摘要:
The invention proposes a digital signal coding method including a step of analysing (E1) the digital signal (IM) into a plurality of frequency sub-band signals distributed according to at least two different frequency bands, at least one first sub-band signal having a lower frequency and at least one second sub-band signal having a higher frequency, characterised in that it includes, for each second sub-band signal, the steps of: dividing (E4) the second sub-band signals into blocks (Bi,n), selecting (E9) blocks to be coded by setting to a predetermined value, according to a selection criterion, coding the blocks selected by setting to the predetermined value.
摘要:
According to the invention, the method of primary processing of a first set of primary data (IM,f) representing physical quantities includes: a set division step (200A to 202) during which the first set of data is divided into sub-sets of first data, and for each first sub-set of data: a step (205 to 207) of “constructing” a global contractive mapping of the first type, for the said first sub-set of data, whose fixed point constitutes an approximation of all or part of this sub-set. The set of parameters (ai, b) thus determined constitutes a primary representation of the said first set of data.
摘要:
In order to code a digital signal, a simplified version of the digital signal is determined, containing only some of the information contained in the digital signal. The simplified version is coded by means of a predetermined single coding technique. This simplified version is subtracted from the digital signal, so as to obtain a residual signal. From each block of the simplified version, there is selected, for each corresponding block of the residual signal, a coding technique amongst a predetermined number M of coding techniques Ci, where i is an integer between 1 and M. Each block of the residual signal is coded by means of the previously selected coding technique.
摘要:
In order to code a digital signal, it is decomposed (20) into several subsignals; each subsignal is coded (38) by means of a coding technique taken from amongst M coding techniques Ci; and the stream of coded bits thus produced is entered (40) in a first part of a file intended to receive the coded digital signal. Then the application, successively to each coded subsignal, of each decoding technique Di associated with the coding technique Ci is simulated (48); and if and only if at least two different decoding techniques are acceptable, within the meaning of a predetermined likelihood criterion, for decoding the same coded subsignal, there is entered (52) in a second part of the file information making it possible to select, during decoding, the decoding technique associated with the coding technique used for coding this subsignal.
摘要:
A method of creating a file describing a digital image comprises the steps of defining a zoomable area in the image, a zoomable area being defined by its characteristics of location in the image and for which additional data are available, writing the characteristics in a file, and writing in the file a management function for navigation in the image.
摘要:
A trellis filtering of a digital signal is disclosed. A method is provided of analysis filtering of an original digital signal including original samples representing physical quantities. Original samples of the digital signal are transformed by successive calculation steps into high and low frequency output samples. Any sample calculated at a given step is calculated by a predetermined function of original samples, and/or previously calculated samples, the samples being ordered in increasing rank. The signal is processed by successive series of samples, the calculations made on any series not taking into account the samples in a following series, and in that the any series terminates in a low-frequency sample.
摘要:
To filter a digital signal, in which, for each sample of the signal, a plurality of context functions take account of a predetermined number of other samples of the signal: the value of a context function from the plurality of context functions for each sample to be filtered is calculated; the signal is divided into a set of sub-signals corresponding respectively to the different values of the context functions; and, for each sub-signal: an optimal filter is determined according to a first criterion that depends on the values of the sub-signal; and the optimal filter is associated with the context function corresponding to the sub-signal.Application to the coding of a digital signal representing an image.
摘要:
A method of encoding a digital image signal comprising a plurality of samples. The method comprises the following steps, applied during the encoding of each sample with a view to its storage in a buffer. The level of occupancy of the buffer is determined, and the level of occupancy is compared with a predetermined threshold. An encoding mode is determined from among a plurality of encoding modes when the level of occupancy is above the predetermined threshold, and encoding the sample according to the determined encoding mode, and the sample is encoded according to a default encoding mode when the level of occupancy is below the predetermined threshold.
摘要:
A method of decoding an encoded digital image, the encoded data of the image comprising a plurality of predefined resolutions, comprises the steps of: selecting a resolution lower than the highest of the predefined resolutions, determining the predefined resolution immediately above the selected resolution, determining a quantity of data of the determined predefined resolution, as a function of the ratio between the selected resolution and the determined predefined resolution, decoding the image at the determined predefined resolution, as a function of the determined quantity of data, subsampling the decoded image, as a function of the ratio between the selected resolution and the determined predefined resolution.
摘要:
A method of encoding digital samples of a set of data representing physical quantities, the encoding including the determination of a path among the samples of the set. The method includes measuring an encoding cost which depends on the path, and modifying the path, the steps of measuring and modifying being reiterated so as to determine a path which minimizes the encoding cost.