Measurement of extinction angle of pyrocarbon by one diagonal quarter intensity principle

In accordance with the extinction characteristics of pyrocarbons deposited around carbon fibers, this paper proposes a method for measurement of the extinction angle based on the one diagonal quarter intensity principle. It develops a dynamic template matching algorithm during image processing for the purpose of amending the bias of the observed patterns. Meanwhile, the problem of gray information extraction is solved for ellipse sections through rectifying the shape of fiber sections in image sequences. The proposed method can achieve the measurement of extinction angles accurately and effectively, which is suitable for both the condition of vertical section and inclined section. The errors between the values measured by the proposed method and observation are within 1°-2°, which increase with the degree of complexity of the polarized light microscopy (PLM) image texture.