RGB/YUV video convolution system

• US 5,838,299 A
• Filed: 05/03/1995
• Issued: 11/17/1998
• Est. Priority Date: 05/03/1995
• Status: Expired due to Term

• Current Assignee: Apple Inc.
• Original Assignee: Apple Computer Incorporated (Apple Inc.)
• Inventors: Thompson, Laurence A., Smith, R. Steven
• Primary Examiner(s): Garber, Wendy
• Assistant Examiner(s): Vu, Ngoc-Yen, VU, NGOC YEN T
• Application Number:
  US08/433,096
• Time in Patent Office: 1,294 Days
• Field of Search: 345/137, 345/150, 345/153, 345/154, 382/162, 382/167, 382/278, 382/279, 348/138, 348/234, 348/237, 348/660, 348/661, 348/663, 348/664, 358/518, 358/515, 358/516
• US Class Current: 345/615
• CPC Class Codes: G09G 2310/0224 Details of interlacing
• CPC Class Codes: G09G 5/395 Arrangements specially adapted for transferring the contents of the bit-mapped memory to the screen G09G5/399 takes precedence

Abstract

An apparatus and a method are provided for smoothing out high frequency information in an interlaced computer generated display. A computer generated RGB signal is converted into a YUV signal, which is separated into its Y, U, and V components. The Y component is convolved by averaging a current scan line with a line above and a line below the current scan line so that black lines are lightened and white lines are darkened, thus avoiding flicker. Since convolution is only performed on the Y part of the YUV signal, only two line buffers, each having a width equal to the number of bits in the Y component only, are required.

Claims

1. A method for producing an interlaced display of computer generated data including the steps of:

generating video data of n bits;

converting the video data of n bits into luminance-chrominance (YUV) data of n bits;

separating the YUV data into Y, U, and V components of m bits each;

convolving the Y component; and

displaying the convolved Y component and the U and V components, wherein the Y component contains several scan lines, and the step of convolving is performed according to the formula;

space="preserve" listing-type="equation">1/4a+1/2b+1/4c

wherein b is a current scan line of the Y component, a is a scan line immediately above the current scan line, and c is a scan line immediately below the current scan line.

2. A method for producing an interlaced display of computer generated data including the steps of:

generating video data of n bits;

converting the video data of n bits into luminance-chrominance (YUV) data of n bits;

separating the YUV data into Y, U, and V components of m bits each;

convolving only the Y component; and

displaying the convolved Y component and the unconvolved U and V components, wherein the Y component contains several scan lines, and the step of convolving includes the steps;

a) storing a first scan line above a current scan line in a first line buffer;

b) storing a second scan line below the current scan line in a second line buffer and combining the second scan line with the stored first scan line to produce a first combination;

c) dividing the first combination and storing the divided first combination in the first line buffer;

d) combining the current scan line with the divided first combination to produce a second combination; and

e) dividing the second combination to produce an averaged scan line for display.

3. The method of claim 2, wherein the step of convolving further includes, after step e), the steps:

f) moving the second scan line from the second line buffer to the first line buffer, wherein the second scan line becomes a scan line above a next current scan line; and

g) repeating steps a) through e) for all the scan lines of the Y component.

4. The method of claim 2, wherein the first line buffer and the second line buffer are each 8 bits wide.

5. The method of claim 2, wherein said step of generating further includes the step of:

combining video data from a non-computer source and a computer source.

6. The method of claim 2, wherein the video data is red-green-blue (RGB) video data.

7. The method of claim 2, further including the step of gamma correcting the video data before said converting step.

8. The method of claim 2, wherein n=24 bits and m=8 bits.

9. The method of claim 2, further including the step of encoding the convolved Y component and the unconvolved U and V components to a form suitable for display before the displaying step.

10. An apparatus for producing an interlace display of computer generated data including:

means for generating video data of n bits;

converting means for converting the video data of n bits into luminance-chrominance (YUV) data of n bits;

separating means for separating the YUV data into Y, U, and V components of m bits each;

convolving means for convolving only the Y component; and

means for displaying the convolved Y component and the unconvolved U and V components, wherein the Y component contains several scan lines, and the convolving means convolves according to the formula;

space="preserve" listing-type="equation">1/4a+1/2b+1/4c

wherein b is a current line scan line of the Y component, a is a scan line immediately above the current scan line, and c is a scan line immediately below the current scan line.

11. An apparatus for producing an interlaced display of computer generated data including:

means for generating video data of n bits;

converting means for converting the video data of n bits into luminance-chrominance (YUV) data of n bits;

separating means for separating the YUV data into Y, U, and V components of m bits each;

convolving means for convolving only the Y component; and

means for displaying the convolved Y component and the unconvolved U and V components, wherein the Y component contains several scan lines, and the convolving means comprises;

a first line buffer;

a second line buffer;

a combiner; and

a shifter for dividing an output from the combiner, wherein the first line buffer, the second line buffer, the combiner, and the shifter perform the following process;

the first line buffer stores a first scan line above a current scan line, the second line buffer stores a second scan line below the current scan line, the combiner combines the first scan line stored in the first line buffer with the second scan line to produce a first combination, the shifter divides the first combination, the first line buffer stores the divided first combination, the combiner combines the current scan line with the divided first combination stored in the first line buffer to produce a second combination, and the shifter divides the second combination and outputs the divided second combination as an averaged scan line for display.

12. The apparatus of claim 11, wherein after the divided second combination is output for display, the second scan line is moved from the second line buffer to the first line buffer and becomes a scan line above a next current scan line, and the process is repeated by the first line buffer, the second line buffer, the combiner, and the shifter for all the scan lines of the Y component.

13. The apparatus of claim 11, wherein the first line buffer and the second line buffer are each 8 bits wide.

14. The apparatus of claim 11, wherein said means for generating combines video data from a non-computer source and a computer source.

15. The apparatus of claim 11, wherein the video data is red-green-blue (RGB) video data.

16. The apparatus of claim 11, further comprising gamma correcting means for gamma correcting the video data before converting by the converting means.

17. The apparatus of claim 11, wherein n=24 bits and m=8 bits.

18. The apparatus of claim 11, further comprising encoding means for encoding the convolved Y component and the unconvolved U and V components to a form suitable for display before displaying by the displaying means.

19. An apparatus for convolving video data for display, comprising:

a first line buffer for storing a first scan line;

a second line buffer for storing a second scan line;

a combiner for combining the first scan line with the second scan line to form a first combination and for combining the first combination with a current scan line to form a second combination; and

a shifter for dividing the first combination prior to combining by the combiner to form the second combination and for dividing the second combination to provide a convolved output for display.

20. A method for convolving video data for display, comprising the steps of:

storing a first scan line;

storing a second scan line;

combining the first scan line with the second line to form a first combination;

dividing the first combination;

combining the divided first combination with a current scan line to form a second combination; and

dividing the second combination to provide a convolved output for display.