Research On Scheme Of Eliminating Set Marks

Set marks are an important factor that leads to severe woven fabric defects. It is impossible to mend set marks once they are produced. Set marks decrease the quality of fabrics and cause an important loss of money for weaving mills. Set marks are more serious on modern high-speed looms in operation especially when thin fabrics are woven. Researchers at home and abroad are always searching for methods to eliminate set marks. For different cause of set marks, the corresponding resolution is presented. As yet, the problem of set marks is not resolved essentially. How set marks are to be eliminated has become a difficult problem in the world.The development of image processing technique and its application in textile industry are first introduced. The background of this research is also described briefly. Then the basic notions of image processing technique are presented, including bitmap, color systems, palette etc. The digital image processing knowledge relating to this research is emphatically introduced. Following that, the creep and stress relaxations of warp yarns and fabrics is analyzed. Furthermore, the relationship of cloth fell position, beat-up force and set marks is also stated. Due to the creep and stress relaxations of warp yarns and fabrics, the deviation of cloth fell appears; the intensity of the beat-up force varies when loom restarts because of cloth fell drift, which result in variant pick spacing; set marks occur. What has been done to eliminate set marks is also described.A novel scheme to eliminate set marks based on image processing is presented according to the cause of set marks, in which the online detection of cloth fell displacement by image processing is a key to solve this problem. Here, a completely new approach measuring cloth fell displacement is described. A set of experiment equipments are designed that set up to detect the cloth fell displacement, by which the cloth imagecan be grabbed and processed on line and the cloth fell displacement is precisely calculated. Experiments on different conditions of illumination and under tension of the fabric and warp in combination are performed and the suitable ranges of illumination and warp tension of several fabrics for weaving are found, which is helpful to detect the cloth fell displacement directly on the weaving loom.