Method and system for noise reduction with a motion compensated temporal filter

1. A method for the reduction of noise in a current video block, said method comprising:

in a motion compensated temporal filter (MCTF),

generating for the current video block a plurality of candidate motion vectors and a plurality of respective confidence values,

wherein the confidence values provide an indication of accuracy of each of the candidate motion vectors in a prediction process involving a reference block;

selecting one of the candidate motion vectors based on an evaluation of the confidence values, the one of the candidate motion vectors associated with a first confidence value;

generating a first motion compensated block though application of the selected motion vector to a first reference block; and

filtering the current video block and the first motion compensated block according to the first confidence value to generate a current filtered block, the filtering comprising:

scaling the current video block according to a first scaling value;

scaling the first motion compensated block according to a second scaling value; and

combining the current video block with the first motion compensated block, wherein the first and second scaling values are based on the first confidence value.

2. The method of claim 1 , wherein:

scaling the current video block comprises scaling by a first weight to generate a weighted current video block;

scaling the first motion compensated block comprises scaling by a second weight to generate a weighted motion compensated block; and

combining comprises combining the weighted current video block with the weighted motion compensated block to generate the current filtered block.

3. The method of claim 2 , wherein the method further comprises:

adapting the first weight and the second weight according to first confidence value, wherein the first confidence value is measured over a window of pixels associated with the current video block that includes neighboring pixels extending from the current video block in addition to the pixels of the current video block.

4. The method of claim 1 , wherein a height of the current video block and the height of the first motion compensated block are four pixels or less.

5. The method of claim 1 , wherein the method further comprises:

selecting a second motion vector from the plurality of candidate motion vectors based on the evaluation of the confidence values, the second motion vector associated with a second confidence value;

applying the second motion vector to a second reference block to provide a second motion compensated block; and

combining the first and second motion compensated blocks, wherein the filtering comprises filtering the current video block and the combination of the first and second motion compensated blocks to provide the current filtered block.

6. The method of claim 1 , wherein the first reference block is a past video block that is located in a video sequence prior to the current video block.

7. The method of claim 1 , wherein the first reference block is a future video block that is located in a video sequence after the current video block.

8. The method of claim 1 , wherein the first reference block is a past filtered block generated prior to the current filtered block.

9. The method of claim 1 , wherein the filtering is averaging-based.

10. The method of claim 1 , wherein the filtering is based on a quantity of taps that is either fixed or adaptive.

11. The method of claim 1 , wherein the filtering is based on tap weights of equal or non-equal values.

12. A system for the reduction of noise in a current video block, said system comprising:

a motion compensated temporal filter, comprising:

a motion estimator configured to:

receive a reference picture and a current input window, the current input window comprising the current video block and a plurality of neighboring pixels;

generate a plurality of candidate motion vectors and a plurality of confidence values that include a first confidence value, the plurality of confidence values each providing an indication of accuracy of a respective candidate motion vector in a prediction process involving a reference block, the plurality of confidence values corresponding to the plurality of candidate motion vectors associated with the current input window; and

select a first motion vector from the plurality of candidate motion vectors based on the plurality of confidence values, the first motion vector associated with the first confidence value;

a motion compensator configured to generate a motion compensated block based on application of the first motion vector to a first reference block; and

a filter configured to:

apply a first scaling factor to the current video block and a second scaling factor to the motion compensated block, the first and second scaling factors based on the first confidence value; and

combine the current video block and the motion compensated block to generate a current filtered block.

13. The system of claim 12 , wherein the filter is configured to:

scale the current video block by a first weight to generate a weighted current input block;

scale the motion compensated block by a second weight to generate a weighted motion compensated block; and

combine the weighted current input block with the weighted motion compensated block to generate the current filtered block.

14. The system of claim 12 , wherein a height of the current video block and the height of the motion compensated block are four pixels or less.

15. The system of claim 12 , wherein the first reference block is a past video block that is located in a video sequence prior to the current video block.

16. The system of claim 12 , wherein the first reference block is a future video block that is located in a video sequence after the current video block.

17. The system of claim 12 , wherein the first reference block is a past filtered block that was generated by the filter prior to the current filtered block.

18. The system of claim 12 , wherein:

the motion estimator is further configured to select a second motion vector from the plurality of candidate motion vectors based on the plurality of confidence values, the second motion vector associated with a second confidence value;

the motion compensator is further configured to apply the second motion vector to a second reference block to provide a second motion compensated block and combine the motion compensated block and the second motion compensated block; and

the filter is further configured to filter the current video block and the combination of the motion compensated block and the second motion compensated block to provide the current filtered block.

19. The system of claim 12 , wherein the filter is configured as an IIR filter, an FIR filter, or a combination of IIR and FIR filters.

20. A communication device comprising:

an integrated circuit comprising:

a memory configured to store a video sequence;

a motion compensated temporal filter comprising plural circuits, the plural circuits comprising:

a motion estimator configured to select a first motion vector from a plurality of candidate motion vectors that are associated with a current video block, the first motion vector associated with a confidence value that provides an indication of accuracy in a prediction process involving a reference block;

a motion compensator configured to generate a motion compensated block based on application of the first motion vector to a first reference block; and

a filter configured to scale the current video block according to a first scaling factor and the motion compensated block according to a second scaling factor, the first and second scaling factors based on the confidence value, the filter further configured to combine the scaled blocks to generate a current filtered block.

21. The communication device of claim 20 , wherein:

the motion estimator is further configured to select a second motion vector from the plurality of candidate motion vectors based on a second confidence value, the second motion vector associated with the second confidence value;

the motion compensator is further configured to apply the second motion vector to a second reference block to provide a second motion compensated block and combine the motion compensated block and the second motion compensated block; and

the filter is further configured to filter the current video block and the combination of the motion compensated block and the second motion compensated block to provide the current filtered block.

22. The communication device of claim 20 , wherein the filter is configured as an IIR filter, an FIR filter, or a combination of IIR and FIR filters.