In the process of solving a wide range of tasks concerning the Earth surface remote sensing and its state monitoring, the main role is played by the algorithm of the surface image forming and the algorithm of images and their fragments classification as well. From the statistical point of view the solution is based on the maximum-likelihood method. The paper presents analytical equations for likelihood coefficients and the structural scheme of their forming in the solution of radar signal recognition. To analyze the efficiency of the proposed algorithms are found boundary equations for probability calculating of correct signals with the usage of Chernoff-Kailath ratios. This ratios evaluate the upper and lower probability boundaries of correct and incorrect decisions in the case of classification of optional class number from different type surfaces.