Conversion of interlaced video streams into progressive video streams

• US 20050243204A1
• Filed: 02/24/2005
• Published: 11/03/2005
• Est. Priority Date: 04/29/2004
• Status: Active Grant

• Current Assignee: Zhangjiagang Kangde Xin Optronics Material Co., Ltd. (Kangde Xin Composite Material Group Co., Ltd.)
• Original Assignee: Huaya Microelectronics, Inc.
• Inventors: Zhu, Ge
• Granted Patent: US 7,417,686 B2
• Time in Patent Office: Days
• US Class Current: 348/448
• CPC Class Codes: H04N 7/012 Conversion between an interlaced and a progressive signal for graphics images G09G2310/0229

Abstract

A method and system for deinterlacing an interlaced video stream is presented. The method and system determines whether an interlaced video stream is a normal mode video stream or a converted mode video stream. Converted mode video streams, which are interlaced video streams created from an original progressive video stream, are deinterlaced using converted mode deinterlacing, which involves merging two fields to form a frame. Normal mode interlaced video streams are deinterlaced using normal mode deinterlacing, which involves converting a field into a frame using line repeating or some form of interpolation to generate the missing scan lines.

Claims

1. A method of deinterlacing an input interlaced video stream having a plurality of fields to form an output progressive video stream having a plurality of frames, the method comprising:

calculating a plurality of mode detection parameters;

detecting whether a subset of the mode detection parameters exhibits an alternating peak-valley pattern;

classifying the input interlaced video stream based on whether the alternating peak-valley pattern is detected;

performing converted mode deinterlacing when the input interlaced video stream is classified as a converted mode video stream; and

performing normal mode deinterlacing when the input interlaced video stream is classified as normal mode video stream.

2. The method of claim 1, wherein the performing converted mode deinterlacing when the input interlaced video stream is classified as converted mode, comprises merging a processing field with a second field from the input interlaced video stream to form a frame of the output progressive video stream.

3. The method of claim 2, wherein the processing field precedes the second field in the input interlaced video stream.

4. The method of claim 2, wherein the processing field follows the second field in the input interlaced video stream.

5. The method of claim 1, wherein the performing normal mode deinterlacing when the input interlaced video stream is classified as normal mode comprises repeating each scan lines in a current field to form a frame.

6. The method of claim 1, wherein the performing normal mode deinterlacing when the input interlaced video stream is classified as normal mode comprises interpolating two scan lines of a field to form a missing scan line.

7. The method of claim 1, wherein the classifying the input interlaced video stream based on whether the alternating peak-valley pattern is detected, further comprises:

incrementing a mode switch counter when the alternating peak-valley pattern is detected; and

classifying the input interlaced video stream as converted mode when the mode switch counter equals a converted operating mode transition threshold.

8. The method of claim 1, wherein the classifying the input interlaced video stream based on whether the alternating peak-valley pattern is detected, further comprises:

incrementing a mode switch counter when the alternating peak-valley pattern is not detected; and

classifying the input interlaced video stream as normal mode when the mode switch counter equals a normal operating mode transition threshold.

9. The method of claim 1, wherein the detecting whether a subset of the mode detection parameters exhibits an alternating peak-valley pattern, further comprises:

calculating a maximum valley value;

calculating a minimum peak value;

determining whether the minimum peak value multiplied by a valley to peak threshold is greater than the maximum valley value.

10. The method of claim 9, wherein the maximum valley value is the maximum mode detection parameter of a plurality of expected valleys in the subset of mode detection parameter.

11. The method of claim 10, wherein the minimum peak value is the minimum mode detection parameter of a plurality of expected peaks in the subset of mode detection parameters.

12. The method of claim 11, wherein the expected peaks and expected valleys alternate in the subset of mode detection parameters.

13. The method of claim 1, wherein a mode detection parameter of a current field is equal to a number of non-still pixels in the current field that is significantly larger than both a corresponding pixel on a previous line in a previous field and a corresponding pixel on a next line in the previous field or significantly smaller than both corresponding pixels on the next and the previous lines in the previous field.

14. A system for deinterlacing an input interlaced video stream having a plurality of fields to form an output progressive video stream having a plurality of frames, the system comprising:

means for calculating a plurality of mode detection parameters;

means for detecting whether a subset of the mode detection parameters exhibits an alternating peak-valley pattern;

means for classifying the input interlaced video stream based on whether the alternating peak-valley pattern is detected;

means for performing converted mode deinterlacing when the input interlaced video stream is classified as a converted mode video stream; and

means for performing normal mode deinterlacing when the input interlaced video stream is classified as normal mode video stream.

15. The system of claim 14, wherein the means for performing converted mode deinterlacing when the input interlaced video stream is classified as converted mode, comprises means for merging a processing field with a second field from the input interlaced video stream to form a frame of the output progressive video stream.

16. The system of claim 15, wherein the processing field precedes the second field in the input interlaced video stream.

17. The system of claim 15, wherein the processing field follows the second field in the input interlaced video stream.

18. The system of claim 14, wherein the means for performing normal mode deinterlacing when the input interlaced video stream is classified as normal mode comprises means for repeating each scan lines in a current field to form a frame.

19. The system of claim 14, wherein the means for performing normal mode deinterlacing when the input interlaced video stream is classified as normal mode comprises means for interpolating two scan lines of a field to form a missing scan line.

20. The system of claim 14, wherein the means for classifying the input interlaced video stream based on whether the alternating peak-valley pattern is detected, further comprises:

means for incrementing a mode switch counter when the alternating peak-valley pattern is detected; and

means for classifying the input interlaced video stream as converted mode when the mode switch counter equals a converted mode transition threshold.

21. The system of claim 14, wherein the means for classifying the input interlaced video stream based on whether the alternating peak-valley pattern is detected, further comprises:

means for incrementing a mode switch counter when the alternating peak-valley pattern is not detected; and

means for classifying the input interlaced video stream as normal mode when the mode switch counter equals a normal mode transition threshold.

22. The system of claim 14, wherein the means for detecting whether a subset of the mode detection parameters exhibits an alternating peak-valley pattern, further comprises:

means for calculating a maximum valley value;

means for calculating a minimum peak value;

means for determining whether the minimum peak value MPV multiplied by a valley to peak threshold is greater than the maximum valley value.

23. The system of claim 22, wherein the maximum valley value is the maximum mode detection parameter of a plurality of expected valleys in the subset of mode detection parameter.

24. The system of claim 23, wherein the minimum peak value is the minimum mode detection parameter of a plurality of expected peaks in the subset of mode detection parameters.

25. The system of claim 24, wherein the expected peaks and expected valleys alternate in the subset of mode detection parameters.

26. The system of claim 14, wherein a mode detection parameter of a current field is equal to a number of non-still pixels in the current field that is significantly larger than both a corresponding pixel on a previous line in a previous field and a corresponding pixel on a next line in the previous field or significantly smaller than both corresponding pixels on the next and the previous lines in the previous field.

27. A deinterlacing system for deinterlacing an input interlaced video stream having a plurality of fields to form an output progressive video stream having a plurality of frames, the deinterlacing system comprising:

a buffer coupled to receive the input interlaced video stream;

a mode detector coupled to the buffer and configured to detect whether the input interlaced video stream is in a converted mode; and

a field merging and conversion unit coupled to the buffer and the mode detector and configured by the mode detector to perform converted mode deinterlacing when the input interlaced video stream is in the converted mode and to perform normal mode deinterlacing when the input interlaced video stream is in a normal mode.

28. The deinterlacing system of claim 27, wherein the buffer comprises:

a first field buffer;

a second field buffer;

a third field buffer; and

a fourth field buffer.

29. The deinterlacing system of claim 28, wherein the buffer is configured to operate as a circular buffer.

30. The deinterlacing system of claim 27, wherein the mode detector comprises:

a mode detection parameter calculation unit coupled to the buffer; and

a mode detection parameter FIFO coupled to the mode detection parameter calculation unit.

31. The deinterlacing system of claim 30, wherein the mode detection parameter calculation unit is configured to calculate a mode detection parameter of a current field in the buffer.

32. The deinterlacing system of claim 31, wherein the mode detection parameter calculation unit is configured to store the mode detection parameter in the mode detection parameter FIFO.

33. The deinterlacing system of claim 30, wherein the mode detector further comprises a mode analysis unit coupled to the mode detection parameter FIFO and the field merging and conversion unit.

34. The deinterlacing system of claim 33, wherein the mode analysis unit is configured to determine whether the input interlaced video stream is a converted mode video stream.

35. The deinterlacing system of claim 34, wherein the mode analysis unit configures the field merging and conversion unit to perform converted mode deinterlacing when the input interlaced video stream is a converted mode video stream.

36. The deinterlacing system of claim 34, wherein the mode analysis unit configures the field merging and conversion unit to perform normal mode deinterlacing when the input interlaced video stream is not a converted mode video stream.

37. The deinterlacing system of claim 34, wherein the mode analysis unit further comprises a peak valley pattern checker configured to detect alternating peak valley patterns using data from the mode detection parameter FIFO.

38. The deinterlacing system of claim 37, wherein the peak valley pattern checker further comprises:

a peak detector configured to detect an alternating peak valley pattern having a peak at a mode detection parameter corresponding to a specific field; and

a valley detector configured to detect an alternating peak valley pattern having a valley at the mode detection parameter corresponding to the specific field.

39. The deinterlacing system of claim 38, wherein the peak valley pattern checker further comprises a still image detector.

40. The deinterlacing system of claim 37, wherein mode analysis unit further comprises:

a mode switch;

a expected peak/valley register; and

mode analysis controller.