• Journal of the Institute of Electronics Engineers of Korea SP
• /
• v.44 no.6
• /
• pp.1-8
• /
• 2007

In this paper, research on joint optimization of the image spatial registration and the exposure compensation is conducted. The exposure compensation is performed in a frame work of the intensity compensation based on the polynomial approximation of the relationship between images. This compensation is jointly combined with the registration problem employing the Gauss-Newton nonlinear optimization method. In this paper, to perform for a simple and stable optimization, the block-coordinate method is combined with the Gauss-Newton optimization and extensively compared with the traditional approaches. Furthermore, regression analysis is considered in the compensation part for a better stable performance. By combining the block-coordinate method with the Gauss-Newton optimization, we can obtain a compatible performance reducing the computational complexity and stabilizing the performance. In the numerical result for a particular image, we obtain a satisfactory result for 10 repeats of the iteration, which implies a 50% reduction of the computational complexity. The error is also further reduced by 1.5dB compared to the ordinary method.

• Journal of The Korean Astronomical Society
• /
• v.50 no.5
• /
• pp.139-149
• /
• 2017

The Korea Astronomy and Space Science Institute plans to develop a coronagraph in collaboration with National Aeronautics and Space Administration (NASA) and to install it on the International Space Station (ISS). The coronagraph is an externally occulted one-stage coronagraph with a field of view from 3 to 15 solar radii. The observation wavelength is approximately 400 nm, where strong Fraunhofer absorption lines from the photosphere experience thermal broadening and Doppler shift through scattering by coronal electrons. Photometric filter observations around this band enable the estimation of 2D electron temperature and electron velocity distribution in the corona. Together with a high time cadence (<12 min) of corona images used to determine the geometric and kinematic parameters of coronal mass ejections, the coronagraph will yield the spatial distribution of electron density by measuring the polarized brightness. For the purpose of technical demonstration, we intend to observe the total solar eclipse in August 2017 with the filter system and to perform a stratospheric balloon experiment in 2019 with the engineering model of the coronagraph. The coronagraph is planned to be installed on the ISS in 2021 for addressing a number of questions (e.g., coronal heating and solar wind acceleration) that are both fundamental and practically important in the physics of the solar corona and of the heliosphere.

• The Bulletin of The Korean Astronomical Society
• /
• v.39 no.1
• /
• pp.35.2-35.2
• /
• 2014

Today, it is widely accepted that dense environments tend to accelerate galaxy evolution. However, according to recent studies, the environments where galaxies evolve most considerably are galaxy groups rather than galaxy clusters. In an isolated group, the central host galaxy and its satellites co-evolve and interact with each other; as a result, they tend to have similar properties. Such conformity between host and satellite galaxies are relatively well known in galaxy groups, but it is hardly studied what happens after such galaxy groups merge into a galaxy cluster. Recently, J. H. Lee et al. (2014) have found that the colors of bright galaxies in WHL J085910.0+294957, a galaxy cluster at z = 0.3, show a measurable correlation with the mean colors of faint companions around them, which may be the vestige of infallen groups in the cluster. As a follow-up study, we explore more galaxy clusters, Abell 3659 and Abell 1146 at z ~ 0.1, using deep images obtained from the Magellan (Baade) 6.5-m telescope. Cluster members are selected based on the distributions of color, size and concentration along magnitude and spatial distribution. We investigate the dependence of the mean colors of faint companion galaxies on local environments and the properties of adjacent bright galaxies. After comparing the results with those in J. H. Lee et al. (2014), we discuss the origin of the relationships between bright galaxies and their faint companions based on their dependence on cluster properties.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.18 no.6
• /
• pp.1355-1360
• /
• 2014

In this paper, we apply the learning of the mobile robot insect augmented reality Digilog Book. In the era of electronic, book written in paper space just have moved to virtual reality space. The virtual reality, constraints spatial and physical, in the real world, it is a technique that enables to experience indirectly situation not experienced directly as user immersive experience type interface. Applied to the learning robot Digilog Book that allows the fusion of paper analog and digital content, using the augmented reality technology, to experience various interactions. Apply critical elements moving, three-dimensional images and animation to enrich the learning, for easier block assembly, designed to grasp more easily rank order between the blocks. Anywhere at any time, is capable of learning of the robot in Digilog Book to be executed by the mobile phone in particular.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.20 no.10
• /
• pp.2001-2006
• /
• 2016

The stereo radiation detection system detects the gamma source and acquires two dimensional left and right images for gamma source and visible objects using the detection result. And then the system measures the distance to the radiation source from the system in 3D space using stereo vision algorithm. In this paper, we implemented the fast detection algorithm for gamma source from the system in 3D space to reduce the detection time with image processing algorithms. Additionally, the system's performance is verified through experiments on gamma irradiation facilities. As a result, if the fast detection algorithm applied to the system, we can confirm that the detection system represents a 35% better performance than the conventional detection method that is full scanning to acquire the stereo image. We also have visualized a gamma source distribution through a 3D monitor using the stereo vision algorithm in order to provide the information of radiation spatial distribution to the user efficiently.

• The Transactions of the Korea Information Processing Society
• /
• v.2 no.5
• /
• pp.691-700
• /
• 1995

Most fractal image codings using fractal concept require long encoding time because a large amount of computation is needed to find an optimal affine transformation point. Such a problem can be solved by designing a block classifier fitted to characteristics of image blocks. In general, it is possible to predict more precise and various types of blocks in frequency domain than in spatial domain. In this paper, we propose a block classifier to predict the block type using characteristics of DCT(Discrete Cosine Transform). This classifier has merits to enhance the quality of decoded images as well as to reduce the encoding time meeting fractal features. AC coefficient values in frequency domain make it possible to predict various types of blocks. As the results, the number of comparisons between a range block and the correspoding domain blocks to reach an optimal affine transformation point can be reduced. Specially, signs of DCT coefficients help to find the optimal affine transformation point with only two isometric transformations by eliminating unnecessary isometric transformations among eight isometric transformations used in traditional fractal codings.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.29 no.4C
• /
• pp.533-540
• /
• 2004

This paper proposes a new multispectral image data compression algorithm that can efficiently reduce spatial and spectral redundancies by applying classified prediction, a Karhunen-Loeve transform (KLT), and the three-dimensional set partitioning in hierarchical trees (3-D SPIHT) algorithm in the wavelet transform (WT) domain. The classification is performed in the WT domain to exploit the interband classified dependency, while the resulting class information is used for the interband prediction. The residual image data on the prediction errors between the original image data and the predicted image data is decorrelated by a KLT. Finally, the 3-D SPIHT algorithm is used to encode the transformed coefficients listed in a descending order spatially and spectrally as a result of the WT and KLT. Simulation results showed that the reconstructed images after using the proposed algorithm exhibited a better quality and higher compression ratio than those using conventional algorithms.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
• /
• 1995.12a
• /
• pp.22-32
• /
• 1995

The purpose of this study is to estimate not only the watershed soil loss but also its temporal changes of Kyungan River basin, the study area, due to the land development. To analyze the soil loss of the river basin, USLE was employed. GIS and remote sensing were also utilized to estimate the soil loss. The data for this analysis consist of a series of thematic map and remotely sensed data. The remotely sensed images for this study are Landsat TM(Oct, 28, 1997 & Sep. 22, 1992), In Kyungan River basin, not only the detection of temporal changes of land use and GVI, but also the estimation of soil loss provided very significant factors that affect to the watershed environment quality. The management of the factors of vegetative cover, slope steepness and length were the keys to reduce soil loss and solve conservation and protection issues of Kyungan River basin. GIS application with USLE to the watershed analysis allows the planner to recognize sensitive sites and to plan strategies to minimize soil loss.

• Geomechanics and Engineering
• /
• v.7 no.4
• /
• pp.375-401
• /
• 2014

It is generally accepted that material heterogeneity has a great influence on the deformation, strength, damage and failure modes of rock. This paper presents numerical simulation on rock failure process based on the characterization of rock heterogeneity by using a digital image processing (DIP) technique. The actual heterogeneity of rock at mesoscopic scale (characterized as minerals) is retrieved by using a vectorization transformation method based on the digital image of rock surface, and it is imported into a well-established numerical code Rock Failure Process Analysis (RFPA), in order to examine the effect of rock heterogeneity on the rock failure process. In this regard, the numerical model of rock could be built based on the actual characterization of the heterogeneity of rock at the meso-scale. Then, the images of granite are taken as an example to illustrate the implementation of DIP technique in simulating the rock failure process. Three numerical examples are presented to demonstrate the impact of actual rock heterogeneity due to spatial distribution of constituent mineral grains (e.g., feldspar, quartz and mica) on the macro-scale mechanical response, and the associated rock failure mechanism at the meso-scale level is clarified. The numerical results indicate that the shape and distribution of constituent mineral grains have a pronounced impact on stress distribution and concentration, which may further control the failure process of granite. The proposed method provides an efficient tool for studying the mechanical behaviors of heterogeneous rock and rock-like materials whose failure processes are strongly influenced by material heterogeneity.

• Investigative Magnetic Resonance Imaging
• /
• v.19 no.2
• /
• pp.67-75
• /
• 2015

Purpose: To investigate the value of image post-processing software (FreeSurfer, IBASPM [individual brain atlases using statistical parametric mapping software]) and inversion time (TI) in volumetric analyses of the hippocampus and to identify differences in comparison with manual tracing. Materials and Methods: Brain images from 12 normal adults were acquired using magnetization prepared rapid acquisition gradient echo (MPRAGE) with a slice thickness of 1.3 mm and TI of 800, 900, 1000, and 1100 ms. Hippocampal volumes were measured using FreeSurfer, IBASPM and manual tracing. Statistical differences were examined using correlation analyses accounting for spatial interpretations percent volume overlap and percent volume difference. Results: FreeSurfer revealed a maximum percent volume overlap and maximum percent volume difference at TI = 800 ms ($77.1{\pm}2.9%$) and TI = 1100 ms ($13.1{\pm}2.1%$), respectively. The respective values for IBASPM were TI = 1100 ms ($55.3{\pm}9.1%$) and TI = 800 ms ($43.1{\pm}10.7%$). FreeSurfer presented a higher correlation than IBASPM but it was not statistically significant. Conclusion: FreeSurfer performed better in volumetric determination than IBASPM. Given the subjective nature of manual tracing, automated image acquisition and analysis image is accurate and preferable.