By explanation of two deferent determination methods and by analysis of and comparison between the calculation(measurement) results obtained by using there two methods, the author found out a better method to determine the strand diameter.

In view of existing hairiness and scratch in the yarn black board,through some methods such as smoothness processing,threshold value division and image repairing,can come up with a clear digital image without noise points and exactly measure the yarn diameter.

In this paper,we analyze development and defects of image processing techniques and provide some recognition algorithms to detect the structural parameter in woven fabrics,such as warp and weft densities,yarn diameter,linear density of the yarn and yarn twist angles using Digital Image Processing and realize automatically function of system with mixed program VB and MATLAB.

Exploration is made into the quantitative relationship between the geometry factors A and B of the crosshead and the diameter of the insulated conductor and die zize.

Through measuring the light intensity, we can get the diameter of wire rod.