System and Method for Compressing Images and Video

• US 20140348439A1
• Filed: 08/11/2014
• Published: 11/27/2014
• Est. Priority Date: 09/26/2008
• Status: Active Grant

• Current Assignee: Futurewei Technologies Incorporated (Huawei Investment & Holding Co., Ltd.)
• Original Assignee: Futurewei Technologies Incorporated (Huawei Investment & Holding Co., Ltd.)
• Inventors: Han, Bing, Wu, Dapeng Oliver, Tian, Jun, Yu, Hong Heather
• Granted Patent: US 9,204,169 B2
• Time in Patent Office: Days
• US Class Current: 382/250
• CPC Class Codes: H04N 19/12 Selection from among a plurality of transforms or standards, e.g. selection between discrete cosine transform [DCT] and sub-band transform or selection between H.263 and H.264
• CPC Class Codes: H04N 19/132 Sampling, masking or truncation of coding units, e.g. adaptive resampling, frame skipping, frame interpolation or high-frequency transform coefficient masking
• CPC Class Codes: H04N 19/176 the region being a block, e.g. a macroblock
• CPC Class Codes: H04N 19/18 the unit being a set of transform coefficients
• CPC Class Codes: H04N 19/44 Decoders specially adapted therefor, e.g. video decoders which are asymmetric with respect to the encoder
• CPC Class Codes: H04N 19/46 Embedding additional information in the video signal during the compression process H04N19/517, H04N19/68, H04N19/70 take precedence
• CPC Class Codes: H04N 19/48 using compressed domain processing techniques other than decoding, e.g. modification of transform coefficients, variable length coding [VLC] data or run-length data motion estimation in a transform domain H04N19/547; processing of decoded motion vectors H04N19/513
• CPC Class Codes: H04N 19/60 using transform coding
• CPC Class Codes: H04N 19/61 in combination with predictive coding
• CPC Class Codes: H04N 19/62 by frequency transforming in three dimensions H04N19/63 takes precedence
• CPC Class Codes: H04N 19/625 using discrete cosine transform [DCT]
• CPC Class Codes: H04N 19/645 by grouping of coefficients into blocks after the transform

Abstract

A system and method for image and video compression using compressive sensing is provided. An embodiment method for compressing an image having a plurality of image blocks includes selecting an image block from the plurality of image blocks to compress, computing a sum of sinusoidal signals at different frequencies and amplitudes representation for the selected image block, quantizing the amplitudes of the sinusoidal signals at different frequencies, and saving the quantized amplitudes as a first compressed image block. The method also includes truncating the quantized amplitudes, thereby producing truncated quantized amplitudes, saving the truncated quantized amplitudes as a second compressed image block, and selecting either the first compressed image block or the second compressed image block as a final compressed image block. The selecting is based on a measure of the quality of the first compressed image block and the second compressed image block.

Claims

1. A method for compressing an image having a plurality of image blocks, the method comprising:

selecting, by a processor, an image block from the plurality of image blocks to compress;

computing, by the processor, a sum of sinusoidal signals at different frequencies and amplitudes representation for the selected image block;

quantizing, by the processor, the amplitudes of the sinusoidal signals at the different frequencies;

saving, by the processor, in memory the quantized amplitudes as a first compressed image block;

truncating, by the processor, the quantized amplitudes to produce truncated quantized amplitudes;

saving, by the processor, in memory the truncated quantized amplitudes as a second compressed image block; and

selecting, by the processor, either the first compressed image block or the second compressed image block as a final compressed image block, wherein the selecting is in accordance with a comparison of a first quality of the first compressed image block and a second quality of the second compressed image block.

2. The method of claim 1, wherein computing the sum of the sinusoidal signals comprises applying a discrete cosine transform to the selected image block.

3. The method of claim 1, wherein truncating the quantized amplitudes comprises eliminating any amplitudes of the sinusoidal signals above a specified frequency.

4. The method of claim 3, wherein the specified frequency is fixed.

5. The method of claim 3, wherein the specified frequency is dynamically selected in accordance with a specified percentage of a total sum of the amplitudes of the sinusoidal signals.

6. The method of claim 1, wherein selecting either the first compressed image block or the second compressed image block comprises:

decompressing the first compressed image block and the second compressed image block; and

selecting a higher quality one of the decompressed image blocks.

7. The method of claim 1, wherein selecting either the first compressed image block or the second compressed image block comprises:

computing a first total variance of the selected image block;

computing a second total variance of the first compressed image block;

selecting the first compressed image block when the first total variance of the first compressed image block is less than the second total variance of the selected image block; and

selecting the second compressed image block when the first total variance of the first compressed image block is greater than the second total variance of the selected image block.

8. The method of claim 1, wherein selecting either the first compressed image block or the second compressed image block comprises:

classifying a texture of the selected image block, wherein there are at least three texture classes, wherein the texture classes comprise low, medium, and high textures;

selecting the second compressed image block when the texture class of the selected image block is medium; and

selecting the first compressed image block when the texture class of the selected image block is low or high.

9. The method of claim 1, further comprising setting a flag associated with the final compressed image block, wherein the flag indicates whether the final compressed image block was compressed with or without compressive sensing.

10. The method of claim 1, further comprising entropy coding the final compressed image block for insertion into a compressed bit stream.

11. An apparatus for compressing an image having a plurality of image blocks, the apparatus comprising:

a processor; and

a computer readable storage medium storing programming for execution by the processor, the programming including instructions to;

select an image block from the plurality of image blocks to compress;

compute a sum of sinusoidal signals at different frequencies and amplitudes representation for the selected image block;

quantize the amplitudes of the sinusoidal signals at the different frequencies;

save in memory the quantized amplitudes as a first compressed image block;

truncate the quantized amplitudes to produce truncated quantized amplitudes;

save in the memory the truncated quantized amplitudes as a second compressed image block; and

select either the first compressed image block or the second compressed image block as a final compressed image block, in accordance with a comparison of a first quality of the first compressed image block and a second quality of the second compressed image block.

12. The apparatus of claim 11, wherein the instructions to compute the sum of the sinusoidal signals comprise instructions to apply a discrete cosine transform to the selected image block.

13. The apparatus of claim 11, wherein the instructions to truncate the quantized amplitudes comprise instructions to eliminate any amplitudes of the sinusoidal signals above a specified frequency.

14. The apparatus of claim 13, wherein the specified frequency is fixed.

15. The apparatus of claim 13, wherein programming further includes instructions to dynamically select the specified frequency in accordance with a specified percentage of a total sum of the amplitudes of the sinusoidal signals.

16. The apparatus of claim 11, wherein the instructions to select either the first compressed image block or the second compressed image block comprise instructions to:

decompress the first compressed image block and the second compressed image block; and

select a higher quality one of the decompressed image blocks.

17. The apparatus of claim 11, wherein the instructions to select either the first compressed image block or the second compressed image block comprise instructions to:

compute a first total variance of the selected image block;

compute a second total variance of the first compressed image block;

select the first compressed image block when the first total variance of the first compressed image block is less than the second total variance of the selected image block; and

select the second compressed image block when the first total variance of the first compressed image block is greater than the second total variance of the selected image block.

18. The apparatus of claim 11, wherein the instructions to select either the first compressed image block or the second compressed image block comprise instructions to:

classify a texture of the selected image block, wherein there are at least three texture classes, wherein the texture classes comprise low, medium, and high textures;

select the second compressed image block when the texture class of the selected image block is medium; and

select the first compressed image block when the texture class of the selected image block is low or high.

19. The apparatus of claim 11, wherein the programming further includes instructions to set a flag associated with the final compressed image block, wherein the flag indicates whether the final compressed image block was compressed with or without compressive sensing.

20. The apparatus of claim 11, wherein the programming further includes instructions to entropy code the final compressed image block for insertion into a compressed bit stream.