Image composition method, image composition apparatus, and data recording media

• US 6,483,521 B1
• Filed: 02/01/1999
• Issued: 11/19/2002
• Est. Priority Date: 02/02/1998
• Status: Expired due to Fees

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Boon, Choong Seng, Takahashi, Jun, Kadono, Shinya
• Primary Examiner(s): Luu, Matthew
• Application Number:
  US09/241,886
• Time in Patent Office: 1,387 Days
• Field of Search: 345/582, 345/586, 345/587, 345/611-613, 345/615, 345/629, 345/630, 345/634, 345/639, 345/640, 345/641
• US Class Current: 345/630
• CPC Class Codes: G06T 15/04 Texture mapping

Abstract

In an image composition method, a first image signal which forms a first image space including an object of an arbitrary shape and includes a shape signal indicating the shape of the object and a texture signal indicating the texture of the object, is composited with a second image signal which forms a second image space and includes a texture signal indicating the texture of the image, thereby generating a composite image signal which forms a third image space. This method comprises a composition ratio calculation step of calculating the composition ratio of the texture signal of a target pixel to be processed, by arithmetic on the shape signals of pixels positioned inside a target region in the first image space, the target region including the target pixel; and a pixel composition step of performing composition of the texture signals between the target pixel and a pixel included in the second image space and corresponding to the target pixel, based on the composition ratio calculated; wherein a composite texture signal obtained by the composition is used as the texture signal of a pixel included in the third image space and corresponding to the target pixel. Therefore, the image quality at the boundary of the object in the composite image is improved.

Claims

1. An image composition method for compositing a first image signal which forms a first image space including an object of an arbitrary shape and includes a shape signal indicating the shape of the object and a texture signal indicating the texture of the object, and a second image signal which forms a second image space and includes a texture signal indicating the texture of the image, thereby generating a composite image signal which forms a third image space, said method comprising:

composition ratio calculation step of calculating the composition ratio of the texture signal of a target pixel to be processed, by arithmetic on the shape signals of pixels positioned inside a target region in the first image space, said target region including the target pixel; and

pixel composition step of performing composition of the texture signals between the target pixel and a pixel included in the second image space and corresponding to the target pixel, based on the composition ratio calculated;

wherein a composite texture signal obtained by the composition is used as the texture signal of a pixel included in the third image space and corresponding to the target pixel.

2. The image composition method of claim 1 further comprising:

shape decision step of deciding, based on the shape signal of each pixel in the first image space, as to whether each pixel is positioned inside the object or not; and

said composition ratio calculation step wherein, when the result of the decision is that the target pixel is positioned inside the object, the composition ratio is calculated using the shape signals of the pixels in the target region.

3. The image composition method of claim 1 further comprising:

shape decision step of deciding, based on the shape signal of each pixel in the first image space, as to whether each pixel is positioned inside the object or not; and

said composition ratio calculation step wherein, when the result of the decision is that the target pixel is positioned inside the object, the composition ratio is obtained by calculating the average of the shape signals of the pixels in the target region.

4. The image composition method of claim 1 wherein, in said composition ratio calculation step, the composition ratio is calculated based on an arithmetic expression which is obtained by transforming the arithmetic on the shape signal such that the multiplier or divisor in the arithmetic becomes a power of 2.

7. The image composition method of claim 1 wherein, in said pixel composition step, the texture signal of the pixel included in the third image space and corresponding to the target pixel is obtained by referring to a table containing the results of multiplication on all the combinations between the values of the composition ratios and the values of the texture signals.

9. A data storage medium containing a program for making a computer perform an image composition process, said program being constructed so that the computer performs an image composition process according to any of image composition methods as defined in claim 1.

5. An image composition method for compositing a first image signal which forms a first image space including an object of an arbitrary shape and includes a shape signal indicating the shape of the object and a texture signal indicating the texture of the object, and a second image signal which forms a second image space and includes a texture signal indicating the texture of the image, thereby generating a composite image signal which forms a third image space, said method comprising:

shape decision step of deciding whether each pixel is positioned inside the object or not, based on the shape signal of each pixel in the first image space;

composition ratio calculation step of calculating the composition ratio of the texture signal of the target pixel, based on the number of pixels positioned inside the object in a target region including the target pixel, when the result of the decision is that the target pixel is positioned inside the object; and

pixel composition step of performing composition of the texture signals of the target pixel and a pixel included in the second image space and corresponding to the target pixel, based on the composition ratio calculated;

wherein a composite texture signal obtained by the composition is used as the texture signal of a pixel included in the third image space and corresponding to the target pixel.

6. The image composition method of claim 5 wherein, in said composition ratio calculation step, a composition ratio which has previously been calculated according to the number of pixels positioned inside the object in the target region and stored in a table, is obtained from the table, according to the number of pixels inside the object, which number is obtained from the shape signals of pixels positioned inside the target region.

8. The image composition method of claim 5 wherein, in said pixel composition step, the texture signal of the pixel included in the third image space and corresponding to the target pixel is obtained by referring to a table containing the results of multiplication on all the combinations between the numbers of pixels positioned inside the object in the target region and the values of the texture signals.