Method and device for processing and decoding a coded digital signal
First Claim
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1. Method of processing a coded digital signal including a set of samples obtained by coding a set of original samples representing physical quantities using a multiresolution coding format, and including a set of information relating to a size w, h of the set of original samples and its resolution res, comprising the steps of:
- locating a subset of original samples of given size zulx, zuly, zh, zw and resolution zres in the set of original samples according to the set of information relating to the size w, h and the resolution res of this set;
determining, amongst coefficients of a low-frequency sub-band LLO of a last decomposition level obtained by decomposition into frequency sub-bands of the set of original samples, a number of coefficients per dimension of the signal which correspond to the located subset;
deciding, at the decoding side, to modify or not to modify the size of the located subset according to the determined number of low-frequency sub-band coefficients before restoring the located subset, said deciding step including taking into account at least one predetermined criterion representing a quality level for the restored subset of original samples of the digital signal; and
modifying the size of the located subset of original samples, in which the modification is an increase in the size of the subset of original samples,wherein by representing, in a space of dimensions corresponding to the dimensions of the digital signal, a position of the coefficients of the low-frequency sub-band of the last decomposition level and a position of the subset of original samples delimited by a boundary, the increase in the size of the subset consists of moving the boundary so as to add to the subset at least one coefficient of the low-frequency sub-band per dimension of the digital signal, the at least one added coefficient being situated close to the boundary before the movement thereof.
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Abstract
The present invention concerns a method of processing a coded digital signal containing on the one hand a set of samples of different types obtained by coding a set of original samples representing physical quantities and on the other hand a set of information representing original samples and parameters used during the coding, characterized in that it includes the following steps:
- determining the subset of samples corresponding to a part of the coded digital signal using the set of information,
- obtaining the number of samples of at least one predetermined type and which are contained in the given subset of samples,
- deciding with regard to a modification of the determined subset of samples according to the number of samples obtained.
34 Citations
20 Claims
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1. Method of processing a coded digital signal including a set of samples obtained by coding a set of original samples representing physical quantities using a multiresolution coding format, and including a set of information relating to a size w, h of the set of original samples and its resolution res, comprising the steps of:
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locating a subset of original samples of given size zulx, zuly, zh, zw and resolution zres in the set of original samples according to the set of information relating to the size w, h and the resolution res of this set; determining, amongst coefficients of a low-frequency sub-band LLO of a last decomposition level obtained by decomposition into frequency sub-bands of the set of original samples, a number of coefficients per dimension of the signal which correspond to the located subset; deciding, at the decoding side, to modify or not to modify the size of the located subset according to the determined number of low-frequency sub-band coefficients before restoring the located subset, said deciding step including taking into account at least one predetermined criterion representing a quality level for the restored subset of original samples of the digital signal; and modifying the size of the located subset of original samples, in which the modification is an increase in the size of the subset of original samples, wherein by representing, in a space of dimensions corresponding to the dimensions of the digital signal, a position of the coefficients of the low-frequency sub-band of the last decomposition level and a position of the subset of original samples delimited by a boundary, the increase in the size of the subset consists of moving the boundary so as to add to the subset at least one coefficient of the low-frequency sub-band per dimension of the digital signal, the at least one added coefficient being situated close to the boundary before the movement thereof. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13, 14, 15)
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2. Method of processing a coded digital signal including a set of samples obtained by coding a set of original samples representing physical quantities using a multiresolution coding format, and including a set of information relating to a size w, h of the set of original samples and its resolution res, comprising the steps of:
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locating a subset of original samples of given size zulx, zuly, zh, zw and resolution zres in the set of original samples according to the set of information relating to the size w, h and the resolution res of this set; determining, amongst coefficients of a low-frequency sub-band LL0 of a last decomposition level obtained by decomposition into frequency sub-bands of the set of original samples, a number of coefficients per dimension of the signal which correspond to the located subset; deciding, at the decoding side, to modify or not to modify the size of the located subset according to the determined number of low-frequency sub-band coefficients before restoring the located subset, said deciding step including taking into account at least one predetermined criterion representing a quality level for the restored subset of original samples of the digital signal; and modifying the size of the located subset of original samples, in which the modification is a reduction in the size of the subset, wherein by representing, in a space with dimensions corresponding to the dimensions of the digital signal, a position of the coefficients of the frequency sub-bands obtained by decomposition of the set of original samples and a position of the subset of original samples delimited by a boundary, the reduction in the size of the subset consists of moving the boundary so as to remove part of the subset and all the frequency sub-band coefficients situated in the part of the subset.
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3. Method of processing a coded digital signal including a set of samples obtained by coding a set of original samples representing physical quantities using a multiresolution coding format, and including a set of information relating to a size w, h of the set of original samples and its resolution res, comprising the steps of
locating a subset of original samples of given size zulx, zuly, zh, zw and resolution zres in the set of original samples according to the set of information relating to the size w, h and the resolution res of this set; -
determining, amongst coefficients of a low-frequency sub-band LL0 of a last decomposition level obtained by decomposition into frequency sub-bands of the set of original samples, a number of coefficients per dimension of the signal which correspond to the located subset; and deciding, at the decoding side, to modify or not to modify the size of the located subset according to the determined number of low-frequency sub-band coefficients before restoring the located subset, said deciding step including taking into account at least one predetermined criterion representing a quality level for the restored subset of original samples of the digital signal, in which, by representing, in a space of dimensions corresponding to the dimensions of the digital signal, a position of the coefficients of the frequency sub-bands obtained by decomposition of the set of original samples and a position of the subset of original samples delimited by a boundary, said method further comprises a step of adding to this subset at least one coefficient of a frequency sub-band other than the low sub-band per dimension of the digital signal, the at least one added coefficient being situated close to the boundary before the movement thereof.
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4. Device for processing a coded digital signal including a set of samples obtained by coding a set of original samples representing physical quantities using a multiresolution coding format, and a set of information concerning a size w, h of the set of original samples and its resolution res, comprising:
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means for locating a subset of original samples of given size zulx, zuly, zh, zw and resolution zres in the set of original samples according to the set of information of size w, h and resolution res of this set; means for determining, amongst coefficients of a low-frequency sub-band LL0 of a last decomposition level obtained by decomposition into frequency sub-bands of the set of original samples, a number of coefficients per dimension of the signal which correspond to the located subset; means for deciding, at the decoding side, to modify or not to modify the size of the located subset according to the determined number of low-frequency sub-band coefficients, said means for deciding taking into account at least one predetermined criterion representing a quality level for the restored subset of original samples of the digital signal; and means for restoring the located subset, said means for deciding being adapted to make a decision with regard to a modification of the size of the located subset before said means for restoring restore the located subset, wherein, by representing, in a space of dimensions corresponding to the dimensions of the digital signal, a position of the coefficients of the frequency sub-bands obtained by decomposition of the set of original samples and a position of the subset of original samples delimited by a boundary, it is added to this subset at least one coefficient of a frequency sub-band other than the low sub-band per dimension of the digital signal, the at least one added coefficient being situated close to the boundary before the movement thereof. - View Dependent Claims (16, 17, 18, 19, 20)
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5. Device for processing a coded digital signal including a set of samples obtained by coding a set of original samples representing physical quantities using a multiresolution coding format, and a set of information concerning a size w, h of the set of original samples and its resolution res, comprising:
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means for locating a subset of original samples of given size zulx, zuly, zh, zw and resolution zres in the set of original samples according to the set of information of size w, h and resolution res of this set; means for determining, amongst coefficients of a low-frequency sub-band LL0 of a last decomposition level obtained by decomposition into frequency sub-bands of the set of original samples, a number of coefficients per dimension of the signal which correspond to the located subset; means for deciding, at the decoding side, to modify or not to modify the size of the located subset according to the determined number of low-frequency sub-band coefficients, said means for deciding taking into account at least one predetermined criterion representing a quality level for the restored subset of original samples of the digital signal; means for restoring the located subset, said means for deciding being adapted to make a decision with regard to a modification of the size of the located subset before said means for restoring restore the located subset; and means for modifying the size of the located subset of original samples, wherein said means for modifying comprise means for increasing the size of the subset of original samples, wherein by representing, in a space of dimensions corresponding to the dimensions of the digital signal, a position of the coefficients of the low-frequency sub-band of the last decomposition level and a position of the subset of original samples delimited by a boundary, the increase in the size of the subset consists of moving the boundary so as to add to the subset at least one coefficient of the low-frequency sub-band per dimension of the digital signal, the at least one added coefficient being situated close to the boundary before the movement thereof.
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6. Device for processing a coded digital signal including a set of samples obtained by coding a set of original samples representing physical quantities using a multiresolution coding format, and a set of information concerning a size w, h of the set of original samples and its resolution res, comprising:
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means for locating a subset of original samples of given size zulx, zuly, zh, zw and resolution zres in the set of original samples according to the set of information of size w, h and resolution res of this set; means for determining, amongst coefficients of a low-frequency sub-band LL0 of a last decomposition level obtained by decomposition into frequency sub-bands of the set of original samples, a number of coefficients per dimension of the signal which correspond to the located subset; means for deciding, at the decoding side, to modify or not to modify the size of the located subset according to the determined number of low-frequency sub-band coefficients, said means for deciding taking into account at least one predetermined criterion representing a quality level for the restored subset of original samples of the digital signal; means for restoring the located subset, said means for deciding being adapted to make a decision with regard to a modification of the size of the located subset before said means for restoring restore the located subset; and means for modifying the size of the located subset of original samples, in which said means for modifying comprise means for reducing the size of the subset, wherein by representing, in a space with dimensions corresponding to the dimensions of the digital signal, a position of the coefficients of the frequency sub-bands obtained by decomposition of the set of original samples and a position of the subset of original samples delimited by a boundary, the reduction in the size of the subset consists of moving the boundary so as to remove part of the subset and all the frequency sub-band coefficients situated in the part of the subset.
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Specification