U.S. Philips Corporation

Koninklijke Philips Corporation N.V.

St-ericsson Sa

St-ericsson (france) Sas

Oct Circuit Technologies International Limited

Antoine Chouly

Americo Brajal

Stéphane Auberger

Delphine Legrand

David Gianella

Sabine V Giorgi

V&eacute;ronique Brun

Khaled Fazel

Bruno Ballarin

Laurent Rouvellou

Estelle Lesellier

Flavio Daffara

Sabine Jourdan

Américo Brajal

Am&eacute;rico Brajal

Olivier Pothier

Fazel Khaled

Sandrine Merigeault Rhein

Josep Casals Castane

Stephane Auberger

Methods of processing a frame in a video sequence of digital images are provided. The methods include determining a global motion vector for the frame relative to a previous frame in the sequence, deriving a jitter function from the global motion vector, the jitter function including an estimate of undesired motion of the frame relative to the previous frame, and determining whether the frame is blurred above a first predetermined threshold. If the frame is blurred above the first predetermined threshold, stabilizing the frame using the jitter function and applying a deblur function to the frame.

Video stabilisation with deblurring

An image sequence comprises at least a first image and a second image. A motion vector (MV(1)) is associated to these first and second images and is defined in a coordinate system having at least a first direction and a second direction, the second direction being different from said first direction. This motion vector has a first previous component value (MV(0)) in the first direction. A method processes both images in order to determine an estimate of the motion vector based on the first previous component value. To this purpose, the method defines a first image portion in the first image and a second image portion in the second image based on the first previous component value of the motion vector. Then, the method determines a first characteristics vector for the first image in the first image portion and a second characteristics vector for the second image in the second image portion. The first and second characteristics vectors are compared to estimate a first shift value between the first and second images. At last, a second current component value and a first current component value are obtained and the motion vector is defined by these first and second current component values.

Global motion vector estimation

The invention relates to a method for estimating a blurriness value based on a series of at least two frames acquired within a period of time greater than or equal to a given exposure time, the frames being grouped in at least one couple of frames, characterized in that it comprises determining, for each couple of frames of the series, first and second values corresponding to a displacement according to a first direction and a second direction, between the first frame and the second frame of a couple of frames, determining a first blur measure for one direction among the first and second directions by calculating a metric based on the displacement values for each couple of frames of at least a subset of the series, determining a second blur measure for the other direction among the first and second directions by calculating a metric applied to the displacement values for each couple of frames of the series of frames and determining a blurriness value based on the first and second blur measures.

Estimation of picture motion blurriness

The invention particularly relates to a method for identifying an image acquisition feature of a digital image oriented in a coordinate system having a reference axis. According to the invention, this method comprises the steps of: (A) detecting the contours of each distinctive element of the image; -(B) forming a list including each contour constituted by a rectilinear segment; (C) searching, in the list of rectilinear contours, a pair of significant rectilinear segments; (D) in the case where step (C) is successful, checking for a condition of relative symmetry of the significant rectilinear segments with respect to the reference axis; and (E) producing, respectively in the case where step (D) is successful and in the case where one of steps (C) and (D) fails, a data respectively representative of the presence and absence of perspective in the image acquisition, with respect to the reference axis.

Method and device for identifying an image acquisition feature of a digital image and apparatus for implementing such a device

According to one example embodiment, a communication system includes a transmitter and a receiver for receiving symbols from a phase-shift shift keying modulation. The system also includes estimation means for estimating a frequency error relating to a symbol based on a sequence of symbol phases. The receiver includes calculation means for calculating a phase sequence, called an initial sequence, based on decisions made on symbols. The receiver also includes means for detecting and correcting phase jumps in this initial sequence in order to supply a phase sequence, called a final sequence, to the frequency error estimation means.

Detection and correction of phase jumps in a phase sequence

The invention relates to digital transmissions. It particularly relates to a new transmission system (DVB-S2), which is backward compatible with a primary transmission system (DVB-S), enabling a receiver of the primary system to receive signals transmitted by a transmitter of the new transmission system. The principle of the invention is based on using a hybrid QPSK/Non-Uniform 8-PSK modulation. The hybrid modulation is specified by a periodic binary pattern indicating, for each symbol, which modulation is used.

Backward compatible DVB-S standard transmission system

A digital transmission system utilizing data coding at the transmitter and data decoding at the receiver, the decoding being iterative, reliability data about soft decisions being calculated for each iteration. The last iteration results in a hard decision. Soft decisions are transformed so as to normalize the mean value of the reliability data, using evolutive weighting of the soft decisions with the received data. The coding is preferably a product code concatenated with a block code such as, for example, a Reed Solomon code. Such coding is well suited to upstream transmission in an interactive satellite communication system.

Digital transmission system, decoder and decoding method

Block detection method for a channel subjected to fading

The invention proposes an efficient method of determining, in an arbitrary assembly of non-uniformly distributed points, the point which is nearest from a characteristic of a given analog signal. It is particularly applicable to the detection of symbols in a PCM modem. The method comprises the step of considering successive search intervals, each search interval being obtained by splitting up a preceding search interval into two intervals, each interval comprising a number of points, the numbers being equal or different by one, such that one of these two intervals which comprises the received point constitutes the next search interval.

Method of searching the point which is the nearest from a characteristic of a received signal in an assembly of non-uniformly distributed points

A system and method is disclosed for transmitting TDMA packets between interactive terminals and a head station using a transmission medium. The system includes an iterative method for determining an optimal sampling instant by computing the average amplitudes only for a predetermined number of the input samples, determining a maximum of the average amplitudes of these samples, deriving an approximation of the optimal sample using the maximum, repeating the average amplitude computation for input samples between the approximation and a neighboring sample whose previously computed average amplitude is the largest, and comparing of the result of each average amplitude computation with a previously computed maximum corresponding to the previous approximation for deriving a new approximation of the optimal sample.

Searching the optimal sampling instant in a TDMA packet transmission system

The invention relates to a system for transmitting TDMA packets between interactive terminals and a head station via a transmission medium, in which the receiver effects a oversampling of the received signal so as to retrieve the optimal sample corresponding to the transmitted symbol. The invention proposes a method of recovering this optimal sampling instant very rapidly by performing a polynomial interpolation computation between the generated oversamples so as to derive the optimal sampling instant and by filtering the received signal by means of a low-pass filter centered at the optimal sampling instant.

Estimating the optimal sampling instant in a TDMA packet transmission system

Method of forming a set of constellations which is intended to be used for transmitting data between a transmitter and a receiver

A method of estimating the frequency at the receiving end for a packet transmission system, for estimating a carrier frequency error between received symbols (r ) and transmitted symbols (c ). An error function (H(&Dgr;{circumflex over (f)})) defined for minimizing a magnitude which is representative of an average distance between the received symbols compensated in phase (r&prime; ) and estimations of the received symbols affected by a frequency error estimation (&ccirc; e ) is computed. The estimations of the received symbols affected by the frequency error estimation are obtained by varying the frequency error (&Dgr;{circumflex over (f)}) in an acquisition interval (&lsqb;&minus;f , &plus;f &rsqb;) for estimations of the transmitted symbol (&ccirc; ). The estimations of the transmitted, symbols (&ccirc; ) are obtained based on a threshold relating to the phase of the received symbol which is compensated in phase (r&prime; ), in the case of a modulation of the PSK type. For a modulation of the QPSK (Quadrature PSK), the threshold decision is based on the sign of the real and imaginary parts of the received, phase-compensated symbol (r&prime; ).

Semi-NDA frequency correction at the receiving end in a packet transmission system

An iterative decoder and decoding method for decoding a binary block code defined by a parity check matrix. The parity matrix is processed several times row-by-row so that each iteration of the decoding corresponds to the decoding of the code defined by a row of the matrix for received data. For decoding an extended code, each row defines two separate codes which are decoded with each iteration.

Iterative decoding for binary block codes

The invention relates to a system for transmitting packets from interactive terminals to a head station. The terminals intended for consumers are provided with local oscillators which are not very accurate and use carriers having frequency errors which are relatively large with respect to the theoretical reference value (Fp). The invention provides an improvement of the reception of signals having such a frequency shift at the receiver end. To this end, the invention provides a method of estimating the frequency error &Dgr;{circumflex over (f)}, which consists of rapidly obtaining the maximum value of a discrete error function denoted Z(&Dgr;{circumflex over (f)}) for a given accuracy (Acc) by computing the function Z(&Dgr;{circumflex over (f)}) for a minimal number of points.

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Paris, France

Antoine Chouly