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The nep counts and its distribution in web were studied by applying the image processing technique with the statistical method. Two hundred samples of nep were caught with a HP scanner. After that, the nep's images were processed with digital image processing technique including image thresholding and masking so that the nep counts and its distribution can be calculated. In this study, we also define a new calibration for the level of nep size according to the distribution from those 200 nep samples. A web formation is carried out with a roller drafting device. Six to twelve carded slivers or combed slivers can be available. A size of 10x10(in2) of the web is used as the testing sample. The artificial neural network technique was applied in this study to order to identify the trash and fibers from the neps. The experimental results show that the neps have irregular shapes in their appearances. The nep sizes are ranging from 0.1296~3.9872 mm2. The nep sizes are divided into 8 levels which are 0.045~0.08 mm2, 0.08~0.16 mm2, 0.18~0.32 mm2, 0.32~0.50 mm2, 0.50~0.98 mm2, 0.98~1.81 mm2, 1.81~3.61 mm2, 3.65~7.29 mm2, respectively. Their contents in percentage are 0, 21%, 31%, 17%, 4.5% and 0.5%, respectively. The mean deviation of nep counts between our system and the ASTM test method is 17 % , and that between our system and the USTER AFIS-N is 32% in comparison with the test results. Our system has more total amount of nep counts in unit weight than the USTER AFIS-N, while it has less than amount of nep counts in unit weight than ASTM test method. Generally, the identification extent can reach 96 % for the identification of trash and fibers from the neps.
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