Hardware architecture for real-time distance transform

A distance transform (DT) converts a binary image consisting of foreground (feature) and background (non-feature) pixels into a gray level image where each pixel contains the distance from the corresponding pixel to the nearest foreground pixel. The computation of the exact Euclidean DT is computationally complex task and, therefore, approximations are typically utilized. In this paper, an area-efficient architecture for computing a DT approximation is presented. The architecture utilizes order-based encoded distance representation allowing simple bitwise operations to be used for determining the distance to the nearest foreground pixel in the constrained neighborhood. Tabulated distance values are used thus cumulative errors are avoided. Due to the simple operations realtime operation can be expected.