Nonhomogeneous scaling optimization for realtime image resizing

Patch-Based Image Warping for Content-Aware Retargeting

“…The proposed approach is inspired by the work [7], and the goal of shape preservation is similar to [8]- [10]. However, there are substantial differences between our approach and these approaches.…”

“…However, due to the different scaling factors of quads, an object occupying several quads may suffer from inconsistent scaling and deformation. To ease this problem, Zhang et al [8], Guo et al [9], Jin et al [10], and Hung et al [24] propose to force visually salient objects to undergo similarity transformations during resizing. These approaches perform very well on shape preservation of local objects.…”

“…In contrast to discretely removing pixels in homogenous regions, the continuous approaches optimize a mapping or warping using several deformation and smoothness constraints [1], [2], [4], [7]- [10]. In the work of Liu et al [1], a non-linear warping is proposed to preserve important content.…”

“…Second, a similarity transformation constraint is introduced to preserve visually salient content. Third, instead of using a triangle mesh as a control mesh in warping, which may have the problem of inconsistency in triangle orientations [9], [10], following the approach [7], we use a quad mesh with grid orientation constraints to avoid skew artifacts.…”

Internet visual media processing: a survey with graphics and vision applications

“…Extracting objects of interest, or salient objects, is an active topic in cognitive psychology [109], neurobiology [25], and computer vision [83]. Doing so enables various applications including visual media retargeting [45,58,112] as well as non-photorealistic rendering [47].…”