Method and system for optimizing image sharpness during coding and image enhancement
View Patent ↗The present invention relates to a method and system for controlling the quality of video data by selecting the optimal quantization parameter during encoding. The system is configured to perform quantization for one or more macroblocks using a different range of step sizes, then the kurtosis for the respective quantized data is performed to determine the macroblock and the corresponding quantization step size that yields the highest kurtosis value. The quantization step size that generates the highest kurtosis value is selected to the blocks of input-video data during encoding.
1. A method for controlling the sharpness quality of video data, the method comprising the steps of:
(a) converting input-video data into blocks;
(b) performing a discrete cosine transform (DCT) on the blocks of said input-video data to produce blocks of DCT coefficients; (c) selecting a quantization parameter providing a highest kurtosis output to one of the blocks of said DCT coefficients; and,
(d) quantizing the blocks of said DCT coefficients using said selected quantization parameter to produce quantized data.
2. The method of claim 1 , further comprising the steps of encoding said qunatized data into a predetermined, standard compliant packet, and transmitting said standard compliant packet.
3. The method of claim 2 , wherein the step of encoding is performed using a Huffman code.
4. The method of claim 1 , wherein the step of (c) selecting said quantization parameter comprises the steps of:
quantizing the blocks of said DCT coefficients using a predetermined range of step sizes and determining the kurtosis thereof; and,
determining one of the blocks of said DCT coefficients and the corresponding step size that yields the highest kurtosis output.
5. The method of claim 1 , wherein said input video data is one of JPEG and MPEG signals.
6. An apparatus for controlling the sharpness quality of input-video data, comprising:
means for converting said input-video data into blocks;
means for transforming the blocks of said input video into blocks of DCT coefficients,
a quantizer adaptively quantizing an output from said transforming means using a quantization parameter to produce quantized data; and,
a sharpness controller coupled to said quantizer for selecting said quantization parameter based on quantizing the blocks of said DCT coefficients using a predetermined range of step sizes and calculating kurtosis thereof, and selecting one of said step sizes that yields a highest kurtosis as said quantization parameter.
7. The apparatus of claim 6 , further comprising an encoder for encoding said qunatized data into a predetermined, standard compliant packet.
8. The apparatus of claim 6 , wherein said kurtosis indicates a sharpness quality of the blocks of said input-video data.
9. The apparatus of claim 6 , wherein said input-video data is one of JPEG and MPEG signals.
10. A method for controlling the sharpness quality of video data, the method comprising the steps of:
(a) converting input-video data into blocks;
(b) performing motion-estimation analysis on the blocks of said input-video data to generate a reference signal;
(c) performing a discrete cosine transform (DCT) on the blocks of said input-video data to produce blocks of DCT coefficients;
(d) selecting a quantization parameter providing a highest kurtosis output to one of the blocks of said DCT coefficients; and,
(e) quantizing the blocks of said DCT coefficients using said selected quantization parameter to produce quantized data.
(f) encoding said quantized data and said reference signal into a predetermined, standard compliant packet, and transmitting said standard compliant packet.
11. The method of claim 10 , further comprising the step of storing said standard compliant packet for subsequent transmission.
12. The method of claim 10 , further comprising the steps of inverse quantizing and transforming said quantized data into decompressed data, and storing said decompressed data for subsequent generation of said reference signal.
13. The method of claim 10 , wherein the step of (d) selecting said quantization parameter comprises the steps of:
quantizing the blocks of said DCT coefficients using a predetermined range of step sizes and determining the kurtosis thereof; and,
determining a block and the corresponding step size that yields the highest kurtosis output.
14. The method of claim 10 , wherein said input-video data is one of JPEG and MPEG signals.
15. An apparatus for controlling the sharpness quality of input-video data, comprising:
means for converting said input-video data into blocks;
means for performing motion-estimation analysis on the blocks of said input-video data to generate a reference signal;
means for transforming the blocks of said input video into blocks of DCT coefficients and quantizing the blocks of said DCT coefficients using a quantization parameter to produce quantized data;
a sharpness controller coupled to said transforming means for selecting said quantization parameter based on quantizing the blocks of said DCT coefficients using a predetermined range of step sizes and calculating kurtosis thereof, and selecting one of said step sizes that yields a highest kurtosis as said quantization parameter; and,
an encoder configured to receive and encode said quantized data and said reference signal into a predetermined, standard compliant packet.
16. The apparatus of claim 15 , wherein said kurtosis indicates a sharpness quality of the blocks of said input-video data.
17. The apparatus of claim 15 , wherein said input-video data is one of JPEG and MPEG signals.
18. The apparatus of claim 15 , further comprising a buffer configured to receive an output of said encoder for storing said standard compliant packet for subsequent transmission.
19. The apparatus of claim 15 , further comprising:
an inverse converter coupled to receive the output of said transforming means to operatively inverse-quantize and transform said quantized data into decompressed data; and,
a memory for storing said decompressed data for subsequent generation of said reference signal.