• Journal of Korean Society for Geospatial Information Science
• /
• v.23 no.1
• /
• pp.81-88
• /
• 2015

Various satellite sensors having ranges of the visible, infrared, and thermal wavelengths have been launched due to the improvement of hardware technologies of satellite sensors development. According to the development of satellite sensors with various wavelength ranges, the fusion and integration of multisensor images are proceeded. Image matching process is an essential step for the application of multisensor images. Some algorithms, such as SIFT and SURF, have been proposed to co-register satellite images. However, when the existing algorithms are applied to extract matching points between optical and thermal images, high accuracy of co-registration might not be guaranteed because these images have difference spectral and spatial characteristics. In this paper, location of control points in a reference image is extracted by SURF, and then, location of their corresponding pairs is estimated from the correlation of the local similarity. In the case of local similarity, phase correlation method, which is based on fourier transformation, is applied. In the experiments by simulated, Landsat-8, and ASTER datasets, the proposed algorithm could extract reliable matching points compared to the existing SURF-based method.

• Proceedings of the Acoustical Society of Korea Conference
• /
• 1998.06e
• /
• pp.319.2-322
• /
• 1998

본 논문에서는 반음절 단위 HMM을 이용한 연속 숫자 음성인식 시스템의 2단계로 이루어지는 화자 적응 알고리즘을 수행하였다. 음성인식 시스템에서 사용되는 훈련데이터의 양이 많더라도 발성속도, 발성크기 등의 화자 발성 습관에 따라 화자독립 음성인식 시스템에서는 많은 문제점들이 발생하게 된다. 불특정 화자를 대상으로 한 음성 인식에 있어서 개인차에 의한 변동을 대처하는 방법으로 유효한 음향적 특성을 추출하기 위해 스펙트럼의 동적인(Dynamic) 특성을 주로 이용하고 있다. 따라서 본 논문에서는 화자 적을 기법의 하나인 frequency warped spectral matching 방법을 연속숫자 음성 인식시스템에 적용하였으며, 이때 인식에 의한 적절한 화자별 스케일링 계수 선정 방법을 수행하여 오인식률이 감소함을 확인하였다.

• Proceedings of the KSRS Conference
• /
• 2006.03a
• /
• pp.341-343
• /
• 2006

The current spectral shape matching method (SSMM), developed by Ahn and Shanmugam (2004), relies on the assumption that the path radiance resulting from scattered photons due to air molecules and aerosols and possibly direct-reflected light from the air-sea interface is spatially homogeneous over the sub-scene of interest, enabling the retrieval of water-leaving radiances ($L_w$) from the satellite ocean color image data. This assumption remains valid for the clear atmospheric conditions, but when the distribution of aerosol loadings varies dramatically the above postulation of spatial homogeneity will be violated. In this study, we present the second version of SSMM which will take into account the horizontal variations of aerosol loading in the correction of atmospheric effects in SeaWiFS ocean color image data. The new version includes models for the correction of the effects of aerosols and Raleigh particles and a method fur computation of diffuse transmittance ($t_{os}$) as similar to SeaWiFS. We tested this method over the different optical environments and compared its effectiveness with the results of standard atmospheric correction (SAC) algorithm (Gordon and Wang, 1994) and those from in-situ observations. Findings revealed that the SAC algorithm appeared to distort the spectral shape of water-leaving radiance spectra in suspended sediments (SS) and algal bloom dominated-areas and frequently yielded underestimated or often negative values in the lower green and blue part of the electromagnetic spectrum. Retrieval of water-leaving radiances in coastal waters with very high sediments, for instance = > 8g $m^{-3}$, was not possible with the SAC algorithm. As the current SAC algorithm does not include models for the Asian aerosols, the water-leaving radiances over the aerosol-dominated areas could not be retrieved from the image and large errors often resulted from an inappropriate extrapolation of the estimated aerosol radiance from two IR bands to visible spectrum. In contrast to the above results, the new SSMM enabled accurate retrieval of water-leaving radiances in a various range of turbid waters with SS concentrations from 1 to 100 g $m^{-3}$ that closely matched with those from the in-situ observations. Regardless of the spectral band, the RMS error deviation was minimum of 0.003 and maximum of 0.46, in contrast with those of 0.26 and 0.81, respectively, for SAC algorithm. The new SSMM also remove all aerosol effects excluding areas for which the signal-to-noise ratio is much lower than the water signal.

• Korean Journal of Remote Sensing
• /
• v.26 no.2
• /
• pp.175-188
• /
• 2010

A new correction method is required for the Geostationary Ocean Color Imager (GOCI), which is the world's first ocean color observing sensor in geostationary orbit. In this paper we introduce a new method of atmospheric and the Bidirectional Reflectance Distribution Function(BRDF) correction for GOCI. The Spectral Shape Matching Method(SSMM) and the Sun Glint Correction Algorithm(SGCA) were developed for atmospheric correction, and BRDF correction was improved using Inherent Optical Property(IOP) data. Each method was applied to the Sea-Viewing Wide Field-of-view Sensor(SeaWiFS) images obtained in the Korean sea area. More accurate estimates of chlorophyll concentrations could be possible in the turbid coastal waters as well as areas severely affected by aerosols.

• Journal of Korea Multimedia Society
• /
• v.17 no.9
• /
• pp.1041-1051
• /
• 2014

In this paper, we propose a new image alignment technique based on CUDA SURF in order to solve the initial image alignment problem that frequently occurs in machine vision applications. Machine vision systems using multi-spectral images have recently become more common for solving various decision problems that cannot be performed by the human vision system. These machine vision systems mostly use markers for the initial image alignment. However, there are some applications where the markers cannot be used and the alignment techniques have to be changed whenever their markers are changed. In order to solve these problems, we propose a new image alignment method for multi-spectral machine vision applications based on SURF extracting image features without depending on markers. In this paper, we propose an image alignment method that obtains a sufficient number of feature points from multi-spectral images using SURF and removes outlier iteratively based on a least squares method. We further propose an effective preliminary scheme for removing mismatched feature point pairs that may affect the overall performance of the alignment. In addition, we reduce the execution time by implementing the proposed method using CUDA based on GPGPU in order to guarantee real-time operation. Simulation results show that the proposed method is able to align images effectively in applications where markers cannot be used.

• Journal of Korean Society for Geospatial Information Science
• /
• v.20 no.2
• /
• pp.47-54
• /
• 2012

Additional high resolution satellite images, other period or site, are essential for efficient city modeling and analysis. However, the same ground objects have a radiometric inconsistency in different satellite images and it debase the quality of image processing and analysis. Moreover, in an urban area, buildings, trees, bridges, and other artificial objects cause shadow effects, which lower the performance of relative radiometric normalization. Therefore, in this study, we exclude shadow areas and suggest the selective histogram matching methods for image based application without supplementary digital elevation model or geometric informations of sun and sensor. We extract the shadow objects first using adjacency informations with the building edge buffer and spatial and spectral attributes derived from the image segmentation. And, Outlier objects like a asphalt roads are removed. Finally, selective histogram matching is performed from the shadow masked multi-temporal Quickbird-2 images.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.15 no.1
• /
• pp.48-52
• /
• 2005

In this paper, the spectral shape invariant real-time voice change method is proposed to change one's voice to mechanical voice. For this purpose, LPC analysis and synthesis is used to maintain the spectraum of voice and the pitch of synthesis speech can be changed freely. In the proposed method, gain matching method is applied to excitation signal generator to make the changed voice natural to hear. In order to evaluate the performance of the proposed method, voice change experiments were conducted. Experimental results showed that original speech signal is changed to the mechanical voice signal in which context of the speaker's voice is conveyed correctly in spite of drastic change of pitch. The system is implemented using TI TMS320C6711DSK board to verify the system runs in real time.

• Journal of the Korean Institute of Telematics and Electronics D
• /
• v.35D no.10
• /
• pp.1-6
• /
• 1998

The dielectric effects of plastic packages on GaAs($\varepsilon$$_{r}$=13) MMIC microstrip characteristics are analyzed using the spectral domain method (SDM). As being packaged by typical FR-4 composites ($\varepsilon$$_{r}$=14.2) for PCB substrates and plastic packages, the characteristic impedance is reduced by about 6 %, but the effective dielectric constant is increased by 13 % from those of bare microstrip, respectively. The parasitic effects of the packaging materials can greatly degrade the performance of the packaged MMIC. We also calculated the optimum microstrip width, which maintains the 50 $\Omega$ matching condition after plastic packaging. These calculated results can be used to optimize the plastic packages, and extend the application ranges for low cost MMIC production.n.

• Transactions on Electrical and Electronic Materials
• /
• v.3 no.4
• /
• pp.21-26
• /
• 2002

Color correction methods of chromaticity coordinates using Color Matching Function (CMF) were studied to develop a device-independent portable-type urine analyzer. The reflection spectra were measured for the degrees of 10 test items of the urine reagent strip (urine strip) to develop a portable-type urine analyzer. A computer simulation was performed to quantitatively distinguish the color reactions of the urine system, by using the spectral power distribution of Light Emitting Diode(LED), the reflection of a urine strip, and spectral sensitivity of a photodiode. To develop a device-independent system, chromaticity coordinates were modified to reduce the color deviations in the urine strip, by using the temperature compensation of LED and the color transformation by CMF. The experimental values obtained by developed urine system exhibited the accuracy above 95% for all color samples.

• Journal of the Earthquake Engineering Society of Korea
• /
• v.20 no.1
• /
• pp.9-19
• /
• 2016

Permanent deformation plays a key role in performance based earthquake resistant design. In order to estimate permanent deformation after earthquake, it is essential to secure reliable response history analysis(RHA) as well as earthquake scenario. This study focuses on permanent deformation of an inverted T-type wall under earthquake. The study is composed of two separate parts. The first one is on the verification of RHA and the second one is on an effect of input earthquake motion. The former is discussed in companion paper and the latter in this paper. In order to investigate the effect of an input earthquake motion on the permanent deformation, three bins of spectral matched real earthquake records with different magnitude, regions, epicentral distance are constructed. Parametric study was performed using the verified RHA through the companion paper for each earthquake records in the bins. The most influential parameter affecting permanent displacement is magnitude. The other parameters describing earthquake motion are not significant enough to increase permanent displacement of the inverted T-type wall except for energy related parameters(AI, CI, SEI).