US3883686A
Expired / Lapsed
US
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Method to reduce the effect of a loss of information during transmission compressed band width and device for carrying out the method
Assignee: Telefonaktiebolaget LM Ericsson AB
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Filing: 1973-09-20
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Granted: 1975-05-13
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Expires: 1993-09-20
Abstract
Abstract The invention relates to a method and a device for reducing the effect of a loss of information during transmission at compressed band width, particularly during transmission at compressed band width of a PCM-signal. Each of the serially generated PCM-words indicates the light intensity in picture elements that are serially scanned in a TV-frame, the number of transmitted PCMwords in each TV-frame being less than the number of generated PCM-words. According to the invention the effect of the loss of picture information is reduced in such a manner that when band width comprsssion is made TV-line by TV-line the loss will alternately occur on the left and right edges of the TV-lines on the screen viewed downwards in consecutive order and when band width compression is made TV-field by TV-field the loss will alternately occur on the upper and lower edges of the screen, the loss of picture information only appearing as a lesser degree of resolution along the respective edges of the screen.
Inventors
- 👤 Anton Christian Jacobaeus
- 👤 Lars Ake Wern
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 22:03
CPC Classifications
H; H04; H04N; H04N19/00
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
179 words
Method for reducing the effect of a loss of information during transmission at compressed bandwidth, particularly during transmission at compressed bandwidth of a PCM-signal in which sequentially generated PCM-words indicate the light intensity of picture elements sequentially scanned in a TV-frame, the number of transmitted PCM-words in each TV-frame being less than the number of generated PCM-words, said method comprising the steps of sequentially generating during the scanning of a TV-picture first PCM-words representing the light intensity of the picture elements of the TV-picture, forming a first group of sequential first PCM-words representing one set of picture elements of a TV-picture, forming a second group of sequential first PCM-words representing another set of picture elements of the TV-picture, sequentially in a first order recoding the PCM-words of the first group to second PCM-words representing compressed information about the picture elements of the odd TV-fields; sequentially in an order opposite said first order recoding the PCM-words of the second group to second PCM-words representing compressed information about the picture elements of the even TV-fields, and sequentially transmitting the second PCM-words.
Claim 2
Dependent Claim
179 words
Method for reducing the effect of a loss of information during transmission at compressed bandwidth, particularly during transmission at compressed bandwidth of a PCM-signal in which sequentially generated PCM-words indicate the light intensity of picture elements sequentially scanned in a TV-frame, the number of transmitted PCM-words in each TV-frame being less than the number of generated PCM-words, said method comprising the steps of sequentially generating during the scanning of a TV-picture first PCM-words representing the light intensity of the picture elements of the TV-picture, forming a first group of sequential first PCM-words representing one set of picture elements of a TV-picture, forming a second group of sequential first PCM-words representing another set of picture elements of the TV-picture, sequentially in a first order recoding the PCM-words of the first group to second PCM-words representing compressed information about the picture elements of the odd TV-fields; sequentially in an order opposite said first order recoding the PCM-words of the second group to second PCM-words representing compressed information about the picture elements of the even TV-fields, and sequentially transmitting the second PCM-words.
Claim 3
Dependent Claim
24 words
The method of claim 1 wherein said first and second groups of first PCM-words represent the odd and even lines, respectively, of a TV-frame.
Claim 4
Dependent Claim
24 words
The method of claim 1 wherein said first and second group of first PCM-words represent the odd and even picture fields in a TV-frame.
Claim 5
Dependent Claim
19 words
The method of claim 1 wherein the number of first PCM-words in the first and second groups are equal.
Claim 6
Dependent Claim
172 words
In a system for transmitting TV-pictures, apparatus for transmitting at compressed bandwidth a PCM-signal representing the light intensity of picture elements sequentially scanned in a TV-frame conprising: a coder means for sequentially coding analog light intensity signals to first PCM-words, each PCM-word representing the light intensity of a picture element; storage means for sequentially registering the first PCM-words representing a first set of the picture elements in a first group and for sequentially registering the first PCM-words representing a second set of picture elements in a second group, and for sequentially reading out the first PCM-words of said first group and said second group so that the words of one of the groups are read out in the same order as the first PCM-words are generated by said coder means and the words of the other group are read out in the opposite order; and recoder means recEiving the read-out first PCM-words from said storage means for recoding said first PCM-words to second PCM-words representing compressed coded information about the picture elements.
Claim 7
Dependent Claim
172 words
In a system for transmitting TV-pictures, apparatus for transmitting at compressed bandwidth a PCM-signal representing the light intensity of picture elements sequentially scanned in a TV-frame conprising: a coder means for sequentially coding analog light intensity signals to first PCM-words, each PCM-word representing the light intensity of a picture element; storage means for sequentially registering the first PCM-words representing a first set of the picture elements in a first group and for sequentially registering the first PCM-words representing a second set of picture elements in a second group, and for sequentially reading out the first PCM-words of said first group and said second group so that the words of one of the groups are read out in the same order as the first PCM-words are generated by said coder means and the words of the other group are read out in the opposite order; and recoder means recEiving the read-out first PCM-words from said storage means for recoding said first PCM-words to second PCM-words representing compressed coded information about the picture elements.
Claim 8
Dependent Claim
22 words
The apparatus of claim 5 wherein said first and second groups are associated with odd and even lines respectively of a TV-frame.
Claim 9
Dependent Claim
22 words
The apparatus of claim 5 wherein said first and second groups are associated with odd and even fields, respectively, of a TV-frame.
Claim 10
Dependent Claim
104 words
The apparatus of claim 5 further comprising a derecoder means for sequentially decoding said second PCM-words to third PCM-words identical to said first PCM-words, another storage means for sequentially in the same order registering in a third group the third PCM-words identical to the first PCM-words of said first group and for sequentially in the same order registering in a fourth group the third PCM-words identical to the first PCM-words of said second group; and decoder means for sequentially in the same order decoding the third and fourth groups of PCM-words to form a signal representing the original light intensity of the picture elements.
Claim 11
Dependent Claim
19 words
The apparatus of claim 8 wherein the number of first PCM-words in the first and second groups are equal.
Claim 12
Dependent Claim
18 words
The apparatus of claim 8 wherein each of the storage means comprises a shift register for each group.
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) | 1978-05-12 | 1978-11-11 | 1979-05-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-05-12 | 1982-11-11 | 1983-05-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-05-12 | 1986-11-11 | 1987-05-13 | $7700.00 | Window Closed / Lapsed |