EP0180345A2
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EP
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Method and apparatus for picture signal encoding and decoding
Assignee: NEC Corp
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Filing: 1985-10-03
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Granted: —
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Expires: 2005-10-03
Abstract
Abstract In a code conversion system for picture signals, e.g. television signals, a coding parameter is selected by using N scanning lines of the picture signal as a unit so as to encode the picture signal by using the coding parameter. When coding operations with respect to the picture signal carried out every N scanning lines are repeated in succession and provide the same coding result, a repetition number is produced to encode the coding operations, thus providing a code conversion system suitable for a low transmission bit rate of picture signals. The system is especially applicable to a predictive coding system. Then the input picture signal (1000) is supplied to a predictive coding circuit (20) and a motion vector detector (10). The motion vector (2000) is supplied to the predictive coding circuit (20) and to a variable length coding circuit (30) which also receives a prediction error signal (2030) from the predictive coding circuit (20). The variable length coding circuit (30), under the control of a coding control circuit (40) produces a multiplexed output (3000) comprising coding mode, motion vector code, and prediction error code signals. The picture signal can be recovered as an output (6000) by a variable length decoding circuit (50) and a predictive decoding circuit (60) hav ing complementary processes.
Inventors
- 👤 Toshio C/O Nec Corporation Koga
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-28 16:26
CPC Classifications
H; H04; H04N; H04N19/00; H04N19/50; H04N19/503; H04N19/51; H04N19/30
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
90 words
A code conversion method for a picture signal wherein an operation is carried out to select a coding parameter by using N scanning lines (N is a positive integer) of said picture signal as a unit so as to encode said picture signal by using said coding parameter, characterized in that when coding operations with respect to said picture signal carried out every N scanning lines are repeated in succession to provide the same coding result, an operation is carried cut to encode a repetition number of said coding operations.
Claim 2
Dependent Claim
90 words
A code conversion method for a picture signal wherein an operation is carried out to select a coding parameter by using N scanning lines (N is a positive integer) of said picture signal as a unit so as to encode said picture signal by using said coding parameter, characterized in that when coding operations with respect to said picture signal carried out every N scanning lines are repeated in succession to provide the same coding result, an operation is carried cut to encode a repetition number of said coding operations.
Claim 3
Dependent Claim
219 words
An encoder for a picture signal comprising: a) code conversion means responsive to successive picture signals correlative with each other to apply a predetermined code conversion based on quantization to each picture signal so as to limit the output level of the picture signal on the basis of a quantization for selecting one of quantization characteristics in accordance with a coding parameter selected using N scanning lines as a unit, b) first coding means operative to encode information indicative of said coding parameter every N scanning lines, c) second coding means operative to encode said picture signal outputted from said code conversion means every N scanning lines, a) judging means provided in said first coding means to judge as to whether an output of said first coding means is the same as that of immediately preceding N scanning lines to produce a coincidence signal when both the outputs are coincident with each other, e) third coding means, provided in said first coding means, being repsonsive to said coincident signal from said judging means to encode a repetition number of the coding operations every N scanning lines, and f) multiplexer means operative to multiplex outputs from said first and second coding means or outputs from said first, second and third means depending upon the output status of said judging means.
Claim 4
Dependent Claim
219 words
An encoder for a picture signal comprising: a) code conversion means responsive to successive picture signals correlative with each other to apply a predetermined code conversion based on quantization to each picture signal so as to limit the output level of the picture signal on the basis of a quantization for selecting one of quantization characteristics in accordance with a coding parameter selected using N scanning lines as a unit, b) first coding means operative to encode information indicative of said coding parameter every N scanning lines, c) second coding means operative to encode said picture signal outputted from said code conversion means every N scanning lines, a) judging means provided in said first coding means to judge as to whether an output of said first coding means is the same as that of immediately preceding N scanning lines to produce a coincidence signal when both the outputs are coincident with each other, e) third coding means, provided in said first coding means, being repsonsive to said coincident signal from said judging means to encode a repetition number of the coding operations every N scanning lines, and f) multiplexer means operative to multiplex outputs from said first and second coding means or outputs from said first, second and third means depending upon the output status of said judging means.
Claim 5
Dependent Claim
90 words
An encoder as set forth in claim 2, wherein said code conversion means comprises a vector detection circuit(10 operative to detect a motion vector from saio input (20) picture signal, a prediction coding circuit/responsive to said input picture signal and said motion vector from said (10) vector detection circuit/to produce a prediction signal so as to effect predictive coding for production of a prediction error signal, thereafter being subject to quantization to select one of quantization characteristics in accordance with a coding control signal fed from a coding cotrol circuit(40).
Claim 6
Dependent Claim
53 words
An encoder as set forth in claim 3, wherein there ( 3 0) is provided a variable length coding circuit / responsive to said coding control signal, said prediction error signal and said motion vector, said variable length coding (30) circuit/including said first and second coding means (300, 302) and-said multiplexer means (303).
Claim 7
Dependent Claim
131 words
An encoder as set forth in claim 4, wherein said (300) (310) first coding means/comprises mode coding means/responsive to said coding control signal to encode said coding control signal with a line synchronization being added (312) thereto, a subtractor/operative to calculate a difference between a current coding control signal and a coding control signal delayed by a time required for scanning N (313) lines, a coincidence circuit/functioning as said judging means to produce said coincidence signal when it detects zero, a counter (314) responsive to said coincidence signal to (315) make an incremental operation, a coding circuit/operative to encode a counted value indicative of repetition number, (317) and a multiplexer/operative to multiplex said coding mode signal to which said line synchronization is added and an decoded output indicative of repetition number.
Claim 8
Dependent Claim
52 words
An encoder as set forth in claim 5, wherein said (316) first means further comprises a control circuit responsive (313) to said output from said zero detection circuit/and a signal indicating that coding operation in saic second (302) means/is completed to deliver a control signal to said 314) counter/and said multiplexer (317).
Claim 9
Dependent Claim
85 words
An encoder as set forth in claim 4, wherein said (30) variable length coding circuit/further comprises a coding circuit (301) operative to encode said motion vector from said (10) (304) vector detection circuit¿ and a buffer memory/operative to effect speea matching between a speec of information obtained as a multiplexed output from said multiplexer (303) means/and a transmission speed to transmit coded information thus speed-matched and to deliver a signal indicative of buffer occupancy to said coding control (40) means/for creating said coding control signal.
Claim 10
Dependent Claim
181 words
A decoder for a picture signal, said decoder responsive to the picture signal coded so that its output level is limited to a predetermined range in accordance with a coding parameter selected using N scanning lines as a unit, wherein when coding operations with respect to said picture signal carried out every N scanning lines are repeated in succession, said coded picture signal includes a coded repetition number of the coding operations, saia decoder comprising: a) means responsive to information indicating said coding parameter, said picture signal and said repetition number of said coding operations to separate them from each other, b) first decoding means operative to decode said coding parameter from said separating means, c) second decoding means operative to decode said coded picture signal from said separating means by using an output from said first decoding means, and d) control means responsive to said information indicative of said coded repetition number of said coding operations from said separating means, to produce a decoded picture signal from said second decoding means by a decoded repetition number of said coding operations.
Claim 11
Dependent Claim
181 words
A decoder for a picture signal, said decoder responsive to the picture signal coded so that its output level is limited to a predetermined range in accordance with a coding parameter selected using N scanning lines as a unit, wherein when coding operations with respect to said picture signal carried out every N scanning lines are repeated in succession, said coded picture signal includes a coded repetition number of the coding operations, saia decoder comprising: a) means responsive to information indicating said coding parameter, said picture signal and said repetition number of said coding operations to separate them from each other, b) first decoding means operative to decode said coding parameter from said separating means, c) second decoding means operative to decode said coded picture signal from said separating means by using an output from said first decoding means, and d) control means responsive to said information indicative of said coded repetition number of said coding operations from said separating means, to produce a decoded picture signal from said second decoding means by a decoded repetition number of said coding operations.
Claim 12
Dependent Claim
36 words
A decoder as set forth in claim 8, wherein there (50). is provided a variable length decoding circuit/for performing functions of said separating means, said first (500, 502) and second decoding meaner and said control means.
Claim 13
Dependent Claim
36 words
A decoder as set forth in claim 9, wherein said (50) variable length decoding circuit/includes a first decoding (500) circuit/operative to decode said coding parameter and said information indicative of repetition number of said coding operations.
Claim 14
Dependent Claim
55 words
A decoder as set forth in claim 10, wherein when said picture signal is decoded based on a predictive coding system, said variable length decoding circuit (50) (502) further comprises a second decoding circuit/operative to decode a coded prediction error signal, and a third (501) decoding circuit / operative to decode a coded motion vector.
Claim 15
Dependent Claim
29 words
A decoder as set forth in claim 11, wherein said (50) variable length decoding circuit/further comprises a (503) buffer memory/for transmission speed matching provided at tne preceding stage thereof.
Claim 16
Dependent Claim
128 words
A decoder as set forth in claim 12, wherein said first decoding circuit comprises a mode decoding circuit(510) operative to decode said coding mode signal, a latch (513) circuit/for latching said decoded coding mode signal, a (511) decoder/operative to decode said information indicative of (513) repetition number to allow said latch circuit/to latch said decoded coding mode signal, and a control circuit(512) responsive to coded information indicative of repetition number from said detector and a signal indicating that decoding operation is completed from said second decoding (502) circuit/to output a command for stopping latch operation (513) to saia latch circuit/, to output a command for stopping repetitive operation to said third decoding circuit and to output a command for initiating decoding operation to said mode decoding circuit (510).
References Cited (Backward Citations)
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