基于Hertel取样的棉纤维长度可测性研究

Study on the Possibility of Measuring Cotton Length Based on Hertel Sampling

为研究在照影仪曲线上测量棉纤维长度指标的可能性,对Hertel取样采用计算机模拟的方法发现实际照影仪曲线与理论照影仪曲线有偏差,且微小偏差就会对长度指标产生较大影响。当叠加了幅度为±3%、±5%、±10%的光电噪声,通过Harr小波频谱分析,找到了有效的滤波算法,对照影仪曲线进行校正。在校正过的照影仪曲线上测算的棉纤维长度,其重复性在95%的置信水平上,主体长度在1.0 mm内,品质长度在0.73 mm内,平均长度在1.4 mm内。当光电随机噪声为±3%时,20 000根和50 000根取样的短纤维率,其单次测量不确定度在90%的置信水平上接近±2%。

To study the possibility of measuring cotton length in fibrogram, it was found out that for Hertel sampling computer simulation, the constructed fibrograms do not fully fit the theoretical ones, and their slight difference caused large changes in measured length results. Effective filtering algorithm which can rectify the fibrograms added by opto-electric noises with magnitude of ± 3% , ± 5% or ± 10% respectively has been invented by analysing their spectrum and the calculated length distributions with Harr wavelet. So the revised reproducibility of the results fell within 1.0 mm for modal length, 0. 73 mm for quality length and 1.4 mm for mean length at a confidence level of 95%. For the samples of 20 000 fibres and 50 000 fibres grabbed, the reproducibility of short fibre content was very close to ± 2% at a confidence of 90% when the opto-electric noises within ±3%.