EP0685136A1 - Procede d'enregistrement d'images a debit reduit et dispositif pour sa mise en uvre - Google Patents
Procede d'enregistrement d'images a debit reduit et dispositif pour sa mise en uvreInfo
- Publication number
- EP0685136A1 EP0685136A1 EP94905757A EP94905757A EP0685136A1 EP 0685136 A1 EP0685136 A1 EP 0685136A1 EP 94905757 A EP94905757 A EP 94905757A EP 94905757 A EP94905757 A EP 94905757A EP 0685136 A1 EP0685136 A1 EP 0685136A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- image
- recording
- prediction
- channel
- input
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Ceased
Links
Classifications
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B20/00—Signal processing not specific to the method of recording or reproducing; Circuits therefor
- G11B20/10—Digital recording or reproducing
- G11B20/18—Error detection or correction; Testing, e.g. of drop-outs
- G11B20/1879—Direct read-after-write methods
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
- H04N19/50—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using predictive coding
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
- H04N19/50—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using predictive coding
- H04N19/503—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using predictive coding involving temporal prediction
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N5/00—Details of television systems
- H04N5/76—Television signal recording
- H04N5/91—Television signal processing therefor
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N5/00—Details of television systems
- H04N5/76—Television signal recording
- H04N5/91—Television signal processing therefor
- H04N5/92—Transformation of the television signal for recording, e.g. modulation, frequency changing; Inverse transformation for playback
- H04N5/926—Transformation of the television signal for recording, e.g. modulation, frequency changing; Inverse transformation for playback by pulse code modulation
- H04N5/9261—Transformation of the television signal for recording, e.g. modulation, frequency changing; Inverse transformation for playback by pulse code modulation involving data reduction
- H04N5/9262—Transformation of the television signal for recording, e.g. modulation, frequency changing; Inverse transformation for playback by pulse code modulation involving data reduction using predictive coding
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N5/00—Details of television systems
- H04N5/76—Television signal recording
- H04N5/91—Television signal processing therefor
- H04N5/93—Regeneration of the television signal or of selected parts thereof
- H04N5/94—Signal drop-out compensation
- H04N5/945—Signal drop-out compensation for signals recorded by pulse code modulation
Definitions
- the present invention relates to a method for recording images at a reduced rate and a device for its implementation.
- Applications include digital recorders for high definition television.
- CODEC image coding and decoding devices
- the signal emitted is not random. Between each image sample, representing one or more pixels, there are correlation properties. In addition, the eye does not perceive all information in the same way.
- psychovisual coding takes into account the properties linked to the visual receiver, that is to say the eye of the observer. They consist in deceiving the eye at best, by reproducing a signal different from the original signal, but containing information relevant to the observer. This type of coding is irreversible.
- adaptive differential coding does not consist in coding the video signal itself, but the difference between this signal and a prediction signal which is known to the receiver.
- a known type of architecture of an adaptive differential coding device for the transmission of images uses two inter-image prediction loops, also called inter loops, at the input and at the output of the main coding and decoding circuit.
- each loop The purpose of each loop is to reconstruct an estimated image from the current image taken by each loop.
- the reconstructed image is then compared with the following image at the moment when this is transmitted to the input and to the output of the transmission device.
- the inter input loop generally comprises from the input to the output, a decoder, called a local decoder, an addition operator and an image prediction device.
- the image taken by the input loop is decoded by the local decoder then added to the prediction signal estimated from a previous image to reconstruct an image which is compared to the current image present at the input of the device. transmission.
- the image prediction device comprises an image memory and possibly an image estimator with motion compensation.
- the signal transmitted to the input of the transmission channel therefore corresponds to a coded error signal resulting from the difference between the current image present at the input of the device and the prediction signal.
- the error signal is decoded by a second decoder, called a remote decoder, then injected on the second loop which adds to the decoded error signal a prediction signal identical to that delivered by the first loop .
- the prediction signal of the second loop is estimated from the previous transmitted image, reconstructed at the output of the device, taken by the second loop.
- Image transmission devices generally comprise at the input and at the output of the transmission channel a rate adaptation device between the main coding / decoding circuit and the transmission channel which also incorporates an error correction function. due to transmission through the transmission channel.
- digital recorders are generally provided with input and output with error correction devices.
- the subject of the invention is a method of recording images at a reduced bit rate, using differential coding and decoding with adaptive inter-picture prediction, characterized in that it consists, after having introduced means of recording and reading of digital information in a main image coding and decoding circuit, to record a prediction error signal resulting from the comparison between an image to be recorded and a predicted image from the read image previous on at least one recording medium, and to read after recording, the prediction error recorded on the recording medium, and in that it consists in reconstructing an image from the error signal of prediction, read and decoded at the output of the main circuit and an image from a single prediction delivered by a single prediction loop taking the previous reconstructed image, and comparing the image from has the same prediction with the next image to be recorded at the entrance to the main circuit, taking into account recording errors to avoid their propagation from one image to another.
- FIG. 1 a block diagram of an embodiment of a device for implementing the method according to the invention.
- the device according to the invention has the advantages that it allows on the one hand to reduce the overall size of the image recording device by using a single decoder, a single prediction loop and, by including the recording / reading of a digital recorder in the main coding and decoding circuit. It also allows you to correct recording errors to prevent them from spreading from one image to another.
- FIG. 1 An embodiment of a device for implementing the method according to the invention is illustrated in FIG. 1.
- This embodiment comprises a main coding and decoding circuit 1 delimited by a discontinuous closed line and a single loop 2 also delimited by a discontinuous closed line which re-injects a portion of the signal from the input and the output of the main circuit 1. output of the device according to the invention.
- a video signal X is injected at the input of the main circuit 1 onto a first operand input of a subtraction operator 3.
- the video signal X is for example a sequence of television images.
- the output signal e of the subtraction operator 3 is the result of the subtraction of a current image X injected at the input of the main circuit 1 with a prediction P from the prediction loop 2.
- the corresponding signal e a prediction error signal is injected at the input of a coding means 4, or coder, digitally coding the signal e received at the input of the coder 4.
- the output of the coder 4 is coupled to first means 5 of variable length coding and error correction, hereinafter referred to as VLC English abbreviation for Variable Length Coding, making it possible to adapt the bit rate of digital information coming from coder 4 to that of recording and reading means 6 at the input of which the output of the encoder 4 is coupled.
- VLC English abbreviation for Variable Length Coding makes it possible to adapt the bit rate of digital information coming from coder 4 to that of recording and reading means 6 at the input of which the output of the encoder 4 is coupled.
- the output of the recording and reading means 6 is coupled to the input of a second VLC 7, performing the inverse function of the first VLC 5, which is also associated with an error correction function.
- the output of the second VLC 7 is coupled to the input of a decoding means, or decoder 8, at the output of which the error signal ej is restored.
- the output of the decoder 8 is coupled to a first operand input of an addition operator 9.
- the image X reconstructed at the output of the addition operator 9 is taken by loop 2 and injected at the input prediction means 10 comprising an image storage device, not shown, possibly associated with an estimation device, also not shown, performing motion compensation between two consecutive images.
- the output of the prediction means 10 is coupled to both the input and the output of the main circuit 1 respectively by a second operand input of the subtraction operator 3 and by a second operand input of the addition operator 9.
- the image X thus reconstituted takes account of recording errors between two consecutive images.
- An embodiment of the recording and reading means 6 of a device for implementing the method according to the invention is illustrated in FIG. 2.
- This embodiment includes an input E common to a first channel 11, called the direct channel, and to a second channel 12, called the recording / playback channel.
- the output of the recording / playback channel 12 and the output of the direct channel 11 are respectively coupled to a first R / W input and to a second M input of a switching means 13 making it possible to select one of the two channels 11 and 12 for recording followed by reading or for direct reading of a signal between the input E and the output S of the recording and reading means 6.
- the two channels 11 and 12 can each be assimilated to a small transmission channel belonging to a recording device using only one decoder, both local and remote.
- the recording device according to the invention comprising this embodiment makes it possible to integrate the coding and decoding functions in the same housing.
- the notions of "local” and "remote" decoders known in transmission devices lose their meaning.
- a device commonly called in the English language “scanner” generally comprises separate write and read heads. This makes it possible to check, in operating mode "Read after Write” Anglo-Saxon name for reading after writing, the validity of the current recording at any time.
- the read and write heads continuously scan the recording medium, for example a magnetic tape, thus allowing the almost instantaneous reading of what has just been recorded on the recording medium.
- Anglo-Saxon designation meaning "control” the recording function of the video recorder is disconnected. In this operating mode, only the direct reading function via the direct reading channel of the video recorder is operational for checking the information to be recorded.
- the "Read after Write” R / W and “monitoring” M modes are selected by the switching device 13.
- the recording / playback channel 12 allows digital information to be written to the recording medium, such as a magnetic tape, and then to read this information almost instantly after recording to the tape.
- the information read on the magnetic tape is then transmitted through the magnetic recording / reading channel 12 of the video recorder, used as a transmission channel, at the output S of the recording and reading means 6.
- the information transmitted undergoes a simple delay due to processing which in most cases, for television images for example, is of the order of the duration of a video frame, ie approximately 20 ms. This delay is compensated in loop 2.
- the recording / reading channel 12 being part of the main coding / decoding circuit 1, the errors linked to the recording are taken into account by the device at the time of reading, that is to say when the information is transmitted to the output S of the recording and playback facilities 6.
- the recording / playback channel 12 is disconnected.
- the direct read channel 11 of the recorder selected by the switching device 13 is then used as a transmission channel to allow the device according to the invention to continue to operate in closed loop.
Abstract
Description
Claims
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR9301607A FR2701623B1 (fr) | 1993-02-12 | 1993-02-12 | Procédé d'enregistrement d'images à débit réduit et dispositif pour sa mise en Óoeuvre. |
FR9301607 | 1993-02-12 | ||
PCT/FR1994/000112 WO1994018794A1 (fr) | 1993-02-12 | 1994-01-28 | Procede d'enregistrement d'images a debit reduit et dispositif pour sa mise en ×uvre |
Publications (1)
Publication Number | Publication Date |
---|---|
EP0685136A1 true EP0685136A1 (fr) | 1995-12-06 |
Family
ID=9444008
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP94905757A Ceased EP0685136A1 (fr) | 1993-02-12 | 1994-01-28 | Procede d'enregistrement d'images a debit reduit et dispositif pour sa mise en uvre |
Country Status (5)
Country | Link |
---|---|
EP (1) | EP0685136A1 (fr) |
JP (1) | JPH08506459A (fr) |
FR (1) | FR2701623B1 (fr) |
SG (1) | SG65580A1 (fr) |
WO (1) | WO1994018794A1 (fr) |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5763978A (en) * | 1980-10-06 | 1982-04-17 | Nec Corp | Transmitter of picture signal |
JPS60173984A (ja) * | 1984-02-20 | 1985-09-07 | Fujitsu Ltd | 符号伝送誤り訂正方式 |
FR2660138B1 (fr) * | 1990-03-26 | 1992-06-12 | France Telecom Cnet | Dispositif de codage/decodage de signaux d'image. |
JPH04358486A (ja) * | 1991-06-04 | 1992-12-11 | Toshiba Corp | 高能率符号化信号処理装置 |
JP2699703B2 (ja) * | 1991-07-31 | 1998-01-19 | 松下電器産業株式会社 | 動き補償予測方法とそれを用いた画像信号符号化方法 |
-
1993
- 1993-02-12 FR FR9301607A patent/FR2701623B1/fr not_active Expired - Fee Related
-
1994
- 1994-01-28 JP JP6517706A patent/JPH08506459A/ja active Pending
- 1994-01-28 EP EP94905757A patent/EP0685136A1/fr not_active Ceased
- 1994-01-28 SG SG1996007109A patent/SG65580A1/en unknown
- 1994-01-28 WO PCT/FR1994/000112 patent/WO1994018794A1/fr not_active Application Discontinuation
Non-Patent Citations (1)
Title |
---|
See references of WO9418794A1 * |
Also Published As
Publication number | Publication date |
---|---|
SG65580A1 (en) | 1999-06-22 |
FR2701623B1 (fr) | 1995-11-17 |
JPH08506459A (ja) | 1996-07-09 |
WO1994018794A1 (fr) | 1994-08-18 |
FR2701623A1 (fr) | 1994-08-19 |
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Legal Events
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PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
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Owner name: THOMSON MULTIMEDIA |
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17Q | First examination report despatched |
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STAA | Information on the status of an ep patent application or granted ep patent |
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18R | Application refused |
Effective date: 19980530 |