Abstract: A method for decoding a bitstream comprising a sequence of encoded images. The method includes: obtaining first information from first encoded data contained in the bitstream; determining a list of coding parameters on the basis of the first information and of at least one predefined list of coding parameters; obtaining second information from second encoded data contained in the bitstream, the second information corresponding to a coding parameter among the coding parameters in the list of coding parameters; determining an element of a reconstructed image corresponding to an element of an image in the sequence of images, by means of the coding parameter corresponding to the second information and of encoded data representative of the element of the image in the sequence; wherein the size of the second encoded data depends on the number of coding parameters in the list of coding parameters.

Abstract: A dynamically reconfigurable video surveillance system includes at least one video camera, a remote server, at least one viewing terminal, means making it possible to record the video sequences captured by the camera or cameras, said system being characterized in that: the video camera or cameras and the remote server include means for communicating with one another across a telecommunications network; the video camera or cameras include means for compressing the video sequences captured, the compression rate being adapted dynamically by taking account of the control messages originating from the remote server; the video camera or cameras include means for analyzing said video sequences in the compressed domain, to characterize the activity detected in their field of vision and to forward the result of this characterization to the remote server; the remote server include means for computing for each of the compressed video streams originating from the video camera or cameras a command making it possible to pa

Abstract: A method for estimating a bit rate and the distortion of at least one compressed image using at least one wavelet transform operation delivering at least one sub-band b containing coefficients, said sub-band being subdivided into at least one packet of coefficients associated with a compression quality layer, said packet also including a packet header and being transmitted through a propagation channel, said method including estimating a distortion Dbc linked to a compression of the coefficients of said packet, estimating a distortion D?bc linked to a corruption or loss of said packet, estimating a compression bit rate Lb, estimating a sensitivity {tilde over (D)}bc of said packet according to Dbc and D?bc and the bit rate Lb, and estimating a distortion of said image linked to a decompression of said packet based on {tilde over (D)}bc.

Abstract: A dynamically reconfigurable video surveillance system includes at least one video camera, a remote server, at least one viewing terminal, means making it possible to record the video sequences captured by the camera or cameras, said system being characterized in that: the video camera or cameras and the remote server include means for communicating with one another across a telecommunications network; the video camera or cameras include means for compressing the video sequences captured, the compression rate being adapted dynamically by taking account of the control messages originating from the remote server; the video camera or cameras include means for analyzing said video sequences in the compressed domain, to characterize the activity detected in their field of vision and to forward the result of this characterization to the remote server; the remote server include means for computing for each of the compressed video streams originating from the video camera or cameras a command making it possible to pa

Abstract: A method for estimating a bit rate and the distortion of at least one compressed image using at least one wavelet transform operation delivering at least one sub-band b containing coefficients, said sub-band being subdivided into at least one packet of coefficients associated with a compression quality layer, said packet also including a packet header and being transmitted through a propagation channel, said method including estimating a distortion Dbc linked to a compression of the coefficients of said packet, estimating a distortion D?bc linked to a corruption or loss of said packet, estimating a compression bit rate Lb, estimating a sensitivity {tilde over (D)}bc of said packet according to Dbc and D?bc and the bit rate Lb, and estimating a distortion of said image linked to a decompression of said packet based on {tilde over (D)}bc.

Abstract: A method is provided for protecting a compressed video stream that may be decomposed into a foreground plane composed of objects of a first type and a background plane composed of objects of a second type against errors during the transmission of this stream on an unreliable link, characterized in that it comprises at least the following steps: a) analyzing the stream in the compressed domain so as to define various image areas in which redundancy will be added, the motion estimation vectors and the transformed coefficients obtained in the compressed domain are transmitted to the redundancy addition step; b) adding redundancy to the objects of said areas determined in the previous step, a), while taking account of the motion estimation vectors and of the transformed coefficients obtained in the compressed domain; c) transmitting the set of areas forming the image.

Abstract: In a method to protect and/or detect information in a data transmission system, the pieces of data exchanged have a format comprising one or more headers and a data zone. The method comprises at least one step for the insertion, into at least one header, of at least one EPB marker segment comprising redundancy data to detect and/or correct errors.

Abstract: A process for watermarking images that includes embedding into the images before their transmission a message by modifying the data characteristic of the images. Further, a co-watermarking is performed by periodic embedding of a binary matrix into the image to determine on reception the co-ordinates of the origin of the initial image and allow the registration of the images received relative to this origin so as to make it possible to read the embedded message. Such a process may find particular application to the transmission of stationary or video images.

Abstract: In a method to protect and/or detect information in a data transmission system, the pieces of data exchanged have a format comprising one or more headers and a data zone. The method comprises at least one step for the insertion, into at least one header, of at least one EPB marker segment comprising redundancy data to detect and/or correct errors.