• KIEAE Journal
• /
• v.13 no.4
• /
• pp.3-10
• /
• 2013

This study aims to identify convenient surrounding of the hospital room to be improved by specifically focusing on light environment and to examine a change of inflow of the daylight in the hospital room by using blind and light shelf device as base data of preliminary research for comprehending the relationship between healing environment and natural day light. Simulation analysis on previous facilities and the installation of horizontal light shelf that derives the inflow of day light has been specifically referred by using ECOTECT2011 program. In case of C-facility that mostly adjoined to exterior spaces, it was shown to be closer to a proper uniformity factor when an angle was controlled on the light shelf with blind installed at the same time. However, it was not overall appropriate because of visual displeasure occurred from inflow of much day light. In conclusion, it is the form of flat surface such as H-facility that provides an effect after installing the device to derive day light. Especially, it was shown that interior day light environment was improved when installing blind and controlling the angle at the same time.

• Smart Structures and Systems
• /
• v.22 no.2
• /
• pp.209-221
• /
• 2018

Efflorescence is a phenomenon primarily caused by a carbonation process in concrete structures. Efflorescence can cause concrete degradation in the long term; therefore, it must be accurately assessed by proper inspection. Currently, the assessment is performed on the basis of visual inspection or image-based inspection, which may result in the subjective assessment by the inspectors. In this paper, a novel approach is proposed for the objective and quantitative assessment of concrete efflorescence using hyperspectral imaging (HSI). HSI acquires the full electromagnetic spectrum of light reflected from a material, which enables the identification of materials in the image on the basis of spectrum. Spectral angle mapper (SAM) that calculates the similarity of a test spectrum in the hyperspectral image to a reference spectrum is used to assess efflorescence, and the reference spectral profiles of efflorescence are obtained from theUSGS spectral library. Field tests were carried out in a real building and a bridge. For each experiment, efflorescence assessed by the proposed approach was compared with that assessed by image-based approach mimicking conventional visual inspection. Performance measures such as accuracy, precision, and recall were calculated to check the performance of the proposed approach. Performance-related issues are discussed for further enhancement of the proposed approach.

• Journal of the Korean Solar Energy Society
• /
• v.31 no.6
• /
• pp.132-138
• /
• 2011

Inducing the natural lighting into building has been commonly applied to the spaces where artistic objects are displayed to create better visual environment for the appreciation. The direct natural lighting, especially through top lighting system may, however, bring forth discoloing of highly light-sensitive materials such as paintings or demanding additional cooling load. In addition, it causes to create glare against appreciators or to yield in visual distraction due to the extreme contrast on the inner surfaces of the spaces. Shading device such as louver is capable of preventing such voidable cases with careful manipulation. This study aims to provide basic design guide-line when the flat-form louver has to be applied to top lighting system. Interaction between the daylight and louver was simulated by Reluxpro program with variation of the attachment location, the angle of the lover, surface reflectivity, to obtain the illumination of the floor surface. This study yields the louver just under the top lighting window with 90 degree angle gives the most desirable way of employment when the uniform illumination on the floor surface is required.

• Korean Journal of Optics and Photonics
• /
• v.19 no.4
• /
• pp.302-309
• /
• 2008

We present the precise visual measurement method of rotational displacements using two different moire fringes simultaneously generated by repeated sinusoidal gratings. We investigate the variation of moire fringes depending on rotational displacements through computer simulation and experiment using a rotator in detail. The moire fringes are composed of the wide linear fringe part with a long period and the narrow linear fringe part with a short period. These parts are superior to the angle detection of more than 12 degrees and less than 12 degree, respectively. Additionally, the method can be visually used in the determination of the rotational direction by observing the moire fringe's direction.

• Archives of design research
• /
• v.19 no.5 s.67
• /
• pp.181-190
• /
• 2006

This study was designed to investigate how the size perception of letters is influenced by its relation to the ground, visual angle, physical size, letter space and cognitive direction. As a stimulus, a word in the Numeral and Hangul respectively were used in Experiments I and II. Fifty four different configurations consisting of two grounds, three visual angles and nine physical sizes were used as test patterns in Experiment I, and one hundred and eight different configurations consisting of two ground, three directions, two letter spaces and nine physical sizes were used in Experiment II. Subjects were asked to make magnitude estimates for perceived size of test patterns in both Experiments I and II. The results imply that the ground and visual angle affected the perceived size of the Numeral as a focal figure. We found that in Experiment I, the perceived size of the focal letter was clearly underestimated when the rate of physical size was larger than the real size which was a hundred(as the size of standard stimulus), and it was overestimated when the rate of physical size was smaller than a hundred. It was found that the effect of Delboeuf illusion influenced the perceived size of letter. The result of Experiment II shows that the ground, physical size, letter space and the cognitive direction affected the perceived size of Hangul as a focal figure. These findings suggest that size illusion of letters is caused by the size relationship (contrast or assimilation) between a letter perceived as figure and its ground.

• Journal of the Korean Society for Precision Engineering
• /
• v.28 no.11
• /
• pp.1323-1329
• /
• 2011

The purpose of study was to analyze how the visual information affects balance control of individuals during single leg stance. A total of 27 young normal people (20 males and 7 females, age: $13.7{\pm}2.6$, height: $162.3{\pm}13.2$ cm, weight: $53.9{\pm}13.9$ kg) was voluntarily involved in the experiment. The subjects were requested to maintain balance for 20 seconds with eyes both open and closed on a force plate and then foot ground reaction data were collected for that duration. Results showed that mean velocity of COP in closed eyes condition was larger 1.84 times than that of the open-eyes condition and range of vertical angle was increased approximately one degree in the closed eyes condition. To accomplish a balance, the frequency power in mediolateral and anteroposterior components of the foot-ground reaction force was increased by 1.3~1.4 times. Consequently, visual absence during single leg stance can result in critical loss of balance and lead to instability of body control.

• Journal of Welding and Joining
• /
• v.18 no.3
• /
• pp.60-67
• /
• 2000

In this study, we constructed a preview-sensing visual sensor system for weld seam tracking in GMA welding. The visual sensor consists of a CCD camera, a diode laser system with a cylindrical lens and a band-pass-filter to overcome the degrading of image due to spatters and/or arc light. To obtain weld joint position and edge points accurately from the captured image, we compared Hough transform method with central difference method. As a result, we present Hough transform method can more accurately extract the points and it can be applied to real time weld seam tracking. Image processing is carried out to extract straight lines that express laser stripe. After extracting the lines, weld joint position and edge points is determined by intersecting points of the lines. Although a spatter trace is in the image, it is possible to recognize the position of weld joint. Weld seam tracking was precisely implemented with adopting Hough transform method, and it is possible to track the weld seam in the case of offset angle is in the region of $\pm15^{\circ}$.

• Transactions of the Korean Society of Pressure Vessels and Piping
• /
• v.7 no.3
• /
• pp.8-14
• /
• 2011

The clogging of the flow area at the tube support plates(TSPs), especially at the upper TSPs results in the water level oscillation of a steam generator during normal operation. A reduction of the TSP flow area causes to increase in pressure drop within the two-phase flow zone, which destabilizes the boiling flow through the tube bundle. This phenomenon was occasionally observed at a few domestic and foreign nuclear power plants. One of the methods for defining the flow area clogging is visual inspection, which is the most effective inspection method. The results of the visual inspection for TSPs' flow area are clogging images on TSPs' quartrefoil lobes. These images are complexly distorted due to lens aberration and external factors like the distance to a subject and angle etc. In this work, we developed the analysis algorithm for clogging image of the TSP flow area of steam generators. For this purpose, we designed an image verification device applicable to the camera employed in the field for visual inspection and then, we demonstrated the validity of image analysis algorithm by using this device and commercial autoCAD program.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.29 no.2
• /
• pp.14-21
• /
• 2001

This study aims to analyze visual structure by evaluating the view from five building sites around An-ap pond, and attempt to determine which site commands the best view and will provide the most active use. The results of this study can be summarized as follows: According to the questionnaire survey of experts on the relations of dominancy-subordination(´chu-jong´), vacancy-solidness(´heo-sil´), sparsity-density(´so-mil´) based on ancient oriental Yin-Yang theory and analysis of visual structure on angle of elevation, depression, and the landscape-component ratio to be seen through five building sites around the west of An-ap pond, building site three was selected as the building site which has the best landscape. Therefore, it is estimated that building site three played the role of core-building site. According to the result of correlation analysis, the greater the increased in the component ratio of sky, mountain ,the greater the degree of harmony within the landscape. As well, the degree of harmony increased when the landscape component ratio of a distant view was greater than that of a near view. Moreover, it was proved that the relationships of ´chu-jong´, ´heo-sil´, ´so-mil´ are correlative, not independent.

• International Journal of Korean Welding Society
• /
• v.1 no.2
• /
• pp.23-29
• /
• 2001

In this study, a preview-sensing visual sensor system is constructed far weld seam tracking in GMA welding. The visual sensor system consists of a CCD camera, a diode laser system with a cylindrical lens, and a band-pass-filter to overcome the degrading of image due to spatters and/or arc light. Among the image processing methods, Hough transform method is compared with the central difference method from a viewpoint of the capability for extracting the accurate feature position. As a result, it was revealed that Hough transform method can more accurately extract the feature positions and it can be applied to real time weld seam tracking. Image processing which includes Hough transform method is carried out to extract straight lines that express laser stripe. After extracting the lines, weld joint position and edge points are determined by intersecting the lines. Even though the image includes a spatter trace on it, it is possible to recognize the position of weld joint. Weld seam tracking was precisely implemented with adopting Hough transform method, and it is possible to track the weld seam in the case of offset angle is in the region of $\pm$ $15^{\circ}$.