Region adaptive unsharp masking based Lanczos-3 interpolation for video intra frame up-sampling

Increasing the resolution of a video intra frame using various interpolation techniques not only gives a blurring effect but also results in the loss of fine details and critical edge information. In order to resolve this problem, an efficient, no reference, hybrid interpolation technique is proposed here. The proposed method makes use of a combination of anticipatory, spatial domain, region adaptive, unsharp masking operation coupled with Lanczos-3 interpolation for retaining some of the fine details and critical edge information in the reconstructed video frame. The region adaptive unsharp masking is a preprocessing approach which sharpens the intra frame regions locally as per their statistical local variance so as to compensate the blurring caused by the subsequent Lanczos-3 interpolation technique. The degree of sharpening is increased as per the rise in the statistical local variance of a neighborhood and vice versa. Furthermore, the unsharp masking operation is made globally adaptive by multiplying the unsharp mask with a global scaling factor which is obtained by adding one to the global variance of an intra frame. Experimental results reveal that the proposed method outperforms most of the existing interpolation techniques in terms of peak-signal-to-noise-ratio (PSNR) as well as visual quality for different types of video sequences.