EP0103488A2
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EP
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Method and apparatus for encoding and decoding video
Assignee: New York Institute of Technology
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Filing: 1983-09-14
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Granted: —
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Expires: 2003-09-14
Abstract
Abstract This concerns an apparatus and method for encoding and/or decoding video signals for use in a compatible high definition television system or in other applications. In a form of the disclosure there is provided an encoder which includes means (300) for storing an input frame as an array of digital pixel values, and means (600) for interrogating the stored array and for generating a sum signal (I) and at least one difference signal (X, Y, Z). The sum signal is representative of the sum of the pixel values in a group of pixels. The difference signal (e.g. X n ) is representative of the difference between thetotal of the pixel values in some of the pixels (Ao n , Bo n ) in the group and the total of the pixel values of other pixels (A in , Bin) in the group. The sum signal and the difference signal are generated for a multiplicity of groups which cover the video frame. The sum signal is generated at a relatively high information refresh rate and the difference signal is generated at a relatively low information refresh rate. The decoder includes means for storing the sum signal and each of the difference signals, and means for combining the sum and difference signals to obtain an output pixel value for each pixel of an output video frame. In another form of the invention (Fig. 20), electronic processing is performed to obtain low and high spatial frequency component representations of the image represented by the video signal, and these are stored in a digital memory in the encoder. Output frames of the low spatial frequency component representation are produced at a fast frame refresh rate, and output frames of the high spatial frequency component representation are produced at a slow frame refresh rate.
Inventors
- 👤 William E. Glenn
- 👤 Robert L. Dhein
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-06 14:11
CPC Classifications
H; H04; H04N; H04N9/00; H04N9/79; H04N9/87; H04N11/00; H04N11/24; H04N5/00; H04N5/76; H04N5/765; H04N5/77; H04N5/772; H04N7/00; H04N7/01; H04N7/0117; H04N7/012; H04N9/797; F; F02; F02B; F02B75/00; F02B75/02; F02B2075/022; F02B2075/027; H04N5/91; H04N5/92; H04N5/9201; H04N5/9205
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
112 words
A method of encoding a video signal for subsequent decoding and video image reproduction, for use in a high-definition television system, comprising the steps of: deriving a representation of low spatial frequency components of the images represented by the video signal (standard resolution luminance, R-Y, B-Y, Figures 20, 21); deriving a representation which includes high spatial frequency components of the images represented by the video signal; (high resolution luminance, R-Y, B-Y); producing output frames of the low spatial frequency component representation at a first refresh rate; and producing output frames of the high spatial frequency component representation at a second frame refresh rate which is slower than the first frame refresh rate.
Claim 2
Independent Claim
112 words
A method of encoding a video signal for subsequent decoding and video image reproduction, for use in a high-definition television system, comprising the steps of: deriving a representation of low spatial frequency components of the images represented by the video signal (standard resolution luminance, R-Y, B-Y, Figures 20, 21); deriving a representation which includes high spatial frequency components of the images represented by the video signal; (high resolution luminance, R-Y, B-Y); producing output frames of the low spatial frequency component representation at a first refresh rate; and producing output frames of the high spatial frequency component representation at a second frame refresh rate which is slower than the first frame refresh rate.
Claim 3
Dependent Claim
24 words
A method according to claim 1, in which the second frame refresh rate is in the range from 3 to 15 frames per second.
Claim 4
Dependent Claim
19 words
A method in accordance with claim 1, wherein the second frame refresh rate is approximately 5 frames per second.
Claim 5
Dependent Claim
38 words
A method according to claim 1, 2 or 3, whererein the encoding includes delaying (2250, Figure 22) the output frames of the low spatial frequency component representation with respect to the output frames of high spatial frequency representation.
Claim 6
Dependent Claim
19 words
A method according to claim 4, wherein a delay in the range from 30 to 200 milliseconds is introduced
Claim 7
Dependent Claim
96 words
A method in accordance with claim 1, comprising deriving a representation of low spatial frequency components using a low-pass filter (2010) for the video signal and forming weighted sums (2026-2029) of corresponding elements of three consecutive scan lines of a frame of the video signal, centered around alternate scan lines of the said frame; and deriving a representation which includes high spatial frequency components by selecting alternately the high frequency signal components of the said alternate scan lines and the low and high frequency signal components of the scan lines between the said alternate scan lines.
Claim 8
Independent Claim
55 words
A method of decoding a signal resulting from the encoding method of any one of claims 1 to 6, comprising combining the low spatial frequency component representation with the high spatial frequency component representation converted from the slower second frame refresh rate to the faster first frame refresh rate, to obtain the decoded video signal.
Claim 9
Independent Claim
235 words
A method of transmitting and receiving a video signal, comprising encoding the video signal by storing an input video frame as an array of digital pixel values, and interrogating the stored array and generating a sum signal representative of the sum of the pixel values in a group of pixels and a difference signal or difference signals representative of the difference between the total of the pixel values of some of the pixels in the group and the total of the pixel values of other pixels in the-group, the sum signal and the difference signal or signals being generated for a multiplicity of groups which cover the video frame, the sum signal being generated at the faster first information refresh rate and the difference signal or signals being generated at the second slower information refresh rate; and further comprising converting the encoded sum signal and the encoded difference signal or each of the encoded difference signals into analog signals; transmitting the analog signals; receiving the analog signals and recovering therefrom the digital sum and difference signals, and thereafter decoding the video signal by storing the sum signal, storing the difference signal or each of the difference signals and combining the sum and difference signals for corresponding groups of pixels to obtain a pixel value for each pixel of an output video frame corresponding to the pixel value of the corresponding pixel of the input array.
Claim 10
Independent Claim
235 words
A method of transmitting and receiving a video signal, comprising encoding the video signal by storing an input video frame as an array of digital pixel values, and interrogating the stored array and generating a sum signal representative of the sum of the pixel values in a group of pixels and a difference signal or difference signals representative of the difference between the total of the pixel values of some of the pixels in the group and the total of the pixel values of other pixels in the-group, the sum signal and the difference signal or signals being generated for a multiplicity of groups which cover the video frame, the sum signal being generated at the faster first information refresh rate and the difference signal or signals being generated at the second slower information refresh rate; and further comprising converting the encoded sum signal and the encoded difference signal or each of the encoded difference signals into analog signals; transmitting the analog signals; receiving the analog signals and recovering therefrom the digital sum and difference signals, and thereafter decoding the video signal by storing the sum signal, storing the difference signal or each of the difference signals and combining the sum and difference signals for corresponding groups of pixels to obtain a pixel value for each pixel of an output video frame corresponding to the pixel value of the corresponding pixel of the input array.
Claim 11
Dependent Claim
97 words
Apparatus for encoding a video signal, comprising: means responsive to the video signal for deriving a representation of low spatial frequency components of the images represented by the video signal; means responsive to the video signal for deriving a representation which includes high spatial frequency components of the images represented by the video signal; means for producing output frames of the low spatial frequency component representation at a first frame refresh rate; and means for producing output frames of the high spatial frequency component representation at a second frame_refresh rate, slower than the first frame refresh rate.
Claim 12
Dependent Claim
97 words
Apparatus for encoding a video signal, comprising: means responsive to the video signal for deriving a representation of low spatial frequency components of the images represented by the video signal; means responsive to the video signal for deriving a representation which includes high spatial frequency components of the images represented by the video signal; means for producing output frames of the low spatial frequency component representation at a first frame refresh rate; and means for producing output frames of the high spatial frequency component representation at a second frame_refresh rate, slower than the first frame refresh rate.
Claim 13
Dependent Claim
24 words
Apparatus as defined in claim 9, in which the second frame refresh rate is in the range from 3 to 15 frames per second.
Claim 14
Dependent Claim
73 words
Apparatus in accordance with claim 9, wherein the video signal is a colour video signal, the said component representations correspond to luminance and two colour difference signals at approximately R-Y and B-Y, and the output frames of the high frequency component representation at the second slower frame refresh rate are in the ranges 3 to 15 frames per second for luminance and for R-Y and 3 to 30 frames per second for B-Y.
Claim 15
Dependent Claim
40 words
Apparatus according to claim 9, 10 or 11, wherein the encoder includes means (2250. Fig.22) for delaying the output frames of the lower spatial frequency component representation with respect to the output frames of the high spatial frequency component representation.
Claim 16
Dependent Claim
106 words
Apparatus in accordance with claim 9, in which the means for deriving a representation of low spatial frequency components includes a low-pass filter (2010) for the video signal and means (2026-2029) for forming weighted sums of corresponding elements of three consecutive scan lines of a frame of the video signal, centered around alternate scan lines of the said frame; and the means for deriving a representation which includes high spatial frequency components includes means (2070) selecting alternately the high frequency signal components of the said alternate scan lines and the low and high frequency signal components of the scan lines between the said alternate scan lines.
Claim 17
Dependent Claim
126 words
Apparatus according to claim 9, in which the encoder includes: means/for storing an input video signal as an array of pixel values; means (600) for interrogating the stored array and for generating a sum signal representative of the sum of the pixel values in a group of pixels and a difference signal representative of the difference between the total of the pixel values of some of the pixels in the group and the total of the pixel values of other pixels in the group, the sum signal and the difference signal being generated for a multiplicity of groups which cover the video frame; the sum signal being generated at the faster information refresh rate and the difference signal being generated at the slower information refresh rate.
Claim 18
Dependent Claim
83 words
Apparatus as defined in claim 14, in which input video frames of the video signal are stored as arrays of pixel values and in which the means for interrogating the stored arrays generates a plurality of distinct different signals representative of the difference between the total of the pixel values of some of the pixels in the group and the total of pixel values of other pixels in the group; each of the difference signals being generated at the slower information refresh rate.
Claim 19
Dependent Claim
52 words
Apparatus in accordance with claim 15, (Figs. 6 and 8) comprising means for interrogating the stored arrays for a series of successive frames, the sum signal being generated for each frame of the series and the distinct difference signals being generated in cyclic succession (690), one for each frame of the series.
Claim 20
Dependent Claim
75 words
Apparatus according to claim 14, 15 or 16, wherein a digital memory (320) in the encoder, for storing input frames of pixels, has a plurality of output ports which operate under the control of output clocks to access simultaneously the pixel values of a plurality of stored pixels, and wherein the means (Figs. 6 and 8) for generating the sum and difference signals includes means for combining the pixel values from the said output ports.
Claim 21
Dependent Claim
46 words
Apparatus for decoding a signal encoded by the apparatus of claim 14 or 15, the decoder including means (12) for storing the sum signal and means (1122-1124) for storing the difference signals, and combining means (Fig. 13) operative to combine the stored sum and difference signals.
Claim 22
Dependent Claim
55 words
Decoding apparatus in accordance with claim 18, wherein the number of pixels in output video frames of the decoder is substantially the same as the number of pixels in the input video frame arrays, and the pixel values of output video frames correspond to pixel values of corresponding pixels of the input video frame arrays.
Claim 23
Dependent Claim
56 words
Decoding apparatus according to claim 18 or 19, including a digital memory (1121) for storing the sum signal and a plurality of further digital memories (1122-1124) for storing the difference signals, the digital memories being clocked in at a relatively slow clock rate and clocked out to the combining means at a relatively fast clock rate.
Claim 24
Dependent Claim
35 words
Decoding apparatus in accordance with claim 20, wherein each of the digital memories holding the difference signals is read out a plurality of times for each time that new information is read into the memory.
Claim 25
Dependent Claim
76 words
Apparatus for transmitting and receiving video signals, including video signal encoding apparatus in accordance with any one of claims 14 to 17, wherein the pixel values are digital pixel values, the apparatus further comprising means for converting the encoded sum signal and encoded difference signals into analog signals, means for transmitting the analog signals, means for recovering the digital sum and difference signals, and decoding apparatus in accordance with any one of claims 18 to 21.
Claim 26
Dependent Claim
29 words
Apparatus in accordance with claim 22, wherein the means for transmitting the analog signals includes coding means for identifying the individual difference signals when the difference signals are recovered.
References Cited (Backward Citations)
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