Position encoding optical device and method

An optical device for encoding the position of a light peak generated by an optical processor receiving an image to be processed as generated by an imaging device illuminated by a laser source, said processor comprising first Fourier transform means for performing the Fourier transform of said input image to generate a corresponding transformed input image in the spatial frequency domain within an area defined by a Fourier transform filter plane, optical mask means disposed within said area, said second optical mask means implementing a filter mask function to generate a combined image in the spatial domain, and second Fourier transform means for performing the inverse Fourier transform of said combined image to generate said light peak at a peak image plane, said optical device comprising:

• a diffractive optical element disposed within said peak image plane and including an array of diffractive cells each being disposed at a predetermined position with respect to a predetermined reference point on said diffractive optical element, each said cells being capable of generating a unique optical diffraction pattern when illuminated, at least one of said cells being positioned to receive said light peak and generating its unique optical diffraction pattern accordingly at an output image plane;
• and
• one or more optical detectors disposed at said output image plane and responsive to said optical diffraction pattern to generate one or more encoded signals indicative of the position of said light peak with respect to said reference point.

A method of encoding the position of a light spot, said method comprising the steps of:

• a) forming an image of said light spot at a corresponding position within an input image plane and with respect to a predetermined reference point of said plane;
• b) generating a unique optical diffraction pattern associated with said corresponding position at an output image plane;
• and
• c) detecting said unique optical diffraction pattern to generate one or more encoded signals indicative of the position of said light spot image with respect to said reference point.