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US 10,760,893 B2Granted
Apparatus and method for processing the signal in master slave interferometry and apparatus and method for master slave optical coherence tomography with any number of sampled depths
AssigneeUniversity of Kent
InventorsAdrian Podoleanu, Sylvain Rivet, Adrian Bradu, Michael Maria
Life of this patent
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Abstract
The present invention related to an apparatus and method for master slave interferometry, referred to as Complex Master Slave (CMS). The method and apparatus can be used to provide complex-valued measurements of a signal reflected from an axial position inside an object or of signals reflected from points at several axial positions inside an object.
Claims20
An apparatus for master slave interferometry of an object, the apparatus comprising:
- an interferometer having a pair of interferometer arms, wherein one of the interferometer arms is configured to hold the object, and wherein the interferometer is driven by an optical source and configured to irradiate the object and to output an output optical signal as a result;
- a photodetecting block configured to acquire the output optical signal at the interferometer output, and to output an electrical signal array {I(1), I(2), . . . I(R)}, with a component I(r) for each resolvable spectral component in the source spectrum, wherein r=1, 2 . . . R, wherein R is a positive integer larger or equal to 2;
- a Master Storage Block configured to store P master signals, wherein the master signals are electrical signal arrays {I(1), I(2), . . . I(R)} output by the photodetecting block and P is a positive integer larger or equal to 2 and wherein at least two master signals for respective optical path differences in the interferometer are acquired using the photodetecting block, and wherein the master signals are obtained with a model object in one of the arms of the interferometer and from irradiating the model object using the interferometer;
- a Phase Recovery Calculator configured to receive the master signals from the Master Storage Block and to calculate the phases of the master signals by calculating the argument of the complex form of the master signals;
- a Synthesiser, configured to receive the phases of the master signals from the Phase Recovery Calculator and to generate two Synthesised Arrays, G={G(1), . . . , G(r), . . . , G(R)} and H={H(1), . . . , H(r), . . . , H(R)} based on the phases of the master signals;
- a Mask Generator having inputs for receiving the synthesised arrays and a plurality of control inputs, wherein the Mask Generator is configured to output an integer number, Q, of synthesized complex masks, each synthesized complex mask being a complex reference signal array, SM(q)={SM(q,1), SM(q,2), . . . SM(q,R)}, q=1, 2 . . . Q, for Q optical path differences in the interferometer, with a component SM(q,r) for each resolvable spectral component within the source spectrum,
- wherein the synthesised complex masks are calculated based on the two synthesised arrays;
- a Preparation Storage configured to receive and store the synthesised complex masks from the Mask Generator;
- and
- a plurality of Q Reflectivity Calculators, each with two inputs, wherein each Reflectivity Calculator processes two arrays, the complex mask SM(q) and F[I], where F[I] is a function of the electric signal array I and either F[I]=I or F[I] is the Fourier Transform of the electrical signal array I, wherein each Reflectivity Calculator outputs a complex reflectivity value C(q), from a depth in the object as determined by the optical path difference of the complex reference signal arrays, SM(q).
7 more elements
A method for Master Slave interferometry of an object using an interferometer having a pair of interferometer arms with an object placed in one of the interferometer arms and configured to irradiate the object and output an optical signal, and a photodetecting block for receiving the optical signal output by the interferometer, the method comprising:
- at a Master step, acquiring, using the photodetecting block, at least two master signal array measurements for respective optical path differences in the interferometer, wherein the master signal array measurements are obtained with a model object in one of the arms of the interferometer and from irradiating the model object using the interferometer;
- storing the acquired master signals in a Master Storage Block;
- calculating, by a Phase Recovery Calculator, a phase associated with each of the master signals;
- generating, by a Synthesiser, two arrays G={G(1), . . . ,G(r), . . . ,G(R)} and H={H(1), . . . , H(r), . . . , H(R)}, based on the phases calculated by the Phase Recovery Calculator, wherein R is any number and r=1, 2, . . . R;
- in a Preparation step generating, by a Mask Generator, Q synthesized complex masks SM(q) for Q values of optical path difference (OPD) in an interferometer, where each synthesized complex mask SM(q) is a complex reference signal obtained from the master signal array measurements, and Q is any number and q=1, 2, . . . Q;
- in a slave step, acquiring, using the photodetecting block, a slave signal proportional to an optical measuring spectrum at the output of the interferometer, wherein the slave signal is acquired with the object in one of the interferometer arms and upon irradiating the object with the interfereometer;
- and
- where by processing the Q complex reference signals and the slave signal, Q amplitudes A(q) and Q phases Φ(q) are obtained for the q part of the slave signal obtained in the slave step that originates from the same optical path difference as that of the reference signal measured.
5 more elements
Dependencies are inferred from the claim text.