In our blog post, Latest optical sensing technology lights the way ahead for new robot designs we gave an overview of advanced 3D sensing solutions, multi-channel spectral sensors and projection lighting systems enable robots to ‘see’ the world around them, and use light to communicate with people. Now, let us take an engineer’s perspective and drill down into considerations and tools for evaluating multi-zone direct time-of-flight sensing.
High accuracy and scalable multi-zone 1D-dToF proximity sensing is often selected for its design flexibility, highest redundancy and most competitive pricing. This enables advanced obstacle detection and environment awareness for a range of up to 5 meters, while simple determination of first (closest) and second (next closest) objects require less compute-intense detection algorithms.
For example, the compact TMF882x from ams OSRAM offers complete multi-zone sensing functionality in a single modular device for applications like laser detect auto-focus (LDAF), home service robots, user presence detection, contactless switching and gesture recognition.
White paper: Understanding time-of-flight sensing
As a leading supplier of ranging sensors which enable the camera auto-focus function in smartphones, ams OSRAM has built up deep expertise in the implementation of time-of-flight sensing that it is transferring to other industrial applications like robotics based on significant market interest.
In the new White Paper, Understanding time-of-flight sensing, I explore in detail how accurate ranging sensors in small, surface-mount packages are spreading from mobile to industrial and consumer applications. Written from an engineer’s perspective, the topics include:
- The types of ToF sensor and their mode of operation
- The sweet spot for direct time-of-flight sensor applications
- Using a dToF sensor in the application: the role of the sensor module algorithm histogram
- Using a dToF sensor in the application:
o optical configuration
o optical design considerations
- How to start developing a dToF sensor-based ranging system
You can register here to download your copy of the white paper
Supporting design engineers to overcome the challenges of their optical designs
The principle of operation of a dToF sensor is simple. However, implementing this principle in practice entails complex hardware and software components, to ensure that the sensor maintains accurate performance even in adverse operating conditions.
The internal VCSEL (vertical cavity surface-emitting laser) emits multiple pulses of 940nm infrared light. Reflections from each pulse can be individually detected by the internal high-sensitivity SPAD (single proton avalanche diode) detector. The time measured by the time-to-digital converter from each received pulse is plotted in a histogram which provides a robust method for the sensor module’s algorithm to determine the degree of confidence which applies to each object detection event.