• Smart Structures and Systems
• /
• v.24 no.6
• /
• pp.769-781
• /
• 2019

Dynamic displacement response of civil structures is an important index for in-construction and in-service structural condition assessment. However, accurately measuring the displacement of large-scale civil structures such as high-rise buildings still remains as a challenging task. In order to cope with this problem, a vision-based system with the use of industrial digital camera and image processing has been developed for long-distance, remote, and real-time monitoring of dynamic displacement of supertall structures. Instead of acquiring image signals, the proposed system traces only the coordinates of the target points, therefore enabling real-time monitoring and display of displacement responses in a relatively high sampling rate. This study addresses the in-situ experimental verification of the developed vision-based system on the Canton Tower of 600 m high. To facilitate the verification, a GPS system is used to calibrate/verify the structural displacement responses measured by the vision-based system. Meanwhile, an accelerometer deployed in the vicinity of the target point also provides frequency-domain information for comparison. Special attention has been given on understanding the influence of the surrounding light on the monitoring results. For this purpose, the experimental tests are conducted in daytime and nighttime through placing the vision-based system outside the tower (in a brilliant environment) and inside the tower (in a dark environment), respectively. The results indicate that the displacement response time histories monitored by the vision-based system not only match well with those acquired by the GPS receiver, but also have higher fidelity and are less noise-corrupted. In addition, the low-order modal frequencies of the building identified with use of the data obtained from the vision-based system are all in good agreement with those obtained from the accelerometer, the GPS receiver and an elaborate finite element model. Especially, the vision-based system placed at the bottom of the enclosed elevator shaft offers better monitoring data compared with the system placed outside the tower. Based on a wavelet filtering technique, the displacement response time histories obtained by the vision-based system are easily decomposed into two parts: a quasi-static ingredient primarily resulting from temperature variation and a dynamic component mainly caused by fluctuating wind load.

• Journal of Korean Ophthalmic Optics Society
• /
• v.14 no.2
• /
• pp.53-59
• /
• 2009

Purpose: The aims of this study are to conduct a fact-finding survey of eyeglasses use based on the visual acuity of middle and high school students in Busan. Methods: A total of 821 middle and high school students from four different schools participated by Self-administered qustionnaire test on July, 2007. Results: Among these students, 74.3% of the students had low vision and 66.26% of the students wore eyeglasses. The percentage of non glasses-wearers were 13.77% in low vision and 15.26% of the students had low vision in glasses-wearers. The reason why they did not wear eye glasses and why they did not change eyeglasses prescription was they did not feel any inconvenience in their usual life. Conclusions: Many students have bad eyesight due to limited spheres of environment and they do not feel any inconvenience of non-wearing eyeglasses in spire of their bad eyesight.

• Korean Journal of Remote Sensing
• /
• v.4 no.1
• /
• pp.31-40
• /
• 1988

Low-cost microcomputer systems can be assembled which possess computing power, color display, memory, and storage capacity approximately equal to graphic workstactions. A low-cost, flexible, and user-friendly IBM/PC/XT/AT based image processing system has been developed and named as KMIPS(KAIST (Korea Advanced Institute of Science & Technology) Map and Image Processing Station). It can be easily utilized by the resource managers who are not computer specialists. This system can: * directly access Landsat MSS and TM, SPOT, NOAA AVHRR, MOS-1 satellite imagery and other imagery from different sources via magnetic tape drive connected with IBM/PC; * extract image up to 1024 line by 1024 column and display it up to 480 line by 672 column with 512 colors simultaneously available; * digitize photographs using a frame grabber subsystem(512 by 512 picture elements); * perform a variety of image analyses, GIS and terrain analyses, and display functions; and * generate map and hard copies to the various scales. All raster data input to the microcomputer system is geographically referenced to the topographic map series in any rater cell size selected by the user. This map oriented, georeferenced approach of this system enables user to create a very accurately registered(.+-.1 picture element), multivariable, multitemporal data sets which can be subsequently subsequently subjected to various analyses and display functions.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.15 no.5
• /
• pp.1814-1828
• /
• 2021

Low-light image enhancement is a key technique to overcome the quality degradation of photos taken under scotopic vision illumination conditions. The degradation includes low brightness, low contrast, and outstanding noise, which would seriously affect the vision of the human eye recognition ability and subsequent image processing. In this paper, we propose an approach based on deep learning and Retinex theory to enhance the low-light image, which includes image decomposition, illumination prediction, image reconstruction, and image optimization. The first three parts can reconstruct the enhanced image that suffers from low-resolution. To reduce the noise of the enhanced image and improve the image quality, a super-resolution algorithm based on the Laplacian pyramid network is introduced to optimize the image. The Laplacian pyramid network can improve the resolution of the enhanced image through multiple feature extraction and deconvolution operations. Furthermore, a combination loss function is explored in the network training stage to improve the efficiency of the algorithm. Extensive experiments and comprehensive evaluations demonstrate the strength of the proposed method, the result is closer to the real-world scene in lightness, color, and details. Besides, experiments also demonstrate that the proposed method with the single low-light image can achieve the same effect as multi-exposure image fusion algorithm and no ghost is introduced.

• Journal of Preventive Medicine and Public Health
• /
• v.27 no.3 s.47
• /
• pp.557-567
• /
• 1994

This study was conducted to examine the effect of chronic low dose organic solvent exposures in the industries towards then neurobehavioral functions of workers. Subjective symptoms on neurobehavioral function as well as a visual reaction time test (Flicker test) were administered to 94 exposed and 162 unexposed workers in a oil refinery and some other auto-repair shops. The results obtained were as follows : 1. Symptom complaints were higher and Flicker test values were lower in exposed workers than in unexposed workers. 2. Flicker valus were Inversely correlated with urinary Hippuric acid concentration in exposed workers(r=-0.26, p<0.05). 3. Flicker valus were inversely co..elated with Subjective symptom score(r=-0.15, p<0.05). Low Flicker value were also related with some subjetive symptoms such as 'Dimmed vision', 'Nightmare', 'Weakness on extrimity' in workers as a whole. While symptoms of 'Dimmed vision ', 'Nightmare' only observed among exposed workers.

• IEMEK Journal of Embedded Systems and Applications
• /
• v.17 no.2
• /
• pp.77-83
• /
• 2022

In this paper, the two-stage object detection approach is proposed to implement a deep learning-based label inspection system on edge computing environments. Since the label printed on the products during the production process contains important information related to the product, it is significantly to check the label information is correct. The proposed system uses the lightweight deep learning model that able to employ in the low-performance edge computing devices, and the two-stage object detection approach is applied to compensate for the low accuracy relatively. The proposed Two-Stage object detection approach consists of two object detection networks, Label Area Detection Network and Character Detection Network. Label Area Detection Network finds the label area in the product image, and Character Detection Network detects the words in the label area. Using this approach, we can detect characters precise even with a lightweight deep learning models. The SF-YOLO model applied in the proposed system is the YOLO-based lightweight object detection network designed for edge computing devices. This model showed up to 2 times faster processing time and a considerable improvement in accuracy, compared to other YOLO-based lightweight models such as YOLOv3-tiny and YOLOv4-tiny. Also since the amount of computation is low, it can be easily applied in edge computing environments.

• Journal of Korean Ophthalmic Optics Society
• /
• v.16 no.1
• /
• pp.51-60
• /
• 2011

Purpose: This study was to investigate visual performance and subjective satisfaction with multifocal soft contact lenses at near works in university students. Methods: In a cross-over study design, 26 students (6 male, 20 female) who did not have any ocular disorder with at least 20/20(1.0) binocular vision were fitted with singlevision lenses (SofLens$^{TM}59$, Bausch + Lomb Co. USA) or multifocal lenses (SofLens Multifocal, Bausch + Lomb Co. USA). After 2 weeks, visual performance assessments included visual acuity, stereoacuity and contrast sensitivity function at distance and near. Near point of accommodation, accommodative facility, near point of convergence, vergence facility and near range of clear vision at near were examined. Students' satisfaction and preference were measured using survey questionaries. Results: Subjects maintained at least 20/20 binocular vision with multifocal and single-vision lenses at distance and near. There was no difference between multifocal and single-vision lenses in stereoacuity, contrast sensitivity function and vergence facility at far and near. The near point of accommodation, accommodative facility, near point of convergence and the near range of clear vision with multifocal lenses were better than single-vision lenses. On the survey questionaries, subjects reported that they preferred and satisfied with multifocal lenses with near works, and single-vision lenses with distance works. Conclusions: The majority of university students preferred multifocal to single vision lenses because multifocal lenses provided better visual performance at near works. This study suggests that multifocal lens is helpful for young adult in prolonged near works.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.2
• /
• pp.202-208
• /
• 2016

In this study, the defect in connection with a C-tray was inspected using a low-cost camera. The four test items were the device overlapping in the tray, the bending of the tray, the loaded quantity of the tray, and the device pocket leaving, an algorithm was developed for defining and detecting the above defect types. Therefore, the developed handling system could extend the application of the stack of the c-tray and provide a quantity verification inspection on the packing processing. The machine operation control program, which can ensure the optimal inspection image to match the scan speed, was developed and the control program that can process the user gui and the vision image utilizing the control was developed. Overall, a mechanical system that is practicable for obtaining an image and processing the vision data was designed.

• Journal of rehabilitation welfare engineering & assistive technology
• /
• v.8 no.3
• /
• pp.213-219
• /
• 2014

This study applied the data of 384 senior citizens over 65 years old having difficulties in everyday life, among the ageing research panel of Korea Labor Institute in 2000, due to their visual impairment in the final analysis to investigate factors affecting the use of vision aids by the aged with visual impairment. The analysis was based on the service usage Andersen-Newman model and the factors were classified into preceding factors, potential factors and desire factors. To examine the effects of each factors on the use of vision aids by the aged with visual impairment, logistic regression analysis was carried out. In the analysis results, the level of vision aids usage was shown to increase significantly with unemployed status and higher education level in the preceding factors, lower subjective stratum consciousness in the potential factors, and higher cognitive function in the desire factors. The limitation and implication of this study were suggested on the basis of the results.

• Journal of Digital Contents Society
• /
• v.15 no.6
• /
• pp.751-761
• /
• 2014

Color deficient people do not have sufficient discernment for the colors with low saturation and brightness and at the same time express their negative emotions regarding emotion distortion. The purpose of recovering the distortion of the vision which is the basis for emotion is to increase positive emotions rather than negative ones that those with color vision deficiency feel when they experience digital culture contents. Contrast increases saturation and brightness by differing the direction of their conversion and by doing so, delivers emotion distortion such as dynamic vs. static and vivid vs. somber that the original images intend to convey to those with color vision deficiency by reducing such a contrast. In this respect, this study proposes a contrast-based color conversion method to convert saturation and brightness in the zone of color conversion and identifies if this method can reduce emotion distortion by using color conversion simulation and user test.