A 16$, times $16 Pixel Distance Sensor With In-Pixel Circuitry That Tolerates 150 klx of Ambient Light

摘要

A time-of-flight depth sensor is presented employing a correlation based concept. The pixels are able to suppress contributions of ambient light up to 150 klx autonomously and directly in the electronic circuits consuming only 2 $mu$A, each. All 16$,{times},$ 16 pixels capture the depth information simultaneously at maximally 16 frames per second using an external A/D converter (ADC). Additionally, an embedded 12-bit ADC can be used for converting the analog output values of the pixels to the digital domain at lower frame rates. Distance measurements in a range of 0–3.2 m show standard deviations in the centimeter range and a linearity error within ${-}1/{+}2$ cm. The influence of extraneous light is expressed as a relative distance error which is also in the centimeter range. A complete impression of the sensor system is given by discussing the pixel circuits, the ADC design, the design of the modulated light source providing 0.9 W optical power in the near infrared, and the auxiliary setup including an FPGA board. Additionally, a sensor model is provided to predict the measurement error due to stochastic sources. Three-dimensional snapshots as well as a comparison with state-of-the-art sensors and products complete the paper.