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.

中文翻译：

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具有可编程感兴趣区域的小型化红外深度传感器的表征，可实现危害测绘应用

超声波传感器主导了小型化深度测量应用，例如机器人防撞和手杖危险检测，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，但是，ToF 深度感应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图. 我们针对距离测量精度、噪声、误差和可容忍的环境照明开发方法并呈现表征结果。在存在零干扰环境光的情况下，对于反射率为 73% 的目标，红外 ToF 传感器在 3000 毫米的距离内保持优于 2% 的精度。我们表征了该感兴趣区域启用的空间分辨率，并以 2.5° 的步长找到高达 15.7° 的离轴指向。许多危险检测系统可能正在移动，这会动态改变深度传感器的位置和指向。我们演示了使用 9 自由度（3 轴加速度计、陀螺仪和磁力计）惯性测量单元 (IMU) 来跟踪传感器指向。ToF 传感器与 IMU 相结合，构成了小型化深度映射解决方案的基础，该解决方案在 30Hz 下运行时功耗为 97.5mW，并且需要与微控制器的简单串行接口。