Imec Vzw

Vrije Universiteit Brussel

Other

Imec

Jan Cornelis

Gauthier Lafruit

Adrian Munteanu

Peter Schelkens

Hugo De Man

Ivo Bolsens

Jan Bormans

Ioannis Andreopoulos

Geert Van Der Auwera

A bit stream representing n-dimensional data structures may be encoded and decoded. A part of the data can be mappable within predefined similarity criteria to a part of the data of another data structure. The similarity criteria may include, a spatial or temporal shift of the data. The data structures are typically sequential video frames such as is used in motion estimation and/or compensation of moving pictures, and a part of the data structure may be a block of data within a frame. The shift may be any suitable shift such as linear translation, rotation, or change of size. Digital filtering may be applied to a reference or other frame of data to generate subbands of a set of subbands of an overcomplete representation of the frame by calculations performed at single rate. The digital filtering may be implemented in a separate filter module or in software.

Method and system for subband encoding and decoding of an overcomplete representation of the data structure

Images are subband transformed to create a plurality of subband images. Each subband image includes a plurality of pixels. Each pixel is represented by a plurality of bits with each bit associated to a certain quantization level. Encoding of an image requires scanning essentially all the bits of essentially all the pixels of the image. While scanning in a particular order, one can exploit dependencies within groups of bits consecutively scanned for encoding purposes. Thus, bits of groups can be encoded together. In a subband and transformed image, the scanning order or scanning curve is defined by indicating in which order the system traverses the several subbands and the several quantization levels. One method is characterized in that the set of scanned bits which will be encoded together, and which thus form a group, bits of at least two different sub-images and at least two different quantization levels are recognized.

Methods and apparatus for progressive transmission of subband images

A method of determining the motion vector of a block of a video frame with respect to a reference video frame. The video frame and reference video frame comprising pixels, wherein each pixel has a pixel value. The method comprises first determining a plurality of sets of error norms, wherein each error norm within one of the sets is related to a different position of the block in the reference video frame, wherein the error norms are calculated by a norm of an error which is given by functions of the pixel values of the block of the video frame and the reference video frame, and wherein each set of the plurality of sets is related to a different function. Second, the motion vector is selected with the smallest error norm.

Method and system for video compression

The present invention relates to a method and apparatus for compressing digital data, such as the digital representation of a colored image. A scanning routine is described which aims to maintain the integrity of regions of the image that the human visual system also finds important. Pixel data from the image data includes color components, e.g., intensities of three or more colors such as red, green and blue or cyan, magenta and yellow. When the color components of the pixels are represented in color space, the axes of which are the three color components with the intensities thereof as variables, it has been found experimentally, particularly for artificial or synthetic images, that significant regions in the image tend to produce clusters of points in color space. In accordance with the invention, the color space is scanned by a space filling curve to convert the coordinates in color space into a one dimensional matrix such as a histogram. If certain types of space filling curves are used, e.g., a step-wise curve such as the Peano or Hilbert fractal, the clusters of points in color space tend to produce clusters of points in the histogram. Having obtained the histogram, it is segmented into a series of bins. These bins are used to segment the original image into regions which are coded. Although the invention has been described with respect to color images and 3-D color space, the method and apparatus may be useful with other types of data and with multidimensional spaces.

Data compression method and apparatus

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Overijse, Belgium

Jan Cornelis