Possibilities for Increasing the Signal-To-Noise Ratio in Technical Vision Systems of Robotic Complexes Using Laser Structured Lighting

The development of high-resolution machine vision systems with a long observation distance is an urgent task. The possibilities to increase the observation distance by increasing the signal-to-noise ratio (SNR) based on the use of the active parallax method are discussed in the article. The achievable observation distance in such systems is determined by the brightness of the illumination source and the ratio of the brightness of the illumination source to the brightness of the background illumination (the SNR for the photodetector pixel). The goal of the investigation: The article considers the possibility of further increasing the SNR in machine vision systems with laser structured lighting due to the use of pulsed or repetitively pulsed mode of the backlight laser in combination with a time-gated photodetector. This allows to realize a machine vision system with gating, which will provide an increase in the observation distance due to the time cutoff of the background component of the recorded image. In the current scientific literature, the data on machine vision systems with temporal gating of the photodetector device are not known. Methods: To consider the possibilities of increasing the SNR in vision systems, a numerical analysis by analytical formulas was used for the parameters and the operating conditions typical for robotic technical systems. The data on the number of solar photons reflected by the object and backscattering photons arising from scattering of the both solar and laser radiation were used to calculate the SNR in machine vision systems with a conventional-type matrix photodetector and with a time-gated photodetector. Results: The calculation analysis has shown that, the using of laser illumination repetitively pulsed mode and a gated photodetector device allows to increase significantly both the SNR and the observation distance. Practical significance: The proposed technical vision system implementation can improve the characteristics of robotic systems.