Method for flicker detection in image signal

1. A flicker detection method for detecting flicker in an image signal, the method comprising:

using a computing device to perform the following:

(a) determining luminance differences between neighboring pixels in a line of pixels;

(b) comparing each luminance difference to a non-zero luminance threshold to determine whether each luminance difference is greater than the luminance threshold;

(c) in response to determining that a luminance difference is greater than the luminance threshold, increasing a sum of luminance differences that are greater than the luminance threshold by the respective luminance difference;

(d) performing a motion estimation using the sum to determine a motion displacement;

(e) performing a motion compensation on a current frame data using the motion displacement to yield a compensated frame data;

(f) determining a difference between a previous frame data and the compensated current frame data; and

(g) detecting the flicker using the difference determined in step (f).

2. The method of claim 1 , wherein the flicker is partially removed by steps (a)-(c).

3. The method of claim 1 , wherein steps (a)-(c) use a line memory.

4. The method of claim 3 , wherein step (a) determines the luminance difference between the neighboring pixels, and wherein each of the neighboring pixels are placed in neighboring two lines, respectively.

5. The method of claim 1 , wherein the line of pixels is one of a row of pixels and a column of pixels.

6. The method of claim 1 , wherein in step (d), an initial position of the motion estimation is decided depending on a search range.

7. The method of claim 6 , wherein step (d) comprises:

calculating a sum of absolute difference (SAD) from the initial position to a block size of a search window; and

selecting the least SAD as the motion displacement.

8. The method of claim 1 , wherein step (f) comprises determining a difference between the previous frame data and the compensated current frame data in a direction of the line of pixels of step (a).

9. The method of claim 8 , wherein the direction is one of a row direction and a column direction.

10. The method of claim 1 , wherein step (g) comprises:

filtering the difference between the previous frame data and the compensated current frame data to thereby detect a plurality of local minima; and

detecting a flicker period by using the local minima.

11. The method of claim 10 , wherein the flicker period is used for determining whether flicker has occurred.

12. The method of claim 1 , wherein step (f) comprises:

filtering the difference between the previous frame data and the compensated current frame data to thereby detect a plurality of local maxima; and

detecting a flicker period by using the local maxima.

13. The method of claim 12 , wherein the flicker period is used for determining whether flicker has occurred.

14. A method comprising:

using a computing device to perform at least the following:

determining luminance differences between neighboring pixels in a line of pixels;

comparing each luminance difference to a luminance threshold to retain luminance differences greater than the luminance threshold and remove luminance differences less than the luminance threshold for a sum of luminance differences greater than the luminance threshold;

summing up the retained luminance differences that are greater than the luminance threshold to yield the sum of luminance differences greater than the luminance threshold; and

detecting flicker by using a difference between a previous frame data and a compensated current frame data.

15. The method of claim 14 , further comprising performing a motion estimation using the sum to determine a motion displacement.

16. The method of claim 15 , further comprising performing a motion compensation on a current frame data using the motion displacement to yield the compensated frame data.

17. The method of claim 16 , further comprising determining a difference between a previous frame data and the compensated current frame data.

18. A method of detecting a period of a flicker in image data, the method comprising:

performing motion compensation on image data to produce motion-compensated image data; and

detecting the period of the flicker using the motion-compensated image data;

wherein performing motion compensation on image data includes:

performing motion estimation to determine a motion displacement; and

performing motion compensation on a current frame data using the motion displacement to yield a compensated current frame data.

19. The method of claim 18 , wherein said performing motion compensation on a current frame data comprises moving a previous frame data a direction and amount indicated by the determined motion displacement to yield the compensated current frame data.

20. The method of claim 18 further comprising determining a difference between a previous frame data and the compensated current frame data, wherein the period of the flicker is detected using the determined difference.