阅读说明：本技术 一种基于扫频激光器的频域oct成像方法 (Frequency domain OCT imaging method based on swept-frequency laser ) 是由 徐亚伟 傅国胜 焦力群 卢瑞祥 陶魁园 董勇 刘子旭 鲁坤 匡皓 陆维 李晓冉 于 2020-08-25 设计创作，主要内容包括：一种基于扫频激光器的频域OCT成像方法,其特征是使用多通道采集卡,将k-clock信号和OCT图像信号分别输入到多通道采集卡的输入端口使用采集卡的内部时钟进行采集,将采集后的k-clock信号进行相位提取,根据相位提取k域重映射矢量,通过重映射矢量对图像干涉信号进行k域重采样。本发明对硬件要求低,有利于大规模生产,并且可以很容易的扩展成像范围。(A frequency domain OCT imaging method based on a swept-frequency laser is characterized in that a multi-channel acquisition card is used, k-clock signals and OCT image signals are respectively input to an input port of the multi-channel acquisition card and are acquired by using an internal clock of the acquisition card, the acquired k-clock signals are subjected to phase extraction, k-domain remapping vectors are extracted according to the phases, and k-domain resampling is carried out on image interference signals through the remapping vectors. The invention has low requirement on hardware, is beneficial to large-scale production and can easily expand the imaging range.)

1. A frequency domain OCT imaging method based on a swept-frequency laser is characterized in that a multi-channel acquisition card is used, k-clock signals and OCT image signals are respectively input to an input port of the multi-channel acquisition card and are acquired by using an internal clock of the acquisition card, the acquired k-clock signals are subjected to phase extraction, k-domain remapping vectors are extracted according to the phases, and k-domain resampling is carried out on image interference signals through the remapping vectors.

2. The frequency-domain OCT imaging method based on the swept-frequency laser as claimed in claim 1, wherein the k-clock signal is two or more.

Technical Field

The invention relates to a frequency domain OCT system based on a frequency-swept laser, which is suitable for the field of narrow cavity imaging and the like, is particularly suitable for the imaging of OCT on cavities such as blood vessels, esophagus and the like, and particularly relates to a frequency domain OCT imaging method based on the frequency-swept laser.

Background

At present, OCT and other techniques are widely used for diagnosis and treatment of various diseases. OCT techniques are divided into time domain OCT and frequency domain OCT. The time domain OCT adopts a broadband light source, the z-axis delay is adjusted through a reference arm, the imaging of different depths of an object to be detected is realized, the speed is low, and the clinical practicability is low; frequency domain OCT is divided into two categories: one is a frequency domain OCT system based on a broadband light source and a spectrometer structure; the other is frequency domain oct (ofdi) based on a swept laser and point detector configuration. Due to the high imaging speed and the simple structure of the OFDI, the OFDI is widely applied and researched in clinic. Since OFDI uses a swept-frequency laser for imaging, the wavelength of the swept-frequency laser changes with time, but in order to obtain z-axis depth information during OCT imaging, fft of interference signals in k (k =2 × pi/λ) space is required, and when k is a non-uniform interval, resolution is reduced, image quality is affected, and therefore k-domain resampling of original interference signals is required. A traditional frequency domain OCT system based on a swept-frequency laser adopts an external k-clock signal as a clock signal of a collecting card for resampling. A new frequency domain OCT system based on a swept-frequency laser is proposed.

Disclosure of Invention

The invention aims to solve the problem that the sampling signal of the existing frequency domain OCT clock is single, and provides a frequency domain OCT imaging method based on a swept-frequency laser.

The technical scheme of the invention is as follows:

a frequency domain OCT imaging method based on a swept-frequency laser is characterized in that a multi-channel acquisition card is used, k-clock signals and OCT image signals are respectively input to an input port of the multi-channel acquisition card and are acquired by using an internal clock of the acquisition card, the acquired k-clock signals are subjected to phase extraction, k-domain remapping vectors are extracted according to the phases, and k-domain resampling is carried out on image interference signals through the remapping vectors.

The invention has the beneficial effects that:

1. the imaging range of conventional schemes depends on the k-clock signal and the coherence length. The bandwidth of the k-clock signal must be 2 times the imaging range according to the sampling law. The requirement on hardware is high, and the large-scale production is not facilitated. The imaging range of the newly proposed scheme depends on the number of sampling points, the sampling rate and the coherence length, and the number of the sampling points can be set through software, so the method has low requirement on hardware, is beneficial to large-scale production, and can easily expand the imaging range.

2. The invention can also compensate unstable factors such as the phase and the wavelength of the laser by setting a plurality of k-clock signals. The method is particularly suitable for occasions with high requirements on phase, wavelength and polarization stability, such as polarization sensitive OCT and Doppler OCT.

3. The invention can also realize the algorithms of background noise filtering, remapping algorithm (such as NUFFT and the like), logarithmic transformation, polar coordinate transformation, pseudo-color enhancement and the like. These algorithms can be implemented on the acquisition card or on the computer.

Drawings

Fig. 1 is a schematic diagram of the signal acquisition principle of the present invention.

Detailed Description

The invention is further described below with reference to the figures and examples.

As shown in fig. 1.

A frequency domain OCT imaging method based on a swept-frequency laser is different from a traditional frequency domain OCT system based on the swept-frequency laser, and an external k-clock signal is adopted as a clock signal of an acquisition card to perform resampling. The method comprises the steps of using a multi-channel acquisition card, respectively inputting a k-clock signal and an OCT image signal into an input port of the multi-channel acquisition card, using an internal clock of the acquisition card to carry out acquisition, carrying out phase extraction on the acquired k-clock signal, extracting a k-domain remapping vector according to the phase, and carrying out k-domain resampling on the image interference signal through the remapping vector. As shown in FIG. 1, the imaging range of the present invention depends on the number of sampling points, the sampling rate and the coherence length, and the number of sampling points can be set by software, so the new scheme has low requirement on hardware, is favorable for large-scale production, and can easily expand the imaging range. In addition, a plurality of k-clock signals can be arranged to compensate unstable factors such as the phase and the wavelength of the laser, and the method is particularly suitable for occasions with high requirements on the phase, the wavelength and the polarization stability, such as polarization sensitive OCT and Doppler OCT. Similarly, the method can also filter background noise and process images by adopting filtering, remapping algorithms (such as NUFFT and the like), logarithmic transformation, polar coordinate transformation, pseudo-color enhancement and other algorithms, and the algorithms can be realized on an acquisition card or a computer.

The present invention is not concerned with parts which are the same as or can be implemented using prior art techniques.