digital image processing
L.F. Kupchenko, A.S. Rubyak
The article is dedicated to the development of the principles of dynamic spectral filtration of optical signals to decrease influence interference, which produces the background and propagation medium. The authors of this article suggest using the processing of optical radiation, which provides selection of wanted signal spectral component based on priori information about spectral characteristics of target and interference radiation. It has been achieved using controllable filters with maximal transmittance for spectral component of target radiation and minimal transmittance for optical signal of interference, moreover, spectral selection of optical radiation has been realized with the help of acousto-optic interaction. In contrast to spectral filtration systems, in which selective device forms the image of target in narrow spectral regions, in this work spectral filtration device is used as a filter with controllable transmittance. The article consists of four parts. The first part is dedicated to the development of the principles of radiation spectral filtration using the vector representation of the optical signals. There is shown that the signal of controlled transmittance has been computed using the principles of multidimensional Euclidean geometry, and priori information about spectral characteristics of target and interference radiation. In the second part the authors determine the vector characteristics of filter, which provides the increase of the required detection parameters. There has been shown that vector characteristics of filter depend on properties of target and background optical signals. The third part is dedicated to the digital color image processing using the principles of dynamic spectral filtration. There has been developed the method of color image processing to mark out the targets, which differentiate from inhomogeneous background by spectral signatures. The fourth part is dedicated to the verification of general principles of dynamic spectral filtration to increase target contrast with spectral characteristics different from background characteristics. The physical experiment, in which acousto-optical cell was used as controlled selective device, confirmed capability of the target optical signal selection observed on inhomogeneous background.