Abstract: Disclosed is a process for producing an animation of the multipage type, in which each still image of the animation has scalability properties. Preferably, each still image is to be saved on at least two levels, the first level containing few details and each following level providing additional details to the preceding level.

Abstract: A method for reducing the entropy of an original matrix, includes a step using a wavelet transformation of the original matrix into a transformed matrix, a quantization coefficient corresponding to each wavelet level, the wavelet transformation being calculated in fixed decimal point using a first number of digits at least equal to 1, for example 3 digits, after the decimal point. Such a method is particularly advantageous for image compression.

Abstract: A method for compressing an image, includes: calculating a level of hues of the image over at least all of one layer of the image; depending on the type of hues of the representative layer, classifying the image in one of the following three classes: a first class if the image is of a graphics type; a second class if the image is of a highly contrasted type; a third class if the image is of a low-contrasted type; and, choosing a compression processing type depending on the class of the image: difference processing, if the image is of the first class; frequency processing, if the image is of the third class; and, if the image is of the second class: for lossless or low-loss compression, preferably using difference processing, and, in the other cases preferably using frequency processing.

Abstract: An encoding method for encoding successive layers of an initial matrix into a compressed matrix and restoring it as a restored matrix, each cell of the initial matrix containing a respective initial numerical value; each cell of the compressed matrix containing a respective compressed numerical value corresponding to the respective initial numerical value; each cell of the restored matrix containing a respective restored numerical value corresponding to the respective initial numerical value; is characterized in that to encode, one applies: —wavelet transforms applied to the entire matrix over a limited number of levels, such that a residual level remains with dimensions larger than or equal to 2×2; then, a differential encoding of the residual level, i.e., a compression of the residual level by obtaining differences with each of the values of the residual level.

Abstract: Disclosed is a process for producing an animation of the multipage type, in which each still image of the animation has scalability properties. Preferably, each still image is to be saved on at least two levels, the first level containing few details and each following level providing additional details to the preceding level.

Abstract: A method for encoding a series of symbols using several models of the arithmetic or range coder type and including steps where each model is associated with a belonging criterion, the series is run through in order to determine, for each symbol, the encoding model to which each symbol belongs, according to the criteria; then a probability of occurrence of each symbol in the corresponding model is determined; then the series is run through by encoding each symbol successively; and a file is formed from the code thus obtained.

Abstract: A method for compressing an image, includes: calculating a level of hues of the image over at least all of one layer of the image; depending on the type of hues of the representative layer, classifying the image in one of the following three classes: a first class if the image is of a graphics type; a second class if the image is of a highly contrasted type; a third class if the image is of a low-contrasted type; and, choosing a compression processing type depending on the class of the image: difference processing, if the image is of the first class; frequency processing, if the image is of the third class; and, if the image is of the second class: for lossless or low-loss compression, preferably using difference processing, and, in the other cases preferably using frequency processing.

Abstract: An encoding method for encoding successive layers of an initial matrix into a compressed matrix and restoring it as a restored matrix, each cell of the initial matrix containing a respective initial numerical value; each cell of the compressed matrix containing a respective compressed numerical value corresponding to the respective initial numerical value; each cell of the restored matrix containing a respective restored numerical value corresponding to the respective initial numerical value; is characterized in that to encode, one applies: —wavelet transforms applied to the entire matrix over a limited number of levels, such that a residual level remains with dimensions larger than or equal to 2×2; then, a differential encoding of the residual level, i.e., a compression of the residual level by obtaining differences with each of the values of the residual level.

Abstract: Method of manufacturing a plate heat exchanger of the type comprising a plurality of plates and possibly of separating elements, made of a brazable material, which define circuits for the circulation of fluids and are assembled to one another by brazing. The brazing takes place after the foils of brazing alloy have been deposited on the regions to be brazed. The foils and the regions to be brazed are co-rolled before the brazing. The invention is applicable to the reboiler-condensers of air separation plants.

Abstract: A process for the cryogenic separation of mixtures containing oxygen to obtain a produce having a high concentration of oxygen. In this process, a heat and material exchange occurs in counter-current between a descending liquid and a rising gas in at least one transfer zone including a bundle of organized linings consisting of cross-undulated metallic layers. In at least one transfer zone where the concentration of oxygen is higher than 98%, the layers are made of a sheet of aluminum having a thickness between 0.3 and 1 mm. Additionally, the bundles of layers have a specific surface lower than 400 m.sup.2 /m.sup.3.