Characterization of a Miniaturized IR Depth Sensor With a Programmable Region-of-Interest That Enables Hazard Mapping Applications
Characterization of a Miniaturized IR Depth Sensor With a Programmable Region-of-Interest That Enables Hazard Mapping Applications
复制标题
具有可编程感兴趣区域的微型红外深度传感器的特性，可实现危险绘图应用
作者：
Ryan M. Jans;A. Green;L. Koerner
超声波传感器在机器人碰撞避免和手杖危险检测等小型化深度测量应用中占据主导地位，但空间分辨率有限。光学飞行时间（ToF）深度传感器提供了提高空间分辨率的潜力，然而，ToF深度感测相机对于手持应用来说可能太大且耗电。我们通过实验评估红外ToF传感器（ST VL53L1X）来解决这一差距，该传感器使用单光子雪崩光电二极管阵列来提供粗略的空间分辨率，同时保持小型化和低功耗，从而允许在手持应用中生成危险地图。我们开发的方法和目前的表征结果的距离测量精度，噪声，误差和可容忍的环境照明。在零干扰环境光的情况下，对于73%反射率的目标，IR ToF传感器在3000 mm的距离内保持优于2%的精度。我们描述了这个感兴趣区域的空间分辨率，并以2.5°的步长找到了高达15.7°的离轴指向。许多危险检测系统可能正在移动，这动态地改变深度传感器的位置和指向。我们演示了使用9度的自由度（3轴加速度计，陀螺仪和磁力计）惯性测量单元（IMU）跟踪传感器指向。ToF传感器与IMU相结合，形成了小型化深度映射解决方案的基础，该解决方案在30 Hz下工作时消耗97.5 mW，并且需要与微控制器的简单串行接口。
Ultrasonic sensors have dominated miniaturized depth measurement applications such as robot collision avoidance and walking cane hazard detection yet have limited spatial resolution. Optical time-of-flight (ToF) depth sensors offer the potential for improved spatial resolution, however, ToF depth-sensing cameras may be too large and power-hungry for hand-held applications. We address this gap by experimentally evaluating an infrared ToF sensor (the ST VL53L1X) that uses a single-photon avalanche photodiode array to provide coarse spatial resolution while remaining miniaturized and low-power, thus allowing the generation of hazard maps in hand-held applications. We develop methods and present characterization results for distance measurement accuracy, noise, error, and tolerable ambient illumination. The IR ToF sensor sustains accuracy better than 2% up to a distance of 3000mm for a 73% reflective target in the presence of zero interfering ambient light. We characterize the spatial resolution enabled by this region-of-interest and find off-axis pointing of up to 15.7° in steps of 2.5°. Many hazard detection systems may be moving, which dynamically changes the position and pointing of the depth sensor. We demonstrate the use of a 9-degree-of-freedom (3-axis accelerometer, gyroscope, and magnetometer) inertial measurement unit (IMU) to track sensor pointing. The ToF sensor combined with an IMU forms the basis for a miniaturized depth mapping solution that consumes 97.5mW when operating at 30Hz, and requires simple serial interfaces to a microcontroller.