Multiplexing optical system and feature vector transformation apparatus using the same; feature vector detecting and transmitting apparatus; and recognition and classification system using these apparatuses

A multiplexing optical system for performing a Fourier transform in parallel on multiplexed vector information as an object to be processed and further performing an inverse Fourier transform in parallel on the Fourier transformed vector information, said multiplexing optical system including at least:

• a lens array for performing an inverse Fourier transform in parallel,
• wherein the following condition is satisfied in an arbitrary cross-section containing an optical axis of said lens array:
• k.sub.d p.sub.d .ltoreq.p.sub.t
• where p.sub.t is a pitch of said lens array for inverse Fourier transform;
• p.sub.d is a sampling pitch of transformed information in a feature transform plane where information transformed by said optical system is obtained;
• and k.sub.d is a number of components of transformed information in the feature transform plane which corresponds to one multiplex portion.

A multiplexing optical system for multiplexing vector information as an object to be processed, and performing a Fourier transform in parallel on the multiplexed vector information, and further performing an inverse Fourier transform in parallel on the Fourier transformed vector information, said multiplexing optical system comprising:

• object vector multiplexing means for multiplexing object vector information as an object to be processed by placing the object vector information on parallel beams of light traveling in various directions;
• multiple Fourier transform means consisting essentially of a large-aperture lens for performing a Fourier transform on the multiplexed object vector information in parallel and simultaneously;
• and
• multiple inverse Fourier transform means consisting essentially of a lens array for performing an inverse Fourier transform in parallel and simultaneously on the object vector information Fourier transformed by said multiple Fourier transform means;
• wherein the following condition is satisfied:
• (r.sub.F -.alpha..sub.max .lambda.f.sub.F)/f.sub.F -w.sub.T /f.sub.T .gtoreq.2h/f.sub.F
• where f.sub.F is a focal length of said large-aperture lens;
• r.sub.F is an overall effective aperture of said large-aperture lens;
• f.sub.T is a focal length of each lens element constituting said lens array for inverse Fourier transform;
• w.sub.T is a width of a light beam emanating from said lens array for inverse Fourier transform in correspondence to each multiplex region and reaching a feature transform plane;
• h is a distance from an optical axis extending through a center of said large-aperture lens to a center of that lens element in said lens array for inverse Fourier transform which is the farthest from the optical axis;
• .alpha..sub.max is a maximum spatial frequency needed by a filter serving as feature transform means installed in a Fourier transform plane;
• and .lambda. is a wavelength of light used.

In a feature vector transformation apparatus comprising object vector input and display means for entering vector information into a system as an object to be processed;

• object vector multiplexing means for multiplexing the entered vector information;
• multiple Fourier transform means for performing a Fourier transform in parallel on the multiplexed vector information to an extent corresponding to a multiplex level of the multiplexed vector information;
• multiple inverse Fourier transform means having a lens array consisting essentially of a number of lens elements which corresponds to said multiplex level for performing an inverse Fourier transform in parallel on Fourier transformed images obtained by said multiple Fourier transform means to an extent corresponding to said multiplex level;
• and feature transform means for performing feature transformation in parallel on the Fourier transformed images obtained by said multiple Fourier transform means, said feature transform means being disposed in a Fourier transform plane, thereby outputting images containing finally transformed features to a feature transform plane,
• the improvement wherein said multiple Fourier transform means includes a multiplexing optical system, said multiplexing optical system including a Fourier transform lens for performing a Fourier transform in parallel,
• wherein the following condition is satisfied in an arbitrary cross-section containing an optical axis of said Fourier transform lens:
• k.sub.R .lambda.f.sub.F /a<p
• where k.sub.R is a number of components of each multiplex portion of the multiplexed vector information;
• p is a pitch between zero-order portions of Fourier transformed information concerning adjacent multiplex portions obtained in the Fourier transform plane;
• a is an effective display size of each multiplex portion;
• .lambda. is a wavelength of light used;
• and f.sub.F is a focal length of said Fourier transform lens.

In a feature vector transformation apparatus comprising object vector input and display means for entering vector information into a system as an object to be processed;

• object vector multiplexing means for multiplexing the entered vector information;
• multiple Fourier transform means for performing a Fourier transform in parallel on the multiplexed vector information to an extent corresponding to a multiplex level of the multiplexed vector information;
• multiple inverse Fourier transform means having a lens array consisting essentially of a number of lens elements which corresponds to said multiplex level for performing an inverse Fourier transform in parallel on Fourier transformed images obtained by said multiple Fourier transform means to an extent corresponding to said multiplex level;
• and feature transform means for performing feature transformation in parallel on the Fourier transformed images obtained by said multiple Fourier transform means, said feature transform means being disposed in a Fourier transform plane, thereby outputting images containing finally transformed features to a feature transform plane,
• the improvement which includes a multiplexing optical system for performing a Fourier transform in parallel on multiplexed vector information as an object to be processed and further performing an inverse Fourier transform in parallel on the Fourier transformed vector information, said multiplexing optical system including at least:
• a lens array for performing an inverse Fourier transform in parallel,
• wherein the following condition is satisfied in an arbitrary cross-section containing an optical axis of said lens array:
• k.sub.d p.sub.d .ltoreq.p.sub.t
• where p.sub.t is a pitch of said lens array for inverse Fourier transform;
• p.sub.d is a sampling pitch of transformed information in the feature transform plane where information transformed by said optical system is obtained;
• and k.sub.d is a number of components of transformed information in the feature transform plane which corresponds to one multiplex portion.

In a feature vector transformation apparatus comprising object vector input and display means for entering vector information into a system as an object to be processed;

• object vector multiplexing means for multiplexing the entered vector information;
• multiple Fourier transform means for performing a Fourier transform in parallel on the multiplexed vector information to an extent corresponding to a multiplex level of the multiplexed vector information;
• multiple inverse Fourier transform means having a lens array consisting essentially of a number of lens elements which corresponds to said multiplex level for performing an inverse Fourier transform in parallel on Fourier transformed images obtained by said multiple Fourier transform means to an extent corresponding to said multiplex level;
• and feature transform means for performing feature transformation in parallel on the Fourier transformed images obtained by said multiple Fourier transform means, said feature transform means being disposed in a Fourier transform plane, thereby outputting images containing finally transformed features to a feature transform plane,
• the improvement which includes a multiplexing optical system for multiplexing vector information as an object to be processed, and performing a Fourier transform in parallel on the multiplexed vector information, and further performing an inverse Fourier transform in parallel on the Fourier transformed vector information, said multiplexing optical system comprising:
• object vector multiplexing means for multiplexing object vector information as an object to be processed by placing the object vector information on parallel beams of light traveling in various directions;
• multiple Fourier transform means consisting essentially of a large-aperture lens for performing a Fourier transform on the multiplexed object vector information in parallel and simultaneously;
• and
• multiple inverse Fourier transform means consisting essentially of a lens array for performing an inverse Fourier transform in parallel and simultaneously on the object vector information Fourier transformed by said multiple Fourier transform means;
• wherein the following condition is satisfied:
• (r.sub.F -2.alpha..sub.max .lambda.f.sub.F)/f.sub.F -w.sub.T /f.sub.T .gtoreq.2h/f.sub.F
• where f.sub.F is a focal length of said large-aperture lens;
• r.sub.F is an overall effective aperture of said large-aperture lens;
• f.sub.T is a focal length of each lens element constituting said lens array for inverse Fourier transform;
• w.sub.T is a width of a light beam emanating from said lens array for inverse Fourier transform in correspondence to each multiplex region and reaching the feature transform plane;
• h is a distance from an optical axis extending through a center of said large-aperture lens to a center of that lens element in said lens array for inverse Fourier transform which is the farthest from the optical axis;
• .alpha..sub.max is a maximum spatial frequency needed by a filter serving as said feature transform means installed in the Fourier transform plane;
• and .lambda. is a wavelength of light used.