IMAGE AND VIDEO PROCESSING APPARATUSES AND METHODS

The disclosure relates to an image processing apparatus for compressing or decompressing a segment of an image, the segment being non-rectangular and comprising a plurality of pixels, each pixel comprising a pixel value, the pixel values of the plurality of pixels forming a pixel value vector, the apparatus comprising: a processor configured to compress the segment or configured to decompress the segment, wherein compressing the segment comprises computing a plurality of expansion coefficients by expanding the pixel value vector into a plurality of basis vectors, wherein the basis vectors are discrete approximations of solutions of a boundary value problem of the Helmholtz equation on the segment of the image; and wherein decompressing the segment comprises computing the pixel value vector by forming a linear combination of the basis vectors according to the plurality of expansion coefficients.