A trapezoid CMOS image sensor with 2% detection accuracy for traffic monitoring

In this paper, a new multi-resolution CMOS imager sensor with trapezoid pixel array, called TZOID, is presented. It was designed for traffic monitoring to detect the speed and location vehicles approaching a signized intersection. It composes of significantly less number of pixels than a comparable image sensor used in similar application. The unique trapezoid image sensor design eliminates computationally expensive coordinate mapping to extract necessary speed and location information. The TZOID imager approach simplifies the traffic monitoring camera system achieving lower communication bandwidth, low-power consumption and smaller frame memory. A prototype TZOID chip was fabricated in a 0.18μm CMOS process with a 40×152 multi-resolution trapezoid pixel array. The imager achieves 2% accuracy while extracting object location, length and speed information in scaled laboratory testbed.