interpolation

Definition: Inserting extra values based on existing values e.g. introducing extra pixels into an existing digital image. * Used to: (1) resize an image file when a bit-mapped image is enlarged; (2) to give an apparent (but not real) increase to resolution e.g. in scanned images; (3) may be needed when image is rotated and in some other transformations e.g. animation e.g. animation; (4) in some anti-aliasing techniques. * Values of interpolated pixels always depend on values of neighbouring pixels: (a) if it is from the nearest neighbouring pixel, the interpolation is called 'neighbouring'; (b) if from the four pixels at the sides, the interpolation is bicubic; (c) if all eight contiguous pixels, the interpolation is bilinear. * Algorithms are chosen to preserve overall dimensions (as in scanners) or to preserve brightness values, depending on use.

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