Phase-multiplexing-based full-range sweep frequency OCT (Optical Coherence Tomography) imaging method and system

Abstract

The invention discloses a phase-multiplexing-based full-range sweep frequency OCT (Optical Coherence Tomography) imaging method and system. An electrooptical modulator is arranged in a reference arm of the sweep frequency OCT system so as to realize high-speed phase modulation of an interference spectrum. Preset phase change can be kept between adjacent sampling points of the collected interference spectrum through trigger synchronization between a data collecting card and the electrooptical modulator so as to realize collection on phase multiplexing of the interference spectrum in a single sweep frequency period, the data sampling points of the collected interference spectrum are grouped according to corresponding additional phases, the grouped sampling points are respectively mapped in a wave number space with sampling points at equal intervals so as to form phase shift interference spectrum data subsets of the wave number space. Interference spectrum data can be constructed by utilizing the phase shift interference spectrum subsets so as to reconstruct full-range sweep frequency OCT images. On the basis of phase modulation and multiplexing of the interference spectrum in the single sweep frequency period of the electrooptical modulation, the phase shift is fast in speed and high in precision, the image rejection rate is high, and high-sensitivity imaging in an interesting depth area can be realized.

Description

technical field [0001] The invention relates to optical coherence tomography (OCT) technology and frequency-sweeping optical coherence tomography technology, in particular to a full-scale frequency-sweeping OCT imaging method and system based on phase multiplexing. Background technique [0002] Optical coherence tomography (OCT) imaging technology is a promising optical imaging technology that can non-invasively, non-contact, and high-resolution study the internal structure and physiological functions of living biological samples. In vivo imaging has broad application prospects in the early diagnosis of diseases and in vivo biopsy. [0003] The frequency-swept optical coherence tomography system belongs to a Fourier domain optical coherence tomography imaging system. Fourier-domain optical coherence tomography systems can be implemented in two forms, spectral domain OCT systems based on broadband light sources and fast multi-channel spectrometers, and frequency-swept OCT sy...

AI Technical Summary

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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