Zoran (france) S.a.

Zoran (france)

Zoran Corporation

Ecole Polytechnique

Stéphane Mallat

Christophe Bernard

Erwan Le Pennec

Joan Bruna

Jérôme Kalifa

Nicolas Laveau

For subband decomposition of a d-dimensional input signal (S) into a number K of subband components (F-F), a filter bank has a filtering module () transforming the input signal (S) into 2components including a low-frequency component (L) and 2&#x2212;1 higher-frequency components (F), The 2&#x2212;1 higher-frequency components are oversampled, typically by a factor 2, compared to the low-frequency component. The low-frequency component can be further decomposed by means of another filtering module having a similar structure, and the process can be iterated over any number of scales. The reconstruction filter bank has a symmetric structure, with filtering modules adapted to the oversampling of the higher-frequency components. Such filter banks are well suited to various enhancement processing applied to the subband components such as thresholding, reduction of compression distortion, reduction of measurement noise, sharpness enhancement.

Filter banks for enhancing signals using oversampled subband transforms

For compressing a video signal, a local multiscale transform is applied to a frame of the video signal to obtain coefficient blocks. The coefficients of each block are distributed into a plurality of coefficient groups, and for at least one of the groups, a common exponent is determined for encoding the coefficients of the group, and respective mantissas are determined for quantizing the coefficients of the group in combination with the common exponent. Coding data including each exponent determined for a coefficient group and the mantissas quantizing the coefficients of the group in combination with this exponent are stored in an external frame buffer.

Frame buffer compression for video processing devices

A method and apparatus for processing or compressing an n-dimensional digital signal by constructing a sparse representation which takes advantage of the signal geometrical regularity. The invention comprises a warped wavelet packet transform which performs a cascade of warped subband filtering along warping grids of sampling points adapted to the signal geometry. It also comprises a bandeletisation which decorrelates the warped wavelet packet coefficients to produce a sparse representation. An inverse warped wavelet packet transform and an inverse bandeletisation reconstruct a signal from its bandelet representation. The invention comprises a compression system which quantizes and codes the bandelet representation, a decompression system, a restoration system which enhances a signal by filtering its bandelet representation, and a feature vector extraction system for pattern recognition applications of a bandelet representation.

Processing or compressing n-dimensional signals with warped wavelet packets and bandelets

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Paris, France

Stéphane Mallat