Method for efficient compression and decoding of single sensor color image data
View Patent ↗A method is described to greatly improve the efficiency of and reduce the complexity of image compression when using single-sensor color imagers for video acquisition. The method in addition allows for this new image compression type to be compatible with existing video processing tools, improving the workflow for film and television production.
1. A method for compressing color imagery from a single sensor of interleaved color primaries comprising:
retrieving, from a memory buffer of an imaging device, an image plane including a plurality of pixel values of spatially-interleaved color primaries;
separating said spatially-interleaved color primaries into a plurality of independent color channels;
encoding each said plurality of independent color channels into a compressed form;
storing each of said compressed forms in a memory;
decoding said compressed forms into each of said plurality of independent color channels;
storing said plurality of independent color channels into channel memory buffers, and
combining said channel memory buffers into a full color display memory.
2. The method of claim 1 wherein said plurality of independent color channels are differenced by adding and subtracting the values from one color channel from another, so that the results of the differencing are then compressed.
3. The method of claim 1 wherein the extraction of the plurality of independent color channels is performed directly upon the source image plane, thereby reducing the memory storage requirements for the compression operation.
4. The method of claim 1 wherein the compressed technique used is wavelet compression.
5. The method of claim 1 wherein the decoding of said plurality of independent color channels is mathematically identical to the encoded plurality of independent color channels for a lossless reconstruction.
6. The method of claim 1 wherein the decoding of said plurality of independent color channels is different than the encoded plurality of independent color channels for a lossy reconstruction.
7. The method of claim 1 wherein a subset of said plurality of color primary channels is selected to be decoded for viewable presentation, thereby further reducing the decoding complexity for an image sequence.
8. The method of claim 1 wherein the decompression of said plurality of color primary channels is performed directly into the said display memory, thereby reducing the memory storage requirements for the decoder operation by outputting directly to the display memory.
9. The method of claim 1 wherein the decoded presentation is at the same resolution as the individual color primary channels, thereby further reducing the decoding complexity for previewing an image sequence.
10. The method of claim 1 wherein the decoded presentation is at the resolution requested by the calling application by scaling individual color primary channels to the requested size, thereby providing compatibility with a range of calling applications.
11. The method of claim 1 wherein the decoded presentation is at full resolution and full quality by performing a de-Bayer filter as selected by an operator, thereby providing an operator full control over the decoded image quality.
12. An apparatus for presenting a compressed Bayer image, comprising:
a memory including a plurality of channel memory buffers; and
a processor coupled to the memory, wherein the processor is configured to:
retrieve compressed data, where the compressed data is generated by a compression process including:
retrieving, from a memory buffer of an imaging device, an image plane including a plurality of pixel values of spatially-interleaved color primaries;
separating said spatially-interleaved color primaries into a plurality of independent color channels; and
encoding each said plurality of independent color channels into a compressed form;
decoding the compressed forms into each said plurality of independent color channels;
storing the independent color channels into the channel memory buffers; and
combining the channel memory buffers into the full color display memory.
13. The apparatus of claim 12 wherein the decoding of said plurality of independent color channels is mathematically identical to the encoded plurality of independent color channels for a lossless reconstruction.
14. The apparatus of claim 12 wherein the decoding of said plurality of independent color channels is different than the encoded plurality of independent color channels for a lossy reconstruction.
15. The apparatus of claim 12 wherein a subset of said plurality of color primary channels is selected to be decoded for viewable presentation, thereby further reducing the decoding complexity for an image sequence.
16. The apparatus of claim 12 wherein the decompression of said plurality of color primary channels is performed directly into the display memory, thereby reducing the memory storage requirements for the decoder operation by outputting directly to the display memory.
17. The apparatus of claim 12 wherein the decoded presentation is at the same resolution as the individual color primary channels, thereby further reducing the decoding complexity for previewing an image sequence.
18. The apparatus of claim 12 wherein the decoded presentation is at the resolution requested by a calling application by scaling individual color primary channels to the requested size, thereby providing compatibility with a range of calling applications.
19. The apparatus of claim 12 wherein the decoded presentation is at full resolution and full quality by performing a de-Bayer filter as selected by an operator, thereby providing the operator full control over the decoded image quality.