Method for smoothing staircase effect in enlarged low resolution images

Abstract

A method in the field of image enhancement is described for smoothing the staircase effect in electronic images. These staircases may be introduced by electronic zooming of an original image having a low spatial resolution or by the application of a lossy compression algorithm, such as JPEG, to the image data. According to one example, for each pixel of the image local gradients are computed according to four directions. A first direction associated with the highest local gradient is selected. In order to smooth the image in a second direction, orthogonal to the first direction, the pixel value is changed according to the values of pixels situated along the second direction in the neighborhood of the pixel. Optionally, the smoothed image data may be subsequently sharpened by a method including the use of gradients.

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