• Journal of Korea Water Resources Association
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• v.48 no.8
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• pp.659-672
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• 2015

In flow velocity measurement of natural rivers, taking images with proper image quality is the fundamental and the most important step. Since flood peaks generally occur in night time, it is very difficult to capture proper images in that time. The present study aims to test a far infra-red camera as a adequate alternative to resolve the various problems in measuring flood discharges. The far infra-red cameras are able to capture images in night time without help of any extra illuminations. Futhermore they are not affected by fog nor smoke, hence they can be adapted for a fixed-type surface image velocimeters. For comparison, a commercial camcorder and a near infra-red cameras were used together. The test images were taken at a day time and a night time, and the image acquisition work were performed at an artificial flow channel of the Andong River Experiment Station. The analyzed results showed that the far infra-red camera would be a good instrument for surface image velocimeters, since they were able to capture regardless light condition. There are, however, a few minor problems in their accuracy of the analyzed results. About their accuracy a more study would be required.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.7
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• pp.1346-1367
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• 2011

As the size of camera modules is decreasing and as the computing performance of portable devices is improving, taking photos has become a part of daily life. However, existing photo management programs and products that manage such photos still require extensive user effort to facilitate the sharing and browsing of images. It is especially difficult for novice users to manage and share photos. In this paper, we develop a round-robin concept-driven user preference feedback mechanism for achieving direct photo sharing, instant display, and easy management using optimized user controls and user preference-driven classification. Compared with commercial photo management systems, our proposed solution provides new features: optimized user controls, direct sharing and instant display, and user preference feedback driven classification. These new features boost the round-robin concept-driven user preference feedback. This paper proposes a photo finder that automatically searches for photos in storage spaces or cameras. The proposed photo finder relies on user preference feedback to share photos by leveraging user preferences, and the round-robin connection transmits photos to the family's digital photo frame or web album by arbiter. The proposed method saves time and spares users the effort required for photo management. Moreover, this method does not merely direct photo sharing and simple photo management, but it also increases the satisfaction level of users viewing the photos.

• Journal of Aerospace System Engineering
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• v.10 no.4
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• pp.17-25
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• 2016

In this study, an optical system for a lens-shifting method that compensates for microvibration of a high-agility small satellite has been designed. The lens-shifting method is an image-stabilization technique that can be applied to compensate for the optical path disturbed by microvibration. The target optical system is designed by using Code-V, a commercial optical-design code. The specifications for real satellite cameras have established the requirements for optical design. The Ray aberration curve, spot diagram, and MTF curve were carried out to verify if the designed optical system meets the requirements or not. The designed Schmidt-Cassegrain optical system with field flattener and a vibration-reduction lens has been verified to meet the optical requirements, 33% of MTF at Nyquist frequency, GSD of 2.87 m, and vibration coefficient of 0.95~1.0.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.12
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• pp.111-119
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• 2016

Most commercial digital cameras acquire the colors of an image through the color filter array, and interpolate missing pixels of the image. Because of this fact, original pixels and interpolated pixels have different statistical characteristics. If colors of an image are modified, the color filter array pattern that consists of RGB channels is changed. Using this pattern change, a color forgery detection method were presented. The conventional method uses the number of pixels that exceeds the maximum or minimum value of pre-defined block by only exploiting green component. However, this algorithm cannot remove the flat area which is occurred when color is changed. And the conventional method has demerit that cannot detect the forged image with rare green pixels. In this paper, we propose an enhanced color forgery detection algorithm using the normalization and weighted sum of the color components. Our method can reduce the detection error by using all color components and removing flat area. Through simulations, we observe that our proposed method shows better detection performance compared to the conventional method.

• Journal of Broadcast Engineering
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• v.21 no.4
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• pp.515-524
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• 2016

Infrared (IR) wavelength is out of visible range and thus usually cut by hot filters in general commercial cameras. However, some information from the near-IR (NIR) range is known to improve the overall visibility of scene in many cases. For example when there is fog or haze in the scene, NIR image has clearer visibility than visible image because of its stronger penetration property. In this paper, we propose an algorithm for fusing the RGB and NIR images to obtain the enhanced images of the outdoor scenes. First, we construct a weight map by comparing the contrast of the RGB and NIR images, and then fuse the two images based on the weight map. Experimental results show that the proposed method is effective in enhancing visible image and removing the haze.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.05a
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• pp.355-358
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• 2016

Recently, As the interest of the drone has increased the fields such as broadcasting, disaster site and leisure which uses the drone has been constantly expanded. However, an invasion of a person's privacy and a threat of hacking attack also have increased as population of drone. High-resolution cameras mounted on drones can take a photo or real-time video anytime and anywhere. It causes the invasion of privacy from private houses, buildings, and hotels. In this paper, we perform a security vulnerability assessment tests on the camera's from common commercial drones and we propose the countermeasures to protect the drones against unauthorized attacker who attempts to access the drone's camera from internal or external. Through this research, we expect the Aviation Act and legislation accept the concept of security and provide the polices such as drones equipped with security devices from the production stage to promote drone industry.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.8
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• pp.1737-1744
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• 2010

The Image sensor needs various image processing to improve image quality. ISP(Image Signal Processor) performs various image processing. Conventional vision cameras have own software ISP functions and perform in PC instead of using commercial ISP chips. However these methods have problems such as large computation for image processing. In this paper, we proposed ISP that significantly reduced chip area by efficient sharing of hardware and software. Large operation blocks are designed to hardware for high performances, and we used hardware simultaneously with software considering the size of the hardware. The implemented ISP can process VGA(640*4800) images and has 91450 gate sizes in 0.35um process.

• The Journal of the Korea institute of electronic communication sciences
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• v.19 no.1
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• pp.309-316
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• 2024

Facial recognition technology is widely used in various fields but faces challenges due to its vulnerability to fraudulent activities such as photo spoofing. Extensive research has been conducted to overcome this challenge. Most of them, however, require the use of specialized equipment like multi-modal cameras or operation in high-performance environments. In this paper, we introduce LH-FAS v2 (: Lightweight Head-pose-based Face Anti-Spoofing v2), a system designed to operate on a commercial webcam without any specialized equipment, to address the issue of facial recognition spoofing. LH-FAS v2 utilizes FSA-Net for head pose estimation and ArcFace for facial recognition, effectively assessing changes in head pose and verifying facial identity. We developed the VD4PS dataset, incorporating photo spoofing scenarios to evaluate the model's performance. The experimental results show the model's balanced accuracy and speed, indicating that head pose estimation-based facial anti-spoofing technology can be effectively used to counteract photo spoofing.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.39 no.3
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• pp.187-201
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• 2021

Recently, the demand for a 3D urban spatial information infrastructure for storing, operating, and analyzing a large number of digital data produced in cities is increasing. CityGML is a 3D spatial information data standard of OGC (Open Geospatial Consortium), which has strengths in the exchange and attribute expression of city data. Cases of constructing 3D urban spatial data in CityGML format has emerged on several cities such as Singapore and New York. However, the current ecosystem for the creation and editing of CityGML data is limited in constructing CityGML data on a large scale because of lack of completeness compared to commercial programs used to construct 3D data such as sketchup or 3d max. Therefore, in this study, a method of constructing CityGML data is proposed using commercial 3D mesh data and 2D polygons that are rapidly and automatically produced through aerial LiDAR (Light Detection and Ranging) or RGB (Red Green Blue) cameras. During the data construction process, the original 3D mesh data was geometrically transformed so that each object could be expressed in various CityGML LoD (Levels of Detail), and attribute information extracted from the 2D spatial information data was used as a supplement to increase the utilization as spatial information. The 3D city features produced in this study are CityGML building, bridge, cityFurniture, road, and tunnel. Data conversion for each feature and property construction method were presented, and visualization and validation were conducted.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.6C
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• pp.801-814
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• 2004

In this paper, we propose a block adaptive binarization (BAB) using a modified quadratic filter (MQF) to binarize business card images acquired by personal digital assistant (PDA) cameras effectively. In the proposed method, a business card image is first partitioned into blocks of 8${\times}$8 and the blocks are then classified into character Hocks (CBs) and background blocks (BBs). Each classified CB is windowed with a 24${\times}$24 rectangular window centering around the CB and the windowed blocks are improved by the pre-processing filter MQF, in which the scheme of threshold selection in QF is modified. The 8${\times}$8 center block of the improved block is barbarized with the threshold selected in the MQF. A binary image is obtained tiling each binarized block in its original position. Experimental results show that the MQF and the BAB have much better effects on the performance of binarization compared to the QF and the global binarization (GB), respectively, for the test business card images acquired in a PDA. Also the proposed BAB using MQF gives binary images of much better quality, in which the characters appear much better clearly, over the conventional GB using QF. In addition, the binary images by the proposed BAB using MQF yields about 87.7% of character recognition rate so that about 32.0% performance improvement over those by the GB using QF yielding about 55.7% of character recognition rate using a commercial character recognition software.