Environment Observation Module for the Deci Zebro: Obstacle and Motion Detection using a Laser Rangefinder and Optical Flow
O. Oosterlee (TU Delft - Electrical Engineering, Mathematics and Computer Science)
S. Peterse (TU Delft - Electrical Engineering, Mathematics and Computer Science)
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Abstract
A Camera Submodule for the Environment Observation Module for a Zebro robot was designed. It is able to collect and process data about obstacles on a Raspberry Pi and send this to the main processor of the Environment Observation module using UART.
The two main functions that were implemented are a laser rangefinder based on triangulation and a motion detector based on optical flow. The laser rangefinder calculates the distance to an obstacle by finding its own laser point in a frame. Testing showed that it is especially accurate at short distances (0-4 cm), and the range can differ between 0.30 to 6m due to environmental light and obstacle color.
The motion detector uses dense optical flow data that is provided by the h264 encoder of the Pi Camera. This data is filtered and moving obstacles are grouped together. In the tests, a moving obstacle was detected every time, but 29% also showed false positives due to large egomotion.