Optical rangefinder and imaging apparatus with chiral optical arrangement

A passive optical rangefinder, comprising:

• a) a photosensor adapted to transform an image projected onto it into a corresponding electronic image;
• b) an imaging system adapted to provide projection of the image of at least one object on the photosensor;
• c) spectral processing means adapted to provide the spatial spectrum of the image by spectral decomposition;
• d) defocus processing means adapted to provide the distance from the object to the rangefinder based on a degree of defocus of the image;
• and
• e) an optical arrangement comprising,
• (1) at least one chiral optical arrangement adapted to provide chiral modulation such that the degree of displacement of the spatial spectrum relative to a reference pattern depends on the degree of defocus of the image, with the spatial spectrum comprising at least one detectable feature, with
• i. chiral modulation meaning modulation of phase and amplitude of light such that the generalized pupil function of the optical system is not invariant under parity transformation,
• ii. reference pattern meaning any synthetic structure in the spatial spectrum domain suitable to measure the degree of displacement, and
• iii. a detectable feature created by the optical arrangement independent from the object for allowing determination of the degree of displacement of the spatial spectrum relative to the reference pattern, and
• (2) additional processing means adapted to derive the degree of defocus of the image from the degree of displacement by comparison of the spatial spectrum with the reference pattern.