Patent ID: 8842939

Claim:
A direction-adaptive image upsampling system using double interpolation performed by a processor, the system comprising: a plurality of double interpolation (DI) units with different interpolation functions, said DI units being concurrently coupled to receive an input image and respectively generate corresponding double-interpolated images and associated double-interpolated differences at the same time, wherein, for each pixel and each said DI unit, the double-interpolated difference is a pixel value difference between the input image and the associated double-interpolated image; a decision unit coupled to receive the double-interpolated differences from the plurality of DI units at the same time for deciding the DI unit that has an optimal interpolation around a pixel under process; and an adaptive selector, for each pixel, configured to select the double-interpolated image associated with the DI unit having the optimal interpolation as an output image; wherein each said DI unit comprises the following elements that are connected in the specified order: a first upsampling unit with the associated interpolation function configured to first interpolate the input image, thereby resulting in an interpolated image; a down-sampling unit configured to down sample the interpolated image, thereby resulting in a plurality of down-sampled images; a plurality of second upsampling units with the same associated interpolation function configured to second interpolate the down-sampled images respectively, thereby resulting in a plurality of the double-interpolated images; a plurality of difference units, each of which being configured to generate the associated double-interpolated difference that is the pixel value difference between the input image and the corresponding double-interpolated image; and a double-interpolated image selector configured to select the double-interpolated image that has the associated double-interpolated difference having least value.