Video signal capturing apparatus

In a video signal capturing apparatus with a simple construction capable of distinguishing fields in units of a color field, a separation circuit separates from input video signals, vertical synchronizing signals that lead fields in a one-to-one relationship. A field counter formed by, for example, a scale-of-four counter, counts the number of vertical synchronizing signals. Based on the count value of the field counter and values set in a register, a timing generating circuit performs data capture in such a manner that color fields are distinguished from each other. If color field 3 is to be captured, a value “3” is set the register. The timing generation circuit compares a count value from the field counter with the set value “13”. When the count value equals 3, the timing generation circuit starts capture of digital video data in the determined field. An even-odd number determining circuit may be provided for distinguishing (i.e., differentiating) an even-numbered field from an odd-numbered field during interlace scanning of the video signal based on the vertical synchronizing signals separated by the separator unit. The timing generation circuit instructs the video data writing control unit to write the digital video data in the memory in such a manner that the odd-numbered field and the even-numbered field are differentiated from each other and the color fields are distinguished from each other.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the present invention will be described in detail with reference to the following figures wherein:

FIG. 1 is a schematic block diagram of a video printer that employs a video signal capturing apparatus according to a first preferred embodiment of the invention; and

FIG. 2 is a circuit block diagram of the video signal capturing apparatus according to the first embodiment;

FIG. 3 is a circuit block diagram of the video signal capturing apparatus according to a second preferred embodiment.

1. A video signal capturing apparatus for capturing digital video data stored in a memory, the digital video data corresponding to image data for use by a processing apparatus, the video signal capturing apparatus comprising:

2. A video signal capturing apparatus according to claim 1, further comprising a converter unit that converts the input video signal into the digital video data which is written in the memory.

3. A video signal capturing apparatus according to claim 1, further comprising an even-odd number determining unit that differentiates an even-numbered field from an odd-numbered field during interlace scanning of the video signal based on the vertical synchronizing signal separated by the separator unit,

4. A video signal capturing apparatus according to claim 1, wherein the writing of digital video data in the memory is performed by a direct memory access.

5. A video signal capturing apparatus according to claim 4, further comprising an even-odd number determining unit that differentiates an even-numbered field from an odd-numbered field during interlace scanning of the video signal based on the vertical synchronizing signal separated by the separator unit,

6. A video signal capturing apparatus according to claim 1, wherein the determining unit includes a scale-of-N counter that counts a number of vertical synchronizing signals separated by the separator unit, N being a number of color fields.

7. A video signal capturing apparatus according to claim 6, further comprising an even-odd number determining unit that differentiates an even-numbered field from an odd-numbered field during interlace scanning of the video signal based on the vertical synchronizing signal separated by the separator unit,

8. A video signal capturing apparatus according to claim 6, wherein the writing of digital video data in the memory is performed using a direct memory access.

9. A video signal capturing apparatus according to claim 8, further comprising an even-odd number determining unit that differentiates an even-numbered field from an odd-numbered field during interlace scanning of the video signal based on the vertical synchronizing signal separated by the separator unit,

10. A method for capturing digital video data stored in a memory, the digital video data corresponding to image data for use by a processing apparatus, the method comprising:

11. A method according to claim 10, further comprising converting the input video signal into the digital video data which is written in the memory.

12. A method according to claim 10, further comprising differentiating an even-numbered field from an odd-numbered field during interlace scanning of the video signal based on the vertical synchronizing signal,

13. A method according to claim 10, wherein the writing of digital video data in the memory is performed by a direct memory access.

14. A method according to claim 13, further comprising differentiating an even-numbered field from an odd-numbered field during interlace scanning of the video signal based on the vertical synchronizing signal,

15. A method according to claim 10, wherein the distinguishing step includes counting a number of separated vertical synchronizing signals using a scale-of-N counter, N being a number of color fields.

16. A method according to claim 15, further comprising differentiating an even-numbered field from an odd-numbered field during interlace scanning of the video signal based on the separated vertical synchronizing signal,

17. A method according to claim 15, wherein the writing of digital video data in the memory is performed using a direct memory access.

18. A video signal capturing apparatus for capturing digital video data stored in a memory, the digital video data corresponding to image data for use by a processing apparatus, the video signal capturing apparatus comprising: