Mirror-image separation method and system based on group delay wavenumber carrier frequency

Abstract

The invention discloses a mirror-image separation method and a system thereof based on group delay wavenumber carrier frequency; a grating-type optical delay line is arranged in a reference arm of a Fourier domain optical coherence tomography system, based on a specific angle between a reflecting mirror and an optical axis vertical plane in the optical delay line, an additional bit phasor linearly varied along with spectrum wavenumber is introduced in each spectrum component to realize a specific group delay in zero-phase delay of reference light. The reference light after group delay is converged with a sample light to form an interference spectrum of relative carrier frequency. An image reconstruction based on rapid Fourier conversion is executed to the interference spectrum, a conjugation mirror image thereof may deviate from a position when no carrier frequency exists, the equivalent offset is much greater than introduced additional optical path amount in each spectrum component so as to effectively separate a direct current component from the conjugation mirror image in the premise of guaranteeing the minimum flexibility reduction of the interference signal, thereby realizing the full range imaging of the Fourier domain optical coherence tomography. The method of the invention can be applied to a spectrum domain optical coherence tomography system and a sweep frequency optical coherence tomography system.

Description

technical field [0001] The present invention relates to optical coherence tomography technology and Fourier domain optical coherence tomography technology, in particular to a method and system for image separation based on group delay wavenumber carrier frequency. Background technique [0002] Optical coherence tomography (OCT) imaging technology is a new type of optical imaging technology that can perform non-invasive, non-contact, high-resolution in vivo imaging of the tissue structure and physiological functions of the tested living sample. It has broad application prospects in the field of early diagnosis of diseases and in vivo biopsy. [0003] The Fourier domain optical coherence tomography system includes two types: the spectral domain optical coherence tomography system and the frequency-swept optical coherence tomography system. The spectral domain OCT system adopts the structure of broadband light source and fast multi-channel spectrometer, and the swept frequency...

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Problems solved by technology

[0005] The above-mentioned methods all have their inherent shortcomings. For example, the method of multi-step phase shifting using piezoelectric ceramic drivers requires multiple measurements of the same position, which reduces the imaging speed and requires high phase stability, which is susceptible to various The influence of environmental disturbance on the phase; the method of using electro-optic phase modulator and acousto-optic frequency shifter needs to introduce more complex and expensive instruments and equipment, and puts forward strict requirements on the data acquisition speed of the system; the use of 3×3 fiber coupler The method is susceptible to the influence of temperature on the coupling coefficient, resulting in the inaccuracy of restoring the complex interference spectrum, which affects the overall complex conjugate suppression rate; the existing anti-image method using dispersion needs to rely on complex iterative algorithms, and the simplification of the algorithm is also difficult. The complex conjugate suppression rate is reduced; the method of double-balanced detection increases the complexity of the system, and the phase difference introduced has high requirements for environmental stability, which is not suitable for fiber-optic systems

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