Coding and decoding of moving pictures based on sprite coding

• US 20010036319A1
• Filed: 03/19/2001
• Published: 11/01/2001
• Est. Priority Date: 03/21/2000
• Status: Active Grant

• Current Assignee: Nippon Hoso Kyokai
• Original Assignee: Nippon Hoso Kyokai
• Inventors: Imaizumi, Hiroyuki, Sakaida, Shinichi, Zheng, Wentao, Shishikui, Yoshiaki, Kanatsugu, Yasuaki
• Granted Patent: US 6,771,823 B2
• Time in Patent Office: Days
• US Class Current: 382/232
• CPC Class Codes: H04N 19/23 with coding of regions that are present throughout a whole video segment, e.g. sprites, background or mosaic

Abstract

A method of coding and transmitting moving pictures includes the steps of coding an extended background image, coding parameters indicative of an image area within the extended background image, coding a foreground picture that is to be composed with a background picture corresponding to the image area indicated by the parameters, coding a defocus value indicative of an extent to which the background picture should blur, and transmitting the coded extended background image, the coded parameters, the coded foreground picture, and the coded defocus value as a data stream to a decoder side. Coding and transmitting of the defocus value makes it possible to defocus the background picture at the decoder end, thereby producing a composed image of the background picture and the foreground picture having natural appearance.

Claims

1. A method of coding and transmitting moving pictures, comprising the steps of:

coding an extended background image;

coding parameters indicative of an image area within the extended background image;

coding a foreground picture that is to be composed with a background picture corresponding to the image area indicated by the parameters;

coding a defocus value indicative of an extent to which the background picture should blur; and

transmitting the coded extended background image, the coded parameters, the coded foreground picture, and the coded defocus value as a data stream to a decoder side.

2. The method as claimed in

claim 1

, further comprising a step of obtaining the defocus value from camera parameters used to take the foreground picture and a distance from a camera to a background object.

3. The method as claimed in

claim 1

, wherein the defocus value is camera parameters used to take the foreground picture and a distance from a camera to a background object.

4. The method as claimed in

claim 1

, further comprising the steps of:

coding an additional extended background image;

coding additional parameters indicative of an image area within the additional extended background image; and

coding an additional defocus value indicative of an extent to which a background picture corresponding to the image area within the additional extended background image should blur,

wherein said step of transmitting transmits the coded additional extended background image, the coded additional parameters, and the coded additional defocus value to the decoder side as part of said data stream.

5. A method of decoding moving pictures, comprising the steps of:

decoding an extended background image;

decoding parameters indicative of an image area within the extended background image;

extracting a background picture from the image area indicated by the decoded parameters within the decoded extended background image;

decoding a foreground picture;

decoding a defocus value indicative of an extent to which the background picture should blur;

blurring the background picture to the extent indicated by the decoded defocus value; and

combining the blurred background picture with the decoded foreground picture.

6. The method as claimed in

claim 5

, wherein the defocus value is camera parameters used to take the foreground picture and a distance from a camera to a background object.

7. The method as claimed in

claim 5

, further comprising:

decoding an additional extended background image;

decoding additional parameters indicative of an image area within the additional extended background image;

extracting an additional background picture from the image area indicated by the additional parameters within the decoded additional extended background image;

decoding an additional defocus value indicative of an extent to which the additional background picture should blur;

selecting either one of the background picture and the additional background picture to be composed with the decoded foreground picture; and

selecting either one of the defocus value and the additional defocus value to be used to blur the selected one of the background picture and the additional background picture.

8. A method of coding and decoding moving pictures, comprising the steps of:

coding an extended background image and a foreground picture separately from each other;

coding parameters indicative of an image area within the extended background image;

coding a defocus value;

decoding the extended background image and the foreground picture;

decoding the parameters;

decoding the defocus value;

extracting a background picture from the image area indicated by the decoded parameters within the decoded extended background image;

blurring the background picture to an extent indicated by the decoded defocus value; and

composing the blurred background picture with the decoded foreground picture.

9. An apparatus for coding moving pictures, comprising:

a coding unit which encodes an extended background image;

a coding unit which encodes parameters indicative of an image area within the extended background image;

a coding unit which encodes a foreground picture that is to be composed with a background picture corresponding to the image area indicated by the parameters;

a coding unit which encodes a defocus value indicative of an extent to which the background picture should blur; and

a stream generation unit which transmits the coded extended background image, the coded parameters, the coded foreground picture, and the coded defocus value as a data stream.

10. An apparatus for decoding moving pictures, comprising:

a decoding unit which decodes an extended background image;

a decoding unit which decodes parameters indicative of an image area within the extended background image;

a background picture generation unit which extracts a background picture from the image area indicated by the decoded parameters within the decoded extended background image;

a decoding unit which decodes a foreground picture;

a decoding unit which decodes a defocus value indicative of an extent to which the background picture should blur;

a defocus unit which blurs the background picture to the extent indicated by the decoded defocus value; and

a synthesizing unit which composes the blurred background picture with the decoded foreground picture.

11. A method of coding and transmitting moving pictures, comprising the steps of:

coding an extended background image;

coding parameters indicative of an image area within the extended background image;

coding a foreground picture that is to be composed with a background picture corresponding to the image area indicated by the parameters;

coding a distortion value indicative of an extent to which the background picture should be distorted due to lens distortion; and

transmitting the coded extended background image, the coded parameters, the coded foreground picture, and the coded distortion value as a data stream to a decoder side.

12. A method of decoding moving pictures, comprising the steps of:

decoding an extended background image;

decoding parameters indicative of an image area within the extended background image;

extracting a background picture from the image area indicated by the decoded parameters within the decoded extended background image;

decoding a foreground picture;

decoding a distortion value indicative of an extent to which the background picture should be distorted due to lens distortion;

distorting the background picture to the extent indicated by the decoded distortion value; and

composing the distorted background picture with the decoded foreground picture.

13. A method of coding and decoding moving pictures, comprising the steps of:

coding an extended background image and a foreground picture separately from each other;

coding parameters indicative of an image area within the extended background image;

coding a distortion value;

decoding the extended background image and the foreground picture;

decoding the parameters;

decoding the distortion value;

extracting a background picture from the image area indicated by the decoded parameters within the decoded extended background image;

distorting the background picture to an extent indicated by the decoded distortion value; and

composing the distorted background picture with the decoded foreground picture.

14. An apparatus for coding moving pictures, comprising:

a coding unit which encodes an extended background image;

a coding unit which encodes parameters indicative of an image area within the extended background image;

a coding unit which encodes a foreground picture that is to be composed with a background picture corresponding to the image area indicated by the parameters;

a coding unit which encodes a distortion value indicative of an extent to which the background picture should be distorted due to lens distortion; and

a stream generation unit which transmits the coded extended background image, the coded parameters, the coded foreground picture, and the coded distortion value as a data stream.

15. An apparatus for decoding moving pictures, comprising:

a decoding unit which decodes an extended background image;

a decoding unit which decodes parameters indicative of an image area within the extended background image;

a background picture generation unit which extracts a background picture from the image area indicated by the decoded parameters within the decoded extended background image;

a decoding unit which decodes a foreground picture;

a decoding unit which decodes a distortion value indicative of an extent to which the background picture should be distorted due to lens distortion;

a distortion unit which distorts the background picture to the extent indicated by the decoded distortion value; and

a synthesizing unit which composes the distorted background picture with the decoded foreground picture.