Figure 1: Human and robot collaboration includes a broad range of possible levels of interaction. (Image source: SICK)
This article will describe the nuances of ToF technology before showing how two off-the-shelf 3D ToF kits— Analog Devices’ AD-96TOF1-EBZ development platform and ESPROS Photonics’ EPC660 evaluation kit—can help developers quickly prototype 3D ToF applications and gain needed experience to implement 3D ToF designs to meet their unique requirements. What is ToF technology? ToF technology relies on the familiar principle that the distance between an object and some source point can be found by measuring the difference between the time that energy is transmitted by the source and the time that its reflection is received by the source (Figure 1). Although the basic principle remains the same, ToF solutions vary widely and bear the
technologies including ultrasound, light detection and ranging (LiDAR), cameras, and millimeter wave (mmWave) RF signals: ■ Ultrasonic ToF solutions offer a low-cost solution but with limited range and spatial resolution of objects
robots move across a path or as drivers park their vehicles. In contrast, mmWave technology provides vehicles with the kind of long-distance sensing capability needed to detect approaching road hazards even when other sensors are unable to penetrate heavy weather conditions. ToF designs can be built around a single transmitter/receiver pair. For example, a simple optical ToF design conceptually requires only an LED to illuminate some region of interest and a photodiode to detect reflections from objects within that region of interest. This seemingly
■ Optical ToF solutions can achieve greater range and
spatial resolution than ultrasonic systems but are compromised by heavy fog or smoke ■ Solutions based on mmWave technology are typically more complex and expensive, but they can operate at significant range while providing information about the target object's velocity and heading despite smoke, fog, or rain Manufacturers take advantage of the capabilities of each technology as needed to meet specific requirements. For example, ultrasonic sensors are well suited for detecting obstructions as
simple design nevertheless requires precise timing and
synchronization circuits to measure the delay. In addition, modulation and demodulation circuits may be needed to differentiate the illumination signal from background sources or support more complex continuous wave methods.
capabilities and limitations inherent in their underlying
we get technical
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