Stmicroelectronics S.r.l.

Mauro De Ponti

Marco Ferretti

Raimondo Schettini

Vittorio Peduto

Anna Valsasna

Carla Brambilla

Gianluca Ciocca

Fabio Brognara

Matteo Boffadossi

A method of classification for a content-based digital-image, including: defining a set of low-level features describing the semantic content of the image, the features being quantities obtainable from the image by means of logico-mathematical expressions that are known beforehand, and the choice of said features depending upon the image classes used for the classification; indexing an image to be classified, with the purpose of extracting therefrom a feature vector, the components of which consist of the values assumed, in the image, by said low-level features; splitting the feature space defined by the low-level features into a plurality of classification regions, to each one of the regions there being associated a respective image class, and each classification region being the locus of the points of the feature space defined by a finite set of conditions laid on at least one component of the feature vector; associating the feature vector to the feature space; identifying, among the classification regions, a specific classification region containing the feature vector extracted from the image to be classified; and identifying the image class associated to the specific classification region identified.

Content-based digital-image classification method

A method of compressing a stream of pixel data relative a two-dimensional object, pixels of which are scanned by rows from a source device to a receiver device, includes defining an extended context window to include a pair of pixels following a last encoded pixel on the row being scanned and the respective triplets of neighboring pixels belonging to the preceding row. The method includes defining a first distinct context array of pixels of the extended context window for the pixel of the pair immediately following the last encoded pixel, and a second context array of pixels of the extended context window for the other pixel of the pair. An extended context value relative to each pixel of the pair is calculated, and the extended context value relative to a first pixel immediately following the last encoded pixel is compared with an extended threshold. If the extended context value is less than the extended threshold, then encoding the first and second pixels of the pair, and if the extended context value relative to the first pixel of the pair exceeds the extended threshold, then carrying out simultaneously a parallel processing and encoding of both pixels according to an encoding routine.

Loss-less compression of still images at enhanced speed

A method for generating sequences of memory addresses for a memory buffer having N*M locations includes making a first address and a last address of every sequence respectively equal to 0 and to N*M&#x2212;1, assigning a first sequence of addresses, and each address but a last address of another sequence of addresses is generated by multiplying a corresponding address of a previous sequence by N, and performing a modular reduction of this product with respect to N*M&#x2212;1. The method further includes calculating a greatest bit length of every address, and calculating an auxiliary constant as the modular reduction with respect to N*M&#x2212;1 of the power of two raised to twice the greatest bit length. Each sequence of addresses includes storing an auxiliary parameter equal to an N+1address of the current sequence, computing a first factor as the modular product with respect to N*M&#x2212;1 of the auxiliary constant based upon a ratio between the auxiliary parameter and the power of two raised to the greatest bit length, and generating all addresses but the last of a sequence by performing the Montgomery algorithm using the first factor and an address index varying from 0 to N*M&#x2212;2 as factors of the Montgomery algorithm, and with the quantity N*M&#x2212;1 as modulus of the Montgomery algorithm, and the greatest bit length as the number of iterations of the Montgomery algorithm.

Method and circuit for generating memory addresses for a memory buffer

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Seregno, Italy

Mauro De Ponti