FRAME RATE CONVERSION APPARATUS FOR VIDEO SIGNAL AND DISPLAY APPARATUS

• US 20080129862A1
• Filed: 12/04/2007
• Published: 06/05/2008
• Est. Priority Date: 12/04/2006
• Status: Active Grant

• Current Assignee: Maxell, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Nakajima, Mitsuo, Mizuhashi, Yoshiaki, Ogino, Masahiro, HAMADA, Koichi
• Granted Patent: US 8,319,887 B2
• Time in Patent Office: Days
• US Class Current: 348/441
• CPC Class Codes: H04N 19/521 for estimating the reliability of the determined motion vectors or motion vector field, e.g. for smoothing the motion vector field or for correcting motion vectors
• CPC Class Codes: H04N 19/577 Motion compensation with bidirectional frame interpolation, i.e. using B-pictures
• CPC Class Codes: H04N 19/587 involving temporal sub-sampling or interpolation, e.g. decimation or subsequent interpolation of pictures in a video sequence
• CPC Class Codes: H04N 5/145 Movement estimation for video coding H04N19/51
• CPC Class Codes: H04N 7/0127 by changing the field or frame frequency of the incoming video signal, e.g. frame rate converter
• CPC Class Codes: H04N 7/014 involving the use of motion vectors motion estimation and compensation in video coding H04N19/51

Abstract

Provided is a frame rate conversion apparatus for inputting a video signal and inserting an interpolation frame into the video signal so as to convert a frame rate of the video signal. The apparatus includes: an input unit for inputting the video signal; a video interpolation unit for generating an interpolation frame and performing an interpolation process of the video signal; and a control unit for controlling the generation process of the interpolation frame by the video interpolation unit. The video interpolation unit performs the interpolation frame generation process by using a plurality of methods, and the control unit controls switching between the plurality of interpolation frame generating methods.

Claims

1. A frame rate conversion apparatus for inputting a video signal and inserting an interpolation frame into the video signal so as to convert a frame rate of the video signal, the apparatus comprising:

an input unit for inputting the video signal,

a video interpolation unit for generating the interpolation frame and performing an interpolation process of the video signal, and

a control unit for controlling the generation process of the interpolation frame by the video interpolation unit,

wherein the video interpolation unit performs the interpolation frame generation process by using a plurality of methods, and

the control unit controls switching between the plurality of methods.

2. The frame rate conversion apparatus as claimed in claim 1, further comprising:

a motion vector search unit for searching a motion vector between a plurality of frames contained in the video signal,

wherein at least one of the methods generates an interpolation pixel in the interpolation frame by using a motion vector having a start point on a first frame temporally preceding the interpolation frame and an end point on a second frame among motion vectors searched by the motion vector search unit.

3. The frame rate conversion apparatus as claimed in claim 2,

wherein the method for generating an interpolation pixel in the interpolation frame by using the motion vector searched by the motion vector search unit performs block matching between a first block contained in the first frame and a second block contained in the second frame so as to search a motion vector having a start point in the first frame and an end point in the second frame and generates an interpolation pixel in the interpolation frame by using some or all of the pixels contained in the first block or the second block which have been subjected to the block matching.

4. The frame rate conversion apparatus as claimed in claim 2,

wherein among the plurality of methods, at least one method other than a method using the motion vector is a method for generating the interpolation frame without using the motion vector.

5. The frame rate conversion apparatus as claimed in claim 2,

wherein among the plurality of methods, at least one method other than the method using the motion vector is a method for generating a pixel of the interpolation frame by linearly interpolating corresponding pixels of the first frame and the second frame.

6. The frame rate conversion apparatus as claimed in claim 2,

wherein switching between the plurality of methods is performed for each predetermined region of a frame of the interpolation frame.

7. The frame rate conversion apparatus as claimed in claim 2,

further comprising a storage unit for storing the motion vector searched by the motion vector search unit and judgment reference information,

wherein the control unit controls switching between the plurality of methods by using the motion vector and the judgment reference information stored in the storage unit.

8. The frame rate conversion apparatus as claimed in claim 2,

further comprising a storage unit for storing the motion vector searched by the motion vector search unit and judgment reference information, and

a histogram calculation unit for calculating a histogram distribution of a direction vector of a motion vector in the entire frame or a predetermined region of the frame by using the motion vector stored in the storage unit,

wherein the judgment reference information contains information on a threshold value, and

the control unit uses the histogram distribution to compare the rate of a number of motion vectors distributed in a part of region within the entire frame or the predetermined region against a number of motion vectors in the entire histogram distribution of the entire frame or the predetermined region, to the threshold value, thereby performing switching between the methods.

9. The frame rate conversion apparatus as claimed in claim 7,

wherein the control unit changes the judgment reference in accordance with the input video.

10. The frame rate conversion apparatus as claimed in claim 7,

wherein the judgment reference information holds predetermined period information, and

the control unit does not perform switching between the plurality of methods until the predetermined period has elapsed after a switching between the methods is performed.

11. A display apparatus for inputting a video signal and inserting an interpolation frame into the video signal so as to display a video of a frame rate different from the video signal, the apparatus comprising:

an input unit for inputting the video signal,

a video interpolation unit for generating the interpolation frame and outputting the video signal into which the interpolation frame has been inserted,

a control unit for selecting a method for generating the interpolation frame by the video interpolation unit, and

a display unit for displaying the video signal outputted by the video interpolation unit.

12. The display apparatus as claimed in claim 11, further comprising:

a motion vector search unit for searching a motion vector between a plurality of frames contained in the video signal,

wherein at least one of the methods is a method for generating an interpolation pixel in the interpolation frame by using the motion vector searched by the motion vector search unit.

13. The display apparatus as claimed in claim 11, wherein at least one of the methods is a method for generating an interpolation pixel in the interpolation frame by the linear interpolation using a plurality of frames contained in the video signal.

14. The display apparatus as claimed in claim 12, wherein the control unit selects a method for generating the interpolation frame by the video interpolation unit in accordance with a number of motion vectors having a predetermined direction and a predetermined motion amount among motion vectors passing through a predetermined region of the interpolation frame in the motion vectors searched by the motion vector search unit.

15. A frame rate conversion apparatus for inputting a video signal and outputting a video signal of a frame rate different from the inputted video signal, the apparatus comprising:

an input unit for inputting the video signal,

a video interpolation unit for generating the interpolation frame and performing an interpolation process of the video signal by using the interpolation frame and by using a plurality of methods,

a control unit for controlling switching between the plurality of interpolation process methods by the video interpolation unit, and

an output unit for outputting an output video signal which has been subjected to the interpolation process of one of the interpolation process methods,

wherein when an input video signal containing a video where a predetermined image shifts in a predetermined direction is inputted to the input unit, the output unit outputs an output video signal subjected to different types of the interpolation process in accordance with the shift speed of the predetermined image contained in the input video signal.

16. The frame rate conversion apparatus as claimed in claim 15,

wherein the output video signal outputted when the shift speed of the predetermined image is at least one shift speed is a video signal subjected to the interpolation process using a motion vector between a plurality of frames contained in the input video signal.

17. The frame rate conversion apparatus as claimed in claim 15,

wherein the output video signal outputted when the shift speed of the predetermined image is at least one shift speed is a video signal obtained by performing a linear interpolation on a plurality of frames contained in the input video signal.

18. The frame rate conversion apparatus as claimed in claim 15,

wherein the interpolation frame contained in the output video signal when the shift speed of the predetermined image is at least one shift speed has the predetermined image between a position of the predetermined image in the first frame temporally preceding the interpolation frame and a position of the predetermined image in a second frame temporally subsequent to the interpolation frame.

19. The frame rate conversion apparatus as claimed in claim 15,

wherein the interpolation frame contained in the output video signal outputted when the shift speed of the predetermined image is at least one shift speed has an image of the same shape as the predetermined image and a different pixel value at each of a position of the predetermined image in the first frame temporally preceding the interpolation frame and a position of the predetermined image in a second frame temporally subsequent to the interpolation frame.

20. The frame rate conversion apparatus as claimed in claim 15,

wherein when a first input video signal containing a video having a predetermined image shifting at a first speed in a predetermined direction inputted to the input unit, the output unit outputs a first output video signal obtained by subjecting the first input video signal to a first interpolation process using a motion vector between a plurality of frames contained in the first input video signal;

and

when a second input video signal containing a video having the predetermined image shifting at a second speed higher than the first speed in the predetermined direction is inputted to the input unit, the output unit outputs a second output video signal obtained by subjecting the second input video signal to a second interpolation process which is different from the first interpolation process.