• Proceedings of the IEEK Conference
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• 2004.08c
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• pp.857-861
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• 2004

This paper describes preliminary results we have obtained in developing a computer vision system based on active IR illumination for real time gaze tracking for interactive graphic display. Unlike most of the existing gaze tracking techniques, which often require assuming a static head to work well and require a cumbersome calibration process for each person, our gaze tracker can perform robust and accurate gaze estimation without calibration and under rather significant head movement. This is made possible by a new gaze calibration procedure that identifies the mapping from pupil parameters to screen coordinates using the Generalized Regression Neural Networks (GRNN). With GRNN, the mapping does not have to be an analytical function and head movement is explicitly accounted for by the gaze mapping function. Furthermore, the mapping function can generalize to other individuals not used in the training. The effectiveness of our gaze tracker is demonstrated by preliminary experiments that involve gaze-contingent interactive graphic display.

• Journal of Electrical Engineering and Technology
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• v.11 no.6
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• pp.1846-1856
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• 2016

This study proposes a novel feature point initialization method in order to improve the accuracy of feature point positions by fusing a vision sensor and a lidar. The initialization is a process that determines three dimensional positions of feature points through two dimensional image data, which has a direct influence on performance of a 6-DoF bearing-only SLAM. Prior to the initialization, an extrinsic calibration method which estimates rotational and translational relationships between a vision sensor and lidar using multiple calibration tools was employed, then the feature point initialization method based on the estimated extrinsic calibration parameters was presented. In this process, in order to improve performance of the accuracy of the initialized feature points, an iterative automatic scaling parameter tuning technique was presented. The validity of the proposed feature point initialization method was verified in a 6-DoF bearing-only SLAM framework through an indoor and outdoor tests that compare estimation performance with the previous initialization method.

• Journal of Institute of Control, Robotics and Systems
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• v.6 no.12
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• pp.1106-1112
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• 2000

In this paper, we present a vision system which measures the cross-section of a hot wire-rod in the steel plant. We developed a mobile vision system capable of accurate measurement, which is strong to vibration and jolt when moving. Our system uses green laser light sources and CCD cameras as a sensor, where laser sheet beams form a cross-section contour on the surface of the hot wire-rod and the reflected light from the wire-rode is imaged on the CCD cameras. We use four lasers and four cameras to obtain the image with the complete cross-section contour without an occlusion region. We also perform camera calibrations to obtain each cameras physical parameters by using a single calibration pattern sheet. In our measuring algorithm, distorted four-camera images are corrected by using the camera calibration information and added to generate an image with the complete cross-section contour of the wire-rod. Then, from this image, the cross-section contour of the wire-rod is extracted by preprocessing and segmentation, and its height, width and area are measured.

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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• 2001.06a
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• pp.1268-1268
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• 2001

The availability of in vivo and in sacco degradability values are limited because those methods require work with fistulated animals and are rather complicated, labour intensive and expensive. That is to say, the dynamics and logistics of the methodology result in considerable work, due to limitations on the amount of samples, number of bags that can be placed in an animal and different time intervals to perform kinetic studies. Therefore, a simpler method is necessary to estimate the degradation characteristics of the feed. In this way, near infrared reflectance spectroscopy has been used to predict degradation characteristics of forages. In other hand, the possibility of achieving successful transfer of spectra and equations between instruments is closely related. The objective of this study was to confirm the potential of NIR to optimize work conditions to avoid duplicated efforts in collaborative trials on animal feeds evaluation between research institutions. For this purpose, one set with forty hays and dehydrated forages samples from SERIDA and ten samples with the same characteristics from SIA, were be used to create a spectral database. A calibration was developed using samples from degradation essays made in SERIDA to predict dry matter and crude protein degradability. With the addition of five samples from SIA in original calibration set, the effect of different origin and location was compensated.

• Journal of the korean society of oceanography
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• v.34 no.4
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• pp.200-206
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• 1999

Seawater sampling is the primary task for the study of the marine environmental parameters that require shipboard or laboratory experiments for their analyses, and is also required for the calibration of some instruments for in situ measurement. A new automatic bottle (AUTTLE) is developed for seawater sampling at any desired time and water depth by self-triggering. Both any type of single or assembled mooring for 15 days and manual actuation by using a remote messenger as existing instantaneous single point water samplers are possible. Its sampling capacity and the resolution of time setting are 2 liters and 1 second, respectively. The result of a field experiment with an optical backscattering sensor (OBS) and a total of 14 AUTTLES for the in situ calibration of the OBS shows that the AUTTLE must improve our understanding on the behavior of the sand/mud mixtures in the environments with high waves and strong tides. The AUTTLE will serve as a valuable instrument in the various fields of oceanography, especially where synchronized seawater sampling at several sites is required and/or the information in storm period is important.

• Proceedings of the Korea Water Resources Association Conference
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• 2004.05b
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• pp.1400-1403
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• 2004

The current industrial development and the Increase of population along Nakdong River have produced a rapid Increase of wastewater discharge. This has resulted in problem of water quality control and management. Although many efforts have been carried out, water quality has not significantly improved. The goal of this study is to design a NGIS-based water quality management system for the scientific water quality control and management in the Nakdong River. For general water quality analysis, QULA2E model was applied to the Nakdong River. A sensitivity analysis was made to determine significant parameters and an optimization was made to estimate optimal values. The calibration and verification were performed by using observed water quality data for Nakdong River. A water qualify management system for Nakdong River was made by connecting the QUAL2E model to ArcView. It allows a Windows-based Graphic User Interface(GUI) to implement all operation with regard to water quality analysis. The modeling system in this study will be an efficient NGIS for planning of water quality management.

• Journal of Korean Society on Water Environment
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• v.31 no.5
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• pp.507-522
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• 2015

In this study, some of the model verification results of STREAM (Spatio-Temporal River-basin Ecohydrology Analysis Model), a newly-developed hybrid watershed model, are presented for the runoff processes of nonpoint source pollution. For verification study of STREAM, the model was applied to a test watershed and a sensitivity analysis was also carried out for selected parameters. STREAM was applied to the Mankyung River Watershed to review the applicability of the model in the course of model calibration and validation against the stream flow discharge, suspended sediment discharge and some water quality items (TOC, TN, TP) measured at the watershed outlet. The model setup, simulation and data I/O modules worked as designed and both of the calibration and validation results showed good agreement between the simulated and the measured data sets: NSE over 0.7 and $R^2$ greater than 0.8. The simulation results also include the spatial distribution of runoff processes and watershed mass balance at the watershed scale. Additionally, the irrigation process of the model was examined in detail at reservoirs and paddy fields.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.11
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• pp.1697-1702
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• 2004

In this paper, we proposed the design and calibration method for the near infrared Acousto-Optic Tunable Filter (AOTF). The theory and design principles of AOTF for the visible light are well known since I.C.Chang has developed the parallel tangent condition for the non-collinear AOTF. Deflection angle, frequency-wavelength relation, spectral resolution, etc. were calculated based on the theory of AOTF. From this result, important parameters - incident and acoustic angle - to fabricate AOTF were decided. We measured the spectral resolution and the relation between electrical driving frequency and the Optical wavelength of diffracted light to calibrate the near infrared AOTF. About 40 ∼ 80 MHz electrical frequency was required to get 1200 ∼ 2200 nm near infrared light. Spectral resolution was less than 10 nm in the near infrared region.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.19 no.2
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• pp.191-201
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• 2007

It was noted by the several researchers that the voltage outputs in response to a single yawed hot-wire sensor in a flow perpendicular to the axis deviate from the theoretical voltage output by King's law and Jorgensen's relation. This study noticed that the calibration coefficients of original Grande's method are not constant and fairly sensitive to the radial angle (${\alpha}_{R}$). For more accuracy, this study interpolated the parameters of the Grande relation as a function of radial angle and compared velocity components with ones by Jorgensen and original Grande relation in the calibration jet flow. Finally, as a test case, 3-dimensional turbulent flows of the inlet plane of 180 degree bend are measured and compared the velocity components by above three methods and showed the characteristics of the flows.

• Journal of Biosystems Engineering
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• v.32 no.4
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• pp.256-262
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• 2007

Image processing systems have been used to measure the plant parameters such as size, shape and structure of plants. There are yet some limited applications for evaluating plant colors due to illumination conditions. This study was focused to present adaptive methods to analyze plant leaf color regardless of illumination conditions. Color patches attached on the calibration bars were selected to represent leaf colors of lettuces and to test a possibility of health monitoring of lettuces. Repeatability of assigning leaf colors to color patches was investigated by two-tailed t-test for paired comparison. It resulted that there were no differences of assignment histogram between two images of one lettuce that were acquired at different light conditions. It supported that use of the calibration bars proposed for leaf color analysis provided color constancy, which was one of the most important issues in a video color analysis. A health discrimination equation was developed to classify lettuces into one of two classes, SOUND group and POOR group, using the machine vision. The classification accuracy of the developed health discrimination equation was 80.8%, compared to farmers' decision. This study could provide a feasible method to develop a standard color chart for evaluating leaf colors of plants and plant health monitoring system using the machine vision.