Method for acquiring near infrared diffusion optical frequency domain information

Abstract

The invention belongs to the field of optical parameter measurement in tissue optical studies, and relates to a method for acquiring near infrared diffusion optical frequency domain information. The method comprises the following steps of: firstly, establishing a two-range detection frequency domain system; secondly, calculating the frequency domain phase delay parameter phi cal of the system by a frequency domain Monte Carlo simulation method; thirdly, taking a detected body as a standard body and changing the detection condition to obtain the output phases of four standard bodies; fourthly, taking the detected body as an unknown organizational body and performing the same detection process as the step (3) to obtain the output amplitudes and output phases of four unknown organizational bodies; fifthly, calculating the amplitude information of the unknown organizational bodies in a frequency domain; and finally, calculating the phase information of the unknown organizational bodies in the frequency domain. By the method for acquiring the near infrared diffusion optical frequency domain information, the influence of factors such as the inherent amplitude fading and inherent phase delay of the system, the method for testing the operation process, and the like can be eliminated.

Description

technical field [0001] The invention belongs to the field of optical parameter measurement in tissue optics, and in particular relates to a method for acquiring near-infrared diffuse light frequency domain information for tissue optics research. Background technique [0002] frequency domain technique (1) It is one of the near-infrared diffuse light detection technologies, and has attracted extensive attention from researchers because of its advantages of large measurable information abundance, high measurement accuracy, and low equipment prices. The so-called near-infrared diffuse light detection technology uses light of a specific wavelength (600-900nm) to irradiate the tissue, detects the distribution of the outgoing light after reaching a few centimeters below the surface of the tissue, and reconstructs the optical density of the tissue under inspection based on the detection results. Characteristic parameters (absorption coefficient μ a , the reduced scattering coeffi...

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Problems solved by technology

The system configuration of the direct absolute correction method is simple; the null detection reference circuit correction method can effectively reduce the system drift and high-frequency circuit noise caused by the light source, but it cannot eliminate the phase and amplitude crosstalk between the reference channel and the measurement channel, and has a negative impact on the reference channel and the measurement channel. The measurement symmetry requirements of the test path are relatively high. Theoretically, the performance of the reference path detector and the measurement path detector are required to be exactly the same; the standard body calibration method with known optical parameters requires the same incident light source power when measuring the standard body and unknown tissue body , so when actually selecting the standard body, it is necessary to make the optical parameters of the standard body similar to the measured tissue, so as to ensure that the data results of the standard body measurement and the unknown tissue measurement can obtain sufficient signal-to-noise ratio under the same input optical power. The geometric structure of the standard body is required to be consistent with the tissue body to be tested to reduce the influence of the test operation process on the data results

For the measurement of tissue diffuse reflection light, none of the above three methods can effectively overcome the influence of coupling factors between the optical fiber and the measured tissue during the measurement process.

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