IP Library › Granted Patent US 9,398,314
Granted Patent B2
US 9,398,314 · App. 12/026,534 · Granted Jul 19, 2016

Entropy coding efficiency enhancement utilizing energy distribution remapping

Inventors: Walid Ali (Sammamish, WA); Shankar Regunathan (Bellevue, WA); Guo-Wei Shieh (Sammamish, WA); Bruce Lin (Redmond, WA); Bharath Siravara (Redmond, WA); Ce Wang (Bellevue, WA)
Assignee: Microsoft Technology Licensing, LLC
H04N19/85
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Quick Facts
Patent No.
US 9,398,314
App. No.
12/026,534
Granted
Jul 19, 2016
Kind
B2
Abstract

Architecture for enhancing the compression (e.g., luma, chroma) of a video signal and improving the perceptual quality of the video compression schemes. The architecture operates to reshape the normal multimodal energy distribution of the input video signal to a new energy distribution. In the context of luma, the algorithm maps the black and white (or contrast) information of a picture to a new energy distribution. For example, the contrast can be enhanced in the middle range of the luma spectrum, thereby improving the contrast between a light foreground object and a dark background. At the same time, the algorithm reduces the bit-rate requirements at a particular quantization step size. The algorithm can be utilized also in post-processing to improve the quality of decoded video.

Claims (32)

1. A computer-implemented picture processing system, comprising:

a memory and a hardware processor respectively configured to store and execute instructions that implement computer-executable components, the computer-executable components comprising:

an input component configured to receive a video signal associated with a picture, the picture including a multimodal energy distribution represented by a plurality of peaks along a luma signal spectrum;

a mapping component configured to map the multimodal energy distribution of the picture to a new energy distribution, the new energy distribution compacted in dark and light regions to reduce bit-rate requirements of the dark and light regions and to enhance contrast in a mid-range region of the luma signal spectrum of the new energy distribution;

a cost component configured to compute a cost associated with selection of the picture from a plurality of pictures and computing the new energy distribution of the picture relative to new energy distributions for the plurality of pictures; and

a decoder configured to decode the video signal using the new energy distribution of the picture.

2. The system of claim 1 , wherein the multimodal energy distribution is a luma energy distribution that is remapped to a more concentrated new luma energy distribution.

3. The system of claim 1 , wherein the mapping component is configured to enhance contrast between darkest and brightest information of the picture by removing multi-regions of concentration of luma signal between the dark and bright regions of the spectrum.

4. The system of claim 1 , wherein the multimodal energy distribution further comprises a chroma energy distribution that is remapped to a more concentrated new chroma energy distribution.

5. The system of claim 1 , wherein the mapping component is a function or a look-up table employed to remove multi-regions of concentration of a luma signal within bright or dark regions of a spectrum.

6. The system of claim 1 , wherein the mapping component is configured to redistribute the energy of the multimodal energy distribution into the new energy distribution as part of codec pre-processing.

7. The system of claim 1 , wherein the mapping component is configured to redistribute the energy of the multimodal energy distribution into the new energy distribution as part of codec post-processing.

8. A computer-implemented method of processing pictures, performed by a computer system executing machine-readable instructions, the method comprising acts of:

measuring luma energy distributions of pictures in a video signal represented by a plurality of signal peaks;

mapping the energy distributions of the pictures into a new luma energy distribution in a selected concentrated range along a luma signal spectrum, the new luma energy distribution compacted in dark and light regions to reduce bit-rate requirements of the dark and light regions and to enhance contrast in a mid-range region of the luma signal spectrum of the new luma energy distribution;

computing a cost associated with selection of the picture from a plurality of pictures and computing the new energy distribution of the picture relative to new energy distributions for the plurality of pictures; and

decoding, by a decoder, the video signal using the new energy distribution of the picture.

9. The method of claim 8 , further comprising mapping a new concentrated energy distribution in a mid-range of a luma signal spectrum to control contrast of a picture.

10. The method of claim 8 , further comprising mapping a new concentrated energy distribution in a chroma spectrum of a picture.

11. The method of claim 8 , further comprising generating a baseline value for a darkest portion of a picture and a baseline value for a brightest portion of the picture.

12. The method of claim 8 , further comprising computing a mapping function for an I-Frame and applying the mapping function for P-Frames and B-Frames in a group of the pictures.

13. The method of claim 8 , further comprising removing multimodal regions in the energy distributions when mapping to the new concentrated energy distributions.

14. A computer-implemented method of processing pictures, performed by a computer system executing machine-readable instructions, the method comprising acts of:

measuring energy distributions of pictures of a video signal represented by a plurality of signal amplitude peaks in luma space;

mapping the energy distributions into new concentrated energy distributions in luma space, the new concentrated energy distributions compacted in dark and light regions to reduce bit-rate requirements of the dark and light regions and to enhance contrast quality in the pictures in a mid-range region of the luma space of the new concentrated energy distribution;

computing a cost associated with selection of the picture from a plurality of pictures and computing the new energy distribution of the picture relative to new energy distributions for the plurality of pictures; and

decoding, by a decoder, the video signal using the new energy distribution of the picture.

15. The method of claim 14 , further comprising removing multimodal effects in the energy distributions when mapping to the new energy distributions.

16. The method of claim 15 , further comprising mapping the new energy distributions to a mid-range of the luma space.

17. The method of claim 14 , further comprising computing a baseline value for a darkest portion of a picture in the luma space and a baseline value for a brightest portion of the picture in luma space.

18. The method of claim 14 , further comprising computing a mapping function for mapping the energy distributions into the new energy distributions, the mapping function computed for an I-Frame and applying the mapping function for P-Frames and B-Frames in a group of the pictures.

19. The method of claim 14 , further comprising generating a look-up table via which the mapping of the energy distributions is performed.

Assignments (2)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Dec 9, 2014
From: MICROSOFT CORPORATION
To: MICROSOFT TECHNOLOGY LICENSING, LLC
Reel/Frame 034542/0001 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Feb 5, 2008
From: ALI, WALID; REGUNATHAN, SHANKAR; SHIEH, GUO-WEI; LIN, BRUCE; SIRAVARA, BHARATH; WANG, CE
To: MICROSOFT CORPORATION
Reel/Frame 020469/0236 →
Continuity (1)
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