Circuit for scan conversion of picture signal using motion compensation

• US 6,509,930 B1
• Filed: 06/19/2000
• Issued: 01/21/2003
• Est. Priority Date: 08/06/1999
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Sugiyama, Masato, Hirano, Yasuhiro, Ishikura, Kazuo, Nakajima, Mitsuo, Matono, Takaaki, Takata, Haruki, Hasegawa, Takashi, Tsuru, Yasutaka
• Primary Examiner(s): HSIA, SHERRIE Y
• Application Number:
  US09/596,555
• Time in Patent Office: 946 Days
• Field of Search: H04/N.701, 348/448, 348/451, 348/450, 348/452, 348/700, 348/699
• US Class Current: 348/452
• CPC Class Codes: H04N 5/145 Movement estimation for video coding H04N19/51
• CPC Class Codes: H04N 5/147 Scene change detection
• CPC Class Codes: H04N 7/012 Conversion between an interlaced and a progressive signal for graphics images G09G2310/0229

Abstract

A low-cost motion-compensated picture signal scan conversion circuit ensuring high picture quality is to be provided. The circuit has a motion-adaptive first interpolation signal generator; a second motion-compensated interpolation signal generator; a motion vector detector; and a setting unit for checking the reliability of motion compensation by comparing signals from the second interpolation signal generator with signals on interlaced scanning lines, and setting the selection of signals from the first and second interpolation signal generators, wherein interlaced scanned signals are converted into progressive scanned signals by setting the threshold so that the threshold become smaller with an increase in the number of re-searched blocks in the detection of motion vectors.

Claims

1. A motion-compensated picture signal scan conversion circuit for converting interlaced scanned picture signals into progressive scanned picture signals provided with:

a first interpolation signal generator for generating signals of scanning lines skipped in interlaced scanning by motion-adaptive interpolation;

a second interpolation signal generator for generating signals of scanning lines skipped in interlaced scanning by motion-compensated interpolation;

a motion vector detector for detecting motions necessary for motion-compensated interpolation; and

a setting unit for checking the reliability of motion compensation by comparing signals from said second interpolation signal generator with signals on interlaced scanning lines, and setting the selection of signals from said first and second interpolation signal generators, wherein;

said setting unit adaptively varies the threshold of the comparison used for checking the reliability according to the number of re-searched blocks in motion vector detection by said motion vector detector, and sets the threshold so that the threshold become smaller with an increase in said number of blocks.

2. A motion-compensated picture signal scan conversion circuit, as claimed in claim 1, wherein:

the threshold of the comparison used for checking the reliability by said setting unit is set according to a linear relationship between the number of re-searched blocks and the threshold.

3. A motion-compensated picture signal scan conversion circuit, as claimed in claim 1, wherein:

the threshold of the comparison used for checking the reliability by said setting unit is set according to a non-linear relationship between the number of re-searched blocks and the threshold.

4. A motion-compensated picture signal scan conversion circuit, as claimed in claim 1, wherein:

the threshold of the comparison used for checking the reliability by said setting unit is set by selecting one of a plurality of alternatives with the motion vector speed detected by said motion vector detector as parameter.

5. A motion-compensated picture signal scan conversion circuit, as claimed in claim 1, wherein:

the threshold of the comparison used for checking the reliability by said setting unit is set, when the motion vectors detected by said motion vector detector indicate vertical panning or vertical rolling, to its upper limit.

6. A motion-compensated picture signal scan conversion circuit, as claimed in claim 1, wherein:

said setting unit selects, when the speed of the motion vectors is not less than the threshold, the signal from said first interpolation signal generator.

7. A motion-compensated picture signal scan conversion circuit, as claimed in claim 1, wherein:

said setting unit is provided with a V edge detector for detecting high frequency vertical components of picture signals and, when the speed of the motion vectors is not less than the threshold, uses the signal from said second interpolation signal generator only in a region around a detected edge region.

8. A motion-compensated picture signal scan conversion circuit, as claimed in claim 1, wherein:

the motion vector detector detects motion vectors from frame pictures of an output picture signal sequence converted into progressive scanned signals.

9. A motion-compensated picture signal scan conversion circuit, as claimed in claim 1, wherein:

the motion vector detector detects motion vectors from frame pictures generated by synthesis of signals in two consecutive fields or intra-field interpolation in an input picture signal sequence.

10. A motion-compensated picture signal scan conversion circuit, as claimed in claim 1, wherein:

signals on interpolation scanning lines in every two consecutive field periods are generated in motion-compensated interpolation from motion vectors detected by the motion vector detector.

11. A motion-compensated picture signal scan conversion circuit, as claimed in claim 1, wherein:

the motion vector detector detects the motion vector for each pixel by signal processing through setting a representative vector using already detector motion vectors around a current block as reference vectors, re-searching, searching of miniblocks resulting from the division of each block horizontally and vertically, and smoothing.

12. A motion-compensated picture signal scan conversion circuit, as claimed in claim 11, wherein:

motion vectors generated by subjecting motion vector information in the estimative encoding by motion compensation to prescribed motion vector conversion are used as reference vectors in setting the representative vector.

13. A motion-compensated picture signal scan conversion circuit, as claimed in claim 1, further provided with:

a unit for detecting scene changing in pictures, wherein;

said detection of motion vectors and generation of interpolation signals by motion compensation are stopped in a region where any scene change has taken place.

14. A television receiver having:

a picture display unit of a progressive scanning type, and

a motion-compensated picture signal scan conversion circuit for converting interlaced scanned picture signals into progressive scanned picture signals, wherein;

the motion-compensated picture signal scan conversion circuit for converting interlaced scanned picture signals into progressive scanned picture signals is provided with a first interpolation signal generator for generating signals of scanning lines skipped in interlaced scanning by motion-adaptive interpolation;

a second interpolation signal generator for generating signals of scanning lines skipped in interlaced scanning by motion-compensated interpolation;

a motion vector detector for detecting motions necessary for motion-compensated interpolation; and

a setting unit for checking the reliability of motion compensation by comparing signals from said second interpolation signal generator with signals on interlaced scanning lines, and setting the selection of signals from said first and second interpolation signal generators, wherein;

said setting unit adaptively varies the threshold of the comparison used for checking the reliability according to the number of researched blocks in motion vector detection by said motion vector detector, and sets the threshold so that the threshold become smaller with an increase in said number of blocks.

15. A data processing terminals for home use having:

a picture display unit of a progressive scanning type, and

a motion-compensated picture signal scan conversion circuit for converting interlaced scanned picture signals into progressive scanned picture signals, wherein;

the motion-compensated picture signal scan conversion circuit for converting interlaced scanned picture signals into progressive scanned picture signals is provided with a first interpolation signal generator for generating signals of scanning lines skipped in interlaced scanning by motion-adaptive interpolation;

a second interpolation signal generator for generating signals of scanning lines skipped in interlaced scanning by motion-compensated interpolation;

a motion vector detector for detecting motions necessary for motion-compensated interpolation; and

a setting unit for checking the reliability of motion compensation by comparing signals from said second interpolation signal generator with signals on interlaced scanning lines, and setting the selection of signals from said first and second interpolation signal generators, wherein;

said setting unit adaptively varies the threshold of the comparison used for checking the reliability according to the number of re-searched blocks in motion vector detection by said motion vector detector, and sets the threshold so that the threshold become smaller with an increase in said number of blocks.

16. A picture display unit having:

a picture display unit of a progressive scanning type, and

a motion-compensated picture signal scan conversion circuit for converting interlaced scanned picture signals into progressive scanned picture signals, wherein;

the motion-compensated picture signal scan conversion circuit for converting interlaced scanned picture signals into progressive scanned picture signals is provided with a first interpolation signal generator for generating signals of scanning lines skipped in interlaced scanning by motion-adaptive interpolation;

a second interpolation signal generator for generating signals of scanning lines skipped in interlaced scanning by motion-compensated interpolation;

a motion vector detector for detecting motions necessary for motion-compensated interpolation; and

a setting unit for checking the reliability of motion compensation by comparing signals from said second interpolation signal generator with signals on interlaced scanning lines, and setting the selection of signals from said first and second interpolation signal generators, wherein;

said setting unit adaptively varies the threshold of the comparison used for checking the reliability according to the number of re-searched blocks in motion vector detection by said motion vector detector, and sets the threshold so that the threshold become smaller with an increase in said number of blocks.