Canon Kabushiki Kaisha

Eric Majani

Bertrand Berthelot

F&eacute;lix Henry

Patrice Onno

James Philip Andrew

Paul Raymond Higginbottom

Felix Henry

Jean-Jacques Moreau

Ioana Donescu

Félix Henry

Maryline Charrier

In order to transform an input digital signal (x) into one or more output digital signals (y) containing even-indexed samples (y) and odd-indexed samples (y), this filtering method includes at least one iteration which contains an operation of modifying even-indexed samples (y) by a function (R) of weighted odd-indexed samples (y), and an operation of modifying odd-indexed samples (y) by a function (R) of weighted even-indexed samples (&#x3b2;(y&#x2212;y)). The weighted samples are obtained by at least one weighting operation. At least one of the weighting operations is applied to the difference between two consecutive even-indexed samples.

Digital filtering methods and devices

A method of encoding an digital image () by a discrete wavelet transform (DWT) to a predetermined level of decomposition on a block by block basis, each block () having a specified size in number of coefficients, is disclosed. The image is divided into tiles, each having dimensions required to produce the number of coefficients in a first dimension of the transformed block at the predetermined level of decomposition, and less than the number of coefficients in a second dimension of the transformed block. At a particular DWT level, tiles are decomposed. HH, HL and LH subband coefficients are accumulated to form blocks of specified size, and these are encoded to a bit stream (). A predetermined number of associated LL subband coefficients are similarly accumulated, the process performed recursively per DWT level until the predetermined decomposition level is attained, and the corresponding LL subband coefficients encoded to the bit stream ().

Encoding method and apparatus

In a digital filtering device adopting wavelet transformation, a memory occupancy level of processed data is decreased. An image is divided into a plurality of first blocks each consisting of W pixels by H pixels. Wavelet transformation is performed on each of the first blocks in order to produce sub-frequency band blocks LL, LH, HL, an HH. Sub-frequency band blocks LL produced from the first blocks are grouped in order to produce second blocks having the same size as the first blocks. Wavelet transformation is performed again on the second blocks.

Device and method for transforming digital signal

A digital signal is transformed in at least two different frequency bands according to at least two different resolutions. The signal is divided into first blocks all having the same predetermined first number of samples. Each of the first blocks is transformed into a plurality of second blocks, any second block under consideration having a second respective number of samples which depends on the resolution of the second block under consideration, and containing samples selected according to their frequency. Second blocks issuing from the transformation of different first blocks are grouped in order to form third blocks all having the same predetermined third number of samples which is at least equal to the largest of the second numbers.

Device and method for transforming a digital signal

Method of modifying the geometric orientation of an image

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.

A method for the geometric transcoding of a compressed data file containing a digital signal of dimension N coded by means of a coding method including at least one step of spectral breakdown into frequency subbands of the digital signal (S). The method includes the steps of extracting symbols associated with the coefficients of the frequency sub-bands of the digital signal and applying a geometric transformation to the symbols. The method further includes the steps of updating N indicator or indicators representing a normal or reversed order of the symbols respectively in N direction or directions of the digital signal and reconstituting the digital signal coded by reversal of the extracting step.

Geometric transcoding of a digital signal

A method and a device by which original digital signals are analysis-filtered, where the original digital signals include original samples representing physical quantities, and where the original samples 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 the original samples and/or previously calculated samples, where the samples are ordered by increasing rank. The signal is processed by successive input blocks of samples, where the calculations made on an input block under consideration take into account only the original or calculated samples belonging to the input block under consideration, and where the input block under consideration and the following input block overlap over a predetermined number of original samples. Output blocks are formed, where each output block corresponds respectively to an input block.

The invention concerns a method of inserting an additional information item in a set of digital data representing physical quantities, the data having been processed by transformation, quantization and entropic coding in order to be compressed, characterized in that it comprises the steps of extracting a subset of low-frequency coefficients, from the set of data, entropic decoding of the coefficients of the subset, modulation of the decoded coefficients by a signal representing the additional information item, so as to form quantized watermarked coefficients, entropic coding of the watermarked coefficients, and insertion of the watermarked encoded coefficients in place of the coefficients of the subset, in the set of data.

Method and device for inserting and detecting a watermark in digital data

A method for the geometric transformation of a compressed image, stored on a source appliance connected to one or more other appliances by a computer communication network, comprising the steps of choosing a set of appliances in the computer communication network adapted to implement a geometric transformation of an image in compressed form; selecting an appliance in the set for implementing the geometric transformation of the image in compressed form; of transmitting the compressed image to the selected appliance if it is different from the source appliance; and geometrically transforming the image in compressed form by means of the selected appliance. This method is used notably for a computer and printer installed on a network.

Method and device for the geometric transformation of an image in a computer communication network

A digital signal transformation method, in which the original samples (x ; y ) of the digital signal are transformed into output samples (y , x ). Any output sample being calculated by a function of original samples, and/or of intermediate samples (t , v , t , v ), and/or of output samples is characterized in that each function is broken down into elementary operations, and the elementary operations of all the functions are ordered so as to minimize the number of samples that are simultaneously necessary. The invention makes it possible to minimize the memory space necessary to calculate the transformation.

Digital signal transformation device and method

The invention proposes a digital filter adapted to transform an input digital signal into two output digital signals. The input digital signal includes input samples (x ). The first output digital signal includes output samples (y ) of odd ranking, each equal to the input sample (x ) of the same ranking decreased by the approximate value of a sum of input samples of even ranking respectively multiplied by first filtering coefficients (p ). The second output digital signal includes output samples (y ) of even ranking, each equal to the input sample (x ) of the same ranking decreased by the approximate value of a sum of output samples of odd ranking respectively multiplied by second filtering coefficients (u ). The second filtering coefficients (u ) are chosen from all the following sets of coefficients: (5/16, 5/16), (&minus;1/16, 5/16, 5/16, &minus;1/16) and (1/256, &minus;15/256, 78/256, 78/256, &minus;15/256, 1/256).

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Rennes, France

Eric Majani