Event Detection Module for Low-Power Camera

Abstract

In this chapter, we first propose an effective low-power image sensor system for event detection. The system consisting of a low-resolution auxiliary sensor and a high-resolution main sensor operates in two different modes, sleep and wakeup. In the sleep mode, only the auxiliary sensor works for event detection and the main sensor remains off for power saving. In the wake-up mode, the main sensor turns on based on the data sensed by the auxiliary sensor and into normal operation. Second, a new background subtraction algorithm which can be used for event detection is proposed. The algorithm works much faster than conventional algorithms and requires less computation which is critical for low-power operation. In addition, utilization of depth information in background subtraction for 3-D image applications is also presented. Finally, hardware implementation of a low power low-resolution CMOS image sensor (CIS) is presented. The CIS fabricated in 0.18 μm CIS process is designed to be used as an auxiliary sensor in the proposed system. The CIS generates 4-bit image data and consumes only 1.45 mW out of 3 V supply.