In this paper, a new method based on phase congruency is proposed to measure pitch lengths and surface braiding angles of two-dimensional biaxial braided composite preforms. Lab space transform and BM3D (block-matching and 3D filter) are used first to preprocess the original acquired images. A corner detection algorithm based on phase congruency is then proposed to detect the corners of the preprocessed images. Pitch lengths and surface braiding angles are finally measured based on the detected corner maps. Experimental results show that our method achieves the automatic measurement of pitch lengths and the surface braiding angles of biaxial braided composite preforms with high accuracy.
 Qu, P., Guan, X., Jia, Y., et al. (2012). Effective elastic properties and stress distribution of 2D biaxial nonorthogonally braided composites. Journal of Composite Materials, 46(8), 997-1008.
 Böhm, R., Hornig, A., Luft, J. et al. (2014). Experimental investigation of the strain rate dependent behaviour of 2D biaxially and triaxially reinforced braided composites. Applied Composite Materials, 21(2), 285-299.
 Ayranci, C., and Carey, J. (2008). 2D braided composites: a review for stiffness critical applications. Composite Structures, 85(1), 43-58.
 Swanek, D. S. S., and Carey, J. (2007). Braided composite materials for the production of lightweight, high rigidity golf shafts. Sports Engineering, 10(4), 195-208.
 Du, G., and Popper, P. (1994). Analysis of a circular braiding process for complex shapes. Journal of the Textile Institute, 85(3), 316-337.
 Potluri, P., Manan, A., Francke, M., et al. (2006). Flexural and torsional behaviour of biaxial and triaxial braided composite structures. Composite Structures, 75(1), 377-386.
 Xu, L., Kim, S. J., Ong, C. H., et al. (2012). Prediction of material properties of biaxial and triaxial braided textile composites. Journal of Composite Materials, 46(18), 2255-2270.
 Shokrieh, M. M., and Mazloomi, M. S. (2012). A new analytical model for calculation of stiffness of threedimensional four-directional braided composites. Composite Structures, 94(3), 1005-1015.
 Kostar, T. D., and Chou, T. W. (1994). Microstructural design of advanced multi-step three-dimensional braided preforms. Journal of composite materials, 28(13), 1180-1201.
 Goyal, D. and Whitcomb, J. D. (2006). Analysis of stress concentrations in 2×2 braided composites. Journal of composite materials, 40(6), 533-546.
 Wan, Z., Li, J. (2006). Braided angle measurement technique for three-dimensional braided composite material preform using mathematical morphology and image texture. AUTEX Research Journal, 6(1), 30-39.
 Gong, L., and Wan, Z. (2006). Automatic measurement technology on braided pitch length of three-dimensional braided composite material preform. Computer Measurement & Control (in Chinese), 14(6), 730-733.
 Wan, Z., Shen, J., and Wang, X. (2004). Measure and research on braided angle of composites preform. Journal of Textile Research (in Chinese), 25(3), 42-44.
 Hernández-López, J. J., Quintanilla-Olvera, A. L., López-Ramírez, J. L., et al. (2012). Detecting objects using color and depth segmentation with kinect sensor. Procedia Technology, 3(1), 196-204.
 Dabov, K., Foi, A., Katkovnik, V., et al. (2006). Image denoising with block-matching and 3D filtering. In: Proceedings of SPIE, Image Processing: Algorithms and Systems, Neural Networks, and Machine Learning, 6064, 1-12.
 Kovesi, P. (1999). Image features from phase congruency. Videre: Journal of computer vision research, 1(3), 1-26.
 Kovesi, P. (2003). Phase congruency detects corners and edges. In the Australian Pattern Recognition Society Conference: DICTA. Sydney, 309-318.
 Orfanidis, J. S. (1988). Optimum Signal Processing: An Introduction. (2nd ed.). Macmillan Publishing Company (New York).