Fraunhofer-Gesellschaft Zur Foerderung Der Angewandten Forschung E.v.

Christian Scherl

Herbert Thoma

Thomas Richter

Joachim Keinert

Wolfgang Heppner

Bilal Ahmed

Christian Minuth

Siegfried Foessel

Heiko Sparenberg

Siegfried Fößel

Miguel Ángel Martínez Del Amor

Manuel De Frutos López

Nisha Bhaskar

Sergej Wtjurin

Stefan Kraegeloh

Tobias Jaschke

Marcus Freisleben

Micha Nietsch

Miguel ÁNgel MARTÍNEZ Del Amor

Manuel De Frutos LÓPEZ

Siegfried FÖSSEL

Miguel Angel MARTÍNEZ Del Amor

There is disclosed an encoder, a decoder, related methods, and non-transitory storage units storing instructions which, when executed by a computer, cause the computer to perform the methods. At an encoder (), after a spatial transformation stage (), there is obtained a spatially transformed version () of input image information () having multiple bands and, for each band, multiple transform band coefficients. After the generation of precincts (), each comprising transform coefficients covering a predetermined spatial area of the input image information (), there is provided a component transformation stage (), to apply one component transformation (CTr) selected () out of a plurality of predetermined component transformations, to each band (') of each precinct (). Hence, there is obtained a spatially transformed and color transformed version () of the input image information (), which is subsequently quantized and entropy encoded.

Encoder, decoder and related methods

An apparatus for decoding a sequence of pictures from a data stream is configured for decoding a picture of the sequence by deriving a residual transform signal of the picture from the data stream; combining a residual transform signal with a buffered transform signal approximation of a previous picture of the sequence so as to obtain a transform signal representing the picture, the transform signal having a plurality of transform coefficients; and subjecting the transform signal to a spectral-to-spatial transformation. The apparatus is configured for deriving the buffered transform signal approximation from a further transform signal representing the previous picture so that the buffered transform signal approximation has approximations of further transform coefficients of the further transform signal.

Apparatus and method for encoding and decoding a sequence of pictures using a buffered transform signal approximation

Operation method of electronic device for encoding and decoding a sequence of pictures using a buffered transform signal approximation

A concept for coding a CFA pattern image is provided, wherein, for each of the sample clusters of the CFA pattern image, having first to fourth sample positions, first to fourth color coordinates are computed, so as to provide an image representation of the CFA pattern image.

Decorrelation transform for a color filter array pattern image

An apparatus for decoding a sequence of pictures from a data stream is configured for decoding a picture of the sequence by: deriving a residual transform signal of the picture from the data stream; combining the residual transform signal with a buffered transform signal of a previous picture of the sequence so as to obtain a transform signal of the picture, the transform signal representing the picture in spectral components; and subjecting the transform signal to a spectral-to-spatial transformation, wherein the buffered transform signal comprises a selection out of spectral components representing the previous picture.

Encoding and decoding a sequence of pictures

An apparatus for decoding a sequence of pictures from a data stream is configured for decoding a picture of the sequence by deriving a residual transform signal of the picture from the data stream; combining a residual transform signal with a buffered transform signal approximation of a previous picture of the sequence so as to obtain a transform signal representing the picture, the transform signal comprising a plurality of transform coefficients; and subjecting the transform signal to a spectral-to-spatial transformation. The apparatus is configured for deriving the buffered transform signal approximation from a further transform signal representing the previous picture so that the buffered transform signal approximation comprises approximations of further transform coefficients of the further transform signal.

A coding efficiency improvement is achieved by performing bit-plane coding in a manner so that coefficient groups for which the set of coded bit-planes is predictively signaled in the datastream, are grouped in two group sets and if a signal is spent in the datastream which signals, for a group set, whether the set of coded bit-planes of all coefficient groups of the respective group set are empty, i.e. all coefficients within the respective group sets are insignificant. In accordance with another aspect, a coding efficiency improvement is achieved by providing bit-plane coding with group-set-wise insignificant signalization according to the first aspect as a coding option alternative relative to the signalization for group sets for which it is signaled that there is no coded prediction residual for the coded bit-planes for the claim groups within the respective group set.

Bit-plane encoder and decoder

Transform coefficients encoder and decoder

Concepts are presented herein how to efficiently create a suitable palette for low complexity image and video coding. A combination of the palette coding with transform coding is feasible.

Image compression technique

Transform block coding is performed very efficiently in terms of computational complexity and compression ratio, by coding the magnitude bits of the transform coefficients distributed in a matrix, in which the magnitude bits of the spectral coefficients are arranged column-wise with the spectral coefficients of the transform block ordered along a row direction of the matrix. That is, magnitude bits within a certain column of the matrix belong to a certain spectral coefficient, while magnitude bits within a certain row of the matrix belong to a certain bit plane. In this configuration, the distribution of non-zero magnitude bits may be condensed towards one corner of the matrix, corresponding to, for instance, the least significant bit plane and corresponding to, by using a scan order among the transform coefficients which sorts the transform coefficients generally in a manner from lowest to highest frequency, the lowest frequency. Various low complexity variants are presented.

Transform block coding

Bit-plane coding

A chroma subsampling having reduced artifacts is achieved by detecting high contrast areas in a luminance channel of an image to be chroma subsampled so as to partition the image into a first region composed of the high contrast areas and a second region distinct from the first region, with chroma subsampling the image in the first region using a first chroma subsampler and chroma subsampling the image in the second region using a second chroma subsampler, with the first chroma subsampler having a higher edge preserving property than compared to the second chroma subsampler. Thereby, bleeding artifacts may be avoided at least partially, while the saturation of the image may be substantially preserved.

Chroma subsampling

A receiver includes a receiver clock oscillator controllable with regard to its receiver oscillator frequency, means for detecting a number of clock periods that the receiver clock oscillator performs in a specifiable period of time, means for extracting a first and a temporally following second reference entry in a received data stream, wherein means for extracting is implemented in order to control means for detecting on the basis of the extracted first and second reference entry with regard to the specifiable period of time, and means for comparing the number of clock periods of the receiver clock oscillator with the information in the second reference entry in order to control the controllable oscillator depending on a comparison result so that the oscillator frequency is increased or decreased so that the oscillator frequency is in a predetermined ratio to a frequency of the clock oscillator in the transmitter or is equal to the frequency of the clock oscillator in the transmitter. This way, in a simple and secure way, without slow phase-locked loops for a jitter suppression, it is guaranteed that the receiver is fixedly synchronized with the transmitter and that simultaneously in case of a receiver array all receivers are also synchronized among each other.

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Uttenreuth, Germany

Christian Scherl