A new technique in ramp response for acoustic imaging of underwater objects

The ramp response of an underwater object yields information about the object's size, orientation and geometrical shape. Based on the physical optics approximate, a simple relation between ramp response and the profile function has been obtained in the illuminated region of the object. The same relation in the shadow region has also been presented. With the profile data from three arbitrary looking angles, the 3-D image of the object can be generated through the technique known as "approximate limiting surface". Instead of the FFT method, a new technique has been developed to obtain a fairly good ramp response. Several different non-dimensional frequency range cases have been discussed for sphere and ellipsoid. And 3-D images have been shown. The study indicates that a fairly good ramp response can be obtained with less frequency domain data.