Application Of Image Processing Techniques To Measure The Knitted Fabric Structure Parameters

As we know, analyzing and measuring fabric's parameters is a uphill task that not only takes time but also a lot of manpower, moreover, it is hard to avoid factitious error due to the disunity of measure standard and the influence of subjective factor, especially, the low measure efficiency can already not meet the needs of small quantity, a variety of breeds and high efficiency in present production. Recently, digital image processing technique has penetrated into many fields about textile inspection and automatic recognition; it changed traditional manual operation in the textile industry, highly enhanced work efficiency and solved many difficulties.Therefore, this dissertation put foreword a method of applying digital image processing technique to automatic measure knitted fabric's parameters which includes the density, the stitch length, the angle of stitch deflection, contrast coefficient of density, superficial hole's percentage and underfill coefficient, cover factor, etc. According to the characteristic of knitted fabric image, put preprocessing on original image, including graying, media filtering and histogram specification which makes the image more favorable for the following step. Then, we can use fast Fourier transforming technique to transform the preprocessed image from space domain into frequency domain. So we can extract useful signals in the fabric images through picking up characteristics in the frequency image, images reconstructing, thinning, etc. We have got the formula of density according to corresponding relationship between frequency domain and space domain and got the corresponding relationship of 2D and 3D stitch length according to correlation analysis and regression analysis which can automatic measure the stitch length exactly. After doing lots of contrast experiments and check analysis, we proved that there are no obvious differences between automatic measurement and manual measurement.Under Windows 2000 environment, we use MATLAB as a tool developed an Automatic Measuring System of Knitted Fabric's Structure Parameters. The interface is friendly and the operation is simple.This dissertation just studied common knitted fabric, the function of density measurement is nearly perfect, but the automatic measurement of stitch length just suit for jersey pattern, it concludes that the automatic method can be adopted in the production, but we need more work to improve it for the industry application.