Edge-Preserving Image Upsampling and Image Warping

The goal of this thesis is to produce sharp and stylized upsampled images. We present cumulative range geodesic filter and bilateral roundup filter, with the former excels at edge sharpening and the latter finds a better balance between edge sharpening and fine-detail preservation. Moreover, we propose a pixel migration idea that relocates pixels in the image plane. We implemented pixel migration using a mass-spring physics simulation. In the context of image upsampling, we assign short rest lengths to pixels along edges, thus the gaps between those pixels are closed, and edge sharpness is recovered. Applying pixel migration on the original image plane, we propose a two-stage approach to painterly rendering of photographs, where the image plane is first warped to produce a distorted or caricatured effect and then the resulting image is rendered with a painterly effect. This work on image warping is published in Expressive, 2015.