Article révisé par les pairs
| Résumé : | We present in this paper a theoretical analysis of the pattern recognition process based on the propagation of the mutual coherence function Г. The 'matched filter' has been first recorded by Fourier holography with a field whose coherence structure is characterized by the function Г0; the recognition itself is performed with a field characterized by PR. We first study the particular case of perfectly coherent illumination in both recording and recognition (Г0 =ГR =1). We show that a decrease of coherence either in the filter recording (Г0≠1 or in the recognition produces a decrease of signal to noise ratio of the process. The ratio of the intensity maxima which localize the signal in partially and perfectly coherent illumination is always inferior to the maximum of the product Г0Г0ГR across the field size. Generally the filter will be recorded with a perfectly coherent field (i.e. TEM00 laser field). For the recognition it would be more suitable to work with a high intensity field (pulsed laser, multimode laser). Consequently, our analysis can be applied to such fields whose spatial degree of coherence is not necessarily high. © 1975 Taylor and Francis Group, LLC. |
