• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2006.06b
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• pp.61-66
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• 2006

This paper proposes a method for generating radar images used in ship handling simulator, which includes mathematical logics based on radar equations and information from Openflight format files. In order to make radar image much similar to that of real radar in PPI type, the proposed mathematical logic derives radar video signals under the consideration of riot only the data form flight format file of simulation scenes, but also geographical radar's position. The proposed method is considered useful to make radar images in ship handling simulator with accuracy and reality.

• Journal of the Korean Institute of Intelligent Systems
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• v.23 no.6
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• pp.577-582
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• 2013

In this paper, the state-of-the-art IVEF Service based on e-Navigation System was represented. The unification of the data exchange format among maritime-related systems is one of vital user-needs of e-Navigation, advantageous in bringing maritime safety and security. This paper propose the method to exchange marine information in IVEF, as recommended by the IALA, between VTS centers and Korea's GICOMS as well as the government-related agencies. To achieve this, a system data flow was designed which it acts as client and server. It enables the sending and receiving of Radar and CCTV images in accordance with the IVEF recommendation document of IALA.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.4
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• pp.499-506
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• 2022

For autonomous ships to be commercialized and be able to navigate in coastal water, they must be able to detect maritime obstacles. One of the most common obstacles seen in coastal area are the farm buoys. In this study, a maritime object detection system was developed that detects buoys using the YOLO algorithm and visualizes the distance and bearing between buoys and the ship through geometric interpretation of camera images. After training the maritime object detection model with 1,224 pictures of buoys, the precision of the model was 89.0%, the recall was 95.0%, and the F1-score was 92.0%. Camera calibration had been conducted to calculate the distance and bearing of an object away from the camera using the obtained image coordinates and Experiment A and B were designed to verify the performance of the maritime object detection system. As a result of verifying the performance of the maritime object detection system, it can be seen that the maritime object detection system is superior to radar in its short-distance detection capability, so that it can be used as a navigational aid along with the radar.

• Journal of the Korean Society of Visualization
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• v.21 no.2
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• pp.83-90
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• 2023

The shape of an airfoil is a critical factor in determining aerodynamic characteristics such as lift and drag. Aerodynamic properties of an airfoil have a decisive impact on the performance of various engineering applications, including airplane wings and wind turbine blades. Therefore, it is essential to analyze the aerodynamic characteristics of airfoils. Various analytical tools such as experiments, computational fluid dynamics, and Xfoil are used to perform these analyses, but each tool has its limitation. In this study, airfoil parameterization, image recognition, and artificial intelligence are combined to overcome these limitations. Image and coordinate data are collected from the UIUC airfoil database. Airfoil parameterization is performed by recognizing images from image data to build a database for deep learning. Trained model can predict the aerodynamic characteristics not only of airfoil images but also of sketches. The mean absolute error of untrained data is 0.0091.

• Journal of Ocean Engineering and Technology
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• v.23 no.1
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• pp.43-47
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• 2009

This paper compares theoretical wave profile and particle kinematics with experimental results generated by a 2 D wave tank. Particle velocity fields of compound waves were acquired using a PIV technique. Synchronization was applied to acquire images of the wave fields, and the time gap between these images was controlled by the user. This technique was applied to investigate the wave breaking mechanism, and the wave profile and velocity distribution in a wave breaking field was obtained.

• Journal of the Korean Society of Visualization
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• v.17 no.3
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• pp.66-69
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• 2019

An image compensating algorithm with high-vibration movement is proposed, using optical flow and the Kalman Filter. The temporal motion vector field is calculated by Optical flow and suspicious vectors are removed or adjusted by the Gaussian interpolation method. The high-vibrated vector filled is stabilized by the Kalman filter. Lastly, compensated images are obtained by affine transformation. This proposed algorithm gives good compensated video images on high-vibration situations.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.7
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• pp.63-70
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• 2010

We developed a new punching system that generates pinholes expressing texts or images on a plastic plate. The pin-holed plate is used as a new glamorous display board reflecting colorful lights from the light emitting diode (LED) installed on the edge side of the plate. The four degree-of-freedom punching system was designed to make same multiple holes on four plastic plates simultaneously. For this motion, we designed a structure for a simultaneous motion of the system. For even reflection of the lights from texts or images on the board and fast production of the pin-holed boards, fast motion including precise position control is very important. We also built a PC-based integrated control system including a GUI program to help users easily design luminous texts or images on the plastic plate. Also, we conducted a performance test of the system to verify the punching speed and position control of the pin holes on the plate.

• The Journal of Korea Robotics Society
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• v.12 no.4
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• pp.385-394
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• 2017

Side scanning sonar (SSS) provides valuable information for robot navigation. However using the side scanning sonar images in the navigation was not fully studied. In this paper, we use range data, and side scanning sonar images from UnderWater Simulator (UWSim) and propose measurement models in a feature based simultaneous localization and mapping (SLAM) framework. The range data is obtained by echosounder and sidescanning sonar images from side scan sonar module for UWSim. For the feature, we used the A-KAZE feature for the SSS image matching and adjusting the relative robot pose by SSS bundle adjustment (BA) with Ceres solver. We use BA for the loop closure constraint of pose-graph SLAM. We used the Incremental Smoothing and Mapping (iSAM) to optimize the graph. The optimized trajectory was compared against the dead reckoning (DR).

• Journal of Ocean Engineering and Technology
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• v.36 no.1
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• pp.32-40
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• 2022

Underwater optical images face various limitations that degrade the image quality compared with optical images taken in our atmosphere. Attenuation according to the wavelength of light and reflection by very small floating objects cause low contrast, blurry clarity, and color degradation in underwater images. We constructed an image data of the Korean sea and enhanced it by learning the characteristics of underwater images using the deep learning techniques of CycleGAN (cycle-consistent adversarial network), UGAN (underwater GAN), FUnIE-GAN (fast underwater image enhancement GAN). In addition, the underwater optical image was enhanced using the image processing technique of Image Fusion. For a quantitative performance comparison, UIQM (underwater image quality measure), which evaluates the performance of the enhancement in terms of colorfulness, sharpness, and contrast, and UCIQE (underwater color image quality evaluation), which evaluates the performance in terms of chroma, luminance, and saturation were calculated. For 100 underwater images taken in Korean seas, the average UIQMs of CycleGAN, UGAN, and FUnIE-GAN were 3.91, 3.42, and 2.66, respectively, and the average UCIQEs were measured to be 29.9, 26.77, and 22.88, respectively. The average UIQM and UCIQE of Image Fusion were 3.63 and 23.59, respectively. CycleGAN and UGAN qualitatively and quantitatively improved the image quality in various underwater environments, and FUnIE-GAN had performance differences depending on the underwater environment. Image Fusion showed good performance in terms of color correction and sharpness enhancement. It is expected that this method can be used for monitoring underwater works and the autonomous operation of unmanned vehicles by improving the visibility of underwater situations more accurately.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2019.11a
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• pp.233-234
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• 2019

We propose a novel algorithm for detecting ship wake trails in optical images of the maritime environment. The proposed algorithm first removes the sky region by localizing the horizon to prevent false wake trails detection. Then, a feature map is computed by employing brightness distortion and chromatic distortion. The feature map is thresholded to obtain a rough estimate of wake trails. Finally, the wake map is refined using the shape prior information. Experimental results show that the proposed algorithm can effectively detect wake trails in images.