Image processing apparatus, image recording apparatus, image reproducing apparatus, camera system, computer program, and storage medium

• US 7,158,682 B2
• Filed: 04/23/2003
• Issued: 01/02/2007
• Est. Priority Date: 04/26/2002
• Status: Expired due to Fees

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Sano, Yutaka
• Primary Examiner(s): Bella; Matthew C.
• Assistant Examiner(s): Bayat; Ali
• Application Number:
  US10/420,887
• Publication Number:
  US 20030219162A1
• Time in Patent Office: 1,350 Days
• Field of Search: 382/232, 382/233, 382/236, 382/238, 382/239, 382/240, 382/248, 382250-251, 375/240.16, 375/240.12, 375/240.08, 375/240.23, 348/154, 348/208.4, 348/416.1, 348/431.1
• US Class Current: 382/236
• CPC Class Codes: H04N 19/61 in combination with predictive coding
• CPC Class Codes: H04N 19/63 using sub-band based transform, e.g. wavelets
• CPC Class Codes: H04N 19/645 by grouping of coefficients into blocks after the transform

Abstract

An image processing apparatus includes an image compression device which performs a discrete wavelet transform of pixel values for each rectangular portion to produce wavelet coefficients, and performs a hierarchical compression coding of the wavelet coefficients for each rectangular portion so that a codestream is produced. A codestream transform device is provided to reduce an amount of code data in the codestream. The codestream transform device comprises a syntax analysis unit which analyzes header information of each rectangular portion in the codestream. A comparison unit determines a similarity of pixel values between a current frame and a preceding frame in the codestream based on a result of the analysis. A codestream generating unit deletes code data of a corresponding rectangular portion of the current frame when the similarity is larger than a given threshold value.

Claims

1. An image processing apparatus which processes image data of a motion picture having a number of frames, each frame being divided into one or a plurality of rectangular portions, the image processing apparatus comprising:

an image compression device performing a discrete wavelet transform of pixel values for each rectangular portion to produce wavelet coefficients, and performing a hierarchical compression coding of the wavelet coefficients for each rectangular portion so that a codestream is produced; and

a codestream transform device provided to reduce an amount of code data in the codestream after the compression coding, the codestream transform device comprising;

a syntax analysis unit analyzing header information of the codestream;

a comparison unit determining a similarity between a current frame and a preceding frame in the codestream based on a result of the analysis of the syntax analysis unit; and

a codestream generating unit deleting code data of a corresponding rectangular portion of the current frame when the similarity is larger than a given threshold value.

2. The image processing apparatus according to claim 1 wherein the comparison unit is provided to determine a similarity of wavelet coefficients between the current frame and the preceding frame and compare the determined similarity with the threshold value.

3. The image processing apparatus according to claim 2 wherein the codestream transform device comprises a decoding unit and an inverse quantization unit, the decoding unit and the inverse quantization unit being provided to produce wavelet coefficients from the codestream, the wavelet coefficients being supplied to the comparison unit.

4. The image processing apparatus according to claim 2 wherein the codestream transform device comprises a packet scramble unit which arbitrarily rearranges the order of packets, constituting the codestream in which the amount of code data is reduced by the codestream generating unit, and describes information of the rearrangement to a header of the codestream.

5. The image processing apparatus of claim 2 wherein the codestream transform device comprises a reference-frame change unit which changes an object of comparison for each of the current frame and the preceding frame being compared by the comparison unit.

6. The image processing apparatuses according to claim 5 wherein the reference-frame change unit is provided to change the threshold value.

7. The image processing apparatuses according to claim 5 wherein the reference-frame change unit is provided to change a range for each of the current frame and the preceding frame being compared by the comparison unit.

8. The image processing apparatuses according to claim 5 wherein the reference-frame change unit is provided to change a color component for each of the current frame and the preceding frame being compared by the comparison unit.

9. The image processing apparatuses according to claim 5 wherein the reference-frame change unit is provided to change the preceding frame which is compared with the current frame by the comparison unit, to another preceding frame.

10. The image processing apparatuses according to claim 5 wherein the reference-frame change unit is provided to change a sub band in which both the frames compared by the comparison unit.

11. An image processing apparatus which processes image data of a motion picture having a number of frames, each frame being divided into one or a plurality of rectangular portions, the image processing apparatus comprising:

a codestream transform device receiving a first codestream after compression coding of image data, the first codestream having code data reduced by comparison between frames in the first codestream, and the codestream transform device compensating for the reduced code data so that a second codestream in which the reduced code data is restored is produced; and

a wavelet expansion unit performing an inverse discrete wavelet transform of the second codestream for each rectangular portion to generate wavelet coefficients,

the codestream transform device comprising;

a syntax analysis unit analyzing header information of the first codestream; and

a codestream generating unit inserting code data of a preceding frame into a current frame in the first codestream when the current frame is detected as containing a deletion code data based on a result of the analysis of the syntax analysis unit, so that the second codestream in which the reduced code data is restored is produced.

12. The image processing apparatus according to claim 11 wherein the codestream transform device comprises a packet descramble unit which reads information of rearrangement of the order of packets from a header of the first codestream, and rearranges the order of packets, constituting the first codestream before the restoration of the reduced code data, in original order according to the read information of the rearrangement.

13. The image processing apparatus according to claim 11 wherein the codestream transform device is provided to compensate for a missing code data of a defective frame in the first codestream by inserting in the defective frame a code data of a frame preceding the defective frame.

14. An image recording apparatus including an image input device and an image processing apparatus, the image input device supplying image data of a motion picture having a number of frames, to the image processing apparatus, the image processing apparatus processing the image data, each frame being divided into one or a plurality of rectangular portions, the image processing apparatus comprising:

an image compression device performing a discrete wavelet transform of pixel values for each rectangular portion to produce wavelet coefficients, and performing a hierarchical compression coding of the wavelet coefficients for each rectangular portion so that a codestream is produced; and

a codestream transform device provided to reduce an amount of code data in the codestream after the compression coding, the codestream transform device comprising;

a syntax analysis unit analyzing header information of the codestream;

a comparison unit determining a similarity between a current frame and a preceding frame in the codestream based on a result of the analysis of the syntax analysis unit; and

a codestream generating unit deleting code data of a corresponding rectangular portion of the current frame when the similarity is larger than a given threshold value.

15. An image reproducing apparatus including an image processing apparatus and an image display device, the image processing apparatus processing image data of a motion picture having a number of frames, each frame being divided into one or a plurality of rectangular portions, the image display unit displaying a reconstructed motion picture with the image data processed by the image processing apparatus, the image processing apparatus comprising:

a codestream transform device receiving a first codestream after compression coding of image data, the first codestream having code data reduced by comparison between frames in the first codestream, and compensating for the reduced code data so that a second codestream in which the reduced code data is restored is produced; and

a wavelet expansion unit performing an inverse discrete wavelet transform of the second codestream for each rectangular portion to generate wavelet coefficients,

the codestream transform device comprising;

a syntax analysis unit analyzing header information of the first codestream; and

a codestream generating unit inserting code data of a preceding frame into a current frame in the first codestream when the current frame is detected as containing a deletion code data based on a result of the analysis of the syntax analysis unit, so that the second codestream in which the reduced code data is restored is produced.

16. A camera system which includes an image recording apparatus and an image reproducing apparatus,

the image recording apparatus including an image input device and a first image processing apparatus, the image input device supplying image data of a motion picture having a number of frames, to the first image processing apparatus, the first image processing apparatus processing the image data, each frame being divided into one or a plurality of rectangular portions, the first image processing apparatus comprising:

an image compression device performing a discrete wavelet transform of pixel values for each rectangular portion to produce wavelet coefficients, and performing a hierarchical compression coding of the wavelet coefficients for each rectangular portion so that a codestream is produced; and

a first codestream transform device provided to reduce an amount of code data in the codestream after the compression coding, the first codestream transform device comprising;

a first syntax analysis unit analyzing header information of the codestream;

a comparison unit determining a similarity between a current frame and a preceding frame in the codestream based on a result of the analysis of the syntax analysis unit; and

a first codestream generating unit deleting code data of a corresponding rectangular portion of the current frame when the similarity is larger than a given threshold value,

the image reproducing apparatus including a second image processing apparatus and an image display device, the second image processing apparatus processing the image data supplied from the first image processing apparatus, the image display unit displaying a reconstructed motion picture with the image data processed by the second image processing apparatus, the second image processing apparatus comprising;

a second codestream transform device receiving a first codestream after the compression coding, the first codestream having code data reduced by comparison between frames in the first codestream, and the second codestream transform device compensating for the reduced code data so that a second codestream in which the reduced code data is restored is produced; and

a wavelet expansion unit performing an inverse discrete wavelet transform of the second codestream for each rectangular portion to generate wavelet coefficients,

the second codestream transform device comprising;

a second syntax analysis unit analyzing header information of the first codestream; and

a second codestream generating unit inserting code data of a preceding frame into a current frame in the first codestream when the current frame is detected as containing a deletion code data based on a result of the analysis of the second syntax analysis unit, so that the second codestream in which the reduced code data is restored is produced.

17. A computer program embodied in a computer-readable medium for causing a computer to execute an image processing method to process image data of a motion picture having a number of frames, each frame being divided into one or a plurality of rectangular portions, the method comprising steps of:

performing a discrete wavelet transform of pixel values for each rectangular portion to produce wavelet coefficients;

performing a hierarchical compression coding of the wavelet coefficients for each rectangular portion so that a codestream is produced;

analyzing header information of the codestream;

determining a similarity between a current frame and a preceding frame in the codestream based on a result of the analysis; and

deleting code data of a corresponding rectangular portion of the current frame when the similarity is larger than a given threshold value, so that an amount of code data in the codestream after the compression coding is reduced.

18. The computer program according to claim 17 wherein the determining step is provided to determine a similarity of wavelet coefficients between the current frame and the preceding frame and compare the determined similarity with the threshold value.

19. The computer program according to claim 18 wherein the determining step includes steps of:

decoding code data in the codestream for each rectangular portion; and

performing an inverse quantization of the decoded data to produce wavelet coefficients for each rectangular portion.

20. The computer program according to claim 18 wherein the method further comprises steps of:

arbitrarily rearranging the order of packets, constituting the codestream in which the amount of code data is reduced; and

describing information of the rearrangement to a header of the codestream.

21. The computer program according to claim 18 wherein the method further comprises a step of changing an object of comparison for each of the current frame and the preceding frame compared in the determining step.

22. A computer program embodied in a computer-readable medium for causing a computer to execute an image processing method to process image data of a motion picture having a number of frames, each frame being divided into one or a plurality of rectangular portions, the method comprising steps of:

receiving a first codestream after compression coding of image data, the first codestream having code data reduced by comparison between frames in the first codestream;

compensating for the reduced code data so that a second codestream in which the reduced code data is restored is produced; and

performing an inverse discrete wavelet transform of the second codestream for each rectangular portion to generate wavelet coefficients, wherein the compensating step comprises steps of;

analyzing header information of the first codestream; and

inserting code data of a preceding frame into a current frame in the first codestream when the current frame is detected as containing a deletion code data based on a result of the analysis, so that the second codestream in which the reduced code data is restored is produced.

23. The computer program according to claim 22 wherein the method further comprises steps of:

reading information of rearrangement of the order of packets from a header of the first codestream; and

rearranging the order of packets, constituting the first codestream before the restoration of the reduced code data, in original order according to the read information of the rearrangement.

24. The computer program according to claim 22 wherein the method further comprises a step of compensating for a missing code data of a defective frame in the first codestream by inserting in the defective frame a code data of a frame preceding the defective frame.

25. A computer-readable storage medium storing a computer program embodied therein for causing a computer to execute an image processing method to process image data of a motion picture having a number of frames, each frame being divided into one or a plurality of rectangular portions, the method comprising steps of:

performing a discrete wavelet transform of pixel values for each rectangular portion to produce wavelet coefficients;

performing a hierarchical compression coding of the wavelet coefficients for each rectangular portion so that a codestream is produced;

analyzing header information of the codestream after the compression coding;

determining a similarity between a current frame and a preceding frame in the codestream based on a result of the analysis; and

deleting code data of a corresponding rectangular portion of the current frame when the similarity is larger than a given threshold value, so that an amount of code data in the codestream after the compression coding is reduced.