• The Journal of Korean Society for Radiation Therapy
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• v.31 no.1
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• pp.67-74
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• 2019

Purpose: The purpose is to correct for position errors caused by long treatment times. By correcting the target motion that can occur during lung SBRT using IntraFraction CBCT. Methods and materials: We analyzed retrospectively the IFM data of 14 patients with two treatment arc in the treatment plan for lung cancer with stereotactic radiotherapy. An IntraFraction Motion was applied to the Arccheck phantom to acquire the Gamma index data. Results : IntraFraction Motion during the first treatment arc is in the left-right(LR), superiorinferior(SI), anterior-posterior(AP) directions were $0.16{\pm}0.05cm$, 0.72 cm(max error), $0.2{\pm}0.14cm$, 1.26 cm, $0.24{\pm}0.08cm$, 0.82 cm and rotational directions was $0.84{\pm}0.23^{\circ}$, $2.8^{\circ}$(pitch), $0.72{\pm}0.23^{\circ}$, $2.5^{\circ}$(yaw), $0.7{\pm}0.19^{\circ}$, $2^{\circ}$(roll). IntraFraction Motion during the second treatment arc is in the LR, SI, AP directions were $0.1{\pm}0.04cm$, 0.37 cm, $0.14{\pm}0.17cm$, 2 cm, $0.12{\pm}0.04cm$, 0.5 cm and rotational directions was $0.45{\pm}0.12^{\circ}$, $1.3^{\circ}$, $0.37{\pm}0.1^{\circ}$, $1^{\circ}$, $0.35{\pm}0.1^{\circ}$, $1.2^{\circ}$. Gamma index pass rates were $82.64{\pm}10.51%$, 48.4 %. Conclusions : In this study, we examined the validity of IntraFraction Motion correction in lung SBRT and the efficiency of IntraFraction CBCT. Due to the nature of SBRT treatment, IFM may increase due to the increased treatment time. It is believed that the increase in IFM with the increase in treatment time can be improved with the use of FFF Beam and additional position correction using CBCT during treatment.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.1
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• pp.70-77
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• 2014

This paper proposes a novel localization algorithm based on ego-motion which used Lucas-Kanade Optical Flow and warping image obtained through fish-eye lenses mounted on the robots. The omnidirectional image sensor is a desirable sensor for real-time view-based recognition of a robot because the all information around the robot can be obtained simultaneously. The preprocessing (distortion correction, image merge, etc.) of the omnidirectional image which obtained by camera using reflect in mirror or by connection of multiple camera images is essential because it is difficult to obtain information from the original image. The core of the proposed algorithm may be summarized as follows: First, we capture instantaneous $360^{\circ}$ panoramic images around a robot through fish-eye lenses which are mounted in the bottom direction. Second, we extract motion vectors using Lucas-Kanade Optical Flow in preprocessed image. Third, we estimate the robot position and angle using ego-motion method which used direction of vector and vanishing point obtained by RANSAC. We confirmed the reliability of localization algorithm using ego-motion based on fisheye warping image through comparison between results (position and angle) of the experiment obtained using the proposed algorithm and results of the experiment measured from Global Vision Localization System.

• Journal of the Korean Orthopaedic Association
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• v.55 no.2
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• pp.154-161
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• 2020

Purpose: To describe the clinical and radiology results of a surgical treatment for clinodactyly due to a longitudinal epiphyseal bracket. Materials and Methods: This study analyzed the records of 11 patients (27 case) with clinodactyly due to a longitudinal epiphyseal bracket who underwent an osteotomy or physiolysis between March 1999 and April 2017. The preoperative range of motion of the proximal and distal interphalangeal joints, the subjective satisfaction of the patient, and the degree of angulation to the ulnar side were examined. The patients were classified into two groups: osteotomy and physiolysis. The results were reviewed retrospectively and compared according to the surgical method. Results: The mean age of the patients who underwent osteotomy was 10.3 years. The average preoperative angle was 25.7° and the average postoperative angle was 13.5° the mean correction rate was 47.4%. The mean age of the patients who underwent physiolysis was 6.0 years the mean preoperative angle was 24.5° and the postoperative angle was 10.7°. The average correction rate was 59.4%. No significant difference in the correction angles was observed between the group who underwent the correction osteotomy and the group who underwent the osteotomy. In each group, the postoperative correction was statistically significant. The range of motion at the last follow-up was not significantly different from the preoperative range of motion. Conclusion: In patients with clinodactyly due to longitudinal epiphyseal bracket, osteotomy or physiolysis may be performed selectively according to age, bone age, and radiological progression. Both surgical methods showed good clinical results and deformity correction.

• The Journal of the Korea Contents Association
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• v.8 no.7
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• pp.120-127
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• 2008

Practical use degree of Motion Capture technology is low in korea game market which did growth of MMORPG putting first. However, that is dance game or FPS, sports game genre is magnified. Therefore, practical use degree of Motion Capture technology is increasing. And, need various research to take advantage of Motion Capture technology effectively. Studied 3D game character animation manufacture pipe line for it. Characteristic of this manufacture pipe line is work classification, correction of two times, Biped format all-in-one to progress Motion Capture technology and keyframe-animation work at the same time. Also, manufacture pipe line that is consisted of this constituent has economic performance, extensity, systemicity.

• KIPS Transactions on Software and Data Engineering
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• v.9 no.2
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• pp.69-76
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• 2020

In this paper, we introduce a method to visualize the contrast diffusion patterns and the dynamic vascular patterns in a contrast-enhanced ultrasound image sequence. We present an imaging technique to visualize parameters such as contrast arrival time, peak intensity time, and contrast decay time in contrast-enhanced ultrasound data. The contrast flow pattern and its velocity are important for characterizing focal liver lesions. We propose a method for representing the contrast diffusion patterns as an image. In the methods, respiratory motion may degrade the accuracy of the parametric images. Therefore, we present a respiratory motion tracking technique that uses dynamic weights and a momentum factor with respect to the respiration cycle. Through the experiment using 72 CEUS data sets, we show that the proposed method makes it possible to overcome the limitation of analysis by the naked eye and improves the reliability of the parametric images by compensating for respiratory motion in contrast-enhanced ultrasonography.

• Korean Journal of Applied Biomechanics
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• v.27 no.1
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• pp.53-58
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• 2017

Objective: The purpose of this study was to compare the accuracy of stride time and stride length provided by a commercial APDM inertial sensor system (APDM) with the results of three dimensional motion capture system (3D motion) during treadmill walking. Method: Five healthy men participated in this experiment. All subjects walked on the treadmill for 3 minutes at their preferred walking speed. The 3D motion and the APDM were simultaneously used for extracting gait variables such as stride time and stride length. Mean difference and root mean squared (RMS) difference were used to compare the measured gait variables from the two measurement devices. The regression equation derived from the range of motion of the lower limb was also applied to correct the error of stride length. Results: The stride time extracted from the APDM was almost the same as that from the 3D motion (the mean difference and RMS difference were less than 0.0001 sec and 0.0085 sec, respectively). For stride length, mean difference and RMS difference were less than 0.1141 m and 0.1254 m, respectively. However, after correction of the stride length error using the derived regression equation, the mean difference and the RMS difference decreased to 0.0134 m and 0.0556 m or less, respectively. Conclusion: In this study, we confirmed the possibility of using the temporal variables provided from the APDM during treadmill walking. By applying the regression equation derived only from the range of motion provided by the APDM, the error of the spatial variable could be reduced. Although further studies are needed with additional subjects and various walking speeds, these results may provide the basic data necessary for using APDM in treadmill walking.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.04a
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• pp.483-487
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• 1996

We consider the estimation of the position and orientation of 6 DOF motion bed (Stewart platform) from the measured cylinder length. The solution of forward kinematics is not solved yet as a useful realtime application tool because of the complity of the equation with multiple solutiple solutions. Hence we suggest an algorithm for the estimation of forward kinematics solution using Luenberger observer withnonlinear error correction term. The Luenberger observer withlinear model shows that the estimation error does not go to zero in steadystate due to the linearization error of the dynamic model. Hence the linear observer is modified using nonlinear measurement error equation and we prove thd practical stability of the estimation error dynamics of the proposed observer using lyapunov function.

• Journal of computational fluids engineering
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• v.19 no.2
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• pp.30-39
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• 2014

We report in this paper the analysis of the motion of a needle and a spring in a viscous fluid under the influence of gravitational force. Lateral shift as well as vertical motion of a needle falling in a viscous fluid has been observed from a simple experiment. We also observed the combined rotation and translation of a falling spring. The trajectory and velocity of the falling needle and the spring were obtained by using an image processing technique. We also conducted numerical simulation for both problems. For the falling-needle problem, we employed a theory; but it turns out that significant correction is required for the solutions to match the numerical and experimental data. For the falling spring problem various theoretical formula were tested for their justification, but none of the existing theories can successfully predict the numerical and experimental results.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.664-667
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• 2008

Since the advent of pedicle screw fixation system, posterior spinal fusion has markedly increased This intemal fixation system has been reported to enhance the fusion rates, thereby becoming very popular procedure in posterior spinal arthrodesis. Although some previous studies have shown the complications of spinal instruments removal, i.e. loss of correction and spinal collapse in scoliosis or long spine fusion patients, there has been no study describing the benefit or complications in lumbar spinal fusion surgery of one or two level. In order to clarify the effect of removal of instruments on mechanical motion profile, we simulated a finite element model of instrumented posterolateral fused lumbar spine model, and investigated the change of mechanical motion profiles after the removal of instrumentation.

• Journal of Biomedical Engineering Research
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• v.39 no.1
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• pp.10-15
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• 2018

In this paper, we present a wearable measurement system for monitoring rounded shoulders. The system contains a shoulder correction band and a stretch sensor that can correct and measure shoulder posture, respectively. The capacitance of the stretch sensor changes linearly according to changes in the shoulders. To verify measurement, a motion analysis system was used as the reference to compare the change in the rounded angles of the shoulders and the change in the stretch sensor's capacitance. The results indicated that there is a high correlation between the two changes and the system can be used as a monitoring device for rounded shoulders.