Method and apparatus for motion adaptive deinterlacing

• US 7,098,958 B2
• Filed: 04/28/2004
• Issued: 08/29/2006
• Est. Priority Date: 09/08/2000
• Status: Expired due to Term

• Current Assignee: Jaldi Semiconductor Corporation (Pixelworks Incorporated)
• Original Assignee: Jaldi Semiconductor Corporation (Pixelworks Incorporated)
• Inventors: Cheng, Gary, Jang, Soo Chang, Wredenhagen, G. Finn, Greggain, Lance
• Primary Examiner(s): Hsia, Sherrie
• Application Number:
  US10/834,760
• Publication Number:
  US 20050099538A1
• Time in Patent Office: 853 Days
• Field of Search: 348/448, 348/441, 348/446, 348/451, 348/452, 348/620, 348/607, 348/624, 382/260, 382/261, 382/266, 382/298, 382/299, 382/300
• US Class Current: 348/452
• CPC Class Codes: H04N 19/117 Filters, e.g. for pre-processing or post-processing sub-band filter banks H04N19/635
• CPC Class Codes: H04N 19/139 Analysis of motion vectors, e.g. their magnitude, direction, variance or reliability
• CPC Class Codes: H04N 19/51 Motion estimation or motion compensation
• CPC Class Codes: H04N 5/142 Edging; Contouring
• CPC Class Codes: H04N 5/144 Movement detection for video coding H04N19/503; analysis of motion in general G06T7/20
• CPC Class Codes: H04N 7/0115 with details on the detection of a particular field or frame pattern in the incoming video signal, e.g. 3:2 pull-down pattern
• CPC Class Codes: H04N 7/012 Conversion between an interlaced and a progressive signal for graphics images G09G2310/0229
• CPC Class Codes: H04N 7/0137 dependent on presence/absence of motion, e.g. of motion zones H04N7/014 takes precedence; movement detection in television signals H04N5/144
• CPC Class Codes: H04N 7/0142 the interpolation being edge adaptive edge detection in television signals H04N5/142; edge-driven scaling G06T3/403

Abstract

An adaptive filter calculates a target pixel from an interlaced video signal. The video signal comprises a plurality of frames, each of which comprises an even and an odd field. The filter comprises a quantized motion calculator and a filter selector. The quantized motion calculator estimates an amount of motion about the target pixel. The filter selector selects a filter in accordance with the estimated amount of motion. The filter applies a first weighting factor to a plurality of current field pixels and a second weighting factor to a plurality of previous field pixels for creating the target pixel.

Claims

1. An adaptive filter comprising:

a motion calculator to calculate motion about a target pixel from an interlaced video signal; and

a filter selector to select a filter responsive to the motion, the filter being adapted to apply a weight factor to pixels in current and previous fields;

where the filter is adapted to apply a first weight factor to pixels in the current field; and

where the filter is adapted to apply a second weight factor to pixels in the previous field.

2. The adaptive filter of claim 1 where the filter includes:

an edge detector to detect an edge about the target pixel.

3. The adaptive filter of claim 2

where information related to the edge is appended to information related to the target pixel.

4. An adaptive filter comprising:

a motion calculator to calculate motion about a target pixel from an interlaced video signal; and

a filter selector to select a filter responsive to the motion, the filter being adapted to apply a weight factor to pixels in current and previous fields;

where the motion calculator is adapted to calculate the motion by calculating a difference between a first and second pixels, the first and second pixels being at same locations in different frames.

5. The adaptive filter of claim 4

where the motion calculator is adapted to calculate the motion according to a plurality of predefined thresholds.

6. The adaptive filter of claim 4

where the motion calculator is adapted to indicate a number of consecutive frames the first pixel is static.

7. The adaptive filter of claim 6

where the number of consecutive frames is appended to information related to the target pixel.

8. An adaptive filter comprising:

a motion calculator to calculate motion about a target pixel from an interlaced video signal; and

a filter selector to select a filter responsive to the motion, the filter being adapted to apply a weight factor to pixels in current and previous fields;

where the filter includes;

a feathering detector to detect a feathering artifact about the target pixel by calculating differences between pixels along a contour.

9. The adaptive filter of claim 8

where the contour is non-linear.

10. The adaptive filter of claim 8

where the feathering detector is adapted to detect the feathering artifact if any number of the differences exceeds a threshold.

11. The adaptive filter of claim 10

where the feathering detector is adapted to detect the feathering artifact if any number of the differences exceeds a threshold for any number of consecutive fields.

12. The adaptive filter of claim 8

where information relating to the feathering artifact is appended to information related to the target pixel.

13. An adaptive filter comprising:

a motion calculator to calculate motion about a target pixel from an interlaced video signal;

a filter selector to select a filter responsive to the motion, the filter being adapted to apply a weight factor to pixels in current and previous fields; and

an edge detector to detect an edge about the target pixel by calculating differences between pixels in even and odd fields.

14. An adaptive filter comprising:

a motion calculator to calculate motion about a target pixel from an interlaced video signal;

a filter selector to select a filter responsive to the motion, the filter being adapted to apply a weight factor to pixels in current and previous fields; and

an edge detector to detect an edge about the target pixel by detecting an edge portion followed by a flat portion followed by another edge portion.

15. A method of adaptively filtering an interlaced video signal, comprising:

calculating motion about a target pixel from the interlaced video signal;

selecting a filter responsive to the calculating;

applying a first weight factor to pixels in a current field; and

applying a second weight factor to pixels in a previous field.

16. The method of claim 15 comprising:

detecting an edge about the target pixel.

17. The method of claim 16 comprising:

appending information relating to the edge to information related to the target pixel.

18. A method of adaptively filtering an interlaced video signal, comprising:

calculating motion about a target pixel from the interlaced video signal;

selecting a filter responsive to the calculating; and

applying a weight factor to pixels in current and previous fields;

where calculating includes calculating a difference between a first and second pixels, the first and second pixels being at same locations in different frames.

19. A method of adaptively filtering an interlaced video signal, comprising:

calculating motion about a target pixel from the interlaced video signal;

selecting a filter responsive to the calculating; and

applying a weight factor to pixels in current and previous fields;

where the calculating includes calculating the motion according to a plurality of predefined thresholds.

20. A method of adaptively filtering an interlaced video signal, comprising:

calculating motion about a target pixel from the interlaced video signal;

selecting a filter responsive to the calculating; and

applying a weight factor to pixels in current and previous fields;

where the calculating includes calculating a number of consecutive frames the first pixel is static.

21. The method of claim 20

where calculating the number of consecutive frames includes appending the number to information related to the target pixel.

22. A method of adaptively filtering an interlaced video signal, comprising:

calculating motion about a target pixel from the interlaced video signal;

selecting a filter responsive to the calculating; and

applying a weight factor to pixels in current and previous fields;

detecting a feathering artifact about the target pixel by calculating differences between pixels along a contour.

23. The method of claim 22

where the detecting includes calculating the differences between pixels along a non-linear contour.

24. The method of claim 22

where the detecting includes detecting the feathering artifact if any number of the differences exceeds a threshold.

25. The method of claim 24

where the detecting includes detecting the feathering artifact if any number of the differences exceeds a threshold for any number of consecutive fields.

26. The method of claim 22 comprising:

appending information relating to the feathering artifact to information related to the target pixel.

27. A method of adaptively filtering an interlaced video signal, comprising:

calculating motion about a target pixel from the interlaced video signal;

selecting a filter responsive to the calculating;

applying a weight factor to pixels in current and previous fields;

detecting an edge about the target pixel; and

calculating differences between pixels in even and odd fields.

28. A method of adaptively filtering an interlaced video signal, comprising:

calculating motion about a target pixel from the interlaced video signal;

selecting a filter responsive to the calculating;

applying a weight factor to pixels in current and previous fields;

detecting an edge about the target pixel; and

detecting an edge portion followed by a flat portion followed by another edge portion.

29. A feathering detecting detector to detect a feathering artifact in adjacent odd and even fields about a target pixel, comprising:

contour selecting means for selecting a contours;

a difference calculator means for calculating a plurality of differences between pixels along the selected contour; and

a threshold means for defining a plurality of predefined thresholds to compare with the calculated differences and for determining if feathering exists about the target pixel responsive to the comparison.

30. The feathering detector of claim 29

where the threshold means are programmable.

31. The feathering detector of claim 29

where the threshold means is adapted to define a plurality of thresholds different from each other to enhance detecting contours having arbitrary shapes.

32. The feathering detector of claim 29

where the threshold means is adapted to determine the feathering if it detects the feathering for a predefined number of consecutive pixels.

33. The feathering detector of claim 32

where the threshold means is adapted to determined the feathering if it detects the feathering concurrently over a plurality of different values for the predefined number of consecutive pixels.