Simultaneous multi-frame subpixel boundary definition using toboggan-based intelligent scissors for image and movie editing
William A. Barrett, Eric N. Mortensen · 2000
Intelligent Scissors is an interactive image segmentation tool that allows a user to select piece-wise globally optimal contour segments (based on an optimal path search in a graph) that correspond to a desired object boundary. This dissertation uses tobogganing to raise the granularity of the image primitive above the pixel level, producing a region-based basic processing unit that is object-centered rather than device-dependent. The resulting region-based elements form the basis for several contributions to the field of computer vision general and to Intelligent Scissors in particular. These contributions reduce the human time and effort needed for object selection with Intelligent Scissors while simultaneously increasing the accuracy of boundary definition. The region-based image primitives resulting from tobogganing form the basis for a graph formulation that is many times smaller than the pixel-based graph used previously by Intelligent Scissors, thus providing faster, more interactively responsive optimal path computations. The object-centered atomic units also provide an efficient and consistent framework in which to compute a 4-parameter edge model, allowing subpixel boundary localization, noise-independent edge blur adjustment, and automatic alpha matte generation and color separation of boundary transition pixels. The increased size of the basic processing unit also facilitates an edge confidence measure that forms the basis for two new techniques called confidence threshold snapping and live-wire path extension, which further reduce the human burden involved with object boundary definition by automatically finding and following object boundaries. Finally, this dissertation presents a new paradigm for simultaneously interacting with multiple frames from a temporal image sequence by parallelizing both the user input and the interactive visual feedback, thus allowing a user to interact with a montage of image frames in order to define the boundary of a moving object while adhering to the same interactive style that has demonstrated to be effective for the single-image Intelligent Scissors.