Method and apparatus for scaling and filtering of video information for use in a digital system

• US 6,064,437 A
• Filed: 09/11/1998
• Issued: 05/16/2000
• Est. Priority Date: 09/11/1998
• Status: Expired due to Term

• Current Assignee: Cirrus Logic Incorporated
• Original Assignee: ShareWave, Inc. (Cirrus Logic Incorporated)
• Inventors: Phan, Michael H., Harwood, Joseph D.
• Primary Examiner(s): Kostak, Victor R.
• Application Number:
  US09/151,505
• Time in Patent Office: 613 Days
• Field of Search: 345/127, 345/327, 348/446, 348/447, 348/910, 348/607, 348/622, 348/625
• US Class Current: 348/446
• CPC Class Codes: G06T 3/40 Scaling of whole images or parts thereof, e.g. expanding or contracting
• CPC Class Codes: G09G 2320/0247 Flicker reduction other than flicker reduction circuits used for single beam cathode-ray tubes
• CPC Class Codes: G09G 5/391 Resolution modifying circuits, e.g. variable screen formats
• CPC Class Codes: H04N 21/4143 embedded in a Personal Computer [PC]
• CPC Class Codes: H04N 21/43615 Interfacing a Home Network, e.g. for connecting the client to a plurality of peripherals home Audio Video Interoperability [HAVI] data switching networks H04L12/2805
• CPC Class Codes: H04N 21/43637 involving a wireless protocol, e.g. Bluetooth, RF or wireless LAN [IEEE 802.11] arrangements for wireless networking or broadcasting of information in indoor or near-field type systems H04B10/114
• CPC Class Codes: H04N 21/440218 by transcoding between formats or standards, e.g. from MPEG-2 to MPEG-4 conversion of standards in analogue television systems H04N7/01
• CPC Class Codes: H04N 5/21 Circuitry for suppressing or minimising disturbance, e.g. moiré or halo
• CPC Class Codes: H04N 5/44 Receiver circuitry for the reception of television signals according to analogue transmission standards H04N5/14 takes precedence
• CPC Class Codes: H04N 7/01 Conversion of standards , e.g. involving analogue television standards or digital television standards processed at pixel level

Abstract

Video information which is organized in a first format is converted to a second format by first scaling the video information to produce scaled video information and then color correcting the scaled video information to produce color corrected video information at a network server. Scaling the video information may be accomplished by first applying a vertical scaling process to the video information to produce vertically scaled video information. Second, an anti-flicker filter may be applied to the vertically scaled video information to produce the scaled video information. The vertical scaling process includes a pixel-by-pixel conversion process wherein, for each group of six scan lines in a frame of the video information, color information for individual pixels which make up the group of six scan lines is scaled to provide color information for pixels in a corresponding group of five scan lines of a frame of the vertically scaled video information. The anti-flicker filter comprises a pixel-by-pixel conversion process wherein for each group of three scan lines in a frame of the vertically scaled video information, color information for individual pixels which make up the three scan lines is scaled to provide color information for pixels in a corresponding scan line of a frame of the scaled video information. Color correcting the scaled video information generally comprises converting R-G-B color information of the scaled video information to Y-U-V color information. The color corrected video information may then be transmitted to a network client via a wireless communication link.

Claims

1. A method, comprising converting video information organized in a first format to a second format by first scaling the video information to produce vertically scaled video information using a pixel-by-pixel conversion process in which for each group of six scan lines in a frame of the video information, color information for individual pixels which make up the group of six scan lines is scaled to provide color information for pixels in a corresponding group of five scan lines of a frame of the vertically scaled video information and subsequently providing color correction to produce color corrected video information.

2. The method of claim 1 wherein scaling the video information includes applying an anti-flicker filter to the vertically scaled video information to produce scaled video information.

3. The method of claim 1 wherein scaling factors used for the color information for individual pixels of each group of six scan lines in the frame of the video information varies between scan lines.

4. The method of claim 3 wherein color information for pixels of a first scan line of the group of six scan lines from the frame of the video information is scaled by a factor of 1 to form the color information for the pixels of a first scan line of the group of five scan lines from the frame of vertically scaled video information.

5. The method of claim 4 wherein the color information for pixels in the remaining scan lines of the group of six scan lines from the frame of video information is merged on a scan line basis to form the color information for the pixels of the remaining scan lines of the group of five scan lines from the frame of vertically scaled information.

6. The method of claim 5 wherein the color information for pixels in the remaining scan lines of the group of six scan lines from the frame of video information is scaled by a predetermined factor on a scan line basis prior to being merged to form the color information for the pixels of the remaining scan lines of the group of five scan lines from the frame of vertically scaled information.

7. The method of claim 2 wherein the anti-flicker filter uses three scan lines of a frame of the vertically scaled video information to produce one scan line of a frame of the scaled video information.

8. The method of claim 2 wherein the anti-flicker filter comprises a pixel-by-pixel conversion process wherein for each group of three scan lines in a frame of the vertically scaled video information, color information for individual pixels which make up the three scan lines is scaled to provide color information for pixels in a corresponding scan line of a frame of the scaled video information.

9. The method of claim 8 wherein scaling factors used by the anti-flicker filter for scaling the pixel color information of the three scan lines of the frame of the vertically scaled video information varies on a scan line basis.

10. The method of claim 9 wherein the anti-flicker filter is configured to normalize multi-bit values of red, green and blue color information of the pixels in the three scan lines of the frame of the vertically scaled video information before applying the scaling factors.

11. The method of claim 2 wherein color correcting the scaled video information comprises converting R-G-B color information of the scaled video information to Y-U-V color information.

12. The method of claim 11 wherein color correcting the scaled video information further comprises normalizing the R-G-B color information to an eight bit format prior to converting the R-G-B color information to Y-U-V color information.

13. The method of claim 12 wherein the Y-U-V color information for the color corrected video information is formatted as 4:

2;

2 digital component video.

14. The method of claim 1 wherein the color information for pixels in the scan lines of the group of six scan lines from the frame of video information is normalized prior to being scaled.

15. A network server, comprising:

a video processor configured to convert video information from a first format to a second format by first scaling the video information to produce vertically scaled video information in which for each group of six scan lines in a frame of the video information, color information for individual pixels which make up the group of six scan lines is scaled to provide color information for pixels in a corresponding group of five scan lines of a frame of the vertically scaled video information and to subsequently provide color correction to produce color corrected video information; and

a radio configured to transmit the color corrected video information to at least one network client across a wireless link.

16. The network server of claim 15 wherein the color corrected video information is compressed prior to transmission.

17. The network server of claim 15 wherein the video processor is further configured to apply an anti-flicker filter to the vertically scaled video information to produce scaled video information.

18. A computer network, comprising:

a server configured to convert video information from a first format to a second format by first scaling the video information to produce vertically scaled video information in which for each group of six scan lines in a frame of the video information, color information for individual pixels which make up the group of six scan lines is scaled to provide color information for pixels in a corresponding group of five scan lines of a frame of the vertically scaled video information and to subsequently provide color correction to produce color corrected video information; and

a client coupled in wireless communication with the server and configured to receive the color corrected video information.

19. The computer network of claim 18 wherein the server is further configured to apply an anti-flicker filter to the vertically scaled video information to produce scaled video information.

20. The computer network of claim 18 wherein scaling factors used for the color information for individual pixels of each group of six scan lines in the frame of the video information varies between scan lines.

21. The computer network of claim 20 wherein color information for pixels of a first scan line of the group of six scan lines from the frame of the video information is scaled by a factor of 1 to form the color information for the pixels of a first scan line of the group of five scan lines from the frame of vertically scaled video information.

22. The computer network of claim 21 wherein the color information for pixels in the remaining scan lines of the group of six scan lines from the frame of video information is merged on a scan line basis to form the color information for the pixels of the remaining scan lines of the group of five scan lines from the frame of vertically scaled information.

23. The computer network of claim 22 wherein the color information for pixels in the remaining scan lines of the group of six scan lines from the frame of video information is scaled by a predetermined factor on a scan line basis prior to being merged to form the color information for the pixels of the remaining scan lines of the group of five scan lines from the frame of vertically scaled information.

24. The computer network of claim 19 wherein the anti-flicker filter uses three scan lines of a frame of the vertically scaled video information to produce one scan line of a frame of the scaled video information.

25. The computer network of claim 19 wherein the anti-flicker filter comprises a pixel-by-pixel conversion process wherein for each group of three scan lines in a frame of the vertically scaled video information, color information for individual pixels which make up the three scan lines is scaled to provide color information for pixels in a corresponding scan line of a frame of the scaled video information.

26. The computer network of claim 25 wherein scaling factors used by the anti-flicker filter for scaling the pixel color information of the three scan lines of the frame of the vertically scaled video information varies on a scan line basis.

27. The computer network of claim 26 wherein the anti-flicker filter is configured to normalize multi-bit values of red, green and blue color information of the pixels in the three scan lines of the frame of the vertically scaled video information before applying the scaling factors.

28. The computer network of claim 19 wherein color correcting comprises converting R-G-B color information of the scaled video information to Y-U-V color information.

29. The computer network of claim 28 wherein color correcting further comprises normalizing the R-G-B color information to an eight bit format prior to converting the R-G-B color information to Y-U-V color information.

30. The computer network of claim 29 wherein the Y-U-V color information for the color corrected video information is formatted as 4:

2;

2 digital component video.

31. The computer network of claim 18 wherein the color information for pixels in the scan lines of the group of six scan lines from the frame of video information is normalized prior to being scaled.