基于荧光偏振分像的多翅翼结构三维全场测量

Three-Dimensional and Full-Field Measurement of Multi-Wing Structure Based on Fluorescence Polarization Imaging

昆虫飞行过程中,翅翼会出现扭转、弯曲、卷翘等交叠现象,各个翅翼间相互遮挡,导致传统光学测量无法直接分辨其飞行姿态。针对透明膜翅的相互遮挡问题,提出基于荧光偏振分像的三维数字图像相关方法,进行多翅翼结构的三维全场变形测量,解决翅翼遮挡的动态测量问题。根据偏振成像原理,采用反射镜、偏振镜与分光棱镜组合的分光光路,实现单个偏振相机测量单色翅翼的三维形貌;结合荧光散斑的光谱特征,在各个相互遮挡的翅翼上制作不同散斑荧光,利用带通滤波片分离各个翅翼上特定光谱的荧光散斑,实现多个翅翼的独立成像和同步测量。开展等厚度薄板相对面形貌、变形的测量实验,标定多个相互遮挡面的测量精度。测量昆虫(知了)翅翼交叠的不同形态,给出了任意相互遮挡翅翼的三维姿态,验证测量方法的可行性。

During insect flight,some overlapping phenomena such as torsion,bending,and warping will appear in the wings,which makes the wings shielded from each other and thus leads to hard discrimination of the flight attitude by traditional optical measurement.To realize the dynamic measurement of mutual occlusion of transparent membranous wings,this paper proposed a three-dimensional(3 D)digital image correlation method based on fluorescence polarization imaging to measure the 3 D full-field deformation of multi-wing structures.According to the principle of polarization imaging,the 3 D morphology of a monochromatic wing can be measured by a single polarization camera in the presence of a splitting optical path integrating mirrors,polarizers and a splitting prism.Depending on the spectral characteristics of fluorescent speckles,different fluorescent speckles were fabricated on different wings that were shielded from each other,and a band-pass filter was used to separate the fluorescent speckles of specific spectra on them,which enabled the independent imaging and synchronous measurement of multiple wings.Firstly,the measurement experiments of the relative surface topography and deformation of the sheet with equal thickness were carried out to calibrate the measurement accuracy of multiple mutually shielded surfaces.Further,the different overlapping forms of insect wings(cicadas)were measured,and the 3 D profile of any mutually shielded wings was given to verify the feasibility of the measurement method.