Accurate and fast ISAR image formation for complex CAD using the shooting and bouncing ray

Accurate and fast inverse synthetic aperture radar (ISAR) image formation using the shooting and bouncing ray (SBR) technique has been examined in order to facilitate precise and fast signature prediction for a known target in target recognition. A fast Fourier transform (FFT)-based convolution scheme has been used to accelerate the image formation using the SBR technique. The scheme represents an image domain ray-tube integration formula, which consists ray-sum procedure, through a convolution operation between an impulse train and a ray spread function. However an interpolation algorithm, which is entailed in the scheme, distracts the image, therefore, a FFT-based accurate convolution scheme is proposed to improve in accuracy of the image formation. The accurate scheme utilizes a modified ray spread function to minimize the distortion. In this paper, we demonstrate the accurate convolution scheme based on the linear interpolation for a complex and realistic 3D CAD model.