Department of Precision Instruments and Mechanology, Tsinghua University, Beijing, China.
Appl Spectrosc. 2010 Aug;64(8):936-41. doi: 10.1366/000370210792081091.
Cotton lint trash is a serious problem in the textile industry. The principle upon which this research is based is that different materials have different spectral absorption, excitation, and emission characteristics. Although white-light imaging is widely used to detect colored foreign-matter contaminants, or "trash", it is almost useless for detecting white trash. The objective of the research described in this paper was to achieve the best trash detection result possible in the spectral range from 250 to 850 nm. Diffuse reflection spectroscopy indicated that the differences in gray value between lint and white trash become significant in the ultraviolet (UV) range, especially from 250 to 350 nm. Fluorescence spectroscopy gave reliable evidence that the UV-induced fluorescence intensity of white trash is much stronger than that of lint. To detect several types of trash simultaneously, the interaction of white-light imaging and UV-induced fluorescence imaging was studied. To avoid the spectral interference caused by white light in fluorescence imaging, a novel method--an alternating imaging detection method--is proposed. Experiments indicated that the advantages of both white-light imaging and UV-induced fluorescence imaging were preserved in the method. The novel method could effectively detect both colored and white trash in real time. This method can also be applied to trash detection in seed cotton, wool, tea leaf, and tobacco leaf.
棉绒废料是纺织工业中的一个严重问题。本研究基于的原理是，不同的材料具有不同的光谱吸收、激发和发射特性。虽然白光成像是广泛用于检测有色外来物质污染物，或“垃圾”，但它对于检测白色垃圾几乎没有用。本文所述研究的目的是在 250 至 850nm 的光谱范围内实现最佳的垃圾检测效果。漫反射光谱表明，棉绒和白色垃圾之间的灰度值差异在紫外线 (UV) 范围内变得显著，特别是在 250 至 350nm 之间。荧光光谱提供了可靠的证据，表明白色垃圾的 UV 诱导荧光强度比棉绒强得多。为了同时检测几种类型的垃圾，研究了白光成像和 UV 诱导荧光成像的相互作用。为了避免荧光成像中白光引起的光谱干扰，提出了一种新的方法——交替成像检测方法。实验表明，该方法保留了白光成像和 UV 诱导荧光成像的优点。该新方法可以实时有效地检测有色和白色垃圾。该方法还可以应用于棉花、羊毛、茶叶和烟叶中的垃圾检测。
