Apparatus for converting screen aspect ratio

• US 6,674,799 B2
• Filed: 02/13/2001
• Issued: 01/06/2004
• Est. Priority Date: 02/28/2000
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Rhee, Seung Hyeon
• Primary Examiner(s): Le, Vu
• Application Number:
  US09/782,425
• Publication Number:
  US 20010017890A1
• Time in Patent Office: 1,057 Days
• Field of Search: 375/240.21, 375/240.25, 375/240.29, 375/240.16, 348/445, 348/913, 348/416.1, 348/699, 348/700
• US Class Current: 375/240.21
• CPC Class Codes: H04N 21/426 Internal components of the client ; Characteristics thereof H04N5/44 takes precedence
• CPC Class Codes: H04N 21/44008 involving operations for analysing video streams, e.g. detecting features or characteristics in the video stream arrangements characterised by components specially adapted for monitoring, identification or recognition of video in broadcast systems H04H60/59
• CPC Class Codes: H04N 21/440272 for performing aspect ratio conversion
• CPC Class Codes: H04N 5/145 Movement estimation for video coding H04N19/51
• CPC Class Codes: H04N 5/147 Scene change detection
• CPC Class Codes: H04N 7/0122 the input and the output signals having different aspect ratios
• CPC Class Codes: H04N 7/014 involving the use of motion vectors motion estimation and compensation in video coding H04N19/51

Abstract

An apparatus converts a screen with an aspect ratio of 4:3 to a screen with an aspect ratio of 16:9. When the input image is given as a frame buffer that is not encoded, the present invention extracts motion vector by performing block motion matching operation, and when the input image is a digitally encoded bit stream, it extracts motion vectors from the decoded data. The motion vectors are subjected to filtering in terms of time and space. The apparatus extracts global motion information from the motion vectors that have been filtered. Utilizing the global motion information extracted from and the partial images from the adjacent frames, the present invention generates the image information that is displayed on the blank regions of the screen. The blank regions on left and right of the screen caused by the differences in the screen aspect ratios are composed from the actual image information.

Claims

1. A video receiver system for displaying video signals received in a first format to a second format and operable with at least one of encoded bit stream signal and sampled video signal, the receiver system comprising:

a decoder for decoding the bit stream signal and outputting a decoded video signal and a motion vector signal included in the bit stream signal;

first and second frame buffers for storing at least one of the decoded video signal and the sampled video signal;

a motion vector estimation unit for estimating block motion vectors by comparing a first frame with a second frame stored in the first and second frame buffers and outputs an estimated motion vector signal, wherein the first and second frames are displaced in time;

a motion vector filter for filtering at least one of the motion vector signal from the decoder and the estimated motion vector signal from the motion vector estimation unit by providing at least one of spatial and temporal filtering and producing a filtered motion vector signal;

a global motion information extraction unit for extracting the global motion information from the filtered motion vector signal and outputting a global motion information signal; and

a composite image generator for generating data for image signal lacking regions in a frame in response to the global motion information signal, the filtered motion vector signal and data from first frame buffer.

2. The video receiver system of claim 1, further comprising a scene change detector for detecting scene change and outputting a scene change detection signal to the composite image generator.

3. The video receiver system of claim 1, wherein the filtered motion vector signal is produced with the spatial filtering by establishing an N×

N window, where N is an integer, on a vector matrix representative of the motion vector signal and taking two-dimensional vector median filtering.

4. The video receiver system of claim 3, wherein the N×

N window comprises a 3×

3 window.

5. The video receiver system of claim 1, wherein the filtered motion vector signal is produced with the temporal filtering by taking scalar median filtering out of motion vector signal that correspond to the identical locations on the M number of consecutive frames, where M is an integer.

6. The video receiver system of claim 1, wherein the composite image generator uses only the filtered motion vector signal to generate the data for image signal lacking regions if the global motion information signal contains invalid global motion information.

7. The video receiver system of claim 1, wherein if the global motion information signal contains valid global motion information, the composite image generator compares the filtered motion vector signal with the global motion information signal and uses only the filtered motion vector signal if the difference between the filtered motion vector signal and the global motion information signal exceeds a predetermined quantity.

8. The video receiver system of claim 1, wherein if the global motion information signal contains valid global motion information, the composite image generator compares the filtered motion vector signal with the global motion information signal and uses only the global motion information signal if the difference between the filtered motion vector signal and the global motion information signal is less than a predetermined quantity.

9. The video receiver system of claim 2, wherein the composite image generator uses only the filtered motion vector signal to generate the data for image signal lacking regions if the scene change detection signal is enabled.

10. The video receiver system of claim 2, wherein if the scene change detection signal is disabled, the composite image generator compares the filtered motion vector signal with the global motion information signal and uses only the filtered motion vector signal if the difference between the filtered motion vector signal and the global motion information signal exceeds a predetermined quantity.

11. The video receiver system of claim 2, wherein if the scene change detection signal is disabled, the composite image generator compares the filtered motion vector signal with the global motion information signal and uses only the global motion information signal if the difference between the filtered motion vector signal and the global motion information signal is less than a predetermined quantity.

12. The video receiver system of claim 1, wherein the composite image generator comprises:

a composite image size calculation unit for calculating the size of a composite image in response to the global motion information signal and a size of a previous composite image;

a parallel shift unit for parallelly shifting the first frame received from the first frame buffer in response to a result of the composite image size calculation unit and outputting a shifted image signal;

a third frame buffer for storing the shifted image signal and outputting a composite signal; and

an image conversion unit for producing the data for image signal lacking regions in a form of a background image signal in response to the global motion information signal, the filtered motion vector signal, the scene change detection signal and the composite signal, wherein the third frame buffer stores the composite signal which comprises the background image signal overwritten by the shifted image signal.

13. The video receiver system of claim 12, wherein a size of the composite image signal is determined by the image conversion unit in response to the global motion control signal and the filtered motion vector signal.

14. A video receiver system for displaying video signals received in a first format to a second format and operable with an input video signal, the receiver system comprising:

a decoder for decoding the input video signal and outputting a decoded video signal and a motion vector signal if provided in the input video signal, wherein if the input video signal is a sampled signal, the decoder is bypassed;

a first frame buffer for storing an output signal from the decoder;

a motion vector filter for filtering the motion vector signal from the decoder by providing at least one of spatial and temporal filtering and producing a filtered motion vector signal;

a global motion information extraction unit for extracting the global motion information from the filtered motion vector signal and outputting a global motion information signal; and

a composite image generator for generating data for image signal lacking regions in a frame in response to the global motion information signal, the filtered motion vector signal and data from the first frame buffer.

15. The video receiver system of claim 14, further comprising:

a second frame buffer; and

a motion vector estimation unit for estimating motion vectors by comparing a first frame with a second frame stored in the first and second frame buffers and outputting an estimated motion vector signal.

16. The video receiver system of claim 15, wherein if the motion vector signal is not provided from the decoder, the motion vector filter filters the estimated motion vector signal from the motion vector estimation unit by providing at least one of spatial and temporal filtering and producing a filtered motion vector signal.

17. The video receiver system of claim 14, further comprising a scene change detector for detecting scene change and outputting a scene change detection signal to the composite image generator.

18. The video receiver system of claim 14, wherein the filtered motion vector signal is produced with the spatial filtering by establishing an N×

N window, where N is an integer, on a vector matrix representative of the motion vector signal and taking two-dimensional vector median filtering.

19. The video receiver system of claim 14, wherein the filtered motion vector signal is produced with the temporal filtering by taking scalar median filtering out of motion vector signal that correspond to the identical locations on the M number of consecutive frames, where M is an integer.

20. The video receiver system of claim 14, wherein the composite image generator uses only the filtered motion vector signal to generate the data for image signal lacking regions if the global motion information signal contains invalid global motion information.

21. The video receiver system of claim 14, wherein if the global motion information signal contains valid global motion information, the composite image generator compares the filtered motion vector signal with the global motion information signal and uses only the filtered motion vector signal if the difference between the filtered motion vector signal and the global motion information signal exceeds a predetermined quantity.

22. The video receiver system of claim 14, wherein if the global motion information signal contains valid global motion information, the composite image generator compares the filtered motion vector signal with the global motion information signal and uses only the global motion information signal if the difference between the filtered motion vector signal and the global motion information signal is less than a predetermined quantity.

23. The video receiver system of claim 17, wherein the composite image generator uses only the filtered motion vector signal to generate the data for image signal lacking regions if the scene change detection signal is enabled.

24. The video receiver system of claim 17, wherein if the scene change detection signal is disabled, the composite image generator compares the filtered motion vector signal with the global motion information signal and uses only the filtered motion vector signal if the difference between the filtered motion vector signal and the global motion information signal exceeds a predetermined quantity.

25. The video receiver system of claim 17, wherein if the scene change detection signal is disabled, the composite image generator compares the filtered motion vector signal with the global motion information signal and uses only the global motion information signal if the difference between the filtered motion vector signal and the global motion information signal is less than a predetermined quantity.

26. The video receiver system of claim 14, wherein the composite image generator comprises:

a composite image size calculation unit for calculating the size of a composite image in response to the global motion information signal and a size of a previous composite image;

a parallel shift unit for parallelly shifting the first frame received from the first frame buffer in response to a result of the composite image size calculation unit and outputting a shifted image signal;

a third frame buffer for storing the shifted image signal and outputting a composite signal; and

an image conversion unit for producing the data for image signal lacking regions in a form of a background image signal in response to the global motion information signal, the filtered motion vector signal, the scene change detection signal and the composite signal, wherein the third frame buffer stores the composite signal which comprises the background image signal overwritten by the shifted image signal.

27. The video receiver system of claim 26, wherein a size of the composite image signal is determined by the image conversion unit in response to the global motion control signal and the filtered motion vector signal.