory and, at that time, generating edge information and performing anti-aliasing, comprising:

a first step of extracting said edge information based on predetermined pixel data drawn in said memory and

a second step of determining the content of processing required for anti-aliasing based on the edge information obtained at said first step and executing the determined processing.

11. An image processing method as set forth in claim 10, wherein said second step determines adjoining pixels for blending with pixels on each edge and the blending ratio and performs blending based on the determined pixels and ratio.

12. An image processing method as set forth in claim 10, wherein said second step includes:

a third step of detecting at which position of what shape of aliasing pattern a pixel being processed is at from said edge information and

a fourth step of measuring a length from a start point of the detected aliasing pattern to the change point where the edge reverses and a length from the change point to where the aliasing pattern ends and

calculates a position of a pixel to be blended with and a coefficient of blending based on information obtained from said third step and fourth step.

13. An image processing method as set forth in claim 12, wherein

the pixel data drawn in said memory includes depth information, and

the first step further comprises scanning a depth information buffer of said memory storing said depth information, finding a second differentiation of the depth information obtained, and extracting edge information based on the second differentiation.

14. An image processing method as set forth in claim 12, wherein

the data generated at the time of drawing to said memory includes a normal vector for every pixel,

a normal vector buffer storing the normal vectors is formed in said memory, and

said first step further comprises scanning the normal vector for each pixels stored in said normal vector buffer and extracting the edge information based on normal vectors obtained.

15. An image processing method as set forth in claim 12, wherein

the pixel data drawn in said memory includes depth information, and

said first step further comprises restoring the normal vector for each pixel from the depth information obtained as a result of scanning the depth information buffer of said memory storing said depth information and the screen coordinates and extracting the edge information based on the restored normal vectors.