• Journal of Advanced Navigation Technology
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• v.27 no.3
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• pp.306-313
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• 2023

Realistic and graphics-based virtual reality content is based on 360-degree videos, and viewport extraction through the viewer's intention or automatic recommendation function is essential. This paper designs a viewport extraction system based on multiple object tracking in 360-degree videos and proposes a parallel computing structure necessary for multiple viewport extraction. The viewport extraction process in 360-degree videos is parallelized by composing pixel-wise threads, through 3D spherical surface coordinate transformation from ERP coordinates and 2D coordinate transformation of 3D spherical surface coordinates within the viewport. The proposed structure evaluated the computation time for up to 30 viewport extraction processes in aerial 360-degree video sequences and confirmed up to 5240 times acceleration compared to the CPU-based computation time proportional to the number of viewports. When using high-speed I/O or memory buffers that can reduce ERP frame I/O time, viewport extraction time can be further accelerated by 7.82 times. The proposed parallelized viewport extraction structure can be applied to simultaneous multi-access services for 360-degree videos or virtual reality contents and video summarization services for individual users.

• Journal of Advanced Navigation Technology
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• v.23 no.5
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• pp.373-379
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• 2019

AeroMACS spectrum is a national resource internationally allocated by ITU at WRC-07. AeroMACS is an airport broadband mobile communication infrastructure based on WiMAX-based IEEE 802.16e that enables real-time video, graphics, voice, and high-speed data transmission. With the approval of ICAO's development technology standards in 2008, 50 airports in 11 countries have already completed the testing of D-TAXI or A-SMGCS technology using the AeroMACS infrastructure in 2019, starting in the United States in 2009. With many advantages in safety and convenience in terrestrial telecommunications operations, the system is becoming an area of performance improvement for airport operations in accordance with ICAO's ASBU plan. This paper examines the current status of domestic development of AeroMACS and lists service areas applicable to airlines and operators. It also seeks to promote safe and efficient next-generation airport mobile communication system services by presenting feasible partners management in the mobile area and use of aircraft communication systems for active technology development.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2020.11a
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• pp.145-147
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• 2020

As deep learning technology advances, there have been many attempts to improve video codecs such as High-Efficiency-Video-Coding (HEVC) using deep learning technology. One of the most researched approaches is improving filters inside codecs through image restoration researches. In this paper, we propose a method 01 replacing the sample adaptive offset (SAO) filtering with a deep neural network. The proposed method uses the deep neural network to find the optimal offset value. The proposed network consists of two subnetworks to find the offset value and its type of the signal, which can restore nonlinear and complex type of error. Experimental results show that the performance is better than the conventional HEVC in low delay P and random access mode.

• Journal of the Korean Institute of Landscape Architecture
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• v.27 no.4
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• pp.131-136
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• 1999

Aerial videography techniques have been used to inventory conditions associated with grassland, forests, and agricultural crop production. Most recently, aerial videography has been used to verity satellite image classifications as part of the natural ecosystem survey. The objectives of this study were: (1) to use aerial video images of the study area, one part of Taean Seashore National Park, for the accuracy assessment, and (2) to determine the suitability of aerial videography as an accuracy assessment, of the land cover classification with Landsat-TM data. Video images were collected twice, summer and winter seasons, and divided into two kinds of images, wide angle and narrow angle images. Accuracy assessment methods include the calculation of the error matrix, the overall accuracy and kappa coefficient of agreement. This study indicates that aerial videography is an effective tool for accuracy assessment of the satellite image classifications of which features are relatively large and continuous. And it would be possible to overcome the limits of the present natural ecosystem survey method.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.20 no.1
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• pp.59-67
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• 2002

Recently, much demand of vector data have increased rapidly such as a digital map instead of traditional a paper map and the raster data such as a high-resolution orthoimage have been used for many GIS application with the advent of industrial high-resolution satellites and development of aerial optical sensor technologies. Aerial photogrammetric technologies using an airship can offer cost-effective and high-resolution color images as well as real time images, different from conventional remote sensing measurements. Also, it can acquire images easily and its processing procedure is short and simple relatively. On the other hand, it has often been used for the production of a small-scale land use map not required high accuracy, monitoring of linear infrastructure features through mosaicking strip images and construction of GIS data. Through this study, the developed aerial photogrammetric system using the airship expects to be applied to not only producing of scale 1:5, 000 digital map but also verifying, editing, and updating the digital map which was need to be reproduced. Further more, providing the various type of video-images, it expects to use many other GIS applications such as facilities management, scenery management and construction of GIS data for Urban area.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.46 no.2
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• pp.84-91
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• 2009

This paper presents an online partial 3D modeling methodology that uses a mobile augmented reality system and aerial photographs, and a tracking methodology that compares the 3D model with a video image. Instead of relying on models which are created in advance, the system generates a 3D model for a real building on the fly by combining frontal and aerial views. A user's initial pose is estimated using an aerial photograph, which is retrieved from a database according to the user's GPS coordinates, and an inertial sensor which measures pitch. We detect edges of the rooftop based on Graph cut, and find edges and a corner of the bottom by minimizing the proposed cost function. To track the user's position and orientation in real-time, feature-based tracking is carried out based on salient points on the edges and the sides of a building the user is keeping in view. We implemented camera pose estimators using both a least squares estimator and an unscented Kalman filter (UKF). We evaluated the speed and accuracy of both approaches, and we demonstrated the usefulness of our computations as important building blocks for an Anywhere Augmentation scenario.

• Spatial Information Research
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• v.16 no.4
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• pp.411-420
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• 2008

To provide technological foundation for periodic and real-time land monitoring over the Korean peninsula where the land cover changes are prevailing, the Land Monitoring Research project was initiated as one of five core projects within the Intelligent National Land Information Technology Innovation Project operated by the Korean Land Spatialization Group (KLSG). This four year project can be categorized into two research themes with nine sub-projects. The first research theme is dealing with the real-time data acquisition from aerial platform and in-situ measurements by ubiquitous sensor network (USN), ground video camera, and automobile-based data collection systems. The second research theme is mainly focused on the development of application systems that can be directly utilized in several public organizations dealing with land monitoring over the nation. The Moderate Resolution Imaging Spectroradiometer (MODIS)-based land monitoring system that is currently under development is one of such application systems designed to provide necessary information regarding the status and condition of land cover in near real-time.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.8
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• pp.748-756
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• 2015

In this paper, we developed a miniaturized real time video compression system satisfying the military environment using ADV212 and FPGA. We present an efficient hardware design scheme for the weight reduction of the device and also a software solution to deal with noisy image signals. Experimental results show that the frame delay is reduced by a factor of 2 or 3 and the device's weight is decreased by a factor of 6 to 7. In order to prove the reliability for the military usage of this development, we examine the environmental test (MIL-STD-810G) and EMI test (MIL-STD-461F). Experimental results show that the developed system satisfies the requirements.

• Journal of the Speleological Society of Korea
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• no.74
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• pp.33-43
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• 2006

The purpose of this study is to scientifically establish the concepts of photogeography, and to present desirable directions for the pursuit of photogeography in Korea. Photogeography is to effectively utilize the documentary and artistic nature of the photo, as an image medium, in the geographic study. The concept of photogeography, along with the term photogeology, is already known widely in foreign countries, and extensive research has been carried out in the field. However, here in Korea, nobody knows the concept of photogeography. Since photogeography has not been systemized as a science, and interest in photography is being minimal, photography, in reality, has in no way been utilized effectively. The photographs used in Photogeography can be classified, according to character, into two major categories, geographic photographs and general photographs, and, according to subject and camera, into still photographs and dynamic photographs. Photographs, such single photographs, slides, air photographs and satellite photographs are in the category of still photographs, while pictures like video and movie pictures are dynamic photographs.

• Journal of Digital Contents Society
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• v.19 no.1
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• pp.165-171
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• 2018

Shadow is a physical phenomenon observed in natural scenes and has a negative effect on various image processing systems such as intelligent video surveillance, traffic surveillance and aerial imagery analysis. Therefore, shadow detection should be considered as a preprocessing process in all areas of computer vision. In this paper, we define and analyze various feature elements for shadow detection in a single natural image that does not require a reference image. The shadow elements describe the intensity, chromaticity, illuminant-invariant, color invariance, and entropy image, which indicate the uncertainty of the information. The results show that the chromaticity and illuminant-invariant images are effective for shadow detection. In the future, we will define a fusion map of various shadow feature elements, and continue to study shadow detection that can adapt to various lighting levels, and shadow removal using chromaticity and illuminance invariant images.