• Korean Journal of Remote Sensing
• /
• v.26 no.5
• /
• pp.465-475
• /
• 2010

Spectral library is a database that archives spectral reflectance and related metadata of earth surface materials. Spectral library plays important role to assist analyzing several types of remote sensor data, to determine suitable wavelength band for detecting a certain material, and to classify hyperspectal image data. This paper describes the structure and content of a spectral library that is suitable for the environment of the Korea peninsula while existing spectral libraries have certain limitations to apply for surface materials covering the region. We designed a spectral library that includes vegetation and man-made materials indigenous to the region. The spectral library also includes spectra of mineral and rock, soil, liquid, and some man-made materials from existing spectral libraries. Newly augmented spectra of vegetation and man-made materials were obtained by spectral measurements in laboratory and field. The spectral library viewer was developed to increase efficiency of usage and searching.

• Korean Journal of Remote Sensing
• /
• v.34 no.4
• /
• pp.649-659
• /
• 2018

The aim of this study is to develop a protocol for obtaining spectral signals that are robust to varying lighting conditions, which are often found in the Polar regions, for creating a spectral library specific to those regions. Because hyperspectral image (HSI)-derived spectra are collected on the same scale as images, they can be directly associated with image data. However, it is challenging to find precise and robust spectra that can be used for a spectral library from images taken under different lighting conditions. Hence, this study proposes a new radiometric calibration protocol that incorporates radiometric targets with a traditional vicarious calibration approach to solve issues in image-based spectrum measurements. HSIs obtained by the proposed method under different illumination levels are visually uniform and do not include any artifacts such as stripes or random noise. The extracted spectra capture spectral characteristics such as reflectance curve shapes and absorption features better than those that have not been calibrated. The results are also validated quantitatively. The calibrated spectra are shown to be very robust to varying lighting conditions and hence are suitable for a spectral library specific to the Polar regions.

• Korean Journal of Remote Sensing
• /
• v.21 no.5
• /
• pp.405-415
• /
• 2005

It is difficult to classify tidal flat surface that is composed of a mixture of mud, sand, water and microphytobenthos. We used a Linear Spectral Unmixing (LSU) method for effectively classifying the tidal flat surface characteristics within a pixel. This study aims at 1) detecting algal mat using LSU in the Saemangeum tidal flats, 2) determining a suitable end-member selection method in tidal flats, and 3) find out a habitual characteristics of algal mat. Two types of end-member were built; one is a reference end-member derived from field spectrometer measurements and the other image end-member. A field spectrometer was used to measure spectral reflectance, and a spectral library was accomplished by shape difference of spectra, r.m.s. difference of spectra, continuum removal and Mann-Whitney U-test. Reference end-members were extracted from the spectral library. Image end-members were obtained by applying Principle Component Analysis (PCA) to an image. The LSU method was effective to detect microphytobenthos, and successfully classified the intertidal zone into algal mat, sediment, and water body components. The reference end-member was slightly more effective than the image end-member for the classification. Fine grained upper tidal flat is generally considered as a rich habitat for algal mat. We also identified unusual microphytobenthos that inhabited coarse grained lower tidal flats.

• Journal of Cadastre & Land InformatiX
• /
• v.51 no.2
• /
• pp.169-184
• /
• 2021

Recently, land cover spectral libraries have been widely used in studies to classify land cover based on hyperspectral images. Overseas, various institutions have built and provided land cover spectral libraries, but in Korea, the building and provision of land cover spectral libraries is insufficient. Against this background, the purpose of this study is to suggest the possibility of using domestic and foreign spectral libraries in the classification studies of domestic land cover. Band matching is required for comparative analysis of the spectral libraries and land cover classification using the spectral libraries, and in this study, an automation logic to automatically perform this is presented. In addition, the directly constructed domestic land cover spectral library and the existing overseas land cover spectral library were comparatively analyzed. As a result, the directly constructed land cover spectral library had the highest correlation coefficient of 0.974. Finally, for the accuracy evaluation, aerial hyperspectral images of the study area were supervised and classified using the domestic and foreign land cover spectral libraries using the SAM technique. As a result of the accuracy evaluation, it is judged that Soils, Artificial Materials, and Coatings among the classification items of the foreign land cover spectral library can be sufficiently applied to classify the cover in Korea.

• Journal of Cadastre & Land InformatiX
• /
• v.46 no.2
• /
• pp.239-251
• /
• 2016

Hyperspectral image is widely used for land cover classification because it has a number of narrow bands and allow each pixel to include much more information in comparison with previous multi-spectral image. However, Higher spectral resolution of hyperspectral image results in an increase in data volumes and a decrease in noise efficiency. SAM(Spectral Angle Mapping), a method based on vector inner product to compare spectrum distribution, is a highly valuable and popular way to analyze continuous spectrum of hyperspectral image. SAM is shown to be less accurate when it is used to analyze hyperspectral image for land cover classification using spectral library. this inaccuracy is due to the effects of atmosphere. We suggest a decision tree based method to compensate the defect and show that the method improved accuracy of land cover classification.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.13 no.3
• /
• pp.623-632
• /
• 2018

The object of this study is the effective utilizations of river environment management technology in the area of river reservoir water by using the technique to detect locations, and to develop algorithms on floating debris. In the floating debris detection areas(The section between the stanks of Dalsung and Gangjung-Goryeong), spectral reflections were measured on floating debris around the river: vegetation(grassland, trees), artifact(concrete, structure etc.), stream water(fresh water, turbid water, algal bloom), and simultaneously characteristics of spectral library were analyzed to river floating debris, respectively.

• The Bulletin of The Korean Astronomical Society
• /
• v.40 no.1
• /
• pp.71.2-71.2
• /
• 2015

We present the high-resolution near-infrared spectra of standard stars observed with Immersion Grating Infrared Spectrograph (IGRINS). IGRINS covers the full spectral range of H and K bands simultaneously with a high spectral resolution (R=40,000), revealing many previously undetected and/or unknown lines. In this work, we present preliminary results of spectroscopic diagnostics for stellar physical parameters. Our ultimate goal is to provide a library of near-infrared spectra of standard stars, which covers all spectral types and luminosity classes, with a high-resolution and high signal to noise ratio ($SNR{\geq}200$).

• Mass Spectrometry Letters
• /
• v.9 no.3
• /
• pp.73-76
• /
• 2018

The number of matched peaks (NMP) is estimated as the spectral similarity measure in tandem mass spectral library searches of small molecules. In the high resolution mode, NMP provides the same reliable identification as in the case of a common dot-product function. Corresponding true positive rates are ($94{\pm}3$) % and ($96{\pm}3$) %, respectively.

• Journal of Environmental Science International
• /
• v.33 no.7
• /
• pp.533-546
• /
• 2024

The coastal urchin barren phenomenon in our country began to spread and expand from the 1980s, centering on the southern coast and Jeju Island, and by the 1990s, it appeared along the east coast and nationwide. The urchin barren phenomenon is mainly conducted through field surveys by diving, but recently, various surveying techniques have been applied. In this study, a spectral library for terrestrial and marine areas was established for the identification of urchin barrens using airborne hyperspectral imagery, and the distribution area was analyzed through the SAM (spectral angle mapper) algorithm. An analysis of the urchin barren phenomenon in the five islands of the West Sea revealed that it occurrs in most areas, with the combined severity of the urchin barren phenomenon in Sapsido and Oeyeondo being approximately 19.9%. Hyperspectral imagery is expected to be highly useful not only for detecting the urchin barren phenomenon but also for managing and monitoring marine fishery resources through the classification of seaweeds.

• The Bulletin of The Korean Astronomical Society
• /
• v.40 no.2
• /
• pp.58.2-58.2
• /
• 2015

We present a library of high spectral resolution (R ~ 40,000) and high signal-to-noise ratio (S/N ~ 200) near-infrared spectra of ~50 late-type stars. The spectra of late-type stars were obtained with Immersion GRating INfrared Spectrograph (IGRINS) covering the full H and K band. The stars are mainly from MK standard stars which have well-defined spectral types and luminosity classes and cover wide ranges of effective temperatures and surface gravities. The spectra are corrected for telluric absorption lines and absolutely flux calibrated using the Two Micron All Sky Survey (2MASS) photometry. In this work, we present the preliminary results of spectroscopic diagnostics for stellar physical parameters. Our ultimate goal is to provide a library of near-infrared spectra of standard stars, which covers all spectral types and luminosity classes, with a high spectral resolution and high signal-to-noise ratio.