Because of the obvious deformation difference for the alkali resistant glass tubes with different internal stress, in this paper, a new method for evaluating the internal stress and annealing quality of alkali resistant glass tubes based on digital image correlation algorithm is proposed. According to the deformation change rate of alkali resistant glass tube that obtained by digital image correlation algorithm, it can directly determine whether the internal stress meets the production standard. The alkali resistant glass tubes which have undergone abnormal(annealing time less than 5 hours and annealing temperature lower than 630 ℃) and normal annealing operation were selected as samples of experimental group and control group. The samples of these two groups were heated to 200 ℃ and then cooled to room temperature. The displacement fields between deformed images and the initial image are calculated by digital image correlation algorithm and the mean values change rate of the displacement fields are regard as the evaluated basis for the internal stress and annealing quality. Since the new method has many advantages such as simple, efficient and non-contact and only two continuous pictures are required in the detection process, it has been applied in the actual industrial production testing. In addition, this method provides a new approach for the internal stress detection of other solid materials.
The research object of surface defects in optical glass processing is mainly focused on the surface of homogeneous monomers, but there are few reports on the surface polishing defects of composite materials with a variety of monomers with different physical and chemical properties. In this paper, the defect samples with different characteristics are obtained by changing the types of optical fiber image transmission elements, adjusting different polishing processes and parameters. The structure and morphology of the defects on the surface of optical fiber image transmission components are observed by white light interferometer and atomic force microscope. The composition at different positions and the combination of chemical elements are determined by Energy Dispersive Spectrometer (EDS). The specific reasons for the defects are analyzed, the optimal polishing process and corresponding parameters are obtained, and the mechanism of the formation of defects on the polished surface of optical fiber image transmission elements is clarified. The results of the study have a certain guiding significance for the control of polishing defects on the surface of composite materials composed of various monomers, and provide data and theoretical support for improving the polishing quality and efficiency of optical fiber image transmission components.
A new method of transmission efficiency and uniformity measurement for optical fiber image transmission component(OFITC) in visible band is proposed. The ray which emitted from the light source is received by a brightness sensor chip, which can convert the rough brightness into the visual brightness of specific area by weighted calculation. The visual brightness matrices of the designated area before and after placing the OFITC are named S1 and S2, respectively. After filtering, the transmission efficiency of OFITC is the quotient of the average values of S1 and S2. In order to calculate the light uniformity, S2 is divided into four parts which are circles or rings. The average of variances of these parts is defined as the uniformity. The brightness sensor chip required by this method is customized according to the size of optical fiber image transmission element. The experimental results can confirm the validity of this measurement method. At last, criteria for transmission efficiency and uniformity evaluation are proposed, which can greatly reduce the judgment error, improve the testing efficiency and save the cost of detection.
The existence of blemishes deteriorates the imaging quality of fiber-optic imaging elements and reduces the yield of finished products in factories. The effective detection of blemishes is a prerequisite for analyzing the causes of blemishes and preventing their generation. An independently developed detection device for fiber-optic imaging elements based on machine vision is implemented to detect blemishes automatically and accurately. The blemish distributions of three typical fiber-optic imaging elements, including a fiber-optic plate (FOP), a fiber-optic inverter (FOI), and a fiber-optic taper (FOT), are compared with each other, and the causes of blemishes in fiber-optic imaging elements are analyzed. The distribution of blemishes in the FOP is random, and the average number (AN) of blemishes in the first zone (central zone) and the second zone (outer zone) with the same area is similar. The AN of blemishes for the FOI prepared by twisting the FOP at high-temperature increases from 272.8 (FOP) to 2125.0, and the AN in the outer zone is 1542.5, higher than that in the central zone. More blemishes are generated by the twisting process, and the distribution of these blemishes is close to the outer zone. A significant amount of chicken wires is found in the outer zone, but the majority of blemishes are still spots. The AN of blemishes for the FOT prepared by stretching the FOP increases from 383.0 (FOP) to 515.0, which is attributed to the increase of the number of blemishes in the first zone from 190.8 to 427.0, but the AN of blemishes in the second zone decreases from 192.3 to 88.0. The stretching process stimulates the formation of blemishes with a distribution that is close to the central ring. These blemishes are randomly distributed inside or at the boundary of the multifiber. Most of the blemishes are still spots.
A novel imaging sensor which is made of image optical-fiber bundle and industrial camera is proposed. All of the image optical fiber component are custom made and the diameters of the mono fibers are only 1 or 2 μm. In order to match the resolution of image optical-fiber bundle, the pixel size of the sensor chip are also smaller than 2 μm. After removing the protective glass window that cover the sensor chip of camera, the high-resolution imaging can be realized by bonding the optical fiber component and the sensor. The theoretical analysis and experimental result show that the resolution of the sensor is larger than 250 lp/mm, which can improve the imaging quality of industrial detection and monitoring. In particular, the proposed imaging sensor is suited for the oil mist or dust detection environment.
The corrosion of optical glass has become the main factor affecting the qualified rate of products, so it is urgent to solve the corrosion of products. It has been found that under the same cleaning conditions, corrosion mostly occurs on the small side, that is, the first side of polishing, while the other side is not corroded. This indicates that cleaning has little effect on the corrosion of fiberboard. Corrosion occurs in polishing and the process of upper and lower discs. According to the different conditions of two-sided processing, the causes and influencing factors of corrosion were analyzed. By refining the processing technology and adjusting the proportions of protective paint, turning temperature and water stain and other process parameters to achieve the goal of effective controlling the corrosion within 2%.
Optic fiber imaging elements are used in weak visible light, X-ray imaging and high-energy particle detection imaging devices. They play an important role as input and output window materials of image intensifiers. Optic fiber imaging elements are arrays of tens of millions of micron-scale single optical fibers arranged regularly. The fabrication process requires several times of fiber drawing and secondary thermal processing such as hot melting pressure, torsion, and stretching. After these processes, there may be spots and linear chicken filaments that are called defects existed on the interface among the fibers and multi-fibers. Due to these defects, the quality of imaging is seriously reduced, and even the misjudgment or omission of image signal recognition can are caused. How to detect such defects has no an ideal solution. Currently, non-quantitative microscopic observation is generally used. This method, however, is high in misjudgment and low in detection efficiency. In this paper, a device for automatic detection of optical fiber image defects based on machine vision algorithms, including its working principle, structure, detection steps and characteristics are introduced. The device not only can automatically measure the size of each defect, but also can count the defect distribution according to the quality zones. The test results are stable and accurate. It is especially suitable for batch detection and research of optic fiber imaging elements.
Based on the high-resolution imaging property of the products of optical fiber material, a novel imaging system is proposed. The prototype of the system is made by coupling CCD chip(CMOS) and a large-scale optical fiber faceplate together. Firstly, the working principle and manufacturing process of large-scale optical fiber faceplate is described. Secondly, the effectiveness and practicability of the prototype of the system is verified by experiment. Finally, the potential application prospect of the imaging system is discussed. The theoretical analysis and experimental result show that the prototype works perfectly under high temperature and pressure condition and the resolution of the image that obtained by the imaging system is larger than 70 lp/mm, which can satisfy the basic imaging requirements in the research fields such as medical diagnosis, industrial detection and monitoring. Further, the novel imaging system provides a new approach for the application of optical fiber product in scientific research.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.