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

• US 7,308,147 B2
• Filed: 12/06/2006
• Issued: 12/11/2007
• 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:
  US11/567,640
• Publication Number:
  US 20070086661A1
• Time in Patent Office: 370 Days
• Field of Search: 382/232, 382/233, 382/236, 382/238, 382/239, 382/240, 382/248, 382/250, 382/251, 375/240.16, 375/240.12, 375/240.08, 375/240.23, 348/154, 348/208, 348/4, 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 comprising:

an image compression unit performing a discrete wavelet transform of pixel values for each of one or a plurality of rectangular portions to produce wavelet coefficients, the rectangular portions being produced by dividing each of a number of frames of a motion picture, and the image compression unit performing a hierarchical compression coding of the wavelet coefficients for each rectangular portion so that a codestream is produced;

a syntax analysis unit analyzing header information of the codestream outputted from the image compression unit;

a memory unit storing the codestream according to a result of the analysis of the syntax analysis unit;

a decoding unit decoding the codestream outputted from the memory unit;

a comparison unit determining a similarity of wavelet coefficients between a current frame and a preceding frame by comparison of the wavelet coefficients between the current frame and the preceding frame; and

a codestream generating unit reducing an amount of code data of a corresponding rectangular portion of the current frame based on the similarity determined by the comparison unit.

2. The image processing apparatus according to claim 1, wherein the codestream generating unit is provided to delete code data of a corresponding rectangular portion of the current frame when the similarity determined by the comparison unit is larger than a given threshold value.

3. An image processing method comprising the steps of:

performing a discrete wavelet transform of pixel values for each of one or a plurality of rectangular portions to produce wavelet coefficients, the rectangular portions being produced by dividing each of a number of frames of a motion picture, and 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 outputted by the compression coding of the wavelet coefficients for each rectangular portion;

storing the codestream in a memory unit according to a result of the analysis in the analyzing step;

decoding the codestream outputted from the memory unit;

determining a similarity of wavelet coefficients between a current frame and a preceding frame by comparison of the wavelet coefficients between the current frame and the preceding frame; and

reducing an amount of code data of a corresponding rectangular portion of the current frame based on the similarity determined in the determining step.

4. The image processing method according to claim 3, wherein the reducing step is provided to delete code data of a corresponding rectangular portion of the current frame when the similarity determined in the determining step is larger than a given threshold value.