A CMOS image sensor with reconfigurable resolution for energy harvesting applications

In this paper, we propose a CMOS image sensor with reconfigurable resolution for energy harvesting applications such as video sensor networks. Depending on the available energy, the spatial resolution of the imager can be adaptively reconfigured to save energy for other units on the sensor node. In contrast to early attempts of energy harvesting image sensor, we propose an asynchronous sensor in which the photodetector itself within the pixel can be used as an energy harvesting device, so that the total available energy will be increased. Low power operation is achieved since the time-to-first spike (TFS) pixel only fires once per frame. Utilizing address-event-representation, the imager can make efficient use of the output bandwidth. System architecture and operation are discussed together with the simulation results. Measurement results for a test structure fabricated in standard 0.35 ¿m CMOS process are also provided. A system model is developed to illustrate the effectiveness of the proposed approach.