DETEKTOROPTIK, INSBESONDERE ZUR VERWENDUNG BEI DER FEHLERPRUEFUNG TEXTILER FLAECHENGEBILDE

First and second pairs of mirrors are oriented to intercept first and second regions respectively of a diffraction pattern and deflect these regions to individual detectors so that simultaneous analysis of the regions of the diffraction pattern can be carried out. The pairs of mirrors can be spaced along the optical axis in a manner to provide focused regions of the diffraction pattern at the detectors wherein the diffraction pattern itself is imaged at two spaced focal planes resulting from astigmatic conditions. The physical arrangement not only overcomes problems introduced by astigmatism but also permits practical physical positioning of individual photo-diode arrays such that simultaneous processing of the regions in the diffraction pattern can be carried out.