Automatic Measurement of Yarn Crimp Using Image Analysis

Abstract

Abstract Automatic crimp measurement system hardware and software have been developed. To measure the crimp of a relatively long yarn specimen under zero tension, a precise linear stage was used along with a high-definition digital microscope. Because of the narrow viewing angle of the microscope, a series of images were captured while the specimen plate was moved. The whole system was built into an opaque enclosure with internal illumination devices to prevent irregular external lighting effects. The relationship between image and world coordinates was established via automatic camera calibration. The shape of the yarn crimp was extracted via a series of image processing techniques, and quantitative information on yarn crimp, such as the crimp ratio and average crimp pitch, was calculated through Fourier series expansion and statistical analysis.