US 8,300,113 B2 · Hadamard multimode optical imaging transceiver

Abstract

Disclosed is a method and system for simultaneously acquiring and producing results for multiple image modes using a common sensor without optical filtering, scanning, or other moving parts. The system and method utilize the Walsh-Hadamard correlation detection process (e.g., functions/matrix) to provide an all-binary structure that permits seamless bridging between analog and digital domains. An embodiment may capture an incoming optical signal at an optical aperture, convert the optical signal to an electrical signal, pass the electrical signal through a Low-Noise Amplifier (LNA) to create an LNA signal, pass the LNA signal through one or more correlators where each correlator has a corresponding Walsh-Hadamard (WH) binary basis function, calculate a correlation output coefficient for each correlator as a function of the corresponding WH binary basis function in accordance with Walsh-Hadamard mathematical principles, digitize each of the correlation output coefficient by passing each correlation output coefficient through an Analog-to-Digital Converter (ADC), and performing image mode processing on the digitized correlation output coefficients as desired to produce one or more image modes. Some, but not all, potential image modes include: multi-channel access, temporal, range, three-dimensional, and synthetic aperture.

Claims18

Dependent claims

A method for capturing an image of a target through a single common sensor and producing at least one image mode of a plurality of potential image modes of said target comprising:

capturing an incoming optical signal at an optical aperture;
detecting said incoming optical signal captured at said optical aperture with a square-law sensor acting as said common sensor to convert said incoming optical signal to an electrical signal;
passing said electrical signal through a low-noise amplifier to produce a Low-Noise Amplified (LNA) signal;
passing said LNA signal through at least one correlator, said at least one correlator having a time scalable Walsh-Hadamard binary basis function;
calculating a correlation output coefficient for said at least one correlator in order to temporally correlate said LNA signal, said correlation output coefficient of said at least one correlator being calculated in accordance with Walsh-Hadamard mathematical principles as a function of said Walsh-Hadamard binary basis function of said at least one correlator;
digitizing said correlation output coefficient of said at least one correlator into a digital correlation output coefficient for said at least one correlator by passing said correlation output coefficient signal through an analog-to-digital converter for said at least one correlator;
and,
performing image mode processing on said digital correlation output coefficient of said at least one correlator in a digital processing domain to produce said at least one image mode of said plurality of potential image modes.

5 more elements

A method for capturing an image of a target through a single common sensor and producing at least one image mode of a plurality of potential image modes of said target comprising:

capturing an incoming optical signal at an optical aperture;
detecting said incoming optical signal captured at said optical aperture with a square-law sensor acting as said common sensor to convert said incoming optical signal to an electrical signal;
passing said electrical signal through a low-noise amplifier to produce a Low-Noise Amplified (LNA) signal;
passing said LNA signal through at least one correlator, said at least one correlator having a time scalable Walsh-Hadamard binary basis function;
providing a plurality of optical sources, each optical source transmitting on a unique optical channel;
modulating an optical channel output signal of each of said plurality of optical sources with a unique Walsh-Hadamard baseband binary code sequence;
modulating said optical channel output signal of each of said plurality of optical sources already modulated with said unique Walsh-Hadamard baseband binary code sequence a second time with a high-frequency spreading code, said high frequency spreading code being common for said plurality of optical sources;
transmitting said twice modulated optical channel output signals by said plurality of optical sources;
optically combining said twice modulated optical channel output signals into a single combined optical output signal using an appropriate optical beam combining system;
reflecting said single combined optical output signal off said target to create a reflected signal, said reflected signal being said incoming optical signal;
providing a plurality of pixel square-law sensors combined as a grid of pixel square-law sensors such that each pixel square-law sensor of said plurality of pixel square-law sensors operates as said square-law sensor;
calculating a correlation output coefficient for said at least one correlator in order to temporally correlate said LNA signal, said correlation output coefficient of said at least one correlator being calculated in accordance with Walsh-Hadamard mathematical principles as a function of said Walsh-Hadamard binary basis function of said at least one correlator and such that said calculation of said correlation output coefficient is further performed with reference to a synchronized reference high-frequency spreading code that is synchronized with said high-frequency spreading code via a synchronizing communication link to said high-frequency spreading code;
digitizing said correlation output coefficient of said at least one correlator into a digital correlation output coefficient for said at least one correlator by passing said correlation output coefficient signal through an analog-to-digital converter for said at least one correlator such that said a plurality of digital correlation output coefficient signals represents a digital frame data cube of combined optical intensity detected at each pixel square-law sensor of said grid of pixel said square-law sensors;
and,
performing image mode processing on said digital correlation output coefficient of said at least one correlator in a digital processing domain to produce said at least one image mode of said plurality of potential image modes, further comprising:
correlating said digital frame data cube in accordance with said Walsh-Hadamard mathematical principles a second time in said digital processing domain using orthogonal Walsh-Hadamard binary code sequences that are orthogonal to said unique Walsh-Hadamard baseband binary code sequences in order to retrieve image data cube information for optical intensity of each unique channel of said plurality of optical sources for each pixel of said grid of pixels;
and,
assembling said image data cube information into a multi-channel access image data cube.

15 more elements

A multimode image acquisition system for capturing an image of a target through a single common sensor and producing at least one image mode of a plurality of potential image modes of said target comprising:

an optical aperture that captures an incoming optical signal;
a detector that detects said incoming optical signal captured at said optical aperture to convert said incoming optical signal to an electrical signal, said detector being a square-law sensor acting as said common sensor;
a low-noise amplifier that receives said electrical signal and produces a Low-Noise Amplified (LNA) signal;
at least one correlator that receives said LNA signal and calculates a correlation output coefficient for said at least one correlator in order to temporally correlate said LNA signal, said at least one correlator having a time scalable Walsh-Hadamard binary basis function, said correlation output coefficient being calculated in accordance with Walsh-Hadamard mathematical principles as a function of said Walsh-Hadamard binary basis function of said at least one correlator;
an analog-to-digital converter that accepts said correlation output coefficient of said at least one correlator and that digitizes said correlation output coefficient into a digital correlation output coefficient signal for said at least one correlator;
and,
a multimode image processing subsystem that performs image mode processing on said digital correlation output coefficient for said at least one correlator in a digital processing domain to produce said at least one image mode of said plurality of potential image modes.

4 more elements

an optical aperture that captures an incoming optical signal;
a detector that detects said incoming optical signal captured at said optical aperture to convert said incoming optical signal to an electrical signal, said detector being a square-law sensor acting as said common sensor;
a low-noise amplifier that receives said electrical signal and produces a Low-Noise Amplified (LNA) signal;
a plurality of optical sources, each optical source transmitting on a unique optical channel;
a Walsh-Hadamard modulating subsystem that modulates an optical channel output signal of each of said plurality of optical sources with a unique Walsh-Hadamard baseband binary code sequence;
a spreading code modulating subsystem that modulates said optical channel output signal of each of said plurality of optical sources already modulated with said unique Walsh-Hadamard baseband binary code sequence a second time with a high-frequency spreading code, said high frequency spreading code being common for said plurality of optical sources;
an optical beam combining system that optically combines said twice modulated optical channel output signals transmitted by said plurality of optical sources into a single combined optical output signal that reflects off said target to create a reflected signal, said reflected signal being said incoming optical signal;
a plurality of pixel square-law sensors combined as a grid of pixel square-law sensors such that each pixel square-law sensor of said plurality of pixel square-law sensors operates as said square-law sensor;
at least one correlator that receives said LNA signal and calculates a correlation output coefficient for said at least one correlator in order to temporally correlate said LNA signal, said at least one correlator having a time scalable Walsh-Hadamard binary basis function, said correlation output coefficient being calculated in accordance with Walsh-Hadamard mathematical principles as a function of said Walsh-Hadamard binary basis function of said at least one correlator;
an analog-to-digital converter that accepts said correlation output coefficient of said at least one correlator and that digitizes said correlation output coefficient into a digital correlation output coefficient signal for said at least one correlator;
and,
a communication link between said spreading code modulating subsystem and a spreading code reference subsystem;
said spreading code reference subsystem that injects said synchronized reference high-frequency spreading code into a plurality of correlators that calculate a plurality of correlation output signals such that said plurality of digital correlation output coefficient signals represents a digital frame data cube of combined optical intensity detected at each pixel square-law sensor of said grid of pixel said square-law sensors, said synchronized reference high-frequency spreading code being said high-frequency spreading code sent from said spreading code modulating subsystem via said communication link;
a multimode image processing subsystem that performs image mode processing on said digital correlation output coefficient for said at least one correlator in a digital processing domain to produce said at least one image mode of said plurality of potential image modes, and further comprising:
a second correlation subsystem that correlates said digital frame data cube in accordance with said Walsh-Hadamard mathematical principles a second time in said digital processing domain using orthogonal Walsh-Hadamard binary code sequences that are orthogonal to said unique Walsh-Hadamard baseband binary code sequences in order to retrieve image data cube information for optical intensity of each unique channel of said plurality of optical sources for each pixel of said grid of pixels;
an assembly subsystem that assembles said image data cube information into a multi-channel access image data cube.

13 more elements

Dependencies are inferred from the claim text.

Hadamard multimode optical imaging transceiver

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Hadamard multimode optical imaging transceiver

Life of this patent

Abstract

Claims18