Three-dimensional measurement of yarn evenness using mirrored images

Abstract

A three-dimensional measurement method for yarn evenness is proposed in this paper. A sample is placed in the image acquisition system and the virtual images and real image are collected in one image by a camera. The geometric relationship of the xoy and the xoz plane of the system is obtained. The multi-view image of sample is calibrated according to the geometric relationship. The intersection method and the tangent method are proposed to determine the key-points of yarn cross-section reconstruction in the xoy plane. 3D model of yarn core is obtained by combining all the yarn cross-sections in the xoz plane. The correlation coefficient between mean area of yarn cross-sections in the proposed method and diameter measured by the Uster TESTER 5 is up to 0.759. The correlation coefficient of CV values between the proposed method and the Uster TESTER 5 is up to 0.944.