FR2800962A1 - Signal synthesis/analysis digital signal filtering having two polyphase signals transformed and polyphase reference signal subtracted then difference signal formed and combination subtracted forming input signal approximation. - Google Patents

Abstract

The digital signal analysis has a polyphase transformer (E1) to generate two polyphase signals. A signal is then selected as reference signal (E2), and a segmented signal formed. A difference signal is formed (E3) using the non selected polyphase signal and finally subtraction of the combination of signals carried out to form a signal approximation (E4).

Description

The present invention relates to the filtering of digital signals, and more particularly to the analysis and synthesis of such signals.

When analyzing a digital signal, such as sound, a still image, or video images, segmenting the signal has many advantages. In particular, segmentation allows a user to manipulate the content of the signal, for example to recognize objects and to follow in the case of a video sequence. Segmentation is a non-linear operation, and is not reversible. In the particular case of an image, the segmentation generally consists in partitioning the image into homogeneous, connected regions, which do not overlap.

For this, the image is considered to be made up of two-dimensional objects. Segmentation is a low-level process which aims to partition the image into a number of sub-elements called regions. The partition is such that the regions are separated and that their meeting constitutes the image. The regions correspond or do not correspond to objects of the image, the term of object referring to information of a semantic nature. Very often, however, an object corresponds to a region or a set of regions. Each region can be represented by information representative of its shape, color or texture.

Conventionally, the methods of compressing a digital image based on segmentation comprise a first step called marking, that is to say that the interior of the regions exhibiting local homogeneity is extracted from the image. Then, a decision step precisely defines the contours of the zones containing homogeneous data. At the end of this step, each pixel of the image is associated with a label identifying the region to which it belongs. The set of all labels all pixels is conventionally called a segmentation map. Finally, in such coding, the last step consists in coding the segmentation map, generally in the form of the outlines of the regions, and relevant parameters representative of the interior of the regions, such as texture and color.

When it is then desired to compress the image, prior segmentation makes it possible to increase the compression ratio. Indeed, with segmentation, compression can be carried out selectively on the objects or regions deemed to be the most important, to the detriment of the others. Thus, for a given compression ratio, that is to say for an authorized number of binary elements, a precise object (typically a person's face in an image of the "head and shoulders" type) could be coded with in a precise way by using a maximum of bits, at the expense of background which will be coded with a minimum of bits.

However, for such processing to be interesting in practice, it is preferable that the data handled is not redundant with respect to the data of the initial image. In other words, it is necessary to keep a critical number of samples.

The present invention aims to provide a method and a device for digital signal analysis which combine critical decomposition and segmentation.

 To this end, the invention proposes a method for analyzing a digital signal representative of physical quantities, characterized in that it comprises steps of polyphase transformation of the digital signal with conservation of the overall number of samples, to generate a predetermined number, minus equal to two, of polyphase signals, selection of at least one of the polyphase signals, to be at least one reference signal, segmentation of the at least one reference signal, to form at least one segmented signal, subtraction of said at least one signal segmented from at least one unselected polyphase signal, to form detail signals, subtracting a combination of the detail signals from said at least one reference polyphase signal, to form an approximation signal. Correlatively, the invention proposes a device for analyzing a digital signal representative of physical quantities, characterized in that it comprises means of polyphase transformation of the digital signal with conservation of the overall number of samples, to generate a predetermined number, at less than two, polyphase signals, means for selecting at least one of the polyphase signals, to be at least one reference signal, means for segmenting the at least one reference signal, to form at least one segmented signal, means for subtracting said at least one segmented signal from at least one unselected polyphase signal, to form detail signals, means for subtracting a combination of the detail signals from said at least one reference polyphase signal, for form an approximation signal.

Thanks to the invention, the signal is segmented, it can thus be further processed, for example compressed, with all the advantages associated with segmentation. In addition, the total number of samples is kept relative to the number of samples of the initial signal. This critical decomposition makes it possible to simplify the manipulations and processing on the data, and does not require an increased memory space compared to the memory space necessary to store the initial signal.

In the absence of any further processing, the invention allows perfect reconstruction of the signal.

In addition, the invention makes it possible to combine a hierarchical segmentation of a digital signal, with a multi-resolution representation of the signal and the conservation of the number of samples of this signal. Two embodiments are thus presented.

In a first embodiment, the invention relates to a method for analyzing a digital signal representative of physical quantities, characterized in that it includes the steps of polyphase transformation of the digital signal with conservation of the overall number of samples, to generate a predetermined number, less than two, of polyphase signals, selection of at least one of the polyphase signals, to be at least a reference signal, segmentation of said at least one reference signal, to form at least one segmented signal, subtraction of said from at least one segmented signal of at least unselected polyphase signal, to form detail signals at current resolution level, selection of a detail signal, subtraction of a combination of the detail signals from the reference polyphase signal, to form an approximation signal at the current resolution level, - repetition of the preceding steps a predetermined number once, considering the selected detail signal as the signal to be analyzed, to form an approximation signal and detail signals at a lower resolution level. In a second embodiment, the invention proposes a method for analyzing a digital signal representative of physical quantities, characterized in that it includes the steps of polyphase transformation of the digital signal with conservation of the overall number of samples, to generate a predetermined number, at least equal to two, of polyphase signals, selection of at least one of the polyphase signals, to be one at least one reference signal, segmentation of said at least one reference signal, to form at least one segmented signal , subtracting said at least one segmented signal minus an unselected polyphase signal, to form detail signals at a current resolution level, subtracting a combination of the detail signals from the reference polyphase signal, to form an approximation signal at current resolution level, - repetition of the previous steps a predetermined number of times, consider nt the approximation signal as signal to be analyzed, replacing the segmentation step by a step of merging said at least one reference signal, to form a merged signal, so as to form an approximation signal and signals details at a lower resolution level.

The invention also relates to devices comprising means for implementing the methods according to the two preceding embodiments.

The segmentation is thus carried out on several levels of resolution. In this case, it is possible to separate the large objects of the image from the fine details of the latter, and for example to access the content of the image with more and more details. One of the consequences of this is to increase the robustness of the treatment. In addition, like segmentation at several hierarchical resolution levels, it is possible to segment the image according to increasingly fine details or objects, as the resolution levels progress.

Thanks to the invention, the segmentation associated with a multi-resolution representation of the signal is not redundant, this does not involve a very large volume of data. The storage, transmission and manipulation of this data are then facilitated compared to a case where the data would be redundant.

It is possible to have access to a hierarchical segmentation map.

In another aspect of the invention, it relates to a method for synthesizing a digital signal representative of physical quantities previously analyzed by the method presented above, characterized in that it comprises the steps of - adding the approximation signal and combining the detail signals of a current resolution level, to form a polyphase signal, - segmenting the previously formed polyphase signal to form a segmented signal, - adding the segmented signal to each of the detail signals, to form signals polyphases, - reverse polyphase transformation of all polyphase signals at current resolution level, to form a detail signal at the immediately higher resolution level.

According to the first embodiment, the invention relates to a method of synthesis of a digital signal representative of physical quantities previously analyzed by the method of the first mode, characterized in that it comprises the steps of - adding approximation signal and combining the detail signals current resolution level, to form a polyphase signal, - segmenting the previously formed polyphase signal to form a segmented signal, - adding segmented signal to each of the detail signals, to form polyphase signals, - transformation reverse polyphase of all polyphase signals of the current resolution level, to form a detail signal at the immediately higher resolution level, - repeating previous steps from the lowest resolution level until a detail signal is formed which is the original digital signal.

According to the second embodiment, the invention provides a method of synthesizing a digital signal representative of physical quantities previously analyzed the method of the second mode, characterized in that it comprises the steps of - adding signal of approximation and of combining the detail signals current resolution level, to form a polyphase signal, - merging previously formed polyphase signal to form a merged signal, - adding merged signal to each of the detail signals, to form polyphase signals, - reverse polyphase transformation of all polyphase signals of the current resolution level, to form a detail signal at the immediately higher resolution level, - repetition of the previous steps from the lowest resolution level, considering the detail signal formed as the detail signal at from the second iteration, and replacing the merge with a he segmentation at the last iteration, until the formation of a detail signal is the original digital signal.

The invention also relates to synthesis devices comprising means for implementing the above methods. The synthetic methods and devices make it possible to reconstruct the signal which had previously been analyzed, and have advantages similar to those previously presented.

The invention also relates to a digital device including the analysis or synthesis device or means for implementing the analysis or synthesis method. This digital device is for example a digital camera, a computer, a fax machine, a photocopier, a scanner or a printer.

The advantages of the digital camera are identical to those previously exposed.

A means of storing information, readable by a computer or by a microprocessor, integrated or not in the device, possibly removable, stores a program implementing the analysis or synthesis process.

The characteristics and advantages of the present invention will appear more clearly on reading a preferred embodiment illustrated by the attached drawings, in which - FIG. 1 schematically represents a data coding device according to the invention, - Figure 2 schematically shows a data decoding device according to the invention, - Figure 3 shows an embodiment of a device according to the invention, - Figure 4 shows an embodiment of a device d analysis according to the present invention, - Figure 5 represents an embodiment of a synthesis device according to the present invention, - Figure 6 represents an embodiment method of analysis according to the present invention, - Figure 7 represents a mode of embodiment synthesis device according to the present invention, - Figure 8 shows an embodiment of analysis device according to l a present invention, - Figure 9 shows an embodiment of the synthesis device according to the present invention, - Figure 10 shows an embodiment of the analysis method according to the present invention, - Figure 11 shows an embodiment of the synthesis method according to the present invention.

According to an embodiment chosen and represented in FIG. 1, a device 2 for analyzing a digital signal according to the invention comprises an input 22 to which a data source 1 is connected. The source comprises for example a memory means, such as random access memory, hard disk, floppy disk, compact disc, for storing data, this memory means being associated with a suitable reading means for reading the data there. means for storing the data in the memory medium can also be provided.

source 1 can for example be a video camera in the case of an image signal or microphone in the case of a sound signal.

analysis device 2 can be integrated into a data processing device TD1, such as a computer for example.

means 3 users of analyzed data are connected at output 27 coding device 2.

user means 3 comprise for example data storage means, and / or data transmission means. FIG. 2 represents a device 5 for synthesizing analyzed data device 2. means 4 users of analyzed data are connected as an input 52 decoding device 5. The means 4 comprise for example data memory means, and / or means of reception of the analyzed data which are adapted to receive the data transmitted the transmission means 3.

synthesis device 5 can be integrated into a data processing device TD2, such as a computer for example.

means 6 users of synthesized data are connected at the output 57 synthesis device 5. The user means 6 are for example means for viewing images, or means for reproducing sounds, depending on the nature of the data processed.

analysis device and the synthesis device can be integrated into the same digital device, for example a digital camera provided with a display screen.

with reference to FIG. 3, an example of a device 10 implementing the invention is described. This device is suitable for analyzing a digital signal and / or synthesizing a previously analyzed digital signal, according to the examples developed below.

The device 10 is here a microcomputer comprising a communication bus 101 to which are connected a central unit 100, read-only memory 102, random access memory 103, screen 104, keyboard 114, hard disk 108, floppy drive 109 suitable for receiving a floppy disk 110, interface 112 for communication with a communication network 113, input-output card 106 connected to a microphone 111. hard disk 108 stores the programs implementing the invention, as well as the data processed according to the invention. programs can also be read from the floppy disk 110, or received via communication network 113, or even memorized in read-only memory more generally, the programs according to the present invention are memorized in a storage means. This storage means can be read by a computer or by a microprocessor. This storage means may or may not be integrated into the device, and may be removable. For example, it can include a magnetic tape, a floppy disk or a ROM (compact disk with frozen memory).

When the device is powered up, the programs according to the present invention are transferred into the random access memory 103 then contains the executable code of the invention and the variables necessary for implementing the invention.

device 10 can receive data to be processed from a peripheral device 107, such as a digital camcorder, any other means of acquiring or storing data.

device 10 can also receive data to be processed from a remote device, via the communication network 1 transmit processed data to a remote device, always via communication network 113.

device 10 can also receive data to be processed from the microphone 11. This data is then a sound signal.

 The screen 104 allows a user in particular to view the data to be processed, and serves, with the keyboard 114, as a user interface. operation of the analysis and synthesis devices according to the invention will now be described.

With reference to FIG. 4, a first embodiment of a device for analyzing a one-dimensional digital signal performs an analysis on two levels of resolution. According to this embodiment, the segmentation is increasingly fine as the resolution decreases.

For the first level of resolution, the device 2 comprises a circuit 21 for extracting polyphase signals which receives an input signal at its input S. The extraction circuit 21 comprises decimators delay circuits, for generating a number M of polyphase signals, where an integer. In the example shown, the integer M is equal to two, and the circuit comprises from input 22 on the one hand a first decimator by two and on the other a delay circuit 211 followed by a second decimator circuit 21 thus produces two undersampled versions of the input signal, which are two polyphase signals X "and X, 2. It should be noted that the decomposition performed is critical, or in other words, that the overall number of samples is kept. The polyphase signals X "and X, 2 thus have the same number of samples between them as the original signal.

polyphase signal X "is selected to be a reference signal. II applied to the input of a segmentation circuit 23. More generally, here at least one polyphase signal is selected to be at least a reference signal. The method segmentation is arbitrary. An embodiment will be detailed below. The segmentation results in a segmented signal XS "representative of a decomposition of the polyphase signal into homogeneous regions.

segmented signal XS "is then transmitted to an operator which subtracts the segmented signal XS" from at least one of the other polyphase signals, which are also applied to operator 24. In the example shown, segmented signal XS "is subtracted of the polyphase signal to form a detail signal Y, 2. The detail signal Y, 2 contains the details that are not part of the segmentation at the current resolution level.

generally, a combination of the detail signals is formed, then it is applied to a second operator 25. In the example shown, detail signal Y, 2 is unique, it is therefore directly applied to the operator 25 to which is also applied the reference polyphase signal The detail signal Y, 2 is thus subtracted from the reference polyphase signal so as to form an approximation signal Y ", which is a signal very close to the result of the segmentation, that is to say signal XS "supplied by segment circuit 23.

Thus, the input signal is analyzed at the first resolution level so as to form an approximation signal Y "in general several detail signals, ie in this particular case, a detail signal Y, 2.

detail signals, here the only detail signal Y, 2, is applied to the input of an analysis block identical to that just described. analysis block includes an extraction circuit 21 ′, a segmentation circuit 23 ′ and two operators 24 ′ and 25 ′, connected to each other in the same way as circuits 21, 23, 24 and 25 which have just been described.

analysis block performs analysis at the second resolution level provides an approximation signal Y2, and detail signals, here a single detail signal Y22.

FIG. 5 represents a first embodiment of the synthesis device 5 corresponding to the analysis device previously described. This device synthesizes on two levels of resolution.

For the first level of resolution, the device 5 receives as input the approximation signal Y2, and the detail signal Y22. To simplify the notations, the signals supplied at the output of the analysis device 2 are repeated, without taking account of any processing which may have been applied to the signals in the meantime. In particular, the signals analyzed can be coded, and therefore decoded before synthesis. If the signals are transmitted, they may suffer losses. Therefore, in reality, the signals applied to the device 5 are generally not absolutely identical to those obtained after analysis.

signals Y2, and Y22 are applied to a first operator 51 which adds them to form a polyphase signal X2 ,. The polyphase signal X2, is applied to a segmenter 52 which forms a segmented signal XS2 ,.

The detail signal Y22 and the segmented signal XS2 are applied to a second operator 53 which adds them to form a polyphase signal X22. polyphase signals X2, and X22 are applied to a reverse polyphase transformation circuit 54 which provides a detail signal Y, 2 at the level of resolution immediately higher than the level processed. The reverse polyphase transformation circuit 54 comprises, from an input, an oversampler 540 connected to a delay 541, itself connected to an adder 542. From another input, the reverse polyphase transformation circuit 54 includes oversampler 543 connected to the adder 542.

For the higher resolution level, the synthesis device 5 comprises synthesis block similar to that which has just been described.

analysis block includes operators and 53 ′, a segmenter a reverse polyphase transformation circuit linked together in an identical manner to circuits 51 to 54 which have just been described. This analysis block receives the signals Y, 2 and Y "to synthesize them, here in signal S.

device 5 outputs a digital signal identical to the digital signal S in the absence of processing or loss of signals between analysis and synthesis.

with reference to FIG. 6, a first embodiment of the method of analysis according to the invention of a digital image, implemented in the analysis device, comprises steps E1 to E6.

The analysis algorithm can be stored in whole or in part in any information storage means capable of cooperating with the microprocessor. This storage means can be read by a computer or by a microprocessor. This storage means is integrated or device, and can be removable. For example, it can include a magnetic tape, a floppy disk, a CD-ROM (compact disk with frozen memory).

 Step E1 is the polyphase transformation of a digital signal to form polyphase signals X; ,, where i is an integer at least equal to two representing the current resolution level and n is an integer less than two representing the current polyphase signal . During the first passage through this step, the digital signal is the original signal S. The next step E2 is the selection of a reference polyphase signal, for example the polyphase signal X; ,, and the segmentation of the latter to form a segmented signal XS;,.

The next step E3 is the formation of the detail signals Y ;, with n different one, at the current resolution level, by subtraction of the signal segments each of the other polyphase signals.

 The next step E4 is the formation of the approximation signal Y ;, by subtracting a combination of the detail signals from the reference signal; .

 The next step E5 is a test to determine whether all the levels of decomposition have been covered. If the answer is negative, this step is followed by step E6 to consider one of the detail signals as the signal to be processed. Step E6 is followed by step E1 previously described.

When the response is positive in step E5, then the analysis of the signal is finished.

with reference to FIG. 7, a first embodiment of the synthesis method according to the invention of a digital image, implemented in the synthesis device, comprises steps E10 to This synthesis method corresponds to the analysis method previously described.

The synthesis algorithm can be stored in whole or in part in any information storage means capable of cooperating with the microprocessor. This storage means can be read by a computer or by a microprocessor. This storage means is integrated or device, and can be removable. For example, it may include a magnetic tape, a CD-ROM diskette (compact disk with frozen memory).

Step E10 is selection of the detail signals and of the signal for approximation of the current resolution level in the decomposition. During the first pass through this step, the lowest resolution level is considered. As previously explained, it is not in the case where there is no processing or loss between the analysis and the synthesis that the signals are considered here are identical to the signals supplied in analysis.

The next step E11 is the sum of the approximation signal of a combination of the detail signals, so as to form a polyphase signal.

The next step E12 is the segmentation of the previously formed signal, to construct a segmented signal.

The next step E13 is the addition of the segmented signal with each of the detail signals, to form polyphase signals.

The next step E14 is the reverse polyphase transformation of previously formed polyphase signals, to construct a detail signal at the immediately higher resolution level.

 The next step E15 is a test to determine whether all the resolution levels have been covered. If the answer is negative, then this step is followed by step E16 to consider the immediately higher level of resolution. Step E16 is followed by the step previously described.

When the response is positive in step E15, this means that the detail signal which has just been constructed in step E14 is the signal S which it wished to synthesize. The synthesis is therefore complete.

Figures 8 to 11 show a second embodiment of the invention, according to which an increasingly coarse segmentation is obtained when resolution decreases, during the analysis of a digital signal. increasingly coarse segmentation, it is understood here that the objects obtained are less and less detailed, that is to say that they encompass a larger part of the image.

FIG. 8 represents the second embodiment of the analysis device 2a. Compared to the device 2 previously described, the device comprises similar elements, which consequently bear the same reference numbers to which the letter 'a' has been added. structural differences of the device 2a compared to the device 2 are as follows.

output of the first analysis block which delivers the approximation signal at the highest resolution level, here the signal Y "is connected to the input of the second analysis block, to analyze the approximation signal Y" at the level of lower resolution. Thus, this no longer the detail signal Y, 2 obtained at the highest resolution level which used for the analysis at the lower resolution level.

Furthermore, from the second level of resolution in the decomposition, the segmentation circuit, here the circuit 23 ', is replaced by a fusion circuit 23'a. The merger will be described below.

FIG. 9 represents the second embodiment of the synthesis device corresponding to the analysis device 2a. Compared to the device 5 previously described, the device 5a has similar elements, which therefore bear the same reference numbers to which the letter 'a' has been added.

 structural differences of the device 5a compared to the device 5 correspond to the differences of the device 2a compared to the device 2, and are as follows.

segmentation circuit 52 is replaced by a fusion circuit 52a. Thus, for all the resolution levels except for the highest resolution, the segmentation is replaced by a fusion which will be described below.

output of the first synthesis block is connected to the operator 51a 'to supply it with the signal Y ".

FIG. 10 represents the second embodiment of the method of analysis according to the invention of a digital image, implemented in the analysis device, comprising steps E20 to E25.

steps are respectively analogous to steps E1 to E6 previously described. The main difference is in step E21, which is a segmentation of the reference polyphase signal during the first pass by this step, that is to say for the highest level of resolution in decomposition, then which is a fusion of the reference polyphase signal during the following passages by this step, that is to say for the lower resolution levels.

In addition, step E25 is modified with respect to step E6 to consider the approximation signal as the signal to be processed.

FIG. 11 represents the second embodiment of the method of synthesis according to the invention of a digital image, implemented in synthesis device, comprising steps E30 to E36.

steps are respectively analogous to steps E10 to previously described. The main difference is in step E32, which merges a reference polyphase signal when passing through this step, except for the last pass in which this step is a reference polyphase signal segmentation, i.e. for the level of highest resolution in decomposition.

will now describe, with reference to FIG. 12, an embodiment of segmentation of a polyphase signal, using a flowchart comprising steps E90 to E92.

 Step E90 is a simplification of the polyphase signal. A simplified version of the polyphase signal, more generally of an image, will be obtained by applying a morphological opening / closing operator to the latter, followed by a morphological reconstruction. full description of this process can be found in the article by Philippe Salembier entitled Morphological multiscale segmentation for image coding published in Signal Processing magazine number 38 of 1994. This type of treatment eliminates objects smaller than a certain size, and restores contours objects that have not been deleted. At the end of this step, there is therefore a simplified version of the polyphase signal, which will be easier to process by the following steps.

The next step E91 is the marking, or extraction of the markers, of the simplified polyphase signal. This step identifies the presence of the homogeneous regions of the simplified polyphase signal, using a criterion which can for example be a criterion of homogeneity of the intensity of the region (flat regions). Concretely, a region growth algorithm is used here for example: the polyphase signal is scanned in its entirety (for example from top to bottom and from right to left). We are looking for a seed, that is to say a point, here a coefficient, representative of a new region (the first coefficient of the polyphase signal will automatically be one). The characteristic of this region (average value) is calculated based on this point. Then all the neighbors of this point are then examined, and for each neighbor there are two possibilities - if the point encountered has an intensity close to the average value of the region considered, it is assigned to the current region, and statistics of this region are updated according to this new element, - if the point encountered has a different intensity (in the sense of proximity criterion) from the average value of the region, it is not affected to the region (it may by be considered as a new germ representative of a new region).

All the neighbors assigned to the current region are then themselves examined, that is to say that all their neighbors are examined (growth phase).

The processing of the region thus continues until all the points neighboring the points belonging to the region have been examined. After this treatment, the region is considered good or bad. If it is bad (typically too small), it is the decision stage which will deal with the points in the region in question. If it is good, the treatment is finished for it. A unique label or identifier is then assigned to all points in the region. The overall treatment then continues with the search for a new germ.

For a region to be considered good or bad, a minimum region size parameter is used. The next step is the decision. It consists in attaching to a region all the points which have no label at the end of the marking step E91 (typically, the points i have been attached to regions that are too small). This step can be carried out simply by considering each point which does not have a label, by assigning it to the neighboring region to which it is closest (in the sense of a proximity criterion).

An embodiment of fusion of a polyphase signal is very close to the segmentation previously described.

In this embodiment, the fusion has the same three stages as the segmentation, but the algorithm is configured so as to force it to consider larger and larger regions as the algorithm unfolds, in increasing the minimum size setting. Thus, the number of regions decreases and several regions are merged into one.

Of course, the present invention is not limited to the described embodiments shown, but encompasses, quite the contrary, any variant within the reach of ordinary skill in the art.

Claims (8)

1. A method of analyzing a digital signal representative of physical quantities, characterized in that it comprises the stages of polyphase transformation (E1, E20) of the digital signal with conservation of the overall number of samples, to generate a predetermined number, at less than two, of polyphase signals, selection (E2, E21) of at least one of the polyphase signals, to be at least one reference signal, segmentation (E2, E21) of the at least one reference signal, for forming at least one segmented signal, subtraction (E3, E22) from said at least one segmented signal from at least one unselected polyphase signal, to form detail signals, subtraction (E4, E23) from a combination of detail signals from said to minus a polyphase reference signal, to form an approximation signal. 2. Method of analysis of digital signal representative of physical quantities, characterized in that it comprises the stages of polyphase transformation (E1) of the digital signal with conservation of the overall number of samples, to generate a predetermined number, at least equal in pairs, of polyphase signals, selection (E2) of at least one of the polyphase signals, to be at least one reference signal, segmentation (E2) of said at least one reference signal, to form at least one segmented signal, subtraction (E3) of said at least one segmented signal of at least one unselected polyphase signal, to form detail signals at a current resolution level, selection of a detail signal, - subtraction (E4) of a combination of the detail signals of the reference polyphase signal, to form an approximation signal at the current resolution level, - repetition of the preceding steps a predetermined number of times s, considering the selected detail signal as the signal to be analyzed, to form an approximation signal and detail signals at a lower resolution level. 3. Method of analysis of digital signal representative of physical quantities, characterized in that it comprises the steps - transformation (E20) polyphase of the digital signal with conservation of the overall number of samples, to generate a predetermined number, at least equal with two, of polyphase signals, - selection (E21) of at least one of the polyphase signals, to be at least one reference signal, - segmentation (E21) of said at least one reference signal, to form at least one segmented signal , - subtraction (E22) of said at least one segmented signal from at least one unselected polyphase signal, to form detail signals at a current resolution level, - subtraction (E23) of a combination of the detail signals from the polyphase signal reference, to form an approximation signal at the current resolution level, - repetition of the preceding steps a predetermined number of times, considering the approximation signal ximation as a signal to be analyzed, replacing the segmentation step with a step of merging said at least one reference signal, to form a merged signal, so as to form an approximation signal and detail signals at a resolution level lower. 4. Method for synthesizing a digital signal representative of physical quantities previously analyzed by the method according to claim 1, characterized in that it comprises the steps of - adding (E11, E31) the signal of approximation and combination of detail signals of a current resolution level, to form a polyphase signal, - segmentation (E12, E32) of the polyphase signal previously formed to form a segmented signal, - addition (E13, E33) of the segmented signal to each detail signals , to form polyphase signals, - inverse polyphase transformation (E14, E34) of all polyphase signals at current resolution level, to form a detail signal at the immediately higher resolution level. 5. Method for synthesizing a digital signal representative of physical quantities previously analyzed by the method according to claim characterized in that it comprises the steps of - adding (E11) the approximation signal and the combination of the details signals of a current resolution level, to form a polyphase signal, - segmentation (E12) of the polyphase signal previously formed to form a segmented signal, - addition (E13) of the segmented signal to each of the detail signals, to form polyphase signals , - reverse polyphase transformation (E14) of all polyphase signals current resolution level, to form a detail signal at the immediately higher resolution level, - reiteration of the preceding steps from the lowest resolution level until the formation of a signal details which the original digital signal. 6. Method for synthesizing a digital signal representative of physical quantities previously analyzed by the method according to claim 3, characterized in that it comprises the steps of - adding (E31) the approximation signal and the combination of the signals details of a current resolution level, to form a polyphase signal, - merging (E32) of the previously formed polyphase signal to form a merged signal, - adding (E33) of the merged signal to each of the detail signals, to form signals polyphases, - inverse polyphase transformation (E34) of all polyphase signals of the current resolution level, to form a details signal at the immediately higher resolution level, - repetition of the previous steps from the lowest resolution level, considering the signal of details formed as a signal details from the second iteration, and by replacing the fusion a segmentation at the last iteration, until the formation of a detail signal which is the original digital signal. 7. A digital signal analysis device representative of physical quantities, characterized in that it comprises - means (21, 21a) of polyphase digital signal transformation with conservation of the overall number of samples, to generate a predetermined number, at less than two, of polyphase signals, - means for selecting at least one of the polyphase signals, to be at least one reference signal, - means (23, 23a) for segmenting the at least reference signal, to form at least one segmented signal, - means (24, 24a) for subtracting said at least segmented signal minus an unselected polyphase signal, for forming details signals, - means (25, 25a) for subtracting a combination of the detail signals of said at least one polyphase reference signal, to form an approximation signal. 8. Device for analyzing a digital signal representative of physical quantities, characterized in that it comprises - means (21) for polyphase transformation of the digital signal with conservation of the overall number of samples, to generate a predetermined number, at least equal to two, of polyphase signals, - means for selecting at least one of the polyphase signals, to be at least one reference signal, - means (23) for segmenting said at least one reference signal, to form at least one segmented signal, - means (24) for subtracting said at least one segmented signal minus an unselected polyphase signal, to form detail signals at a current resolution level, - means for selecting a detail signal, - means (25) for subtraction of a combination of the reference polyphase signal detail signals, to form an approximation signal at the current resolution level, the preceding means being further adapted to reiterating their operation a predetermined number of times, considering the selected detail signal as the signal to be analyzed, to form an approximation signal and detail signals at a lower resolution level. Device for analyzing a digital signal representative of physical quantities, characterized in that it comprises - means (21a) for polyphase transformation of the digital signal with conservation of the overall number of samples, to generate a predetermined number, at least equal to two, of polyphase signals, - means for selecting at least one of the polyphase signals, to be at least one reference signal, - means (23a) for segmenting the at least one reference signal, to form at least one segmented signal , - means (24a) for subtracting said at least one segmented signal minus an unselected polyphase signal, to form detail signals at a current resolution level, - means (25a) for subtracting a combination of the polyphase signal detail signals reference, to form an approximation signal at the current resolution level, the preceding means being further adapted to reiterate their operation a number predetermined times, considering the approximation signal as the signal to be analyzed, replacing the segmentation a fusion of said at least one reference signal, to form a merged signal, so as to form an approximation signal and detail signals at a lower resolution level. Device for synthesizing a digital signal representative of physical quantities previously analyzed by the device according to claim 7, characterized in that it comprises - means (51, 51a) for adding the approximation signal and for combining detail signal a current resolution level, to form a polyphase signal, - means (52, 52a) for segmenting the polyphase signal previously formed to form a segmented signal, - means (53, 53a) for adding the segmented signal to each detail signal , to form polyphase signals, - means (54, 54a) for reverse polyphase transformation of all polyphase signals of the current resolution level, to form a detail signal at the immediately higher resolution level. 11. Device for synthesizing a digital signal representative of physical quantities previously analyzed by the device according to claim 8, characterized in that it comprises - means (51) for adding the approximation signal and for combining the detail signals of a current resolution level, to form a polyphase signal, - means (52) for segmenting the polyphase signal previously formed to form a segmented signal, - means (53) for adding the segmented signal to each detail signal, for forming polyphase signals, - means (54) for reverse polyphase transformation of all polyphase signals of the current resolution level, to form a detail signal at the immediately higher resolution level, the preceding means being further adapted to reiterate their operation from the level resolution until formation of the detail signal which is the original digital signal. Device for synthesizing a digital signal representative of physical quantities previously analyzed by the method according to claim, characterized in that it comprises - means (51a) for adding the approximation signal and combination of detail signals of a current resolution level , to form a polyphase signal, - means (52a) for merging the previously formed polyphase signal to form a merged signal, - means (53a) for adding the merged signal to each detail signal, to form polyphase signals, - means (54a) of reverse polyphase transformation of all polyphase signals of the current resolution level, to form a detail signal at the immediately higher resolution level, the preceding means being further adapted to reiterate their operation from the lowest resolution level, in considering a detail signal formed as a detail signal from the second iteration, and replaces erasing the fusion by segmentation at the last iteration, until the formation of a detail signal which is the original digital signal. 13. Analysis device (10) according to any one of claims 7 to 9, characterized in that the polyphase transformation, selection, segmentation and subtraction means are incorporated in - a microprocessor (100), - a read only memory (102) comprising a program for processing data, and - a random access memory (103) comprising registers adapted to store variables modified during the execution of said program. 14. Synthesis device (10) according to any one of claims 10 to 12, characterized in that the means of addition, segmentation, of reverse polyphase transformation are incorporated in - a microprocessor (100), - a read only memory (102 ) comprising a program for processing data, and - a random access memory (103) comprising registers suitable for recording variables modified during the execution of said program. 15. digital signal processing apparatus, characterized in that comprises means adapted to implement the method according to any one of claims 1 to 6. 16. digital signal processing apparatus, characterized in that comprises the device according to l any of claims 7 to 14.