Yarn evenness measuring system based on yarn section perimeter

The invention relates to a yarn evenness measuring system based on yarn section perimeter. Nonuniform yarn appearance evenness is understood from the perspective of the relation between yarn and fabric. The technology is based on an elliptical yarn section model, a double-axial CCD camera is used for obtaining yarn images in two directions perpendicular to each other, and the novel yarn evenness measuring system is obtained. The system can effectively reduce influences of irregular sections of yarn, yarn hairiness and the like on yarn appearance evenness measuring, yarn appearance evenness measuring is barely influenced by temperature, humidity, atmosphere state and other outside conditions, yarn blending state, yarn optical property difference and the like. Influences of yarn sections on yarn evenness and the deformation relation from yarn to fabric are fully taken into consideration, evaluation of yarn appearance evenness and fabric appearance uniformity is easy, and compared with existing instruments, the