• Journal of Institute of Control, Robotics and Systems
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• v.15 no.4
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• pp.372-378
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• 2009

For effective mobility control of unmanned ground vehicles in outdoor off-road environments, terrain cover classification technology using passive sensors is vital. This paper presents a novel method far terrain classification based on color and texture information of off-road images. It uses a neural network classifier and wavelet features. We exploit the wavelet mean and energy features extracted from multi-channel wavelet transformed images and also utilize the terrain class spatial coordinates of images to include additional features. By comparing the classification performance according to applied features, the experimental results show that the proposed algorithm has a promising result and potential possibilities for autonomous navigation.

• Proceedings of the Korea Contents Association Conference
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• 2004.05a
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• pp.151-160
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• 2004

This research addresses the experimental application of the digital close-range photogrammetric technique for 3D deformation measurement and visualization of road slope. The 3D displacements were extracted by the photo-triangulation based on the bundle adjustment method using the digital imagery. In addition, we produced the digital elevation models, the digital orthorectified images and the 3D perspective view images of the slope employing a digital photogrammetric workstation. Also the inclination map of the slope was generated as the data for monitoring and managing dangerous slopes.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.5
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• pp.397-404
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• 2011

This paper proposes an algorithm capable of extracting corresponding points between a pair of stereo images based on dynamic programming. The purpose of extracting the corresponding points is to provide the stereo disparity data to a road-slope estimation algorithm with high accuracy and in real-time. As the road-slope estimation algorithm does not require dense disparity data, the proposed stereo matching algorithm aims at extracting corresponding points accurately and quickly. In order to realize this contradictory goal, this paper exploits dynamic programming, and minimizes matching candidates using vertical components of color edges. Furthermore, the typical occlusion problem in stereo vision is solved. The proposed algorithm is proven to be effective through experiments with various images captured on the roads.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.1
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• pp.116-125
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• 2014

Road conditions can provide important information for driving safety in driving assistance systems. The input images usually include unnecessary information and they need to be analyzed only in a region of interest (ROI) to reduce the amount of computation. In this paper, a vision-based road ROI determination algorithm is proposed to detect the road region using the positional information of a vanishing point and line segments. The line segments are detected using Canny's edge detection and Hough transform. The vanishing point is traced by a Kalman filter to reduce the false detection due to noises. The road ROI can be determined automatically and adaptively in every frame after initialization. The proposed method is implemented using C++ and the OpenCV library, and the road ROIs are obtained from various video images of black boxes. The results show that the proposed algorithm is robust.

• Korean Journal of Remote Sensing
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• v.33 no.4
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• pp.423-436
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• 2017

This paper presents a deep learning-based road segmentation framework from very high-resolution orthophotos. The proposed method uses Deep Convolutional Autoencoders for end-to-end mapping of orthophotos to road segmentations. In addition, a set of post-processing steps were applied to make the model outputs GIS-ready data that could be useful for various applications. The optimization of the model's parameters is explained which was conducted via grid search method. The model was trained and implemented in Keras, a high-level deep learning framework run on top of Tensorflow. The results show that the proposed model with the best-obtained hyperparameters could segment road objects from orthophotos at an average accuracy of 88.5%. The results of optimization revealed that the best optimization algorithm and activation function for the studied task are Stochastic Gradient Descent (SGD) and Exponential Linear Unit (ELU), respectively. In addition, the best numbers of convolutional filters were found to be 8 for the first and second layers and 128 for the third and fourth layers of the proposed network architecture. Moreover, the analysis on the time complexity of the model showed that the model could be trained in 4 hours and 50 minutes on 1024 high-resolution images of size $106{\times}106pixels$, and segment road objects from similar size and resolution images in around 14 minutes. The results show that the deep learning models such as Convolutional Autoencoders could be a best alternative to traditional machine learning models for road segmentation from aerial photographs.

• Journal of KIISE:Computing Practices and Letters
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• v.5 no.6
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• pp.748-757
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• 1999

본 논문에서는 차량 영역의 추출을 이용한 효율적인 교통 혼잡도 측정 시스템을 설계하고 구현한다. 차량 영역 정보의 추출은 첫째 영역 분할, 둘째 작은 영역의 제거와 영역의 직사각형화, 셋째 영역의 병합 및 삭제의 단계로 나눌 수 있다. 영역 분할 단계에서는 획득한 도로 영상을 영역 기반 영역 분할에 의해 영역으로 분할한다. 그 다음 영역 분할 후의 영역 정보 중 차량 영역을 추출하는데 영향을 미치지 않는 작은 영역들을 제거하고, 남은 영역들을 직사각형화한다. 마지막으로 차선 별로 남은 영역들을 병합, 삭제함으로써 각 차선마다 차량 영역 정보를 추출할 수 있다. 이러한 방법은 배경 영상과 같은 부가적인 정보를 사용하지 않고 도로 자체 영상만으로 교통 혼잡도를 측정할 수 있으며, 그림자의 영향이 없을 경우 적용할 수 있는 기법이다.Abstract In this paper, we designed and implemented an efficient road congestion analysis system using regional information. To extract vehicle regions from a road image, the system process the image in five steps: segmentation, small region elimination, region rectangularization, region merging and region deletion. First, we segment road image by a threshold value. Then, we eliminate useless small regions to extract vehicle region, and perform region rectangularization. Finally, we extract vehicle region of each lane of the road by region merging and deletion. This method has the advantage of measuring road congestion without additional information such as background images. But this method must be applied to road images without shadow.

• Journal of Korean Society for Geospatial Information Science
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• v.10 no.2 s.20
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• pp.77-85
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• 2002

The intention of this study is to extract the spatial and attribute information of road facility for Geospatial Information System(GIS) using graphic solution. Terrestrial photogrammetry has a lot of possibility for the acquisition of road facility information, which has much convenience in locating camera station, selecting the direction, and taking multiple images of the object at the fixed position. This study intended to develop the technique using single frame images only for the raw image data, being able to apply in the case where comparative high accuracy is not required and rigorous photogrammetric method is not available or rapid acquisition of information is need. As the results, we can find the efficiency in plane feature mapping and determining the dimensions of the road facilities.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2007.04a
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• pp.221-224
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• 2007

MMS(Mobile Mapping System) generates a efficient image data for mapping and facility management. However, this image data of MMS has many difficulties in a practical use because of huge data volume. Therefore the important information likes road sign post must be extracted from huge MMS image data. In Korea, there is the HMS(Highway Management System) to manage a national road that acquire the line and condition of road from the MMS images. In the HMS each road sign information is manually inputted by the keyboard from moving MMS. This manually passive input way generate the error like inaccurate position, mistaking input in this research we developed the automatic road sign identifying technique using the image processing and the direct geo-referencing by GPS/INS data. This development brings not only good flexibility for field operations, also efficient data processing in HMS.

• Journal of Institute of Control, Robotics and Systems
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• v.12 no.4
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• pp.395-399
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• 2006

A method to recognize unpaved road region using a 3D depth measurement system is proposed for mobile robots. For autonomous maneuvering of mobile robots, recognition of obstacles or recognition of road region is the essential task. In this paper, the 3D depth measurement system which is composed of a rotating mirror, a line laser and mono-camera is employed to detect depth, where the laser light is reflected by the mirror and projected to the scene objects whose locations are to be determined. The obtained depth information is converted into an image. Such depth images of the road region represent even and plane while that of off-road region is irregular or textured. Therefore, the problem falls into a texture identification problem. Road region is detected employing a simple spatial differentiation technique to detect the plain textured area. Identification results of the diverse situation of unpaved trail are included in this paper.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.301-303
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• 2003

The extraction of 3D road network from high-resolution aerial images is still one of the current challenges in digital photogrammetry and computer vision. For many years, there are many researcher groups working for this task, but unt il now, there are no papers for doing this with TLS (Three linear scanner), which has been developed for the past several years, and has very high-resolution (about 3 cm in ground resolution). In this paper, we present a methodology of road extraction from high-resolution digital imagery taken over urban areas using this modern photogrammetry’s scanner (TLS). The key features of the approach are: (1) Because of high resolution of TLS image, our extraction method is especially designed for constructing 3D road map for next -generation digital navigation map; (2) for extracting road, we use the global context of the intensity variations associated with different features of road (i.e. zebra line and center line), prior to any local edge. So extraction can become comparatively easy, because we can use different special edge detector according different features. The results achieved with our approach show that it is possible and economic to extract 3D road data from Three Linear Scanner to construct next -generation digital navigation road map.