Image and video processing apparatuses and methods

An image processing method for compressing or decompressing a segment of an image, the method comprising:

• compressing or decompressing the segment of the image, wherein the segment is non-rectangular and comprises a plurality of pixels, each pixel of the plurality of pixels comprises a pixel value, and the pixel values of the plurality of pixels form a pixel value vector,
• 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.

A non-transitory storage medium comprising program code that, when executed by a computer, causes the computer to perform an image processing method for compressing or decompressing a segment of an image, by performing the steps of:

• compressing or decompressing the segment of the image, wherein the segment is non-rectangular and comprises a plurality of pixels, each pixel of the plurality of pixels comprises a pixel value, and the pixel values of the plurality of pixels form a pixel value vector,
• 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.