Fast image segmentation on mobile phone using multi-level graph cut

This paper presents a system for an efficient image segmentation on mobile phones using multi-level graph cut. As the computational capacity of mobile devices is often limited, a fluent and smooth image segmentation is a challenging task with existing segmentation algorithms, increased in difficulty by mobile phone cameras continually upgraded to take photos of higher resolution. Our solution is to carefully tweak the classic graph cut algorithm for an interactive image cutout, enhancing the performance without compromising the quality of the segmentation. This is achieved by downsampling the original high-resolution image and selecting a rough cutout region on this low-resolution image with a superpixel based pre-segmentation. The segmented foreground is then mapped back to the full-size image and the image undergoes an adaptive boundary refinement. This second segmentation performs the optimization locally and can be accomplished within milliseconds. We test our system on an Apple iPhone 6 and our experiments show that a high quality segmentation can be achieved in a lag-free manner on the mobile phone even for multi-megapixel images.