• Journal of Korea Multimedia Society
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• v.11 no.6
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• pp.860-868
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• 2008

Human detection techniques in outdoor scenes have been studied for a long time to watch suspicious movements or to keep someone from danger. However there are few methods of human detection in overhead or near-field view scenes, while lots of human detection methods in far-field view scenes have been developed. In this paper, a set of five features useful for human detection in overhead view scenes and another set of four useful features in near-field view scenes are suggested. Eight feature-candidates are first extracted by analyzing geometrically varying characteristics of moving objects in samples of video sequences. Then highly contributed features for each view scene to classifying human from other moving objects are selected among them by using a neural network learning technique. Through experiments with hundreds of moving objects, we found that each set of features is very useful for human detection and classification accuracy for overhead view and near-field view scenes was over 90%. The suggested sets of features can be used effectively in a PTZ camera based surveillance system where both the overhead and near-field view scenes appear.

• Current Optics and Photonics
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• v.6 no.4
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• pp.420-429
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• 2022

In this paper, the details and design process of an optical system for space target detection cameras are introduced. The whole system is divided into three structures. The first structure is a short-focus visible light system for rough detection in a large field of view. The field of view is 2°, the effective focal length is 1,125 mm, and the F-number is 3.83. The second structure is a telephoto visible light system for precise detection in a small field of view. The field of view is 1°, the effective focal length is 2,300 mm, and the F-number is 7.67. The third structure is an infrared light detection system. The field of view is 2°, the effective focal length is 390 mm, and the F-number is 1.3. The visible long-focus narrow field of view and visible short-focus wide field of view are switched through a turning mirror. Design results show that the modulation transfer functions of the three structures of the system are close to the diffraction limit. It can further be seen that the short-focus wide-field-of-view distortion is controlled within 0.1%, the long-focus narrow-field-of-view distortion within 0.5%, and the infrared subsystem distortion within 0.2%. The imaging effect is good and the purpose of the design is achieved.

• KIEAE Journal
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• v.7 no.2
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• pp.31-37
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• 2007

Despite of many supportive research to the usefulness of slide evaluation on environment of outdoor lighting, study method of using slides have provoked many discussions of its manifestation of reality of field conditions. This study aims to compare the results of slide survey with that of field survey. Distant view and short range view of nightscape of Seoul were selected. Field measurement of luminance and chromaticity were conducted and questionnaire survey were conducted. Frequency analysis, T-test, factor analysis were conducted. Results shows that distant view and short range view of field survey have better visual atmosphere than slide survey. In addition, slide survey on distant view shows lowest values. Difference between field survey and slide survey on distant view is much bigger than the results of short range view.

• Journal of Institute of Control, Robotics and Systems
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• v.8 no.2
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• pp.120-125
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• 2002

An optimization approach is used to partition the field of view. A cost function is defined to represent the constraints on the solution, which is then mapped onto a two-dimensional Hopfield neural network for minimization. Each neuron in the network represents a possible match between a field of view and one or multiple objects. Partition is achieved by initializing each neuron that represents a possible match and then allowing the network to settle down into a stable state. The network uses the initial inputs and the compatibility measures between a field of view and one or multiple objects to find a stable state.

• Proceedings of the KSME Conference
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• 2001.11a
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• pp.667-672
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• 2001

An optimization approach is used to partition the field of view. A cost function is defined to represent the constraints on the solution, which is then mapped onto a two-dimensional Hopfield neural network for minimization. Each neuron in the network represents a possible match between a field of view and one or multiple objects. Partition is achieved by initializing each neuron that represents a possible match and then allowing the network to settle down into a stable state. The network uses the initial inputs and the compatibility measures between a field of view and one or multiple objects to find a stable state.

• Science of Emotion and Sensibility
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• v.24 no.4
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• pp.17-28
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• 2021

The purpose of the research was to examine the effect of field of view on egocentric distance perception in the real and virtual environment. The replica that mimicked the real environment condition was used to create the virtual environment condition. We manipulated field of view levels equally in both viewing conditions using glasses that limit the field of view in real-world conditions and limiting the field of view in virtual-world conditions in a manner equivalent to real-world conditions via HMD. Eighteen participants observed the target with a limited field of view in a real and virtual environment without head movement. Then, we measured perceived distance using the timed imagined walking method, which measures the time taken by each participant to mentally walk to the target. The target was shown three times at three different distances from the participants: 3, 4, and 5 m. For the analysis, we converted time estimates into distance estimates. Consequently, the estimated distance in the virtual environment condition was less than the estimated distance in the real environment condition. And as the field of view shrank, the estimated distance also decreased. The estimated distance did not vary with field of view levels in real-world conditions. In the virtual environment, the estimated distance decreased as the field of view decreased, whereas in the real environment, the estimated distance increased. The implications of the results and some future research directions are discussed below.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.10a
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• pp.699-701
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• 2017

Typical operating method for long-range observation cameras are to detect the target at a wide angle of view and to recognize/identify the target with a telephoto angle of view. And the detection/recognition range performance is an important item to evaluate the performance of the defense infrared camera. To increased the detection range performance, the camera's field of view should be narrowed. Due to the narrow field of view, the probability of finding target is relatively low. In this paper, we propose a method to search for target by providing a wide angle view while maintaining detection range performance. M&S and optimized design were used to develop infrared camera with extended field of view and the results of the test summarized.

• Investigative Magnetic Resonance Imaging
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• v.15 no.1
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• pp.11-21
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• 2011

Purpose : Localization using MRI is difficult due to susceptibility induced artifacts caused by metal electrodes. Here we took an advantage of the B0 pattern induced by the metal electrodes by using an oblique-view imaging method. Materials and Methods : Metal electrode models with various diameters and susceptibilities were simulated to understand the aspect of field distortion. We set localization criteria for a turbo spin-echo (TSE) sequence usingconventional ($90^{\circ}$ view) and $45^{\circ}$ oblique-view imaging method through simulation of images with various resolutions and validated the criteria usingphantom images acquired by a 3.0T clinical MRI system. For a gradient-refocused echo (GRE) sequence, which is relatively more sensitive to field inhomogeneity, we used phase images to find the center of electrode. Results : There was least field inhomogeneity along the $45^{\circ}$ line that penetrated the center of the electrode. Therefore, our criteria for the TSE sequence with $45^{\circ}$ oblique-view was coincided regardless of susceptibility. And with $45^{\circ}$ oblique-view angle images, pixel shifts were bidirectional so we can detect the location of electrodes even in low resolution. For the GRE sequence, the $45^{\circ}$ oblique-view anglemethod madethe lines where field polarity changes become coincident to the Cartesian grid so the localization of the center coordinates was more facilitated. Conclusion : We suggested the method for accurate localization of electrode using $45^{\circ}$ oblique-view angle imaging. It is expected to be a novelmethodto monitoring an electrophysiological brain study and brain neurosurgery.

• Journal of the Korean housing association
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• v.17 no.3
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• pp.99-109
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• 2006

The purpose of this study was to analyze the characteristic of each view in an apartment unit in terms of the quality. This study was accomplished by two research methods; the field survey on 181 apartment complexes in Daegu, and the preference evaluation on 24 cases sampled in the sense of its location, i.e. inside or outside of a complex. In the field survey, view targets were categorized into various items such as a building, a road, a mountain, a tree, another apartment, the sky, and so on, and the characteristics of the distance from a viewer to view targets and view of the level in an apartment were analyzed. In the preference evaluation, 24 cases, each one has one of the follows; the natural view, the artificial view, and the combined view of the both, were chosen and those were evaluated by 167 interviewees. As a result, the conclusions from the study were drawn as follows; 1) The view, the combination of buildings, roads, mountains, trees, apartments, and the sky, is usually seen in an apartment unit. 2) The type of view target is more significant to a person than its location. 3) The natural and combined view are preferred to the artificial one. 4) In the case of the same outside view, a person likes the open view more than the somewhat covered one.

• Proceedings of the Korea Contents Association Conference
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• 2009.05a
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• pp.163-168
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• 2009

Since 3D gamers can control points of view and field of view freely, 3D games generate high realities and immersions. On most of 3D games, a point of view and a field of view are determined by positions and FOV(field of view) of camera. Although FOV is a simple technical factor, it leads to graphics distortion and affects immersion of the game and causes some gamers to get physical sickness. Therefore, we will suggest the instruction to operate FOVs in many 3D games by examining and analysing various rendering results with control of FOV and real cases of FOV in published games with same 3D modeling environments.