VLSI architecture for an object change detector for visual sensors

Object detection is a crucial step in visual surveillance. Traditionally, object detection has been performed purely in software in surveillance systems. The problem of object detection, however, becomes critical in the upcoming wireless visual sensors because of size and power constraints. The need for low-power, small size, hardware implementations is greatly felt. This paper introduces a VLSI architecture for Wronskian change detector (WCD). Object detection is done through background subtraction. WCD offers regularity, low complexity and accuracy as well as global illumination changes independency. WCD can be employed in automated visual surveillance on buildings and adjacent parking lots. WCD replaces each pixel by a vector containing luminance value of the pixel and its surrounding area. A linear dependency test is applied to each vector to determine if a change has occurred. WCD is mapped into a 12-processing element array with a fixed window value of 3×3. Design of each processing element is discussed in detail. Based on extensive search, no VLSI implementation of WCD has been reported previously.