Infrared search system comprising means for differentiating between target and background radiation

Claim 1

A SEARCH SYSTEM COMPRISING A RADIATION SENSITIVE DEVICE, MEANS FOR COLLECTING RADIATION FROM AN OPTICAL FIELD AND FOR PROJECTING SAID RADIATION ALONG A PATH ONTO SAID RAIDATION SENSITIVE DEVICE, SAID RADIATION COLLECTING AND PROJECTING MEANS INCLUDING A MIRROR MOUNTED IN SAID RADIATION PATH FOR OSCILLATION ABOUT AN AXIS, MEANS FOR OSCILLATING SAID MIRROR ABOUT SAID AXIS, SAID RADIATION SENSITIVE DEVICE COMPRISING A PLURALITY OF PHOTOSENSITIVE CELLS ALIGNED IN A PLANE INCLUDING SAID MIRROR AXIS, A RETICLE HAVING ALTERNATELY SPACED LINEAR RADIATION OPAQUE AND TRANSPARENT PORTIONS EXTENDING SUBSTANTIALLY PARALLEL TO SAID ALIGNED CELLS MOUNTED BETWEEN SAID ALIGNED CELLS AND MIRROR, A STORAGE CIRCUIT CONNECTED INDIVIDUALLY TO EACH CELL, A DISPLAY MEANS, SWITCHING MEAS FOR CONNECTING THE STORAGE CIRCUITS TO SAID DISPLAY MEANS IN SUCCESSION, AND MEANS REPONSIVE TO SAID SWITCHING MEANS AND SAID MEANS FOR OSCILLATING THE MIRROR FOR INDICATING ON SAID DISPLAY MEANS TWO COORDINATES OF A SOURCE OF RADIATION.