Method and apparatus for measuring tissue topography and optical parameters based on spatial frequency domain imaging

Abstract

The invention provides a method for measuring tissue topography and optical parameters based on spatial frequency domain imaging. The method comprises the following steps: 1, generating modulated light having a certain spatial frequency by a light source; 2, carrying out system calibration by using a reference plane; 3, projecting the modulated light on a to-be-measured tissue and collecting a reflected light image scattered by a sample by a camera; 4, acquiring a three-dimensional surface shape by using the Fourier contouring way; 5, correcting image illumination based on a height and an angle; 6, carrying out Fourier transform row by row, decomposing DC and AC spectral components, and then carrying out inverse Fourier transform to obtain DC and AC component images; and 7, carrying out matching fitting to obtain optical parameters. According to the provided method, surface shape and optical parameter information can be obtained only by one imaging; and since the illuminance error caused by the complex surface shape is corrected, the measurement speed is increased and the precision is improved.

Description

technical field [0001] The invention belongs to the field of optics and measurement technology, and more specifically relates to a method for measuring tissue morphology and optical parameters based on spatial frequency domain imaging, and also relates to a measuring device for measuring tissue morphology and optical parameters based on spatial frequency domain imaging , suitable for measuring the absorption coefficient and reduced scattering coefficient of biological tissue. Background technique [0002] The Chinese patent with the publication number CN105510253A "Apparatus and method for detecting optical characteristics of agricultural product tissue by spatial frequency domain imaging" discloses the spatial frequency domain imaging technology, by projecting sinusoidal modulated light with a certain spatial frequency onto the tissue sample to be tested , the camera collects diffuse light illumination images scattered by tissue, using a specific light transmission model, s...

AI Technical Summary

Problems solved by technology

However, the traditional spatial frequency domain imaging uses the three-phase shift method for demodulation, that is, it is necessary to collect diffuse reflection images of three different phases at the same modulation frequency to analyze the modulation depth at the modulation frequency; and to obtain the absorption coefficient and the reduced Scattering coefficient, it is necessary to measure the modulation depth at two or more modulation frequencies, and multiple imaging of the sample to be tested is required, which restricts the real-time performance of the measurement

In addition, when the surface height of the tissue to be measured is inconsistent, the structured light projected onto the surface of the tissue does not satisfy the sinusoidal distribution law, and the illuminance collected by the camera will also be interfered by the surface shape of the tissue, resulting in data distortion and affecting the optical quality. Accuracy of Parameter Measurements

The Chinese patent with the publication number CN105466889B "A Method for Acquisition of Illuminance on the Surface of Complex Tissues in Spatial Frequency Domain Imaging" proposes a method to reduce the error of illuminance data acquisition by modifying the projected grayscale image and correcting the image collected by the CCD camera. method, but this method needs to calculate the three-dimensional height of the tissue surface and then image again, which further restricts the real-time performance of the measurement

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