AN OBJECTIVE MRTD FOR DISCRETE INFRARED IMAGING-SYSTEMS

An objective method has been developed for measuring the minimum resol vable temperature difference (MRTD) of infrared imaging systems employ ing focal plane detector arrays. The resulting MRTD is uniquely determ ined by applying discrete Fourier analysis, thus avoiding the previous multi-valued problem associated with the non-isoplanatic property of discrete devices. The derivation is based on sinusoidal wave input tar gets but a practical measuring procedure has been developed using conv entional bar patterns; alternatively the MRTD may be calculated by mea suring the MTF using the line spread function.