Determination of an Optimized Weighting Factor of Liver Parenchyma for Six-point Interference Dixon Fat Percentage Imaging Accuracy in Nonalcoholic Fatty Liver Disease Rat Model

Lee, Onseok,Lee, Suk-Jun,Yu, Seung-Man Elsevier 2018 Academic radiology Vol.25 No.12

<P><B>Rationale and Objectives</B></P> <P>The aim of this study was to determine the optimal weighting factor (WF) for precise quantification using six-point interference Dixon fat percentage imaging by analyzing changes in WFs of fatty acid metabolites (FMs) in high-fat-induced fatty liver disease rat model.</P> <P><B>Materials and Methods</B></P> <P>Individual FM-related WFs were calculated based on concentration ratios of integrated areas of seven peak FMs with four phantom series. Ten 8-week-old male Sprague-Dawley rats were used for baseline quantification of fat in liver magnetic resonance imaging or magnetic resonance spectroscopy data. These seven lipid metabolites were then quantitatively analyzed. Spearman test was used for correlation analysis of different lipid proton concentrations. The most accurate WF for six-point interference Dixon fat percentage imaging was then determined.</P> <P><B>Results</B></P> <P>The seven lipid resonance WF values obtained from magnetic resonance spectroscopy data for three different oils (oleic, linoleic, and soybean) were different from each other. In lipid phantoms, except for the phantom containing oleic acid, changes in FP values were significantly different when WFs were changed in six-point interference Dixon fat percentage image. The seven lipid resonance WF values for the nonalcoholic fatty liver animal model were different from human subcutaneous adipose tissue lipid WF values.</P> <P><B>Conclusions</B></P> <P>WF affected the calculation of six-point interference Dixon-based fat percentage imaging value in phantom experiment. If WF of liver parenchyma FM which is specific to each liver disease is applied, the accuracy of six-point interference Dixon fat percentage imaging can be further increased.</P>

Phase‐contrast hard X‐ray microscopy using synchrotron radiation for the diagnosis of onychomycosis

Lee, Onseok,Ha, Seunghan,Lee, Gunwoo,Kim, Jaeyoung,Huang, Jungyun,Jin, Kyeongsik,Oh, Chilhwan Wiley Subscription Services, Inc., A Wiley Company 2010 Microscopy research and technique Vol.73 No.12

<P><B>Abstract</B></P><P>Onychomycosis, or fungal infection of the nail, is a disease seen frequently in clinical settings. However, the rates of positive identification using potassium hydroxide preparations or fungal cultures are relatively low. Precise diagnosis is possible via histopathologic examination to monitor the existence of fungus and performance of a fungal culture for confirmation. Phase‐contrast hard X‐ray microscopy using synchrotron radiation provides 70‐nm spatial resolution and enables imaging of minute internal cellular structures. This study confirms the feasibility of diagnosing onychomycosis using a phase‐contrast hard X‐ray microscope developed at 1B2 beam line using a Pohang light source. Microsc. Res. Tech. 73:1110–1114, 2010. © 2010 Wiley‐Liss, Inc.</P>

A study of a method for distribution analysis of skin color

Ha, Seunghan,Lee, Minhee,Lee, Onseok,Lee, Gunwoo,Kim, Jeayoung,Moon, Jongsub,Kim, Mingi,Oh, Chilhwan Blackwell Publishing Ltd 2009 SKIN RESEARCH AND TECHNOLOGY Vol.15 No.2

<P>Background/aims</P><P>The objective and quantitative assessment of the skin is important in medical and cosmeceutical research. Assessment of color is an important element for analyzing the surface of the skin, which is usually determined subjectively by a doctor or using color analysis devices. These devices, however, cannot provide correct color information because color is construed from the mean value of the observation region, and analysis of color distribution is impossible. The purpose of this paper is to develop an objective analysis method to permit skin color measurement of each pixel unit of an image and analyze the distribution of skin surface color.</P><P>Methods</P><P>The Skin Color Distribution Analyzer (SCDA) is an analysis method newly developed at the Research Institute for Skin Image at Korea University. The SCDA system presented in this paper performed a novel form of quantitative and objective analysis of skin color distribution using each pixel color model parameter found in image wavelength information.</P><P>In this paper, distribution analysis was conducted on normal skin and skin lesions and skin affected by artificially induced irritant contact dermatitis and pigmented nevous. The method selected a grade using a color model parameter. Twenty healthy Korean males participated in this study. A comparative study of the eight anatomical areas was performed, including the exposure and non-exposure parts and the medial aspect and the lateral aspect of the forearm. A reliability test for the SCDA system was also conducted with a spectrometer (SPEC) using the color analysis method.</P><P>Results</P><P>Each skin lesion was precisely segmented by grade and each parameter hada different statistical significance for results of analysis of distribution in pigmented nevous and the artificially induced irritant contact dermatitis. Parameters <I>L</I><SUP>*</SUP>, <I>b</I><SUP>*</SUP>, <I>a</I><SUP>*</SUP>, and EI showed salient traits. Showed resemble measured result in the SCDA system and the SPEC of normal skin. The exposed site, in comparison with the non-exposed site, showed a notable difference in the <I>L</I><SUP>*</SUP> parameter and a significant statistical difference in the <I>x</I> and <I>z</I> parameters, except <I>b</I><SUP>*</SUP>. The comparison of the medial and lateral aspects of the forearm showed a notable difference in the <I>L</I><SUP>*</SUP> parameter and a significant statistical difference in the parameters except <I>y</I> and <I>b</I><SUP>*</SUP>. In the reliability test result using the SCDA system and the SPEC, the SCDA system was highly reliabile in terms of the CV value in all color model parameters.</P><P>Conclusions</P><P>The color distribution analysis method using the SCDA system has revealed an aspect that the existent method of medical research has not shown, and is considered to be more reliable than other methods. This method can provide better study findings because it can be applied to other fields in addition to the medical science field and the ripple effect is thought to be bigger in other science field too.</P>

Development of the Korean Handwriting Assessment for Children Using Digital Image Processing

( Cho Hee Lee ),( Eun Bin Kim ),( Onseok Lee ),( Eun Young Kim ) 한국인터넷정보학회 2019 KSII Transactions on Internet and Information Syst Vol.13 No.8

The efficiency and accuracy of handwriting measurement could be improved by adopting digital image processing. This study developed a computer-based Korean Handwriting Assessment tool. Second graders participated in this study by performing writing tasks of consonants, vowels, words, and sentences. We extracted boundary parameters for each letter using digital image processing and calculated the variables of size, size coefficient of variation (CV), misalignment, inter-letter space, inter-word space, and ratio of inter-letter space to inter-word space. Children were also administered traditional handwriting and visuomotor tests. Digital variables from image processing were correlated with these previous tests. Using these correlations, we established a three-point scoring system that computed test scores for each variable. We analyzed inter-rater reliability between the computer rater and human rater and test-retest reliability between the first and second performances. The validity was examined by analyzing the relationship between the Korean Handwriting Assessment and previous handwriting and visuomotor tests. We suggested the Korean Handwriting Assessment to measure size, size consistency, misalignment, inter-letter space, inter-word space, and space ratio using digital image processing. This Korean Handwriting Assessment tool proved to have reliability and validity. It is expected to be useful for assessing children’s handwriting.

스테레오 비젼에 의한 생체표면 3차원 복원의 최적화 연구

이경채(Kyungchai Lee),이언석(Onseok Lee) 대한전기학회 2017 전기학회논문지 Vol.66 No.2

Unlike regular images, there is no ground truth for bio surface images. Result of biosurface imaging is not only significantly affected by the environment and the condition of the bio surface, it requires more detailed expression than regular images. Therefore, unlike algorithms tested on regular images, studies on bio surface images requires a highly precise optimization process. We aim to optimize the graph cut algorithm, known to be the most outstanding among the stereo visions, by considering baseline, lambda, and disparity range. Optimal results were in the range of 1~10 for lambda. The disparity ranged from -30 to -50, indicating an optimal value in a slightly higher range. Furthermore, we verified the tested optimization data using SIFT.

스테레오 비젼에 의한 생체표면 3차원 복원의 최적화 연구

이경채,이언석,Lee, Kyungchai,Lee, Onseok 대한전기학회 2017 전기학회논문지 Vol.66 No.1

Unlike regular images, there is no ground truth for bio surface images. Result of biosurface imaging is not only significantly affected by the environment and the condition of the bio surface, it requires more detailed expression than regular images. Therefore, unlike algorithms tested on regular images, studies on bio surface images requires a highly precise optimization process. We aim to optimize the graph cut algorithm, known to be the most outstanding among the stereo visions, by considering baseline, lambda, and disparity range. Optimal results were in the range of 1~10 for lambda. The disparity ranged from -30 to -50, indicating an optimal value in a slightly higher range. Furthermore, we verified the tested optimization data using SIFT.

Proposal for a Sensory Integration Self-system based on an Artificial Intelligence Speaker for Children with Developmental Disabilities: Pilot Study

YeJin Wee,Onseok Lee 한국인터넷정보학회 2023 KSII Transactions on Internet and Information Syst Vol.17 No.4

Conventional occupational therapy (OT) is conducted under the observation of an occupational therapist, and there are limitations in measuring and analyzing details such as degree of hand tremor and movement tendency, so this important information may be lost. It is therefore difficult to identify quantitative performance indicators, and the presence of observers during performance sometimes makes the subjects feel that they have to achieve good results. In this study, by using the Unity3D and artificial intelligence (AI) speaker, we propose a system that allows the subjects to steadily use it by themselves and helps the occupational therapist objectively evaluate through quantitative data. This system is based on the OT of the sensory integration approach. And the purpose of this system is to improve children’s activities of daily living by providing various feedback to induce sensory integration, which allows them to develop the ability to effectively use their bodies. A dynamic OT cognitive assessment tool for children used in clinical practice was implemented in Unity3D to create an OT environment of virtual space. The Leap Motion Controller allows users to track and record hand motion data in real time. Occupational therapists can control the user’s performance environment remotely by connecting Unity3D and AI speaker. The experiment with the conventional OT tool and the system we proposed was conducted. As a result, it was found that when the system was performed without an observer, users can perform spontaneously and several times feeling ease and active mind.

The study of a quantitative method for measuring the therapeutic efficacy of 308nm excimer Laser for vitiligo

( Tae Seok Oh ),( Onseok Lee ),( Joo Ha Kim ),( Yoo Sang Baek ),( Won Ung Shin ),( Jae Hwan Kim ),( Hae Jun Song ),( Chil Hwan Oh ) 대한피부과학회 2011 초록집 Vol.49 No.20

Novel severity quantitative analysis method for melasma

( Jaeyoung Kim ),( Geo Han ),( Onseok Lee ),( Seunghan Ha ),( Jaewoo Ahn ),( Chilhwan Oh ) 대한피부과학회 2015 대한피부과학회 학술발표대회집 Vol.67 No.2

Background: Melasma is a common pigmentary skin disease with patchy facial skin discoloration and typically appears on upper cheeks, upper lip, forehead, and chin. The most common severity assessment method of melasma is Melasma Area Severity Index(MASI)score. However,ordinary MASI scoring system has some downsides due to the observer``s subjective visual judgment. Objectives: This study aimed to develop a new advanced severity assessment method of melasma based on computerized optical imaging analysis system. Methods: We proposed a new analysis method for the quantitative assessing of melasma. In order toquantitatvely analyze the involvement area, we divided frontal, cheek and chin region in patients. The divided images were processed to define the melasma lesions by the multi-threshold method and gradient mask were apply to correct the curvature error of facial contour.Degree of darkness and homogenesis were measured based on intensity of gray level and difference of gray level in melasma lesions. Results: The proposed new quantitative assessment method for melasma is more objective and accurate than ordinary MASI method. also, our method is able to quantify a minute difference of pigmented pattern among melasma patients. Conclusion: We developed the quantitative assessment method for melasma using computerized optical imaging analysis.Based on the results, our new computerized optical imaging system could be used as valuable tools to assess the severity of various pigmentary skin diseases

An extended Kalman filter for mouse tracking

Choi, Hongjun,Kim, Mingi,Lee, Onseok Springer-Verlag 2018 Medical & biological engineering & computing Vol.56 No.11