High-resolution fMRI with higher-order generalized series imaging and parallel imaging techniques (HGS-parallel)

Yun, SungDae,Oh, Sung Suk,Han, Yeji,Park, HyunWook Wiley Subscription Services, Inc., A Wiley Company 2009 JOURNAL OF MAGNETIC RESONANCE IMAGING Vol.29 No.4

<B>Purpose</B><P>To develop a novel approach for high-resolution functional MRI (fMRI) using the conventional gradient-echo sequence.</P><B>Materials and Methods</B><P>Echo-planar imaging (EPI) techniques have generally been used for fMRI studies due to their fast imaging time. However, it is difficult for studying brain function at the submillimeter level using this sequence. In addition, EPI techniques have some drawbacks, such as Nyquist ghosts and geometric distortions in the reconstructed images, and subsequently require additional postprocessing to reduce these artifacts. One way of solving these problems is to acquire fMRI data by means of a conventional gradient-echo imaging sequence instead of EPI. To provide a fast imaging time, the proposed method combines higher-order generalized series (HGS) imaging with a parallel imaging technique which is called the HGS-parallel technique.</P><B>Results</B><P>The proposed HGS-parallel technique achieves a 12.8-fold acceleration in imaging time without the cost of spatial resolution. The proposed method was verified through the application of fMRI studies on normal subjects.</P><B>Conclusion</B><P>This study suggests that the proposed method can be used for high-resolution fMRI studies without the geometric distortion and the Nyquist ghost artifacts compared to EPI. J. Magn. Reson. Imaging 2009;29:924–936. © 2009 Wiley-Liss, Inc.</P>

저해상도 Multispectral 영상의 고해상도 재구축

이상훈 ( Sang Hoon Lee ) 大韓遠隔探査學會 2007 大韓遠隔探査學會誌 Vol.23 No.6

본 연구에서는 고해상도의 panchromatic 영상을 이용하여 저해상도의 multispectral 영상을 고해상도로 재구축하는 방법을 제시하고 있다. 제안된 방법은 저해상도와 고해상도 간의 선형 모형 사용하여 실제의 spectral 값에 부합하는 고해상도 영상을 재구축하며 두 단계로 이루어 진다. 첫 단계는 고해상도 feature와 연관된 저해상도의 선형 모형을 이용하여 최소 자승 오류 법에 의한 global 추정 과정이고 두 번째 단계는 재구축된 영상을 지역적으로 원래의 spectral 값과 일관되게 만드는 local 수정 과정이다. 본 연구에서 제안 방법을 이용하여 6m KOMPSAT-1 EOC 자료와 30m LANDSAT ETM+에 적용하였고 또한 IKONOS 1m RGB 영상 생성하였다. 실험 결과는 새로이 제시된 방법이 저해상도 Multispectral 영상의 고해상도 재구축에 탁월한 성능을 가지고 있음을 보여주었다. This study presents an approach to reconstruct high-resolution imagery for multispectral imagery of low-resolution using panchromatic imagery of high-resolution. The proposed scheme reconstructs a high-resolution image which agrees with original spectral values. It uses a linear model of high-and low-resolution images and consists of two stages. The first one is to perform a global estimation of the least square error on the basis of a linear model of low-resolution image associated with high-resolution feature, and next local correction then makes the reconstructed image locally fit to the original spectral values. In this study, the new method was applied to KOMPSAT-1 EOC image of 6m and LANDSAT ETM+ of 30m, and an 1m RGB image was also generated from 4m IKONOS multispectral data. The results show its capability to reconstruct high-resolution imagery from multispectral data of low-resolution.

High-Resolution Satellite Image Super-Resolution Using Image Degradation Model with MTF-Based Filters

정민경,정민영,김용일 대한원격탐사학회 2023 大韓遠隔探査學會誌 Vol.39 No.4

Super-resolution (SR) has great significance in image processing because it enables downstreamvision tasks with high spatial resolution. Recently, SR studies have adopted deep learning networks and achievedremarkable SR performance compared to conventional example-based methods. Deep-learning-based SR modelsgenerally require low-resolution (LR) images and the corresponding high-resolution (HR) images as trainingdataset. Due to the difficulties in obtaining real-world LR-HR datasets, most SR models have used only HRimages and generated LR images with predefined degradation such as bicubic downsampling. However, SRmodels trained on simple image degradation do not reflect the properties of the images and often result indeteriorated SR qualities when applied to real-world images. In this study, we propose an image degradationmodel for HR satellite images based on the modulation transfer function (MTF) of an imaging sensor. Becausethe proposed method determines the image degradation based on the sensor properties, it is more suitable fortraining SR models on remote sensing images. Experimental results on HR satellite image datasets demonstratedthe effectiveness of applying MTF-based filters to construct a more realistic LR-HR training dataset.

A High-Lateral Resolution MALDI Microprobe Imaging Mass Spectrometer Utilizing an Aspherical Singlet Lens

한상윤,Hwan Jin Kim,Tae Kyung Ha 대한화학회 2013 Bulletin of the Korean Chemical Society Vol.34 No.1

We report the construction of a MALDI imaging mass spectrometer equipped with a specially designed laser focusing lens, a compact aspherical singlet lens, that obtains a high-lateral imaging resolution in the microprobe mode. The lens is specially designed to focus the ionization laser (λ = 355 nm) down to a 1 μm diameter with a long working distance of 34.5 mm. With the lens being perpendicular to the sample surface and sharing the optical axis with the ion path, the imaging mass spectrometer achieved an imaging resolution of as good as 5 μm along with a high detection sensitivity of 100 fmol for peptides. The mass resolution was about 900 (m/ Δm) in the linear TOF mode. The high-resolution capability of this instrument will provide a new research opportunity for label-free imaging studies of various samples including tissues and biochips, even for the study at a single cell level in the future.

벡터자료를 이용한 고해상도 위성영상의 토지피복 분류기법에 관한 연구

구자용,장호연 국토지리학회 2006 국토지리학회지 Vol.40 No.3

After the launch of the high resolution image satellite, many methods have been developed to extract the geographic information from high resolution images. However, as the high resolution image has strong spectral variance, current pixel based classification does not work efficiently. The alternative is the field based classification which groups pixels of image by integrating vector polygon data from a GIS database. This method is called per-field classification. This study aims to explore the per-field classification which integrates the high resolution images and vector polygon data and to apply it to the IKONOS image and digital land data. The results of this study prove that the field based classification can be a good alternative of the pixel based classification. In addition, the first classification - later integration seems to work better than the first integration - later classification in terms of accuracy and efficiency. 고해상도 위성이 등장한 이후 이들 영상으로부터 지리정보를 추출하기 위한 다양한 기법이 개발되어 왔다. 그러나 고해상도 영상은 분광변이가 심하기 때문에 기존의 화소기반 분류로는 분류계급을 효과적으로 표현할 수 없다. 고해상도 영상의 경우, 최소단위를 화소로 하는 화소기반 분류보다는 벡터자료에서 추출한 면단위로 분할된 GIS 데이터를 이용하면 분류 정확도가 향상될 수 있다. 본 연구에서는 고해상도 위성영상과 벡터자료를 통합하는 기법인 선통합 후분류 기법과 선분류 후통합 기법을 파악하고 실제의 자료에 적용하여 그 결과를 비교평가하였다. 그 결과 고해상도 위성영상 분류에 있어서 벡터자료를 이용한 분류기법이 화소단위의 분류기법이 가지는 문제점을 보완할 수 있었다. 벡터자료를 통합하는 기법들을 비교한 결과 선분류 후통합 기법이 처리가 용이하면서도 분류정확도가 높은 기법으로 판명되었다.

Ultra-high-resolution SPECT with CdTe for Small-animal Imaging Applications: A Monte Carlo Simulation Study Using A Voxelized Phantom

박수진,이창래,조효민,김희중 한국물리학회 2012 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.60 No.7

Single-photon-emission computed tomography (SPECT) using a pixelated cadmium-telluride (CdTe) detector is a promising technology for high-resolution, small animal imaging. To test the feasibility of our ultra-high-resolution SPECT system with CdTe, we compared the quality of reconstructed images from our SPECT system to those from a conventional small animal SPECT system with a NaI(Tl) detector. The CdTe detector had 0.35 mm × 0.35 mm² pixels, which was similar to the pixel sizes of the available CdTe detector (PID350, AJAT, Finland). The CdTe detector was 44.8 × 44.8 mm² with 128 pixels × 128 pixels and was 1-mm thick. The intrinsic resolutions of CdTe and NaI(Tl) were 0.35 mm and 2.3 mm, respectively. The parallel hole collimator of lead was 25-mm high, and the septum was 0.2-mm high. The parallel hole collimator was hexagonal with a 0.5-mm radius. A SPECT liver scan of a voxelized mouse whole-body (MOBY) phantom was simulated using both our system with CdTe and a conventional system. All SPECT images were obtained using 120 projection views acquired from 0˚ to 360˚ in 3˚ steps. Slices were reconstructed using an ordered subsets expectation maximization (OS-EM) with 5 iterations and 4 subsets. We compared the quality of the images from each system in terms of spatial resolution (FWHM), sensitivity, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR). Our results indicated that the CdTe detector generated reconstructed SPECT images with higher resolution than the conventional scintillation detector. These results demonstrate that SPECT imaging using a pixelated CdTe detector can improve the performance of SPECT systems for small-animal imaging.

A High-Lateral Resolution MALDI Microprobe Imaging Mass Spectrometer Utilizing an Aspherical Singlet Lens

Han, Sang Yun,Kim, Hwan Jin,Ha, Tae Kyung Korean Chemical Society 2013 Bulletin of the Korean Chemical Society Vol.34 No.1

We report the construction of a MALDI imaging mass spectrometer equipped with a specially designed laser focusing lens, a compact aspherical singlet lens, that obtains a high-lateral imaging resolution in the microprobe mode. The lens is specially designed to focus the ionization laser (${\lambda}$ = 355 nm) down to a $1{\mu}m$ diameter with a long working distance of 34.5 mm. With the lens being perpendicular to the sample surface and sharing the optical axis with the ion path, the imaging mass spectrometer achieved an imaging resolution of as good as $5{\mu}m$ along with a high detection sensitivity of 100 fmol for peptides. The mass resolution was about 900 (m/${\Delta}m$) in the linear TOF mode. The high-resolution capability of this instrument will provide a new research opportunity for label-free imaging studies of various samples including tissues and biochips, even for the study at a single cell level in the future.

고해상도 영상에서 기준점 개수에 따른 정확도 평가에 관한 연구

최현,김기홍,박홍기 한국산업융합학회 2018 한국산업융합학회 논문집 Vol.21 No.6

The high-resolution satellite images provided by Kompsat-3A, a multipurpose satellite, have various applications such as digital map generation, 3D image generation, and DEM generation. In order to utilize high-resolution satellite images, the user must create an orthoimage in order to use the image in a suitable manner. The position and the number of the ground reference points affect the accuracy of the orthoimage. In particular, the Kompsat-3A satellite image has a high resolution of about 0.5m, so the difficulty in selecting the ground control points and the accuracy of the selected point will have a great influence on the subsequent application process. Therefore, in this study, we analyzed the influence of the number of ground reference points on the accuracy of the terrestrial satellite images. The high-resolution satellite images provided by Kompsat-3A, a multipurpose satellite, have various applications such as digital map generation, 3D image generation, and DEM generation. In order to utilize high-resolution satellite images, the user must create an orthoimage in order to use the image in a suitable manner. The position and the number of the ground reference points affect the accuracy of the orthoimage. In particular, the Kompsat-3A satellite image has a high resolution of about 0.5m, so the difficulty in selecting the ground control points and the accuracy of the selected point will have a great influence on the subsequent application process. Therefore, in this study, we analyzed the influence of the number of ground reference points on the accuracy of the terrestrial satellite images.

PAN-SHARPENED 고해상도 다중 분광 자료의 영상 복원과 분할

이상훈 대한원격탐사학회 2017 大韓遠隔探査學會誌 Vol.33 No.6

Multispectral image data of high spatial resolution is required to obtain correct information on the ground surface. The multispectral image data has lower resolution compared to panchromatic data. PAN-sharpening fusion technique produces the multispectral data with higher resolution of panchromatic image. Recently the object-based approach is more applied to the high spatial resolution data than the conventional pixel-based one. For the object-based image analysis, it is necessary to perform image segmentation that produces the objects of pixel group. Image segmentation can be effectively achieved by the process merging step-by-step two neighboring regions in RAG (Regional Adjacency Graph). In the satellite remote sensing, the operational environment of the satellite sensor causes image degradation during the image acquisition. This degradation increases variation of pixel values in same area, and results in deteriorating the accuracy of image segmentation. An iterative approach that reduces the difference of pixel values in two neighboring pixels of same area is employed to alleviate variation of pixel values in same area. The size of segmented regions is associated with the quality of image segmentation and is decided by a stopping rue in the merging process. In this study, the image restoration and segmentation was quantitatively evaluated using simulation data and was also applied to the three PAN-sharpened multispectral images of high resolution: Dubaisat-2 data of 1m panchromatic resolution from LA, USA and KOMPSAT3 data of 0.7m panchromatic resolution from Daejeon and Chungcheongnam-do in the Korean peninsula. The experimental results imply that the proposed method can improve analytical accuracy in the application of remote sensing high resolution PAN-sharpened multispectral imagery. 지표면의 공간 정보를 정확히 추출하기 위해서는 고 해상도의 다중 분광 영상 자료를 사용할 필요가 있다. 범색 영상에 비해 상대적으로 낮은 공간 해상도를 갖는 다중 분광 자료의 해상도를 범색 영상 급으로 높이기 위해 PAN-sharpening 융합 기술을 사용한다. 이러한 고해상도 자료를 분석하기 위해서는 화소 기반보다는 객체 기반 분석이 주목을 받고 있다. 객체 기반 영상 분석을 위해서 영상을 구성하는 화소들의집단으로 영상 객체를 생성하는 영상 분할 과정이 선행되어야 한다. RAG(Regional Adjancy Graph)에 의해 형성된 인접 지역을 합병하는 지역 확장을 통해 효과적으로 영상 분할을 할 수 있다. 위성 원격 탐사에서불 완전한 관측 환경으로 수집한 영상 자료에 질 저하가 일어 난다. 정확한 영상 분할을 위해서 동일 지역으로 관측된 분광 값의 변이가 최소화되도록 질의 개선이 필요하다. 동일 지역에 속하는 공간적으로 인접한 이웃들의 화소 값과 차이를 반복적으로 줄여 나가는 과정을 통해 동일 지역에서의 화소 값의 변이를 감소시킬수 있다. 영상 객체를 단위로 사용하는 영상 분류에서 오류를 감소시키기 위해 영상 분할 결과에서 적정한분할 지역 크기를 생성하여야 한다. 분할 지역 크기는 지역 확장 과정에서 합병을 중지하는 단계에 의해 정해지므로 중지 규칙은 영상 분할 결과의 품질을 결정한다. 본 연구에서는 모의 자료 실험을 통하여 분할의정확성에 대해 정량적 평가를 실시하였으며 3개의 PAN-sharpened 고해상도 다중 분광 영상 자료에 대해적용하여 복원의 효과에 대해 실험하였다. 실제 자료의 분석에서는 중지 규칙과 관련된 분할 지역 크기에 대해 정성적으로 평가 하였다. 사용된 원격 탐사 자료는 1m급의 미국 LA지역에서 수집된 Dubaisat-2 자료와0.7 m급의 한반도 대전 지역과 충청남도 지역에서 각각 수집된 KOMPSAT-3 자료이다. 실험 결과는 영상복원은 PAN-sharpened 고해상도 다중 분광 자료의 영상 분할 결과의 정확성을 상당히 제고시킬 수 있다는 것을 보여준다.

Making the Tool and Construct DB for Face Image of High Resolution

전병태 한국지식정보기술학회 2015 한국지식정보기술학회 논문지 Vol.10 No.4

Recently studies for commercializing robot have been actively conducted while robots are being used in various area such as military, medical and education. Since the end of 1970s when welding robot was imported from abroad, robots have been applied to industry sites along with technology development centered on robots in manufacturing industry as major industries like automobile, electronics and semiconductor have grown up. Before selling robot products in the market, appraisal and verification of its performance should be completed. Studies on way of evaluating face recognition performance by intelligent robots have been conducted a lot. High resolution image LED monitor printing is appraised to be the best evaluation model. In order to use face recognition performance evaluation method, images DB of high resolution are necessary. It’s because face images similar to real face can be obtained only when face image of high resolution is printed out in high resolution LED monitor. Most of existing face images constructed in DB is low definition face images and we can say we can’t use this DB because there is much difference from real face when it is printed out in the monitor. This thesis will describe how to produce tool and DB for high resolution face images. The result of experiment shows high resolution image DB can be created.