Spectral calibration method for swept source optical coherence tomography (SS-OCT) system

Abstract

Disclosed is a spectral calibration method for a swept source optical coherence tomography (SS-OCT) system. A transparent sheet is placed in a reference arm of the SS-OCT system. A fixed optical path difference interference signal having an optical path difference of 2nd can be obtained by using the transparent sheet. Interference signals of the system are collected by dense sampling and contain interference signals of the sheet and sample interference signals, the spectral calibration is performed using the interference signals of the sheet, the sample interference signals at equal intervals of the wave number are obtained, the inverse Fourier transform data processing and image reconstruction algorithm are then carried out, and an tomography structure image of the sample can be obtained. The method of the invention realizes the real-time calibration of the system interference signals by using the transparent sheet, has the advantages of simple structure and convenient use, avoids the use of additional devices such as a Mach-Zehnder (MZI) interferometer, and reduces the system cost and complexity.

Description

technical field [0001] The present invention relates to swept frequency optical coherence tomography (Swept source Optical Coherence Tomography, SS-OCT for short), in particular to a spectral calibration method for SS-OCT. Background technique [0002] Optical coherence tomography (OCT for short) is a biomedical optical imaging technique that obtains structural information at different depths of a sample by detecting the intensity of backscattered light from the sample. In vivo detection of biological tissue internal microstructure information and other characteristics. In 1991, J.G.Fujimoto and D.Huang of the Massachusetts Institute of Technology first proposed this concept, and performed in vitro imaging of the retina and coronary arteries. At present, OCT technology has been widely used in clinical diagnosis and research in ophthalmology, dermatology, cardiovascular and other fields. [0003] OCT can be divided into time domain OCT (Time Domain OCT, TD-OCT) and frequenc...

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Problems solved by technology

[0012] 1) The method based on non-uniform discrete Fourier transform proposed by Zhihua Ding et al. directly performs non-uniform discrete Fourier transform on the collected interference signals with equal intervals of wavelength, but this method has a large amount of data processing and time-consuming, and is not applicable For real-time display (see prior art [5], Tong Wu, Zhihua Ding, Kai Wang, Chuan Wang, "Swept sourceoptical coherence tomography based on non-uniform discrete fouriertransform", China Optics Letters (English version), Vol.7, No.10, 941-944, 2009);

[0013] 2) The correction method based on the mirror interference signal proposed by Y.Yasuno et al. This method first uses the mirror as a sample to obtain the interference signal, and then uses the phase information of the interference signal to perform spectral calibration, but it needs to know the wavelength of the light source with time. At the same time, it is considered that the light source remains stable for at least several months, and the sample interference signal collected cannot be calibrated in real time (see prior art [6], Y.Yasuno, V.D.Madjarova, S.Makita, M.Akiba, A. Morosawa, C. Chong, T. Sakai, K.P. Chan, M. Itoh, and T. Yatagai, “Three-dimensional and high-speed swept-source optical coherence tomography for in vivo investigation of human anterior eye segments,” Opt. Express Vol .13, No.25 10652–10664 2005)

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