Regularities of Formation of the Visibility Zone by Active-Pulse Television Vision Systems with a Comparatively Short Duration of Backlight Pulses

Abstract

For the second observation method, a model is proposed for forming the spatial-energy profile (SEP) of the visibility zone for a frequently implemented case in practice, when the duration of the laser illumination pulses of objects ∆t_las is significantly shorter than the duration of the strobe pulses (exposure time) of the photodetector ∆t_pd. Based on the proposed model, analytical expressions are obtained that relate the characteristic distances (points) of the SEP of the visibility zone with the durations of the laser illumination pulses, photodetector strobing and internal (technical) delay, as well as the moments of time corresponding to the end of the front and the beginning of the decay of the strobe pulses for their trapezoidal or triangular shape. Numerical calculations confirmed the validity of the obtained analytical expressions. The possibility of controlling the shape, durations of the front and decay of the SEP by changing the corresponding parameters of the strobe pulses is demonstrated. On the other hand, based on the experimentally recorded SEP, it is possible to determine, for example, the front and tail times of strobe pulses with a trapezoid or triangular shape. It is shown that at ∆t_las << ∆t_pd, the small distance effect (SDE) also manifests itself, which was previously discovered for systems with comparable values of ∆t_las and ∆t_pd. The manifestation of SDE for a rectangular shape of strobe pulses is experimentally demonstrated.