Apparatus and method for rangings and noise reduction of low coherence interferometry LCI and optical coherence tomography OCT signals by parallel detection of spectral bands
First Claim
1. An apparatus for controlling a phase of a signal, comprising:
- a system which is configured to;
(a) obtain at least one interference signal which is based on a first signal from a sample and a second signal from a reference;
(b) during (a), modulate the phase of the at least one interference signal to produce first information;
(c) determine offset information between the first signal and the second signal based on the first information;
(d) control the phase of the at least one interference signal using the offset information to generate second information; and
(e) generate an image which includes a plurality of depth profiles of at least a portion of the sample using the second information.
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Abstract
Apparatus and method for increasing the sensitivity in the detection of optical coherence tomography and low coherence interferometry (“LCI”) signals by detecting a parallel set of spectral bands, each band being a unique combination of optical frequencies. The LCI broad bandwidth source is split into N spectral bands. The N spectral bands are individually detected and processed to provide an increase in the signal-to-noise ratio by a factor of N. Each spectral band is detected by a separate photo detector and amplified. For each spectral band the signal is band pass filtered around the signal band by analog electronics and digitized, or, alternatively, the signal may be digitized and band pass filtered in software. As a consequence, the shot noise contribution to the signal is reduced by a factor equal to the number of spectral bands. The signal remains the same. The reduction of the shot noise increases the dynamic range and sensitivity of the system.
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Citations
27 Claims
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1. An apparatus for controlling a phase of a signal, comprising:
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a system which is configured to; (a) obtain at least one interference signal which is based on a first signal from a sample and a second signal from a reference; (b) during (a), modulate the phase of the at least one interference signal to produce first information; (c) determine offset information between the first signal and the second signal based on the first information; (d) control the phase of the at least one interference signal using the offset information to generate second information; and (e) generate an image which includes a plurality of depth profiles of at least a portion of the sample using the second information. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A method for controlling a phase of a signal, comprising:
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(a) obtaining at least one interference signal which is based on a first signal from a sample and a second signal from a reference; (b) during step (a), modulating the phase of the at least one interference signal to produce first information; (c) determining offset information between the first signal and the second signal based on the first information; (d) using a computing arrangement, controlling the phase of the at least one interference signal using the offset information to generate second information; and (e) using the computing arrangement, generating an image which includes a plurality of depth profiles of at least a portion of the sample using the second information. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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Specification