Autostereoscopic-Raman Spectrometry-Based Three-Dimensional Metrology System for Measurements, Tracking and Identification in a Volume

Featured Application In the industrial manufacturing of transparent semi-transparent materials, such as glass, plastic, resin, crystal or liquid, have wide application use. The cleanliness and purity of these components have very strict requirements, such as smart phone cover plates, liquid crystal display panels and camera lenses. The environments for manufacture process of above-mentioned industrial fields usually have high-standard requirement of cleanliness. Impurities or contaminants, such as fiber and dust, are defects that have to be identified, analyzed and controlled during the process. Although defect detection based on machine vision and neural network has made great progress, performing tracking, measurement or identification of targets of interests in a volume is still very challenging. This demand has already become much more urgent and favored by industrial customers to control the manufacturing quality of the multi-layer structure of glass, plastic or other composite material. Meanwhile, in biomedical industries, transparent or translucid materials or medium are in common use. Various targets of interest in a solution or other medium needs to be tracked, identified and analyzed. In this sense, the proposed Autostereoscopy-Raman Spectrometry-based (ARS) measurement methodology and its developed system in this paper are able to be widely applied to but not limited to the production quality control of multilayer glass structure, the manufacture and assembly of precision optical components, the production process control of liquid crystal panel in a clean room or in a laboratory testing, or analyzing equipment for biomedical applications. Three-dimensional compound measurement within a volume of interest is of great importance in industrial manufacturing and the biomedical field. However, there is no current method that can simultaneously perform spatial localization and 3D measurement in a non-scanning manner as well as the identification of material in a volume. In this paper, an Autostereoscopic-Raman Spectrometry-based (ARS) three-dimensional measurement system is proposed. The target object in a large depth range is initially positioned by the autostereoscopic 3D measurement method, and then the accurate position information is cross-checked and obtained by combining the spectral signal. Meanwhile, the spectral signal at the precise excitation position guided by the autostereoscopic signal also carries the material composition information. In order to verify the proposed ARS method, an associated measurement system was developed, and experimental studies of detecting various fibers of different depths in multi-layer glass structure were conducted. The spatial locations and dimensional information of multiple different targets can be measured in a volume, and their material can also be identified at the same time. The average error between the calculated position processed by the ARS system and the actual spatial position is within sub-micron levels, and the success rate of spectrum acquisition reaches 98%.

Automated summary

This paper introduces a three-dimensional measurement system based on Autostereoscopy-Raman Spectrometry (ARS) for quality control of multilayer glass structure, manufacture and assembly of precision optical components, production process control of liquid crystal panel, and analyzing equipment for biomedical applications, with high accuracy in spatial localization and material identification within sub-micron levels.