Hough Transform for Target Identification from Linear Sensor Array F-K Spectrum

Non-acoustic self-noise observed in towed sonar arrays represents a serious problem for acoustic source detection at low frequency. The decomposition of an array snapshot into its constituent acoustic and non-acoustic components is accomplished using a frequency-wavenumber, or F-K transform. Frequency-wavenumber diagrams can be used in order to differentiate between acoustic and non-acoustic noise. The frequency wavenumber transform is a double Fourier transform, both in time and in space, where the positive time frequencies are plotted along the y axis and the x axis represent the spatial frequency k. The acoustic energy is confined within the V-area of the F-K diagrams. Energy outside this V will highlight non-acoustic energy. From the f-k spectrum, target detection is possible using the principle of line detection by Hough transform. The Hough transform (HT), named after Paul Hough who patented the method in 1962, is a powerful global method for finding lines in an image. It transforms between the Cartesian space and parameter space.