Video signal processing apparatus, image display control method, storage medium, and program

• US 20030210338A1
• Filed: 05/06/2003
• Published: 11/13/2003
• Est. Priority Date: 05/07/2002
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Matsuoka, Masaaki, Honma, Yoshihiro
• Granted Patent: US 7,705,902 B2
• Time in Patent Office: Days
• US Class Current: 348/231.99
• CPC Class Codes: H04N 23/63 by using electronic viewfinders
• CPC Class Codes: H04N 5/772 the recording apparatus and the television camera being placed in the same enclosure
• CPC Class Codes: H04N 5/907 using static stores, e.g. storage tubes or semiconductor memories H04N5/91 takes precedence
• CPC Class Codes: H04N 5/9264 using transform coding

Abstract

A video signal processing apparatus includes two image display memory areas 22 and 24 which alternately repeat input and output operations by receiving a signal obtained by performing predetermined processing for an output image signal from an image sensor 12, an image display unit 28 for displaying an object image represented by image frames sequentially output from the two memory areas, a system controller 40 which, when an image frame is to be input to one of the two memory areas, causes the other one of the two memory areas to output a held image frame, and causes the two memory areas to alternately repeat the input and output operations, thereby switching inputting and outputting of the two memory areas, and a mode determination circuit 272 for determining whether the frame rate of the output image signal from the image sensor 12 is higher or lower than the image display rate of the image display unit 28. On the basis of the determination result, the system controller 40 changes input/output control for the two memory areas.

Claims

1. A video signal processing apparatus including an image sensor for outputting an image signal corresponding to an object image, comprising:

at least two image display memory areas which alternately repeat input and output operations upon receiving a signal obtained by performing predetermined processing for an output image signal from said image sensor;

display means for displaying an object image represented by image frames sequentially output from said two image display memory areas;

control means which, when an image frame is to be input to one of said two image display memory areas, causes the other one of said two image display memory areas to output a held image frame, and causes said two image display memory areas to alternately repeat the input and output operations, thereby switching inputting and outputting of said two image display memory areas; and

determining means for determining whether a frame rate of the output image signal from said image sensor is higher or lower than an image display rate of said display means,

wherein said control means changes input/output control for said two image display memory areas on the basis of a result of determination by said determining means.

2. The apparatus according to claim 1, wherein if said determining means determines that the frame rate of the output image signal from said image sensor is higher than the image display rate of said display means, said control means switches inputting and outputting of said two image display memory areas in accordance with an image display frame switching timing of said display means.

3. The apparatus according to claim 1, wherein if said determining means determines that the frame rate of the output image signal from said image sensor is lower than the image display rate of said display means, said control means switches inputting and outputting of said two image display memory areas in accordance with an image frame switching timing of said image sensor.

4. The apparatus according to claim 1, further comprising image sensing signal processing means for generating a luminance signal and color difference signal from the output image signal from said image sensor, as the predetermined processing.

5. The apparatus according to claim 1, further comprising resizing means for performing a predetermined resizing process for the output image signal from said image sensor, as the predetermined processing.

6. The apparatus according to claim 1, further comprising compressing means for compressing the image signal, and a memory area for recording a compressed image signal output from said compressing means.

7. The apparatus according to claim 6, wherein said compressing means comprises raster-block converting means for receiving the image signal in raster sequence and generating a block-sequential image signal having a desired block size, and block compressing means for compressing the block-sequential image signal generated by said raster-block converting means.

8. The apparatus according to claim 1, wherein upon detecting that image frames are continuously input not less than twice to one of said two image display memory areas, said control means stops inputting of an image frame to said one of said two image display memory areas, and, when an image frame held in the other one of said two image display memory areas is completely output, restarts inputting of an image frame to said other one of said two image display memory areas.

9. The apparatus according to claim 1, wherein said video signal processing apparatus includes a digital still camera and video camera.

10. An image display control method executed by a video signal processing apparatus including an image sensor for outputting an image signal corresponding to an object image, comprising:

a display step of displaying on display means an object image represented by image frames sequentially output from at least two image display memory areas which alternately repeat input and output operations upon receiving a signal obtained by performing predetermined processing for an output image signal from said image sensor;

a control step which, when an image frame is to be input to one of said two image display memory areas, causes the other one of said two image display memory areas to output a held image frame, and causes said two image display memory areas to alternately repeat the input and output operations, thereby switching inputting and outputting of said two image display memory areas; and

a determination step of determining whether a frame rate of the output image signal from said image sensor is higher or lower than an image display rate of said display means,

wherein the control step comprises changing input/output control for said two image display memory areas on the basis of a result of determination in the determination step.

11. The method according to claim 10, wherein if the determination step determines that the frame rate of the output image signal from said image sensor is higher than the image display rate of said display means, the control step comprises switching inputting and outputting of said two image display memory areas in accordance with an image display frame switching timing of said display means.

12. The method according to claim 10, wherein if the determination step determines that the frame rate of the output image signal from said image sensor is lower than the image display rate of said display means, the control step comprises switching inputting and outputting of said two image display memory areas in accordance with an image frame switching timing of said image sensor.

13. The method according to claim 10, further comprising image sensing signal processing means for generating a luminance signal and color difference signal from the output image signal from said image sensor, as the predetermined processing.

14. The method according to claim 10, further comprising resizing means for performing a predetermined resizing process for an output image signal from said image signal processing means, as the predetermined processing.

15. The method according to claim 10, further comprising compressing means for compressing the image signal, and a memory area for recording a compressed image signal output from said compressing means.

16. The method according to claim 15, wherein said compressing means comprises raster-block converting means for receiving the image signal in raster sequence and generating a block-sequential image signal having a desired block size, and block compressing means for compressing the block-sequential image signal generated by said raster-block converting means.

17. The method according to claim 10, wherein upon detecting that image frames are continuously input not less than twice to one of said two image display memory areas, the control step comprises stopping inputting of an image frame to said one of said two image display memory areas, and, when an image frame held in the other one of said two image display memory areas is completely output, restarting inputting of an image frame to said other one of said two image display memory areas.

18. The method according to claim 10, wherein said video signal processing apparatus includes a digital still camera and video camera.

19. A computer-readable storage medium storing a program of an image display control method applied to a video signal processing apparatus including an image sensor for outputting an image signal corresponding to an object image, wherein

the image display control method comprises a display step of displaying on display means an object image represented by image frames sequentially output from at least two image display memory areas which alternately repeat input and output operations upon receiving a signal obtained by performing predetermined processing for an output image signal from said image sensor, a control step which, when an image frame is to be input to one of said two image display memory areas, causes the other one of said two image display memory areas to output a held image frame, and causes said two image display memory areas to alternately repeat the input and output operations, thereby switching inputting and outputting of said two image display memory areas, and a determination step of determining whether a frame rate of the output image signal from said image sensor is higher or lower than an image display rate of said display means, and

the control step comprises changing input/output control for said two image display memory areas on the basis of a result of determination in the determination step.

20. The medium according to claim 19, wherein if the determination step determines that the frame rate of the output image signal from said image sensor is higher than the image display rate of said display means, the control step comprises switching inputting and outputting of said two image display memory areas in accordance with an image display frame switching timing of said display means.

21. The medium according to claim 19, wherein if the determination step determines that the frame rate of the output image signal from said image sensor is lower than the image display rate of said display means, the control step comprises switching inputting and outputting of said two image display memory areas in accordance with an image frame switching timing of said image sensor.

22. The medium according to any one of claims 19 to 21, further comprising image sensing signal processing means for generating a luminance signal and color difference signal from the output image signal from said image sensor, as the predetermined processing.

23. The medium according to claim 19, further comprising resizing means for performing a predetermined resizing process for an output image signal from said image signal processing means, as the predetermined processing.

24. The medium according to claim 19, further comprising compressing means for compressing the image signal, and a memory area for recording a compressed image signal output from said compressing means.

25. The medium according to claim 24, wherein said compressing means comprises raster-block converting means for receiving the image signal in raster sequence and generating a block-sequential image signal having a desired block size, and block compressing means for compressing the block-sequential image signal generated by said raster-block converting means.

26. The medium according to claim 19, wherein upon detecting that image frames are continuously input not less than twice to one of said two image display memory areas, said control means stops inputting of an image frame to said one of said two image display memory areas, and, when an image frame held in the other one of said two image display memory areas is completely output, restarts inputting of an image frame to said other one of said two image display memory areas.

27. The medium according to claim 19, wherein said video signal processing apparatus includes a digital still camera and video camera.

28. A program to be supplied to a video signal processing apparatus including an image sensor for outputting an image signal corresponding to an object image, comprising a display step of displaying on display means an object image represented by image frames sequentially output from at least two image display memory areas which alternately repeat input and output operations upon receiving a signal obtained by performing predetermined processing for an output image signal from said image sensor, a control step which, when an image frame is to be input to one of said two image display memory areas, causes the other one of said two image display memory areas to output a held image frame, and causes said two image display memory areas to alternately repeat the input and output operations, thereby switching inputting and outputting of said two image display memory areas, and a determination step of determining whether a frame rate of the output image signal from said image sensor is higher or lower than an image display rate of said display means,

wherein the control step comprises changing input/output control for said two image display memory areas on the basis of a result of determination in the determination step.

29. The program according to claim 28, wherein if the determination step determines that the frame rate of the output image signal from said image sensor is higher than the image display rate of said display means, the control step comprises switching inputting and outputting of said two image display memory areas in accordance with an image display frame switching timing of said display means.

30. The program according to claim 28, wherein if the determination step determines that the frame rate of the output image signal from said image sensor is lower than the image display rate of said display means, the control step comprises switching inputting and outputting of said two image display memory areas in accordance with an image frame switching timing of said image sensor.

31. The program according to claim 28, further comprising image sensing signal processing means for generating a luminance signal and color difference signal from the output image signal from said image sensor, as the predetermined processing.

32. The program according to claim 28, further comprising resizing means for performing a predetermined resizing process for an output image signal from said image signal processing means, as the predetermined processing.

33. The program according to claim 28, further comprising compressing means for compressing the image signal, and a memory area for recording a compressed image signal output from said compressing means.

34. The program according to claim 33, wherein said compressing means comprises raster-block converting means for receiving the image signal in raster sequence and generating a block-sequential image signal having a desired block size, and block compressing means for compressing the block-sequential image signal generated by said raster-block converting means.

35. The program according to claim 28, wherein upon detecting that image frames are continuously input not less than twice to one of said two image display memory areas, said control means stops inputting of an image frame to said one of said two image display memory areas, and, when an image frame held in the other one of said two image display memory areas is completely output, restarts inputting of an image frame to said other one of said two image display memory areas.

36. The program according to claim 28, wherein said video signal processing apparatus includes a digital still camera and video camera.