US4369464A
Expired / Lapsed
US
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Digital video signal encoding and decoding system
Assignee: Individual
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Filing: 1980-07-08
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Granted: 1983-01-18
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Expires: 2000-07-08
Abstract
Abstract The system encodes a high rate digital video signal conveying picture elements into a low rate digital signal conveying words representative of some picture elements. The system comprises a frame store, a movement detector for detecting the movement area in one frame with respect to the preceding frame, a predictor, a bit distributing circuit for selecting the picture elements to be transmitted, a PCM encoder which encodes the DPCM words of the selected elements according to a quantization law and an interpolating circuit. The number of bits NB allocated to each line in the low rate digital signal is made constant. The movement detector detects two ledge elements defining each line moving area and thereby deduces the maximum number NP and average number B of bits in the element words to be encoded and transmitted. The bit distributing circuit down-counts the bits which remain for allocation to the line and the element words which remain likely to be encoded and compares these down-count totals for selectively controlling the encoding of a moving area element word. A transmitted and encoded word represents the level number with respect to a quantization law associated with the line.
Inventors
- 👤 Jean-Pierre Temime
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 00:16
CPC Classifications
H; H04; H04N; H04N19/00; H04N19/80; H04N19/82; H04N19/10; H04N19/102; H04N19/124; H04N19/134; H04N19/146; H04N19/152; H04N19/50; H04N19/503; H04N19/60; H04N19/61
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
458 words
A digital video system having an encoding device in a transmitter for encoding a digital video signal at a high given rate constituted of PCM words which have a predetermined bit number and are representative of consecutive picture elements of a scanned picture, into a digital encoded signal transmitted on a low rate digital transmission medium conveying words which are representative of present picture elements, the levels of which are susceptible to variation relative to those corresponding to the previous picture, said encoding device comprising: picture storing means for storing the transmitted picture element words after the words have been interpolated; means for detecting the moving area of the picture with respect to the previous stored picture in response to a comparison of the word difference between two words representative of two corresponding elements of the present picture and the previous stored picture with a predetermined threshold; the number of data bits NB allocated to each line of a picture in said digital transmission medium being constant and the average number of bits B allocated to each encoded signal word of a line being greater than or equal to a first predetermined integer; said moving area detecting means producing for each line of a picture the coordinates of the two ledge picture elements defining the moving area of said present picture with respect to the corresponding line of said previous pictures; means for deducing the number NP of picture elements in said moving area of the line likely to be encoded from the produced coordinates of said two ledge picture elements and for deducing said average number of bits B for said line from the ratio NB/NP of said numbers NB and NP; a linear predicting means for delivering DPCM predicted picture element words from the stored picture element words and present picture element words; first and second down-counting means controlled by said movement area detecting means and having their counts C 1 , C 2 set to NB and NP at the start of the moving area of each present picture line for down-counting the number of bits remaining to be allocated to said line and the number of picture element words remaining likely to be encoded at the line element frequency; means connected to down-counting means for comparing the counts of said first and second down-counting means to select the DPCM words representing the picture elements to be transmitted each time C 1 /B≧C 2 ; means receiving said DPCM words and controlled by said comparing means for encoding, according to a predetermined quantization law, said selected DPCM words to multiplex said selected DPCM words in said digital transmission medium; and means connected to said encoding means for linearly interpolating the PCM unselected picture element words.
Claim 2
Dependent Claim
458 words
A digital video system having an encoding device in a transmitter for encoding a digital video signal at a high given rate constituted of PCM words which have a predetermined bit number and are representative of consecutive picture elements of a scanned picture, into a digital encoded signal transmitted on a low rate digital transmission medium conveying words which are representative of present picture elements, the levels of which are susceptible to variation relative to those corresponding to the previous picture, said encoding device comprising: picture storing means for storing the transmitted picture element words after the words have been interpolated; means for detecting the moving area of the picture with respect to the previous stored picture in response to a comparison of the word difference between two words representative of two corresponding elements of the present picture and the previous stored picture with a predetermined threshold; the number of data bits NB allocated to each line of a picture in said digital transmission medium being constant and the average number of bits B allocated to each encoded signal word of a line being greater than or equal to a first predetermined integer; said moving area detecting means producing for each line of a picture the coordinates of the two ledge picture elements defining the moving area of said present picture with respect to the corresponding line of said previous pictures; means for deducing the number NP of picture elements in said moving area of the line likely to be encoded from the produced coordinates of said two ledge picture elements and for deducing said average number of bits B for said line from the ratio NB/NP of said numbers NB and NP; a linear predicting means for delivering DPCM predicted picture element words from the stored picture element words and present picture element words; first and second down-counting means controlled by said movement area detecting means and having their counts C 1 , C 2 set to NB and NP at the start of the moving area of each present picture line for down-counting the number of bits remaining to be allocated to said line and the number of picture element words remaining likely to be encoded at the line element frequency; means connected to down-counting means for comparing the counts of said first and second down-counting means to select the DPCM words representing the picture elements to be transmitted each time C 1 /B≧C 2 ; means receiving said DPCM words and controlled by said comparing means for encoding, according to a predetermined quantization law, said selected DPCM words to multiplex said selected DPCM words in said digital transmission medium; and means connected to said encoding means for linearly interpolating the PCM unselected picture element words.
Claim 3
Dependent Claim
110 words
A digital video system as claimed in claim 1, in which said moving area detecting means further comprises means triggered at the start of the visible portion of each line for counting the elements of said line and means for controlling the reading of said counting means when the absolute difference values of a predetermined number of PCM consecutive picture element words of two corresponding lines of said present picture and said previous picture exceed said threshold and when the differences relative to the PCM consecutive picture element words have the same sign to produce said coordinates of said two ledge picture elements defining moving area of the present line.
Claim 4
Dependent Claim
74 words
A digital video system as claimed in claim 1 or 2, in which said number NP deducing means comprises comparing means for limiting said average number of bits B allocated to each encoded signal word to be equal to a second predetermined integer which said ratio NB/NP is more than a second predetermined integer, and to be equal to said first predetermined integer when said ratio NB/NP is less than said first predetermined integer.
Claim 5
Dependent Claim
118 words
A digital video system as claimed in claim 1, in which said encoding means comprises a PCM encoder for delivering for each selected DPCM picture element word a B-bit word which is representative of the number of the quantization law level of said selected DPCM word and which is multiplexed in said digital transmission medium, a PCM decoder connected to said DPCM encoder for delivering for each B-bit level word a decoded word having said predetermined number of bit number which is representative of the amplitude of the selected DPCM word quantization level and means for adding said decoded word to the corresponding DPCM predicted word in a PCM selected picture element word applied to said interpolating means.
Claim 6
Dependent Claim
111 words
A digital video system as claimed in claim 4, comprising means for calculating the maximum and average values DMAX, D of words in DPCM code for all the picture elements in said moving area of a line L and in which said encoding means selects a quantization law for each line, such that the quantization levels are equidistributed so half are between -D and +D and half are between -DMAX and -D and between D and DMAX and are equal in number to 2 B , the means for calculating including means for computing the quantization level corresponding to this law for each selected DPCM picture element word of said line.
Claim 7
Dependent Claim
97 words
A digital video system as claimed in claim 5, comprising delay means for delaying each line of said high rate digital video signal by a duration of two lines and in which for each line, said moving area detecting means calculating said coordinates of said two ledge picture elements of said moving area of said line during the reception of said line, said maximum and average value calculating means performing said calculation during the reception of the following first line and said encoding means encodes said selected DPCM words during the reception of the following second line.
Claim 8
Dependent Claim
104 words
A digital video system as claimed in claim 5 or 6, in which said maximum and average values calculating means comprises predicting means controlled by said moving area detecting means and analogous to said linear predicting means for calculating DPCM picture element words for all the elements in said moving area of said line based on the PCM picture element words of the corresponding elements transmitted by said high rate digital video signal and element picture words determined by predictions related to transmitted and possibly delayed high rate digital video signal words and to encoded and/or interpolated words stored in said picture storing means.
Claim 9
Dependent Claim
141 words
A digital video system as claimed in claim 4, in which said DPCM encoder comprises means for storing the level numbers of a plurality of predetermined quantization laws and means for storing words representative of the level amplitudes of said quantization laws and in which said count comparing means selects a pair of storage means relating to a quantization law having 2 B levels as a function of said average bit number B and for each selected DPCM element picture word so that said encoder produces a PCM level number word by comparing the selected DPCM element picture word with the level amplitudes of the selected quantization law so that the DPCM decoder produces a decoded word representative of a selected quantification law level by comparing said produced PCM level number word with the level numbers of said selected quantization law.
Claim 10
Dependent Claim
77 words
A digital video system as claimed in claim 8, comprising delay means for delaying each line of said high rate digital video signal by a duration of one line, and in which, for each line, said moving area detecting means calculates said coordinates of said two ledge picture elements of said moving area of said line during reception of said line and said encoding means encodes said selected DPCM words during the reception of the following line.
Claim 11
Dependent Claim
98 words
A digital video system as claimed in claim 4 in which said linear interpolating means comprises means controlled by said count comparison means for distinguishing the PCM selected encoded picture element words and the subsampling order of the PCM untransmitted and unselected subsampled picture element word relative to the moving area of each line, where the subsampling order is greater than or equal to two, and means connected to the output of the adding means for linearly interpolating each subsampled picture element word as a function of its subsampled order and the immediately neighbouring selected picture element words.
Claim 12
Dependent Claim
41 words
A digital video system as claimed in claim 1 or 10, comprising lowpass digital filtering means interconnected between said linear interpolating means and the input of said picture storing means for filtering solely said PCM selected and subsampled element picture words.
Claim 13
Dependent Claim
67 words
A digital video system as claimed in claim 11, in which said filtering means selectively filters said PCM selected and subsampled words of each line by comparing the number NP of elements in said moving area of said line with said constant number of bits NB in terms of the maximum subsampling order likely to be produced by encoding said DPCM picture element words of said line.
Claim 14
Dependent Claim
99 words
A digital video system as claimed in claim 1, in which the number of bits allocated to each line in said digital transmission medium includes a predetermined number of bits which precede said number of data bits NB and which are assigned to a line preamble, said line preamble comprising: (a) a line synchronizing word, (b) words for indicating discriminations regarding the line encoding in said DPCM encoding means and the prediction in said linear predicting means, and (c) two words representative of said coordinates of said two ledge picture elements which define said moving area of said line.
Claim 15
Dependent Claim
248 words
A digital video system as claimed in claim 1 wherein a receiver responsive to the encoded digital signal includes a decoding device for decoding said digital encoded signal from digital transmission medium into a digital video signal having said high given rate, said decoding device comprising: picture storing means for storing the received picture element words after the words have been interpolated; linear predicting means analogous to that of said encoding device for delivering predicted picture element words from stored words; means receiving said coordinates of said two ledge picture elements defining the moving area of each line for thereby deducing said number NP of said picture elements of said line moving area and the number of said data bits B allocated to each encoded signal word; means receiving the encoded signal words for decoding said encoded words into decoded word as a function of said predetermined law; down-counting means and comparing means analogous to those of said encoding device for controlling the reading of said DPCM encoded words in said decoding means at the frequency equal to said high given rate to deduce the PCM selected element picture words by addition to the corresponding predicted words; and means connected to said decoding means for linearly interpolating the PCM unreceived element picture words of said moving area of said line as a function of said selected and received element picture words so as to store the PCM selected and interpolated picture element words in said picture storing means.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-01-17 | 1986-07-19 | 1987-01-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-01-17 | 1990-07-19 | 1991-01-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-01-17 | 1994-07-19 | 1995-01-18 | $7700.00 | Window Closed / Lapsed |