Subjective and Objective Evaluation Methods to Determine the Peak-trough Threshold of the Drape Fabric Node

Abstract

This study focused on the use of subjective and objective evaluation methods to determine the peak-trough threshold of the drape fabric node. Nineteen different dynamic drape images of fabric, obtained using a dynamic drape instrument with a maximum rotation speed of 450 rpm, were used to evaluate the fabric node number and the fabric drape coefficient. After the ANOVA and the Duncan analysis, 13 consistent evaluators for determining the subjective fabric node number were selected from 19 candidates. The mean values of the subjective node numbers were then used as a basis for determining the peak-trough threshold of the drape fabric node. The fabric drape image plot was obtained by a self-devised dynamic drape instrument for fabric, and then converted to a drape waveform diagram. When the mean value of the drop-height between the outward protruding and adjacent dent positions on the drape waveform diagram at rotation speeds from 175 rpm to 450 rpm was taken as the test value, then the 1 % confidence lower limit of the mean drop-height could be used to obtain fabric node numbers which were subjectively and objectively consistent. This meant that the difference in the distance from peak and trough to the center point in the drape profile was 0.30 cm, which was defined as the peak-trough threshold of the node of a fabric drape image plot. The greater the rotation speed, the greater the drape coefficient of wool woven fabric. The smaller the distance from the peak and trough to the center point, the smaller the node number.