Optical pattern recognition on nonvertical imagery

An optical matched spatial filtering system is described that is capable of correlating nonvertical imagery with no loss in the peak intensity and SNR of the output correlation. From the coordinates of the correlation peak, the tilt angle of one camera (or angle of approach of the object being photographed) and the scale of the image (distance from the object) can be determined. Experimental demonstrations of the principle(combined geometrical and optical transformations) on actual imagery are included.