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Image signal processor for detecting duplicate fields

Imported: 23 Feb '17 | Published: 22 Oct '02

Yoshihisa Yamada, Yoshiaki Kato, Tokumichi Murakami

USPTO - Utility Patents

Abstract

An image signal processor is provided which accurately detects duplicate fields of a telecinema signal. The image signal processor includes a duplicate field detecting means for detecting duplicate fields of the telecinema signal and a duplicate field removing means for removing the duplicate fields. The duplicate field detecting means uses a threshold value for detecting a duplicate field and a threshold value for detecting a non-duplicate field to improve the accuracy of detection.

Description

BRIEF DESCRIPTION OF DRAWINGS

The above and other objects, features and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments of the invention in conjunction with the accompanying drawings, in which:

FIG. 1 is a diagram showing a structure of an image signal processor according to one embodiment of the present invention;

FIG. 2 is a diagram showing a structure of a duplicate field detecting means according to one embodiment of the invention;

FIG. 3 is a flow chart showing the operation of the duplicate field determining means;

FIG. 4 is an explanatory chart showing an exemplary process for calculating a threshold value for detecting a non-duplicate field;

FIG. 5 is a diagram showing a structure of duplicate field detecting means according to one embodiment of the invention;

FIG. 6 is a flow chart showing the operation of the duplicate field determining means;

FIG. 7 is a flow chart showing the operation of the duplicate field determining means;

FIG. 8 is an explanatory drawing showing an exemplary process implemented on a trimmed image;

FIG. 9 is an explanatory drawing showing an exemplary process on an image to which a picture-in-picture process has been implemented;

FIG. 10 is an explanatory diagram showing an example in which image disturbance caused by recognition error when an NTSC signal is erroneously recognized as a telecinema signal is reduced;

FIG. 11 is a diagram showing a structure of an image signal processor according to one embodiment of the present invention;

FIG. 12 is a flow chart showing the operation of the duplicate field removing means;

FIG. 13 is an explanatory diagram showing the principle of 3-2 pull-down;

FIG. 14 is a diagram showing a structure of a prior art image signal processor;

FIG. 15 is a diagram showing a structure of a prior art duplicate field detecting means; and

FIG. 16 is an explanatory diagram showing an example in which image disturbance caused by recognition error when an NTSC signal is erroneously recognized as a telecinema signal is reduced.

Claims

1. An image signal processor, comprising:

2. The image signal processor according to claim 1, wherein said duplicate field detecting means comprises:

3. The image signal processor according to claim 2, wherein said duplicate field detecting means adjusts said threshold value for detecting a duplicate field based on a periodicity of said duplicate fields detected by said duplicate field determining means.

4. The image signal processor according to claim 3, further comprising:

5. The image signal processor according to claim 4, wherein said duplicate field determining means increases said threshold value for detecting a duplicate field when a pattern of appearance of duplicate and non-duplicate fields corresponds with said predetermined pattern.

6. The image signal processor according to claim 2, wherein said duplicate field detecting means further comprises:

said duplicate field determining means determines said duplicate field by comparing one of said cumulative values, which is said cumulative value of the current field, with said first threshold value for detecting a duplicate field and comparing the other cumulative values, which are cumulative values for said plurality of fields preceding said current field, with said second threshold value for detecting a non-duplicate field respectively.

7. The image signal processor according to claim 6, wherein said duplicate field detecting means further comprises:

8. The image signal processor according to claim 7, wherein said threshold value determining means determines said second threshold value for detecting a duplicate field such that said second threshold value is in direct said second fields.

9. The image signal processor according to claim 6, wherein

10. The image signal processor according to claim 9, wherein said image signal is telecinema signal of 30 Hz produced from a movie film of 24 Hz, and said duplicate field determining means further comprises:

11. The image signal processor according to claim 2, wherein said duplicate field detecting means detects duplicate fields based on said image signal relating to partial data of a first field.

12. The image signal processor according to claim 2, said duplicate field detecting means further comprising:

said duplicate field determining means is operatively connected to said one-field cumulative adder means, said cumulative value memory, said threshold value memory, and said threshold value determining means, and determines said duplicate field by checking said pattern of appearance of duplicate and non-duplicate fields based on said first threshold value for detecting a duplicate field, said second threshold value for detecting a non-duplicate field, and said plurality of field differential values.

13. The image signal processor according to claim 2, wherein said duplicate field removing means removes one of said plurality of first fields which temporally antecedes and corresponds to a duplicate field detected by said duplicate field detecting means when said detected duplicate field corresponds to said plurality of first fields, and removes said detected duplicate field when said detected duplicate field corresponds to said plurality of second fields.

14. An image signal processor, comprising:

15. The image signal processor according to claim 14, wherein each cumulative value represents a cumulative added absolute value of the difference between temporally offset fields.

16. The image signal processor according to claim 14, wherein said microprocessor determines duplicate fields based on periodic appearance of duplicate fields.

17. The image signal processor according to claim 14, wherein said threshold value for detecting a non-duplicate field is based on the cumulative value for said current field when the cumulative value for said current field is lower than said threshold value for detecting a duplicate field.

18. An image signal processing method, comprising:

19. The image signal processing method according to claim 18, wherein said outputting step includes calculating each cumulative value by cumulatively adding absolute values of the difference between temporally offset fields.

20. The image signal processing method according to claim 18, further comprising:

21. The image signal processor comprising:

22. The image signal processor according to claim 21, wherein said duplicate field detecting means detects said current field as a non-duplicate field when the cumulative value for a previous field of said plurality of fields preceding said current field is less than said second threshold value.

23. The image signal processor according to claim 21, wherein said duplicate field detecting means detects said current field as a duplicate field when the cumulative value for each of said plurality of fields preceding said current field is greater than said second threshold value.

24. The image signal processor according to claim 23, wherein said duplicate field detecting means detects said current field as a duplicate field when the cumulative value for four consecutive previous fields is greater than said second threshold value.

25. The image signal processing method according to claim 18, wherein said step of detecting whether a current field is a duplicate field determines that said current field is a non-duplicate field when the cumulative value for said current field is greater than said threshold for detecting a duplicate field and determines that said current field is a duplicate field when the cumulative value for said current field is less than said threshold for detecting a duplicate field and the cumulative values for said plurality of fields that immediately precede said current field are each greater than said threshold for detecting a non-duplicate field.

26. The image signal processing method according to claim 18, wherein the number of fields immediately preceding said current field is four.

27. The image signal processing method according to claim 18, wherein said step of detecting whether a field is a duplicate field determines that said current field is a non-duplicate field when the cumulative value of one of said plurality of fields that immediately precede said current field is less than said threshold for detecting a non-duplicate field.

28. An image signal processor, comprising:

29. The image signal processor according to claim 21, wherein said duplicate field detecting means comprises:

30. The image signal processor according to claim 29, wherein said duplicate field detecting means adjusts said threshold value for detecting a duplicate field based on a periodicity of said duplicate fields detected by said duplicate field determining means.

31. The image signal processor according to claim 30, further comprising:

32. The image signal processor according to claim 31, wherein said duplicate field determining means increases said threshold value for detecting a duplicate field when a pattern of appearance of duplicate and non-duplicate fields corresponds with said predetermined pattern.

33. The image signal processor according to claim 29, wherein said duplicate field detecting means further comprises:

34. The image signal processor according to claim 33, wherein said duplicate field detecting means further comprises:

35. The image signal processor according to claim 34, wherein said threshold level determining means determines said second threshold value for detecting a duplicate field such that said second threshold value is in direct proportion to said one of said cumulative values.

36. The image signal processor according to claim 33, wherein

37. The image signal processor according to claim 36, wherein said image signal is telecinema signal of 30 Hz produced from a movie film of 24 Hz, and said duplicate field determining means further comprises:

38. The image signal processor according to claim 29, wherein said duplicate field detecting means detects duplicate fields based on said image signal relating to partial data of a first field.

39. The image signal processor according to claim 29, said duplicate field detecting means further comprising:

40. The image signal processor according to claim 29, wherein said duplicate field removing means removes one of said plurality of first fields which temporally antecedes and corresponds to a duplicate field detected by said duplicate field detecting means when said detected duplicate field corresponds to said plurality of first fields, and removes said detected duplicate field when said detected duplicate field corresponds to said plurality of second fields.