Block-edge detecting method and associated device

1. A block-edge detecting method, applied to an image comprising a plurality of pixels, the method comprising:

(a) performing a difference calculation on the plurality of pixels of the image to generate a difference calculation result, comprising:

obtaining a previous difference calculation result corresponding to at least one previous image of the image stream; and

adjusting the difference calculation result of the current image according to the previous difference calculation result;

wherein the image is a current image of an image stream;

(b) generating statistic data according to the difference calculation result with an accumulation approach;

(c) determining a block width according to the statistic data; and

(d) obtaining a plurality of block-edge positions of the image according to the block width.

2. The method as claimed in claim 1 , wherein performing a difference calculation on the plurality of pixels of the image is done by

performing difference calculations on the plurality of pixels of every two adjacent lines of said image; and

generating the statistic data according to the difference calculation result is generated from performing difference calculations on every two adjacent lines of the plurality of pixels of the image.

3. The method as claimed in claim 1 , wherein determining a block width comprises:

(c1) generating a plurality of candidate block-edge positions according to the statistic data; and

(c2) determining the block width according to an interval relationship among the plurality of candidate block-edge positions.

4. The method as claimed in claim 3 , wherein obtaining a plurality of block-edge positions of the image comprises:

selecting an initial block-edge position from the plurality of candidate block-edge positions according to the block width.

5. The method as claimed in claim 4 , wherein obtaining a plurality of block-edge positions of the image further comprises:

generating the plurality of block-edge positions of the image according to the initial block-edge position and the block width.

6. The method as claimed in claim 3 , wherein determining the block width comprises:

generating a candidate block width according to every two candidate block-edge positions of the plurality of candidate block-edge positions;

counting the number of accumulation times of each of the candidate block width according to the calculated plurality of candidate block widths; and

selecting one candidate block width as the block width from the plurality of candidate block widths according to the number of the accumulation times of each of the candidate block widths.

7. The method as claimed in claim 1 , wherein the image is a current image of an image stream, and determining a block width comprises:

obtaining a previous block width corresponding to at least one previous image of the image stream; and

adjusting the block width of the current image according to the previous block width.

8. A block-edge detecting device, applied to an image comprising a plurality of pixels, the device comprising:

a difference calculating unit, for performing a difference calculation on the plurality of pixels of the image to generate a difference calculation result;

an accumulating unit, for accumulating statistic data according to the difference calculation result; and

a determining module, for determining a block width of the image according to the statistic data, and obtaining a plurality of block-edge positions of the image according to the block width, wherein the determining module generates a plurality of candidate block-edge positions according to the statistic data, determines the block width according to an interval relationship among the plurality of candidate block-edge positions, respectively generates a candidate block width with respect to every two candidate block-edge positions of the plurality of the candidate block-edge positions, counting the number of accumulation times of each of the candidate block widths, and selects one candidate block width from the candidate block widths according to the number of accumulation times of each of the candidate block widths.

9. The block-edge detecting device as claimed in claim 8 , wherein the difference calculating unit performs the difference calculation on every two adjacent lines of the plurality of pixels, and the accumulating unit generates the statistic data according to the difference calculation result generated by performing the difference calculation on every two adjacent lines of the plurality of pixels.

10. The block-edge detecting device as claimed in claim 8 , wherein the determining module selects an initial block-edge position according to the block width.

11. The block-edge detecting device as claimed in claim 10 , wherein the determining module generates the plurality of block-edge positions according to the initial block-edge position and the block width.

12. The block-edge detecting device as claimed in claim 8 , further comprising an adjusting module, with the image processed by the block-edge detecting device being a current image of an image stream, the adjusting module being stored with a previous difference calculation result corresponding to at least one previous image of the image stream, for adjusting the difference calculation result of the current image according to the previous difference calculation result.

13. The block-edge detecting device as claimed in claim 8 , further comprising an adjusting module, with the image processed by the block-edge detecting device being a current image of an image stream, the adjusting module being stored with previous statistic data corresponding to at least one previous image of the image stream, for adjusting the statistic data of the current image according to the previous statistic data.

14. The block-edge detecting device as claimed in claim 8 , further comprising an adjusting module, with the image processed by the block-edge detecting device being a current image of an image stream, the adjusting module being stored with a previous block width corresponding to at least one previous image of the image stream, for adjusting the block width of the current image according to the previous block width.

15. A block-edge detecting method, applied to an image comprising a plurality of pixels, the method comprising:

(a) performing a difference calculation on the plurality of pixels of the image to generate a difference calculation result;

(b) generating statistic data according to the difference calculation result with an accumulation approach;

(c) determining a block width according to the statistic data, comprising:

(c1) generating a plurality of candidate block-edge positions according to the statistic data; and

(c2) determining the block width according to an interval relationship among the plurality of candidate block-edge positions;

(c3) generating a candidate block width according to every two candidate block-edge positions of the plurality of candidate block-edge positions;

(c4) counting the number of accumulation times of each of the candidate block widths according to the calculated plurality of candidate block widths;

(c5) selecting a first candidate block width and a second candidate block width from the plurality of candidate block widths according to the number of accumulation times of each of the candidate block widths; and

(c6) calculating a weighted block width as the block width according to sizes of the first candidate block width the second candidate block width and the corresponding accumulation times; and

(d) obtaining a plurality of block-edge positions of the image according to the block width.

16. A block-edge detecting method, applied to an image comprising a plurality of pixels, the method comprising:

(a) performing a difference calculation on the plurality of pixels of the image to generate a difference calculation result;

(b) generating statistic data according to the difference calculation result with an accumulation approach, comprising:

obtaining previous statistic data corresponding to at least one previous image of the image stream; and

adjusting the statistic data of the current image according to the previous statistic data;

wherein the image is a current image of an image stream;

(c) determining a block width according to the statistic data; and

(d) obtaining a plurality of block-edge positions of the image according to the block width.

17. A block-edge detecting device, applied to an image comprising a plurality of pixels, the device comprising:

a difference calculating unit, for performing a difference calculation on the plurality of pixels of the image to generate a difference calculation result;

an accumulating unit, for accumulating statistic data according to the difference calculation result; and

a determining module, for determining a block width of the image according to the statistic data, and obtaining a plurality of block-edge positions of the image according to the block width, wherein the determining module generates a plurality of candidate block-edge positions according to the statistic data, and determines the block width according to an interval relationship among the plurality of candidate block-edge positions, respectively generates a candidate block width with respect to every two candidate block-edge positions of the plurality of candidate block-edge positions, counts the number of accumulation times of each of the candidate block widths according to the calculated plurality of candidate block widths, selects a first candidate block width and a second candidate block width from the plurality of candidate block widths according to the number of accumulation times of each of the candidate block widths, and calculates a weighted block width as the block width according to sizes of the first candidate block width and the second candidate block width and corresponding accumulation times.