• Journal of Korean Society of Forest Science
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• v.13 no.1
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• pp.1-24
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• 1971

In order to elucidate the feasibility to identify the plant species through the photographic tone this study was made. In this study the author made photographs of Juniperus chinensis L., and Populus glandulosa Uyeki, with the panchromatic film using either yellow filter or red filter in different seasons respectively. The author analyzed the value of tone variation at the level of stereoscopic view of the same photographs by using tone scale and Automatic Micro-Photo-Densitometer. The results obtained are summarized as follows: A. Tone scale reading 1. The tone of Populus glandulosa Uyeki was darker than that of Juniperus chinensis L. in a photograph. 2. Regardless of the tree species, tone of photographs obtained with yellow filter was darker than that with red filter. 3. Along the progresses of seasons, the photographic tone was changed. That is, from the spring to the summer it showed darker and than, from the summer to winter it changed lighter. 4. During winter and spring the discrimination between the both species of trees can be easily made by stereoscopic view whether there are leaves on the tree or not rather than by tone observation. 5. Regardless of tree species, variation of tone due to the age was noticed. The older trees have darker tone than the younger one. 6. It is recognized that the yearly difference depends on insolation quantities. 7. The highest reflex light-waves were in between $600m{\mu}$ and $660m{\mu}$ for both species of trees. B. Density reading 1. For the density reading, there was the same tendency as in tone scale reading. 2. The changes of peaks of the scanning curves with Populus glandulosa Uyeki is smoother and takes place in lower position than with Juniperus chinensis L. 3. The scanning curves on the 20th May was smoothest, and change of peaks increased gradually according to the season progresses. 4. In relation to the types of filter the photographs with yellow filter showed less changes of peaks then that with red filter.

• Journal of Sensor Science and Technology
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• v.21 no.6
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• pp.429-433
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• 2012

In this paper, we reduced the optical noise interference in a visible light communication system using two color LEDs. In the transmitter, the original and the inverted signals of the transmitted data modulated a red LED and a blue LED, respectively. In the receiver, a differential detector which is composed of two photodetectors and an optical red filter detected the mixed signal radiated from the two LEDs. In an environment that the optical noise from a fluorescent lamp exists, the signal-to-noise ratio in this system was improved by about 20dB compared to that in the conventional system which uses a single LED and a single photodetector.

• Journal of Institute of Control, Robotics and Systems
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• v.16 no.10
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• pp.982-990
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• 2010

In a target tracking system using image information from a CCD (Charged Couple Device) or an IIR (Imaging Infra-red) sensor, occluded targets can result in track losses. If the target is occlued by background objects such as buildings or trees, probability of track existence will be reduced sharply and track will be terminated due to track maintenance algorithms. This paper proposes data association algorithm based on target existence for the robust tracking performance. we suggest the HPDA (Highest Probability Data Association) algorithm based on target existence and the tracking performance is compared with the established method based on target perceivability. Image tracking simulation that utilizes virtual 3D images and real IR images is employed to evaluate the robustness of the proposed tracking algorithm.

• Journal of the Optical Society of Korea
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• v.11 no.2
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• pp.67-70
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• 2007

A Wide Color Gamut Backlight system was studied using a three-band white Light-Emitting Diode. A three-band white light-emitting diode (LED) was fabricated using an InGaN-based blue LED chip that emits 445-nm blue peak, and a green phosphor and red phosphor that emit 535-nm green and 621-nm red peak emissions, respectively, when excited by 450-nm blue light. Using for this three-band white LED, wide color gamut backlight unit (BLU) was attained. The luminance of BLU and CIE 1931 chromaticity coordinates was $1,700Cd/m^2$ and (0.337, 0.346). Color filter matching simulations for this configuration show that the three-band white LED backlight can be enhanced by up to 16% over conventional white LED backlight color gamut.

• Journal of the Korean Wood Science and Technology
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• v.41 no.5
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• pp.399-405
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• 2013

This study demonstrates the utilization of light microscopy and Fast Fourier Transform-Peak Finding (FPF) method for microfibril angle (MFA) measurement from unstained sections of red pine (Pinus densiflora). To obtain an image with optimal contrast and resolution for MFA measurement, effects of numerical aperture (NA) of condenser lens and color filters were investigated. About 60% of NA of the maximum condenser NA produced an image with optimal contrast, but a color filter with short wavelength range (DAPI) created images with improved resolution. Manual angle measurement and the FPF method were applied to the image with optimal contrast for MFA measurement. The experimental results from the FPF method were considered to be more repeatable and less subjective than those from the manual angle measurement.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.8
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• pp.767-773
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• 2008

This paper presents a localization system based on the use of electric compass and tracking IR light source. Digital RGB(Red, Green, Blue)signal of digital CMOS Camera is sent to CPLD which converts the color image to binary image at 30 frames per second. CMOS camera has IR filter and UV filter in front of CMOS cell. The filters cut off above 720nm light source. Binary output data of CPLD is sent to DSP that rapidly tracks the IR light source by moving Camera tilt DC motor. At a robot toward north, electric compass signals and IR light source angles which are used for calculating the data of the location system. Because geomagnetic field is linear in local position, this location system is possible. Finally, it is shown that position error is within ${\pm}1.3cm$ in this system.

• Journal of The Korean Astronomical Society
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• v.29 no.spc1
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• pp.357-358
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• 1996

Reanalysis of the observations of Mars made at the Hida Observatory in 1975 with a new image processing method is reported. Red filter images taken in the period before vernal equinox (areocentric longitude of the sun Ls=$0^{\circ}$) revealed dark surface features at the northern high latitudes, while blue filter images taken at the same time showed the extensive polar hood. The latitude of the northernmost feature observed was about $67^{\circ}$N. An extensive north polar cap, which is predicted by most of the existing models and observed with Viking, did not exist in our reanalyzed images obtained at the Hida Observatory in 1975.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.709-711
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• 2003

The purpose of this study is to detect the damaged red pine trees by pine wilt disease using high resolution satellite image of IKONOS Geo. IKONOS images are segmented with eCognition image processing software. A segment based maximum likelihood classification was performed to delineate the pine stand. The pine stands are regarded as a potential damage area. In order to develop a methodology to detect the location of damaged trees from the high resolution satellite image, black and white aerial photographs were used as a simulated image. The developed method based on filtering technique. A local maximum filter was adapted to detect the location of individual tree. This report presents a part of the first year results of an ongoing project.

• Journal of Korea Multimedia Society
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• v.22 no.3
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• pp.357-365
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• 2019

In this paper, we suggest the tracking method of moving multi-objects in maritime environments. The image acquisition is conducted using IR(InfraRed) camera sensors on an airborne platform. Under the circumstance of maritime, the qualities of IR images can be significantly degraded due to the clutter influence, which directly gives rise to a tracking loss problem. In order to reduce the effects from the clutters, we introduce a technical approach under Man-In-The-Loop(MITL) system for enhancing the tracking performance. To demonstrate the robustness of the proposed approach based on VTG(Valid Tracking Gate), the simulations are conducted utilizing the airborne IR video sequences: Then, the tracking performances are compared with the existing Kalman Filter tracking techniques.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.15 no.1
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• pp.1-7
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• 2005

Although the Fourier Transform Infra-Red spectrophotometric Direct on Filter(FTIR-DOF) method is a useful analytical technique for quantifying quartz content in respirable dust samples, a number of analytical problems must be taken into consideration such as, to name only a few, inhomogeneous deposition of particles, level of environmental humidity, uneven surface of the filter, and interfering minerals in the sample. This study was designed to select the most suitable wavelength and proper filter material for the method, and to investigate effects of humidity and inhomogeneous deposition of particles on the filter. Samples of respirable dust, created in a dust chamber containing standard material of quartz, were collected using a cyclone equipped with a 25mm filter as a collection medium. The results were as follows; 1. Among seven (7) commercially available filters tested for the FTIR-DOF method, the DM 800 filter showed the best analytical performance having the lowest background absorbance bands and no overlapping peaks at 799, 779, and $695cm^{-1}$. 2. The variations of absorbance due to humidity ranged from 1.0% to 3.3% for $799cm^{-1}$, 1.0% to 3.3% for $779cm^{-1}$, and 8.9%~20.9% for $695cm^{-1}$ peaks, respectively. The $699cm^{-1}$ peak was proved to be most vulnerble to environmental humidity for quantitative analysis of quartz. 3. As for effects of inhomogeneous deposition of samples, the highest variation of absorbance of 10.9% ($13.5{\mu}g$) was observed when using the 695cm-1. The variations of absorbance from the other two peaks, 799 and $779cm^{-1}$, ranged from 1.2 to 3.2%, and 1.4 to 4.1%, respectively. Therefore, the $799cm^{-1}$ peak was considered to be most reliable for quantitative analysis of quartz. The results of this study suggest that, for quantitative analysis of quartz in the respirable dust samples, use of the $799cm^{-1}$ peak can minimize the influence of environmental humidity and inhomogeneous deposition of particles on the filter. The FTIR-DOF method, if adopted for routine analysis of quartz in the respirable dust samples, could save sample preparation time and efforts substantially and also could increase analytical throughputs. Since use of the $799cm^{-1}$ peak is prone to be affected by interferences in the sample, further research on minimizing the effects is needed.