Model-based object characterization with active infrared sensor array

The paper presents a low-cost solution based on reflected infrared light intensity measurements for the determination of characteristic properties of moving objects like form, size, location, trajectory, velocity and surface reflectivity. Two arrays of several infrared (IR) emitter-receiver pairs, working on a reflection light principle and driven alternately, are mounted on opposite sides of the area of observation. In order to model the reflecting surface properly, it is considered to be composed of a number of so called elementary reflectors (ER), effectively decoupling the three components of the received intensity: distance, azimuth and surface reflection angle. Results from measurements with basic object forms are shown proving its potential. The model parameters (number of ERs involved, their position and direction towards the IR sensor) are obtained by an optimization procedure, enabling to recognize virtually every object form by decomposition into ERs.