Vertical Retargeting for Stereoscopic Images via Stereo Seam Carving

Abstract

Vertical retargeting for stereoscopic images using seam manipulation-based approaches has remained an open challenge over the years. Even though horizontal retargeting had attracted a huge amount of interest, its seam coupling strategies were not capable to construct valid seam pairs for vertical retargeting. In this article, we propose two seam coupling strategies for vertical retargeting, namely, real mapping and virtual mapping. Our proposed mapping strategies were implemented to address the problems of multiple assignments and missing assignments, which are able to occur in the straightforward generalization from horizontal retargeting to vertical retargeting. On the basis of our proposed method, stereo seams were allowed to lay across occluded regions and occluding regions in stereo images. We maintained the geometric consistency by removing occluded pixels and corresponding occluding pixels in both stereo images. As a result, our method guarantees valid and geometrically consistent stereo seam pairs to be found in the horizontal direction. We generate vertically retargeted stereo images by removing or adding horizontal seam pairs iteratively. We conducted experiments on a number of indoor and outdoor scenes. Experimental results demonstrated that our method overcomes the limitations of vertical retargeting and is effective in preserving the geometric consistency.