Fourier domain sensing
AssigneeThe Regents of the University of Colorado, a body corporate
InventorsDaniel Feldkhun, Kelvin H. Wagner
Life of this patent
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Abstract
Methods and systems are disclosed of sensing an object. A first radiation is spatially modulated to generate a structured second radiation. The object is illuminated with the structured second radiation such that the object produces a third radiation in response. Apart from any spatially dependent delay, a time variation of the third radiation is spatially independent. With a single-element detector, a portion of the third radiation is detected from locations on the object simultaneously. At least one characteristic of a sinusoidal spatial Fourier-transform component of the object is estimated from a time-varying signal from the detected portion of the third radiation.
Claims40
A method of sensing an object, the method comprising:
- spatially modulating a first radiation to generate a structured second radiation;
- illuminating the object with the structured second radiation such that the object produces a third radiation in response, wherein, apart from any spatially dependent delay, the third radiation has a time variation that is substantially spatially independent;
- detecting, with a single-element detector, a portion of the third radiation from a plurality of locations on the object substantially simultaneously;
- and
- estimating at least one characteristic of one or more sinusoidal spatial Fourier-transform components of the object from a time-varying signal from the detected portion of the third radiation.
A method for measuring one or more sinusoidal spatial Fourier-transform components of an object, the method comprising:
- illuminating the object with a first probing radiation comprising one or more plane-wave components having distinct directions of propagation, wherein the object produces a second radiation in response to such illuminating;
- imparting a distinct frequency shift on each of the probing radiation components;
- detecting, with a single-element detector, a third reference radiation substantially coherent with respect to the first probing radiation and a portion of the second radiation from a plurality of locations on the object substantially simultaneously;
- and
- estimating at least one characteristic of the one or more sinusoidal spatial Fourier-transform components of the object based on a time-varying signal from the detected second and third radiations.
A method for measuring one or more plane-wave components of a first radiation, the method comprising:
- illuminating a single-element detector with the first radiation and with a second radiation substantially coherent with respect to the first radiation, the second radiation comprising one or more plane-wave components having distinct directions of propagation;
- imparting a distinct frequency shift on each of the second radiation components;
- detecting the first and second radiations with the detector substantially simultaneously;
- and
- estimating at least one of amplitude, phase, or direction of propagation of the one or more plane-wave components of the first radiation based on a time-varying signal due to the detected radiations.
A method for measuring one or more sinusoidal spatial Fourier-transform components of a portion of an image formed by a first radiation, the method comprising:
- generating a structured third radiation by spatially modulating a second radiation;
- illuminating a single-element multiphoton detector with the structured third radiation and with the first-radiation image portion;
- detecting the first and third radiations with the multiphoton detector substantially simultaneously;
- and
- estimating a characteristic of the one or more sinusoidal spatial Fourier-transform components of the portion of the image based on a time-varying signal due to the detected radiations.
A method for measuring a sinusoidal spatial Fourier-transform component of a portion of an image formed by a first radiation, the method comprising:
- spatially modulating an amplitude of the portion of the image with a traveling modulation pattern to form a structured second radiation;
- detecting a portion of the structured second radiation from a plurality of locations on the image substantially simultaneously;
- and
- estimating a characteristic of the sinusoidal spatial Fourier transform component of the portion of the image based on a time-varying signal due to the detected radiation.
Dependencies are inferred from the claim text.