• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.9C
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• pp.1298-1305
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• 2004

Most watermarking techniques embed watermarks in the middle frequency range for robustness and invisibility. In our proposed watermarking algorithms embed the gaussian sequence watermark into low frequency area of the wavelet transform domain because the histogram of low sub-band area is composed by similar coefficients. Also, our proposed scheme doesn't need the original image in extraction procedure The experimental results show good robustness against the Check Mark benchmarking tools.

• Journal of radiological science and technology
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• v.46 no.3
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• pp.239-246
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• 2023

In this study, we assessed the effect of reduction of tumor volume in the head and neck cancer by using RANDO phantom in Static Intensity-Modulated Radiation Therapy (S-IMRT) and Volumetric-Modulated Arc Therapy (VMAT) planning. RANDO phantom's body and protruding volumes were delineated by using Contour menu of Eclipse™ (Varian Medical System, Inc., Version 15.6, USA) treatment planning system. Inner margins of 2 mm to 10 mm from protruding volumes of the reference were applied to generate the parameters of reduced volume. In addition, target volume and Organ at Risk (OAR) volumes were delineated. S-IMRT plan and VMAT plan were designed in reference. These plans were assigned in the reduced volumes and dose was calculated in reduced volumes using preset Monitor unit (MU). Dose Volume Histogram (DVH) was generated to evaluate treatment planning. Conformity Index (CI) and R² in reference S-IMRT were 0.983 and 0.015, respectively. There was no significant relationship between CI and the reduced volume. Homogeneity Index (HI) and R² were 0.092 and 0.960, respectively. The HI increased when volume reduced. In reference VMAT, CI and R² were 0.992 and 0.259, respectively. There was no relationship between the volume reduction and CI. On the other hand, HI and R² were 0.078 and 0.895, respectively. The value of HI increased when the volume reduced. There was significant difference (p<0.05) between parameters (D_mean and D_max) of normal organs of S-IMRT and VMAT except brain stem. Volume reduction affected the CI, HI and OAR dose. In the future, additional studies are necessary to incorporate the reduction of the volume in the clinical setting.

• Progress in Medical Physics
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• v.33 no.4
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• pp.142-149
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• 2022

Purpose: This study seeks to compare the dosimetric parameters of the bulk electron density (ED) approach and synthetic computed tomography (CT) image in terms of position variation of the air cavity in magnetic resonance-guided radiotherapy (MRgRT) for patients with pancreatic cancer. Methods: This study included nine patients that previously received MRgRT and their simulation CT and magnetic resonance (MR) images were collected. Air cavities were manually delineated on simulation CT and MR images in the treatment planning system for each patient. The synthetic CT images were generated using the deep learning model trained in a prior study. Two more plans with identical beam parameters were recalculated with ED maps that were either manually overridden by the cavities or derived from the synthetic CT. Dose calculation accuracy was explored in terms of dose-volume histogram parameters and gamma analysis. Results: The D_95% averages were 48.80 Gy, 48.50 Gy, and 48.23 Gy for the original, manually assigned, and synthetic CT-based dose distributions, respectively. The greatest deviation was observed for one patient, whose D_95% to synthetic CT was 1.84 Gy higher than the original plan. Conclusions: The variation of the air cavity position in the gastrointestinal area affects the treatment dose calculation. Synthetic CT-based ED modification would be a significant option for shortening the time-consuming process and improving MRgRT treatment accuracy.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.3
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• pp.621-629
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• 2016

This paper presents a decision method of middle ear disease which is developed in children and adults. In the proposed method, features are extracted from the middle ear disease images and normal images using HoG (histogram of oriented gradient) descriptor and the extracted features are learned by SVM (support vector machine) classifier. To obtain an input vector into SVM, an input image is resized to a predefined size and then the resized image is partitioned into 16 blocks each of which is partitioned into 4 sub-blocks (namely cell). Finally, the feature vector with 576 components is given by using HoG with 9 bins and it is used as SVM learning and classification. Input images are classified by SVM classifier based on the model of learning features. Experimental results show that the proposed method yields the precision of over 90% in decision.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.4
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• pp.2124-2148
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• 2017

Accurate facial expression recognition (FER) requires reliable signal filtering and the effective feature extraction. Considering these requirements, this paper presents a novel approach for FER which is robust to noise. The main contributions of this work are: First, to preserve texture details in facial expression images and remove image noise, we improved the anisotropic diffusion filter by adjusting the diffusion coefficient according to two factors, namely, the gray value difference between the object and the background and the gradient magnitude of object. The improved filter can effectively distinguish facial muscle deformation and facial noise in face images. Second, to further improve robustness, we propose a new feature descriptor based on a combination of the Histogram of Oriented Gradients with the Canny operator (Canny-HOG) which can represent the precise deformation of eyes, eyebrows and lips for FER. Third, Canny-HOG's block and cell sizes are adjusted to reduce feature dimensionality and make the classifier less prone to overfitting. Our method was tested on images from the JAFFE and CK databases. Experimental results in L-O-Sam-O and L-O-Sub-O modes demonstrated the effectiveness of the proposed method. Meanwhile, the recognition rate of this method is not significantly affected in the presence of Gaussian noise and salt-and-pepper noise conditions.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.46 no.5
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• pp.48-55
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• 2009

Prior research works in indoor-outdoor classification have been conducted based on a simple combination of low-level features. However, since there are many challenging problems due to the extreme variability of the scene contents, most methods proposed recently tend to combine the low-level features with high-level information such as the presence of trees and sky. To extract these regions from videos, we need to conduct additional tasks, which may yield the increasing number of feature dimensions or computational burden. Therefore, an efficient indoor-outdoor scene classification method is proposed in this paper. First, the video is divided into the five same-sized blocks. Then we define and use the edge and color orientation histogram (ECOH) descriptors to represent each sub-block efficiently. Finally, all ECOH values are simply concatenated to generated the feature vector. To justify the efficiency and robustness of the proposed method, a diverse database of over 1200 videos is evaluated. Moreover, we improve the classification performance by using different weight values determined through the learning process.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2010.07a
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• pp.260-263
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• 2010

본 논문에서는 주행 중인 차량에서 전방을 향해 장착된 카메라를 통해 입력된 영상에서 측면에 부분적으로 나타나는 차량을 검출하는 방법을 제안한다. 기존 연구에서는 모션 벡터를 이용하여 주변 배경과 관측되는 차량 사이의 모션 벡터 차이를 이용하여 측면 차량을 검출하고 있다. 그러나 모션 벡터를 이용할 경우 정지된 차량이나 전방에서 다가오는 차량의 경우 검출하기 어려운 점이 있다. 이러한 문제를 해결하기 위해 본 논문에서는 모션 벡터를 사용하지 않고 차량 측면 모습에서 특징 정보를 추출하여 SVM 분류기를 통해 측면 차량을 검출하는 방법을 제안한다. 차량 측면 모습의 특징을 뽑기 위해 영상의 밝기 변화에 강인한 국부 이진 패턴을 사용하였고 ROI영역 내에서 차량이 나타나는 위치에 상관없이 차량의 측면 모습을 찾아내기 위해 국부 이진 패턴의 히스토그램을 이용하였다. 실험결과에서는 제안하는 방법이 정지된 차량을 포함하여 88.5%의 정확도로 측면 차량을 검출하는 것을 확인하였다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2011.07a
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• pp.303-304
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• 2011

영역기반 스테레오 매칭의 분야에서 최근 인간의 시각체계(Human Visual System)에 기반하여 영역내의 밝기값과 거리값에 따라 적응적으로 가중치를 부여하는 적응적 영역 가중치(Adaptive Support-Weight) 방법이 좋은 매칭 결과를 보이고 있다. 하지만 이 방법은 영역 윈도우의 크기가 커짐에 따라 기하급수적으로 계산량이 많아지는 단점을 보이고 있다. 이에 Bilateral filter 수식으로 근사화 후 Integral Histogram 기법을 적용하여 영역 윈도우의 크기에 상관없이 상수 시간 O(1) 내에 매칭을 수행하는 연구가 진행되었다. 하지만 이 방법은 근사화 과정에서의 원 ASW 수식을 왜곡하기 때문에 매칭 정확도의 손실을 가져오게 된다. 이에 본 논문에서는 Bilateral 접근 방식, Sub-Block 방식 및 적응적 시차 탐색 방식에 대하여 각 방식에서 필요한 메모리 자원과 소모되는 계산량의 비용과 동시에 매칭 결과 정확도 면에서 비교하고 가장 좋은 접근 방식을 도출하고자 한다.

• Journal of Advanced Marine Engineering and Technology
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• v.12 no.3
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• pp.43-56
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• 1988

The image processing system consisted of the microcomputer IBM PC-XT and the graphic board (16 gray level and $640{\times}400$ pixels resolution) has been proposed, and the image processing softwares programmed in the BASIC and in the assembler language have been developed. The programs are consisted of the main menu and the sub menu, that have contained the subroutine for the capture for image data, the determination of region, the histogram, the change of value, the montage, the skeleton, the mask, the moving, the zoom, the disk access and the print. For the application, the photoelastic fringe data have been captured and analyzed. It was seen that the programs are available for the image processing.

• Proceedings of the IEEK Conference
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• 2002.06d
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• pp.93-96
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• 2002

This paper presents robust and efficient scene-based video watermarking method using visual rhythm (spatio-temporal slice) in compressed domain. Scene change can be detected easily using visual rhythm and video sequences are conveniently edited at the scene boundaries. Therefore, scene-based watermark embedding Process it a natural choice. Temporal spread spectrum can be achieved by applying spread spectrum methods to visual rhythm. Additive Gaussian noise, low-pass filtering, median filtering and histogram equalization attack are simulated for all frames. Frame sub-sampling is also simulated as a typical video attack Simulation results show that proposed algorithm is robust and efficient in the presence of such kind of attacks.