| Fabric drape is one of the most important properties, because it is the main factor that influences the aesthetic appearance of a fabric and clothing comfort. Fabric drape directly affect its price level and, in general, high-grade fabric has good drape. The traditional measurement results of fabric drape by optical projection principle cause the systematic error and are insufficient to describe the aesthetic appearance and clothing comfort. Therefore, the new equipment and methods on the basis of modern science and technology need to be developed to overcome the problems in measuring the fabric drape.In this study, the fabric drape measurement system with the new image method was designed, which mainly consisted of a lifting gearing, a rotating gearing, a motion controller, a backlight board, a CCD, an image capture card, a computer, a relevant software and so on. The lifting gearing can reduce the effect of the manual sample placement on draped fabrics' shape, such as the change of the number of nodes. The sample is tested in the close box, which ids the environmental light. The backlight board provides the even background light, which roves the quality of the captured image. The rotating gearing can provide the test component for measuring the fabric dynamic drape. The test system is a combination of computer technology and control technology, which is the "virtual instrument" system with image acquisition, data analysis and processing functions. The test procedure was supervised by the computer with the relevant software and the control hardware. The test equipment based on the image method won the national invention patent, Patent No. ZL 200510111702.The image method based on the above equipment is characterized by the drape image, which is easily segmented into two sub-images:the draped fabrics' image and the background and analyzed with the special image and data processing software. The image procedure includes determination of the image distortion correction, the best threshold value, and Canny's edge-detection and edge-tracking. According to the image's grads histogram, the best threshold value of edge-detection was determined. The adaptive Canny algorithm detected the image edge by the best threshold value. The edge's contour of draped fabrics was found by edge-tracking. According to the edge's points, we can get many values of fabric drape. The drape coefficient, which can be divided into static and dynamic drape coefficient, reflects the degree of fabric drape. The tester could measure the fabric static/dynamic drape, providing values of number of crest, crest amplitude uniformity, crest angle uniformity and so on.Since one or more color of color fabric is similar to the background one, the edge detection is difficultly processed. With the general image processing method, the drape measurement of color fabric is often error. The image method can effectively test the drape of color fabric.The method of sample placement affects the measurement of the static drape coefficient. But the traditional drape meter less emphasis on the method of sample placement, which has a great influence on the initial drape shape and the measurement of the peak and its uniformity especially. The research designed the new method of sample placement for the measurement of fabric drape. The lifting gearing raised the sample plate and the sample gently from the original to the overhanging place, which could reduce the effect of the manual sample placement on the draped fabric shape. The method can improve the accuracy and reproducibility of the fabric drape measurement. According to the drape measurement of YG811 fabric tester, one of the system has a better stability. As seen from Xbar and R control charts, the process variation was in statistical control, which indicated that the drape tester could be used to measure the drape effectively.The test time will also affect the measurement results of the static drape coefficient (SDC). Thirty pieces of fabrics of different kinds were prepared for measuring the SDC of each fabric every five seconds in the test time of four minutes. Thirty curves of the change in the SDC with time were plotted and divided into two classes:the approximate linear one and the negative exponential one. The change in the SDC with test time revealed the deformation of fabrics, which depended on the structure of fibers, yarns and weave. Textile materials are generally regarded as viscoelastic materials and fabrics as viscoelastic plates. Under the action of gravity, fabrics occur deformed. The deformation of some fabrics happened quickly and then didn't change, but that of other fabrics depended on time.The curve in the dynamic drape coefficient with the rotation speed was a cubic one, whose variance was greater than 0.98 and which could be divided into three sections:AB, BC and CD segments, AB segment rising slowly, BC curve in sharply, and CD to the level. With the rotation speed increasing, a few pieces of the sample has no change in the wave number, but most of the sample has the reduction of the wave number, even in zero, that is, the sample is fully extended into a round. According to the dynamic drape index variation with the rotation speed, the thesis provided that the dynamic drape test rotation speed (50～80) rpm is reasonable.The thesis established the three-dimensional reconstruction model based on the drape image. The reconstruction of single drape image belonged to the surface reconstruction method, which achieved the three-dimensional reconstruction by the establishment of similar objects or surface model's data points. The three-dimensional volume data was generated and combined with morphological characteristics of the fabric drape, the three-dimensional volume data was refined. The reconstruction method of the fabric drape shape was realized by the computer, which created a three-dimensional scene by the OpenGL technology, and set the fabric material and light color shading, and then generated a three-dimensional surface of a smooth well-balanced through the normal average number of flat polygonal technology, and then eliminated objects (hidden surface and hidden line), and finally produced a realistic three-dimensional drape with a good image.
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