Smart active range finder with the capability of high sensitivity, high selectivity and wide dynamic range

摘要

In this paper, a smart active range finder with the capability of high sensitivity, high selectivity and wide dynamic range is presented. A correlation circuit and a current-mode suppression circuit of a constant illumination allow high sensitivity, high selectivity, and high suppression of a background illumination. A logarithmic-response circuit is employed to avoid saturation for wide dynamic range. The photo detector can quickly detect the modulated light by the pixel-parallel correlation. It has advantages to the applications which require both of availability in various backgrounds and a safe light projection for human eyes. The image sensor with 120 × 110 pixels has been developed and successfully tested. The high sensitivity under -18 dB signal-to-background ratio (SBR) is realized in > 48 dB dynamic range. In addition, the image sensor shows high selectivity in a multiple light system due to the suppression of orthogonally modulated lights. The sensor has been applied to the active range finding system and we show a measured range map and its range accuracy.