Measured By The Knitted Fabric Structure Parameters Based On The Matlab Image Processing Technology

Recently, digital image processing technique penetrates textile industry gradually, which accelerates the development of textile industry and realizes manpower change into brainpower. The application area of digital image processing becomes wider and academy studies tend towards industry application. The applications of image processing technique in textile measurement change the traditional manual operation, increase work efficiency and solve many difficulties in textile measurement.In order to solving the problems such as more errors, more time, more work that occurred when man measure the knitted fabric's parameters, the dissertation applied digital image processing to automatic measure the knitted fabrics parameters that include the stitch length, the density, the bias of stitch, superficial hole's percentage and undefiled coefficient, cover factor, etc. and realized high-speed operation and image processing with MATLAB. It tries programming MATLAB and Visual C ++ together and increases the speed of operation greatly.According to the characteristic of knitted fabric image, the dissertation adopts image-processing methods to extracting useful signal in the fabric image. The methods include graying, smoothing, 2D Fast Fourier Transform, picking up characteristics in the frequency image, image reconstruction, thinning etc. It gets the formula of density according to corresponding relationship between frequency domain and space domain and gets the corresponding relationship of 2D and 3D stitch length according to regression analysis and can automatic measure the stitch length exactly. It can test the bias of stitch base the rotation of FFT.It contrast automatic measurement with manual measurement at different yarn, different density, different color and different simple pattern and certified the two methods have no obvious differences between automatic measurement and manual measurement.Automatic measurement of density just studies the simple pattern, and Automatic measurement of stitch length just for jersey pattern, so we need more work to improve it for the industry application.