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In this paper,the ability of likelihood ratio method in the classification of underwater sphericaltargets with the same diameters is investigated.The formulae for probabilities of correct classifi-cation and incorrect classification for various thresholds are developed based on statistic theory.It is shown that these probabilities depend on the mean value and variance of test function.Both ofthem can be determined by the quadrature samples of target echoes. Three target pairs consisting of four spherical targets were used in the experiment.The resultsshow that the performance indices of classification(i.e.the area under the ROC curve)for these threetarget pairs are different and are the functions of S/N raio.As an example,for one pair of them theperformance index increases by 0.0268 on average as the S/N ratio increases by 1 dB when the S/N ratiotakes the value from 0 dB to 5 dB.While the average increasing rate becomes 0.0212/dB when theS/N ratio takes the value from 5 dB to 10 dB.
In this paper, the ability of likelihood ratio method in the classification of underwater sphericaltargets with the same diameter is investigated. The formula for probabilities of correct classifi cation and incorrect classification for various thresholds are developed based on statistic theory. It is shown that these probabilities depend on the mean value and variance of test function.Both of the cans determined by the quadrature samples of target echoes. Three target consisting of four spherical targets were used in the experiment. result result that the performance indices of classification (iethe area under the ROC curve) for these threetarget pairs are different and are the functions of S / N raio.As an example, for one pair of them the performance index increases by 0.0268 on average as the S / N ratio increases by 1 dB when the S / N ratiotakes the value from 0 dB to 5 dB. Whilst the average increasing rate becomes 0.0212 / dB when the S / N ratio takes the value from 5 dB to 10 dB.