Method and apparatus for blocking effect reduction
AssigneeSnell & Wilcox Limited
InventorsMichael James Knee, Jonathan Diggins
Life of this patent
Estimating the term…
Abstract
By utilizing parameters derivable from a compressed bit-stream, measures are obtained of the subjective quality of a decoded picture, without the necessity for reference to source material. A blockiness measure is derived both locally and globally and used to control a de-blocking filter. An estimate of signal-to-noise ratio is derived from quantization values.
Claims16
A method for estimating the signal to noise ratio of a picture signal decoded from a compressed bit-stream, comprising the steps of determining the quantization values employed in said compression, generating a measure of the bit rate of the compressed bit-stream and deriving said estimate by processing said quantization values and said measure of the bit rate.
A method for estimating the signal to noise ratio PSNRestimate of a picture signal decoded from a compressed bit-stream, comprising the steps of determining quantization values q employed in said compression;
- generating a measure c of the bit rate of the compressed bitstream and processing said values and said measure to derive:
- PSNR
- estimate
- =
- PSNR
- 0
- -
- ∑
-
- log
-
-
- q
- N
-
- (
- A
- +
- B
-
- ∑
-
- c
- ·
- f
-
- (
- Mq
- )
- )
- where A is a parameter that can be zero and B is a parameter that can be 1.
Dependencies are inferred from the claim text.