Reconstructing a compressed still image by transformation to a compressed moving picture image

• US 20030169814A1
• Filed: 03/11/2002
• Published: 09/11/2003
• Est. Priority Date: 03/11/2002
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Kellerman, Marcus, Chen, Sherman, Fu, Jiang, Silyaev, Vladimir, Rajakarunanayake, Yasantha, Fisher, Jeff
• Granted Patent: US 7,379,498 B2
• Time in Patent Office: Days
• US Class Current: 375/240.12
• CPC Class Codes: H04N 19/124 Quantisation
• CPC Class Codes: H04N 19/186 the unit being a colour or a chrominance component
• CPC Class Codes: H04N 19/40 using video transcoding, i.e. partial or full decoding of a coded input stream followed by re-encoding of the decoded output stream
• CPC Class Codes: H04N 19/60 using transform coding
• CPC Class Codes: H04N 19/61 in combination with predictive coding
• CPC Class Codes: H04N 19/70 characterised by syntax aspects related to video coding, e.g. related to compression standards
• CPC Class Codes: H04N 19/90 using coding techniques not provided for in groups H04N19/10-H04N19/85, e.g. fractals

Abstract

A transcoder (10) and a decoder (80) reconstruct an image from still image compressed data, such as EXIF data. The transcoder transcodes the still image compressed data into a bit stream of moving picture compressed data, such as an MPEG-2 4:2:2P bit stream with only intra pictures. The decoder (80) decodes the bit stream of moving picture compressed data into a still picture image that can be stored in a digital memory (100).

Claims

1. Apparatus for reconstructing an image from still image compressed data, comprising:

a transcoder arranged to transcode the still image compressed data into a bit stream of moving picture compressed data; and

a decoder arranged to generate the reconstructed image by decoding the bit stream of moving picture compressed data.

2. The apparatus of claim 1 wherein the still image compressed data comprises discrete cosine transformed data and wherein the decoder is arranged to perform a discrete cosine transform.

3. The apparatus of claim 1 wherein the still image compressed data comprises EXIF data and wherein the bit stream of moving picture compressed data comprises MPEG-2 data.

4. The apparatus of claim 3 wherein the EXIF data comprises JPEG data.

5. The apparatus of claim 4 wherein the MPEG-2 data comprises a luminance component, a first chrominance component and a second chrominance component.

6. The apparatus of claim 5 wherein the luminance component is represented by 4 bits, the first chrominance component is represented by two bits and the second chrominance component is represented by two bits.

7. The apparatus of claim 4 wherein the EXIF data comprises a header and wherein the transcoder comprises:

a parser of the header arranged to generate parsed header data;

a JPEG decoder arranged to generate decoded data in response to the parsed header data and to map the decoded data into MPEG-2 syntax elements;

a DC predictor and quantizer arranged to generate MPEG-2 quantization data in response to the MPEG-2 syntax elements;

a Huffman encoder arranged to generate encoded data in response to the quantization data; and

a stream construction device responsive to the encoded data and the MPEG-2 syntax elements to generate MPEG-2 the moving picture compressed data.

8. The apparatus of claim 7 wherein the JPEG decoder is responsive to a specification table.

9. The apparatus of claim 8 wherein the specification table comprises luminance quantization data, chrominance quantization data and Huffman code data.

10. A method of reconstructing an image from still image compressed data comprising:

transcoding the still image compressed data into a bit stream of moving picture compressed data; and

generating the reconstructed image by decoding the bit stream of moving picture compressed data.

11. The method of claim 10 wherein the still image compressed data comprising luminance data, chrominance data, block data, variable length coding data, vertical line data, horizontal line data and DC coefficient data;

wherein the transcoding comprises

converting the still image luminance data to moving picture compatible luminance data,

converting the still image chrominance data to moving picture compatible chrominance data,

converting the still image block data to moving picture compatible block data,

converting the still image variable length coding data to moving picture compatible variable length coding data,

converting the still image vertical line data to moving picture compatible vertical line data,

converting the still image horizontal line data to moving picture compatible horizontal line data, and

converting the still image DC coefficient data to moving picture compatible DC coefficient data;

and wherein the decoding comprises decoding the moving picture compatible luminance data, chrominance data, block data, variable length coding data, vertical line data, horizontal line data and DC coefficient data to form an image.

12. The method of claim 11 wherein the still image block data comprises 8 by 8 block data and wherein the moving picture compatible block data comprises 16 by 16 block data.

13. The method of claim 11 wherein the variable length coding data comprises Huffman coding data.

14. The method of claim 11 wherein the DC coefficient data comprises DC coefficients of intra coded block data.

15. The method of claim 11 wherein the still image compressed data further comprises discrete cosine transformed data and wherein the decoding comprises performing a discrete cosine transform.

16. The method of claim 11 wherein the still image compressed data comprises EXIF data and wherein the moving picture compatible luminance data, chrominance data, block data, variable length coding data, vertical line data, horizontal line data and DC coefficient data comprises MPEG-2 data.

17. The method of claim 16 wherein the EXIF data comprises JPEG data.

18. The method of claim 11 wherein the still image compressed chrominance data comprises a first chrominance component and a second chrominance component.

19. The method of claim 18 wherein the luminance data is represented by 4 bits, the first chrominance component is represented by two bits and the second chrominance component is represented by two bits.