Edge adaptive image expansion and enhancement system and method

Abstract

An edge adaptive system and method for image filtering. The method maps each output pixel onto input image coordinates (110) and then prefilters and resamples the input image pixels around this point to reduce noise and adjust the scale corresponding to a particular operation. Then the edge in the input image is detected based on local (125) and average (127) signal variances in the input pixels. According to the edge detection parameters (129), including orientation, anisotropy and variance strength, the method determines a footprint and frequency response for the interpolation of the output pixel. In a more particular implementation, the method divides the input pixel space into a finite number of directions called skews, and estimates the edge orientation with the nearest skew direction. This further facilitates pixel inclusion in the interpolation of the output pixel.

Description

technical field

[0001] The present invention relates to a filtering method for digital image data processing, more specifically, relates to an edge adaptive filtering for digital image data expansion and enhancement. Background technique

[0002] A digital image is a 2-dimensional array of digital data where each item represents a pixel of the digital image. Each pixel data has several components such as colors, for example, red, green and blue. The main image processing operation is to expand the image by an arbitrary factor and thereby create a dilated image. Deinterlacing is an example of such an operation, where the video domain is upscaled in the vertical direction using a scaling factor of 1:2. It is well known that when building an upscaled image from a raw image, interpolation between raw digital data arrays is required to obtain a high quality output image. Prior art methods of image expansion interpolate the horizontal and vertical dimensions of the digital imag...

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