Other

France Telecom

L'etat Francais

France Telecom Etablissement Autonome De Droit Public

Matra Communication

France Telecom Etablissement Autonome De Droit Public (Centre National

Etat Francais Represente Par Le Ministere Des Postes, Des

Thomson-Cfs

Etat Francais Represente Par Le Ministre Des Postes Et Telecommunications

Etat Francais Represente Par Le Ministre Des Postes, Des

Etat Francais Represented by Le Centre National D'etudes Des

Jacques M Guichard

Georges Buchner

Gerard Eude

Alain Isckia

Alain Poirier

Jacques Labat

Jean-Yves Eouzan

Jean-Claude Hertaux

Geard Eude

Jean-Marc Marczak

Philippe Decaesteke

Marc A Leclercq

Eric Cassimatis

Process for synchronizing the scanning circuit of an image display device

In order to establish a videophone communication from a calling terminal to a called terminal, a communication is established on a first TBCC channel, then a ringing tone is emitted automatically, from the called terminal, to the calling terminal on the first channel and a call is emitted to the telephone set on the second channel B; in response to the unhooking of the telephone handset the two channels are automatically linked from the called terminal; and, in response to a code from the telephone set, the emission is caused of a waiting tone to the calling terminal and a ringing to the called videophone terminal; in the event of acceptance on the part of the subscriber of the called videophone terminal, the establishment of communication is automatically continued in response to the hooking of the set.

Process and terminal for video telephony permitting acceptance, and

Method and device for throughput compression for a videophone camera

Articulated, orientable audiovisual telecommunication terminal

A visual and sound telecommunication system includes an audiovisual terminal, a camera and a handset with earpiece and microphone. The handset has a remote control acting on the terminal and on the camera by way of the terminal.

Visual and sound communication system with remote control means

An apparatus for coding/decoding image signals processes sequential information signals in real time so as to compress the volume of data necessary for representing the corresponding image resulting in a minimum bit rate for transmission of the corresponding image using a transmission network. The coding/decoding apparatus includes a coding arrangement for coding image signals to be transmitted as well as a decoding arrangement for decoding the image signals received. The coding arrangement includes a local image coding loop for images broken down into blocks including a coder incorporating a transformation and quantization arrangement for coding the difference between each block of a local image and the corresponding block of a preceding local image. A decoder of the local image coding loop incorporates a reverse transformation and reverse quantization arrangement for reconstituting each block. The decoding arrangement for decoding the image signals received comprises the decoder of the local image coding loop so as to ensure the decoding of local image blocks and the decoding of the remote image blocks.

Apparatus for the coding/decoding of image signals

An audio and video communications terminal, of the type comprising a housing, a camera provided with an optical system, a display screen, a microphone, a loudspeaker, and a central unit including a sound and image information encoder and decoder, and an interface in association with the elements for communication with another terminal of the same type via a digital transmission network, the terminal further comprising electric motors and clutches for adjusting at least one camera parameter; a manual control suitable for generating control information for adjusting the parameter(s); and a switch for switching between a local adjustment mode in which the control information is applied to the electric motors and clutches, and a remote adjustment mode in which the control information is sent to the other terminal over the digital network in parallel with the sound and image information, and in which control information received from the other terminal, likewise over the digital network and in parallel with sound and image information, is applied to the electric motors and clutches. The invention is applicable to improving user comfort with video telephones.

Audio and video communications terminal with improved adjustments

A table-top terminal for sound and vision communications, of the type associated, in particular, with a telephone set, and comprising a case (100) containing: a display screen monitor (128), a camera (132) having a lens system (130), manual control means, and an electronic assembly for the purposes of control, coding/decoding, and interfacing with a transmission line, wherein, for the purpose of compensating the illumination of a speaker in an environment having overhead ambient lighting and thereby enabling the camera to obtain a balanced image of said speaker, the terminal further includes an auxiliary lighting device (160) having a general emission direction (C) which is essentially upwardly inclined towards the speaker, together with a mechanism for adjusting the light flux emitted by the device as a function of the ambient lighting.

Sound and vision communications terminal including an auxiliary lighting

A terminal for sound and vision communication, of the type associated, in particular, with a telephone set, comprises a case (100) containing a display screen monitor (128), a camera (132) provided with optics (130), an electronic assembly (134) for control, coding/decoding, and telephone line interfacing and control (114). The case (100) comprises a first part (110) via which the terminal is supported on a support surface, and a second part (120) which is hinged to the first part about a substantially horizontal axis (A) and which receives the camera (132) and its optics (130) together with the monitor (128). The terminal is such that, in use, the second part (120) of the case can assume at least two different angular positions relative to the first part (110), corresponding to two different aiming directions (B) for the camera.

Hinged-case sound and vision communications terminal, in particular a

The invention relates to a transmission-reception system for the transmission of animated color images or pictures and sound from two independent channels. The image signal is distributed over two independent channels, the luminance signal occupying one channel, while the chrominance signal, which is multiplexed with the sound, occupies with the sound the other channel. Separate luminance and chrominance signal processors are provided.

Emission-reception system for the transmission of animated color

A telecommunications terminal is provided which has a central unit (100) and a handset (200). The handset houses a microphone (210) and a speaker (220) and is connected to the central unit via a cord (300). The connecting cord has a plurality of wires (301-304) for conveying output signals from the microphone and input signals to the speaker. The telecommunications terminal incorporates at least one function under the manual control of its user. That function is controlled by a switching means (l1, l2; 230) housed in the handset, with the corresponding control signals being conveyed along said cord in the form of phantom D.C. voltages.

Telecommunications terminal with improved control functions

The invention relates to a quantization process in an encoding by transformation for transmission on a low rate link of an image signal, said image signal being processed in the form of blocks, each containing a set of digital data, each block being transformed to produce a transformed block of coefficients (Ci) representing the frequency components of the block, each transformed coefficients of a block being quantified during a scan by comparison with quantization levels, the first being called the threshold, the process being characterized in that the quantization is performed with a threshold (T) able to vary between one transfored coefficient (Ci) and the next (Ci+1) in the scan, depending on whether the transformed coefficient does or does not fulfil the conditions -T&lt;Ci&lt;+T.

Variable threshold quantification process in encoding by transformation

The coding and decoding devices embodying the invention are connected by two paths, a main path and an auxiliary path, of a variable rate digital transmission network. When the main path is capable of dispatching the totality of the information rate that the coding device is able to issue, only a main coder and a main decoder, respectively of the coding and decoding devices, are active. When the main path is not capable of dispatching the totality of the picture information, an auxiliary coder and an auxiliary decoder, respectively of the coding and decoding devices, are also active and the auxiliary path dispatches the part of the information rate that cannot be dispatched by the main path. A decoder and a subtracter are provided in the coding device so as to estimate the part of information not transmitted by the main path.

Method and coding and decoding devices for picture transmission through

A sound and image transmission system which is applicable to television-telephony, uses a single transmission line and multiplexes the image signal and the sound signal with an output which is essentially identical to the rhythm of an encoded image and the sound of the latter image. The encoder and decoder for the image processing lines function for only part of the time, but faster than if they functioned continuously.

Sound and image transmission system

A circuit for the fast calculation of the discrete cosine transform (X.sub.i), 0.ltoreq.i.ltoreq.N-1, in which N=2.sup.n and n is an integer of a signal defined by a sequence (x.sub.i), 0.ltoreq.i.ltoreq.N-1 includes a first adder stage receiving the sequence (x.sub.i), 0.ltoreq.i.ltoreq.N-1, and supplying two sequences (x.sub.i.sup.o) and y.sub.i.sup.i) and 0.ltoreq.i.ltoreq.(N/2)-1, a group of upper half-stages receiving the sequence of x.sup.o.sub.i) and supplying the sequence (X.sub.2q) of the even components of the cosine transform. That group constitutes a circuit for the fast calculation of the cosine transform for a group of (N/2) points and a group of lower half-stages receiving the sequence (y.sub.i) and supplying the sequence (X.sub.2q+1) of the odd components of the cosine transform.

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Paris, France

Jacques M Guichard