• 대한의용생체공학회:의공학회지
• /
• 제41권1호
• /
• pp.28-34
• /
• 2020

In this paper, we introduce motion artifact reduction algorithm for interleaved MRI using an advanced 3D approximation algorithm. The motion artifact framework of this paper is data corrected by post-processing with a new 3-D approximation algorithm which uses data structure for each voxel. In this study, we simulate and evaluate our algorithm using Shepp-Logan phantom and T1-MRI template for both scattered dataset and uniform dataset. We generated motion artifact using random generated motion parameters for the interleaved MRI. In simulation, we use image coregistration by SPM12 (https://www.fil.ion.ucl.ac.uk/spm/) to estimate the motion parameters. The motion artifact correction is done with using full dataset with estimated motion parameters, as well as use only one half of the full data which is the case when the half volume is corrupted by severe movement. We evaluate using numerical metrics and visualize error images.

• 한국정보통신학회논문지
• /
• 제15권12호
• /
• pp.2626-2631
• /
• 2011

CST(C-shape sharp turn)는 물고기가 유영 시 빠른 방향 전환을 위해 물고기 꼬리 부분을 빠르게 C-형태로 구부려 빠르게 방향 전환을 하는 모션을 나타낸다. 그러나 CST와 관련된 모션 궤적 함수는 아직 일반화된 함수가 없다. 본 연구에서는 생물학자들이 실제 물고기의 관측으로부터 나온 순차적인 물고기의 모션 기록을 통하여 CST룰 위한 매우 단순한 모션 함수를 제안하였다. 그리고 이를 모의실험을 통하여 제안된 함수의 유용성을 확인하였다.

• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권2호
• /
• pp.1131-1134
• /
• 2007

To prevent biological influence of images upon viewers, we investigated the characteristics features of images and of viewing environments which can cause photosensitivity seizures and visually-induced motion sickness, and developed some methods of detection and conversion of images that can cause such influence.

• 대한의용생체공학회:의공학회지
• /
• 제30권5호
• /
• pp.381-392
• /
• 2009

Due to the aging effect, older people have relatively weaker muscular performance, less range of motion in the joint articulation, and the lower sense of equilibrium than younger people. These factors attribute to their slow and clumsy ingress/egress motion. In order to analyze ingress/egress motion strategy of the elderly, healthy thirty 65 or more years old volunteers were recruited. The health condition of the each volunteer was verified by the medical checkup and also their physical capabilities were quantified by six fitness tests. Through the video analysis, older driver's ingress/egress motion strategies were classified and statistically investigated. For a comparison purpose, another thirty young volunteers also participated in the same test protocol and their ingress/egress motion strategies were also included in the statistical analysis.

• Transactions on Control, Automation and Systems Engineering
• /
• 제4권1호
• /
• pp.49-55
• /
• 2002

A decrease in the birthrate and aging are progressing in Japan and several countries. In that society, it is important that physically weak persons such as elderly persons are able to take care of themselves. We have been developing exoskeletal robots for human (especially for physically weak persons) motion support. In this study, the controller controls the angular position and impedance of the exoskeltal robot system using multiple fuzzy-neuro controllers based on biological signals that reflect the human subject's intention. Skin surface electromyogram (EMG) signals and the generated wrist force by the human subject during the elbow motion have been used as input information of the controller. Since the activation level of working muscles tends to vary in accordance with the flexion angle of elbow, multiple fuzzy-neuro controllers are applied in the proposed method. The multiple fuzzy-neuro controllers are moderately switched in accordance with the elbow flexion angle. Because of the adaptation ability of the fuzzy-neuro controllers, the exoskeletal robot is flexible enough to deal with biological signal such as EMG. The experimental results show the effectiveness of the proposed controller.

• 한국의학물리학회:학술대회논문집
• /
• 한국의학물리학회 2002년도 Proceedings
• /
• pp.429-431
• /
• 2002

Metabolic analysis of biological tissues, the interventional radiology in MRT (Magnetic Resonance Treatment) and for clinical diagnoses, representation of 4-Dimensional (4D) structural information (x,y,z,t) of biological tissues is required. This paper discusses image representation techniques for those 4D MR Images. We have proposed an image reconstruction method for ultra-fast 3D MRI. It is based on image interpolation and prediction of un-acquired pictorial data in both of the real and the k-space (the acquisition domain in MRI). A 4D MR image is reconstructed from only two 3D MR images and acquired a few echo signals that are optimized by prediction of the tissue motion. This prediction can be done by the phase of acquired echo signal is proportioned to the tissue motion. On the other hand, reconstructed 4D MR images are represented as a 3D-movie by using computer graphics techniques. Rendered tissue surfaces and/or ROIs are displayed on a CRT monitor. It is represented in an arbitrary plane and/or rendered surface with their motion. As examples of the proposed representation techniques, the finger and the lung motion of healthy volunteers are demonstrated.

• 대한의용생체공학회:학술대회논문집
• /
• 대한의용생체공학회 1991년도 추계학술대회
• /
• pp.88-89
• /
• 1991

A method in order to restore the body movement by means of Functional Electrical Stimulation (FES) was considered. Multichannel EMG signals from a normal subject during the rolling-over motion were measured and analyzed. The results of the experiment indicated the synergetic role of the muscles during the desired motion.

• 대한의용생체공학회:학술대회논문집
• /
• 대한의용생체공학회 1997년도 추계학술대회
• /
• pp.579-582
• /
• 1997

The two dimnesional echocardiography is widely used to evaluate regional wall motion abnormaility, because of its abilities to depict left ventricluar wall motion. A new method, color kinesis is a technology or echocardiographic assessment of left ventricular wall motion. In this paper, we proposed a algorithm or color kinesis which is based on acoustic quantification and automatically detects endocardial motion during systole on a frame-by-frame basis. The echocardiograms were obtained in the short-axis views in normal subjects. Automated edge detection and endocardial contour tracing algorithm was applied to each frames, quantitative analysis based on segmentation was performed, and pre-defined color overlays superimposed on the gray scale images. Segmental analysis of color kinesis provided automated, quantitative diagnosis of regional wall motion abnormality.

• 대한의용생체공학회:학술대회논문집
• /
• 대한의용생체공학회 1995년도 춘계학술대회
• /
• pp.123-126
• /
• 1995

The purpose of this paper is to improve ultrasound images using motion estimation and recursive filtering. Although averaging without motion correction can make image blurring, the proposed estimation method improves image SNR without motion blurring by recursively averaging images with motion correction. Computer simulation on the proposed method has been performed to improve phantom and ultrasound fish images and the results show the utility of the proposed method.

• 대한의용생체공학회:의공학회지
• /
• 제39권4호
• /
• pp.153-160
• /
• 2018

3D ultrasound bladder scanners are getting popular in hospitals for the patients with bladder dysfunction. A current bladder scanner adopts a mechanical scan to acquire 3D images and requires two motors and complicated mechanical devices. In this paper, we propose a new ultrasound bladder scanner using hand-motion scan. Instead of two motors and mechanical devices, it has a motion sensor to record transducer positions during hand-motion scan. The experiments with a bladder phantom and volunteers showed similar measurement accuracy to a conventional 3D ultrasound bladder scanner. We expect that the proposed method will reduce the cost and size of the bladder scanner.