NONLINEAR JOINT TRANSFORM CORRELATOR USING ONE-DIMENSIONAL FOURIER TRANSFORMATION

We present a new method for processing the data in a nonlinear joint t ransform correlator (NJTC). The output of the NJTC is obtained after t wo steps. The first step consists of the acquisition of the joint powe r spectrum (JPS) of the images to be correlated. The JPS is in princip le a bidimensional image. The second step is the calculation of the cr oss-correlation function. To do this, the JPS image is compressed to o ne dimension and a 1-D Fourier transform is performed. This significan tly reduces the number of operations required to evaluate the crosscor relation. To improve the cross-correlation sensitivity, a degree of no nlinearity is introduced using an illumination level above the saturat ion threshold of the camera used to acquire the JPS. (C) 1998 Society of Photo-Optical instrumentation Engineers. [S0091-3286(98)02210-7].