• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.05a
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• pp.568-570
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• 2012

The algorithm to distinguish cloud from aerosols in the measurements of Laser Radar is developed. This method use the difference of slope between return signals of cloud and aerosols. The parameters achieved from the algorithm are altitude of cloud top, cloud base, and boundary layer.

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.5
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• pp.258-267
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• 1999

An intelligent safety vehicle(ISV) should have an ability to predict the possibility of an accident and help a driver avoid the accident in advance. The basic function of the ISV is to alert the driver by warning when the collision is to occur. For this purpose, the ISV has to function efficiently in sensing the environmental context. While image processing provides lane information, laser radar senses road obstacles including vehicles. By applying a simple clustering algorithm to radar signals, it is possible to obtain the vehicle information. Consequently, we can identify the existence of the vehicle of interest on my lane. The reliability of the sensing algorithm is evaluated by running on the highway with a test vehicle.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.3
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• pp.307-315
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• 2014

Existing level crossing obstruction detecting system occurs section of not detecting an obstruction by line detecting. Due to installation of decentralized equipment, it has become a problem in terms of safety and maintenance costs. accordingly, We have developed level crossing obstruction detecting system using laser radar sensor in order to solve these problems. In this paper, Describe results of functional test for the developed level crossing obstruction detecting system. functional tests are normal operation test(control unit and sensor unit) and test to display the fault information in event of a failure(control unit and sensor unit). It was confirmed that it works properly all according to functional test of level crossing obstruction detecting system using laser radar sensor.

• Journal of Korean Society for Geospatial Information Science
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• v.16 no.2
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• pp.57-65
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• 2008

The improvement of the performance in laser radar simulation requires fast retrievals of the spatial locations and attributes of objects in response to the laser signals of the simulators. Since the data used in simulation are complex 3D objects such as terrain, buildings and vehicles, and are of large sizes, commonly used 3D modeling tools are not suitable for this use. We proposed a method to store such 3D objects in a database, perform required queries and integrate with visualization tools. We showed the processes for the data modeling based on 3D topological concepts and then building a spatial DBMS. Also, we illustrated the process for accessing and visualizing the stored data using VRML and performed test computations using some laser signal data. With further enhancement on data modeling and LOD problems in visualization, the proposed method will be practically applied in different situations including laser simulation.

• International Journal of Safety
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• v.9 no.2
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• pp.35-40
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• 2010

Many casualties are being occurred due to many misses the railway platform, and the accident occurrence is being increased. Recently in Korea, efforts to prevent casualties fundamentally are being made by installing and operating the PSD(Passenger Screen Door) as to prevent these casualties of passengers. However, in case of the PSD system, although it can solve the problem of public casualties at platform fundamentally, it is impossible to install it at whole railway platforms. This paper proposes the safety equipment using LaserRadar sensor for the prevention against casualties of passengers at platform. The safety equipment using novel sensor is the safety equipment making an approaching train stopped if the falling object is a person by detecting the obstacle at platform, and it has the merit possible to apply it to platform since it may detect accurately under ambient environmental elements such as the snow, rain and yellow dust, etc. also. We manufactured a prototype of the safety equipment to reduce public casualties at platform by using LaserRadar sensor and carried out its performance test, and the result is presented in this paper.

• Journal of the Korean Society of Industry Convergence
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• v.19 no.2
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• pp.62-68
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• 2016

Laser distance measuring systems are used in many fields with high precision. However, when measuring the reflector such as the mirror and the black color, a laser distance measuring system does not guarantee the measurement accuracy. In order to measure the shape of the cargo, this study proposes the radar distance measurement system. The radar distance measuring system is composed of a distance measuring unit with a 24 GHz antenna module, a signal processing and control board and the 1-axis tilting unit. And, this study developed a monitoring program to monitor the measured data. In order to evaluate performance of the developed system, the distance measurement tests are carried out. The distance error was about 6-15 cm. However, considering the size of the cargo, the precision is not a problem. And, cargo shape was measured by using the distance information measured by the 1-axis tilting unit. It could get a 2 dimension shape profile for the cargo stacked in a yard.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.911-912
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• 2013

• Korean Journal of Optics and Photonics
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• v.24 no.1
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• pp.23-28
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• 2013

In this paper, an optical system was designed for 3D imaging laser radar with optical scanner. In order to make it easy to scan, the system was designed to inscribe the transmitting objective lens in the receiving lens. In transmitting optics, the beam expander was designed to have a zoom mechanism so that the transmitted beam size would be 4.8 m or 6.8 m at 1 km distance, when the laser source's numerical aperture value is between 0.13 and 0.22. The beam diameter at the target 1 km away was confirmed by design program. The receiving optics for the returning beam from the target was designed for the $16{\times}16$ array detector with $100{\mu}m$ pixel width. The spot diameter in every pixel was designed and verified to be less than $55{\mu}m$. The receiving optics' obscuration ratio by transmitting optics was 11%.

• Journal of the Korean Institute of Intelligent Systems
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• v.23 no.1
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• pp.35-45
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• 2013

A autonomous vehicle requires improved and robust perception systems than conventional perception systems of intelligent vehicles. In particular, single sensor based perception systems have been widely studied by using cameras and laser radar sensors which are the most representative sensors for perception by providing object information such as distance information and object features. The distance information of the laser radar sensor is used for road environment perception of road structures, vehicles, and pedestrians. The image information of the camera is used for visual recognition such as lanes, crosswalks, and traffic signs. However, single sensor based perception systems suffer from false positives and true negatives which are caused by sensor limitations and road environments. Accordingly, information fusion systems are essentially required to ensure the robustness and stability of perception systems in harsh environments. This paper describes a perception system for autonomous vehicles, which performs information fusion to recognize road environments. Particularly, vision and laser radar sensors are fused together to detect lanes, crosswalks, and obstacles. The proposed perception system was validated on various roads and environmental conditions with an autonomous vehicle.

• Current Optics and Photonics
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• v.1 no.6
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• pp.598-603
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• 2017

Traditional three-dimensional (3-D) laser imaging systems are based on real aperture imaging technology, whose resolution decreases as the range increases. In this paper, we develop a novel 3-D imaging technique based on the synthetic aperture technology in which the imaging resolution is significantly improved and does not degrade with the increase of the range. We consider an imaging laser radar (ladar) system using the floodlight transmitting mode and multi-beam receiving mode. High 3-D imaging resolutions are achieved by matched filtering the linear frequency modulated (LFM) signals respectively in range, synthetic aperture along-track, and the real aperture across-track. In this paper, a novel 3-D imaging signal model is given first. Because of the motion during the transmission of a sweep, the Doppler shift induced by the continuous motion is taken into account. And then, a proper algorithm for the 3-D imaging geometry is given. Finally, simulation results validate the effectiveness of the proposed technique.