Detecting and parameters determining moving objects by time averaging of coherent radiation intensity

摘要

A new method of detection and determination of parameters for weakly reflecting and transparent moving objects is proposed. The method makes use of the coherent radiation scattered from inhomogeneous background surrounding these objects. It is based on pulsed coherent illumination of the objects and the background by two separated coherent sources, registering for each source the intensity of radiation scattered back by the background, and determining the difference between the time-averaged intensity squared and the square of the time-averaged intensity for various averaging times. The method proposed enables one to detect weakly reflecting and transparent objects placed at an arbitrary distance and to determine coordinates, sizes, and velocities of these objects. The probability of object detection is calculated versus variation and correlation radius of the background inhomogeneities under the assumption that the scattered field has Gaussian statistics. The paper presents a last 'shifting' algorithm of processing the signal received by means of the proposed method. The algorithm is based on illuminating the objects and the background by repeated pulses, storing the intensities of the reflected pulses and taking a time average of stored intensities squared and stored intensities in intervals between neighboring reflected pulses. Application of the proposed method for detecting clusters of weakly reflecting and transparent moving polluting particles in inhomogeneous environment and for determining position of clusters and concentration, average size, and average velocity of these particles is discussed.