Abstract: To conform the academic development trend and meet measurement requirements of raw silk fineness at silk nest site. There are some problems in existing raw silk (fiber) fineness measuring instruments and detection methods. A sort of design scheme contain contactless, real-time and dynamic raw silk diameter measurement based on linear CCD array. The goal is to develop a high precision, high accuracy, non-contact, motion detection, ease of computer processing, easy and automatic control equipment connected to the fineness of raw silk photoelectric measuring instrument. This article presents theoretical design of the laser light source, optical system design, CCD image sensor imaging mode selection, the video signal processing experiment and method.secondly the paper proposes the study on how to improve the measuring accuracy of the measuring system from the theory and the various modules of the design parameters. It solve effection in instability of the light illumination and raw silk transparency of raw silk, to avoid CCD saturation due to bright background and the distortion caused by raw silk jitter.Finally, the design is proved in feasibility and practicality through experimental results.

Key words: fineness of raw silk, linear CCD array, laser, optical system design, correlated , double sampling