• Title/Summary/Keyword: Visual threshold

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A Perceptual Rate Control Algorithm with S-JND Model for HEVC Encoder (S-JND 모델을 사용한 주관적인 율 제어 알고리즘 기반의 HEVC 부호화 방법)

  • Kim, JaeRyun;Ahn, Yong-Jo;Lim, Woong;Sim, Donggyu
    • Journal of Broadcast Engineering
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    • v.21 no.6
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    • pp.929-943
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    • 2016
  • This paper proposes the rate control algorithm based on the S-JND (Saliency-Just Noticeable Difference) model for considering perceptual visual quality. The proposed rate control algorithm employs the S-JND model to simultaneously reflect human visual sensitivity and human visual attention for considering characteristics of human visual system. During allocating bits for CTU (Coding Tree Unit) level in a rate control, the bit allocation model calculates the S-JND threshold of each CTU in a picture. The threshold of each CTU is used for adaptively allocating a proper number of bits; thus, the proposed bit allocation model can improve perceptual visual quality. For performance evaluation of the proposed algorithm, the proposed algorithm was implemented on HM 16.9 and tested for sequences in Class B and Class C under the CTC (Common Test Condition) RA (Random Access), Low-delay B and Low-delay P case. Experimental results show that the proposed method reduces the bit-rate of 2.3%, and improves BD-PSNR of 0.07dB and bit-rate accuracy of 0.06% on average. We achieved MOS improvement of 0.03 with the proposed method, compared with the conventional method based on DSCQS (Double Stimulus Continuous Quality Scale).

The Effects of Spiral Taping Theraphy-A Randomisation Controlled Trial

  • Choi, Sung-Hun;Ko, Kyoung-Mo;Kim, Kyung-Woon;Lee, Yoon-Kyung;Lim, Seong-Chul;Jung, Tae-Young;Lee, Kyung-Min;Hwang, Jae-Wok;Seo, Jung-Chul
    • Journal of Acupuncture Research
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    • v.23 no.2
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    • pp.165-172
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    • 2006
  • Objectives : This study was designed to estimate the effects of Spiral Taping theraphy on low back pain or neck pain patients by using pressure pain threshold, visual analogue scale(VAS), and range of motion(ROM). Methods : The patients were allocated into two groups by randomisation. Spiral Taping theraphy group consisted of 11 patients and acupuncture theraphy group consisted of 10 patients. The degree of improvement of neck pain was evaluated by pressure pain threshold, VAS, and ROM before treatment and after treatment. The patients were commonly treated with acupuncture theraphy. After acupuncture Spiral Taping theraphy was peformed in Spiral Taping theraphy group. Results : Pressure pain threshold and VAS were significantly different between two groups. In Spiral Taping theraphy group the pressure pain threshold of the all points was significantly increased and VAS was significantly decreased than control group. But there was no significant difference between the two groups in ROM. Conclusion : The effectiveness of Spiral Taping theraphy on low back pain and neck pain patients was shown through pressure algometer and VAS. These imply that Spiral Taping theraphy may be useful for on low back pain or neck pain. Further study is needed about Spiral Taping theraphy.

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The Effect of Low-intensity Ultrasound (noblelife) on Pain Relief of Upper Trapezius (저강도 초음파치료기 노블라이프가 상부 승모근 통증에 미치는 영향)

  • Lee, Jao-On;Choi, Jong-Duk;Jung, Nak-Su;Choi, Kyu-Hwan
    • Physical Therapy Korea
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    • v.9 no.2
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    • pp.97-105
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    • 2002
  • The purpose of this study was to investigate the effectiveness of the low-intensity ultrasound (noblelife) treatment on the pain points of upper trapezius muscle. The study recruited 20 patients who had trigger points in one side of the upper trapezius. The effectiveness of the low-intensity ultrasound treatment was assessed with subjective pain intensity using visual analog scale (VAS) and pressure pain threshold (PPT). The PPT was measured by pressure threshold algometer. Before and after the treatment, changes of pain were evaluated. Wilcoxon test for VAS data and paired t-test for PPT data were used for statistical significance. Compared to the pain intensity before the treatment, the pain intensity after treatment was significantly decreased (p<.05). Low-intensity ultrasound could be safely used in clinical application and at home for the treatment of patients with pain in upper trapezius muscle.

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Robust Lip Extraction and Tracking of the Mouth Region

  • Min, Duk-Soo;Kim, Jin-Young;Park, Seung-Ho;Kim, Ki-Jung
    • Proceedings of the IEEK Conference
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    • 2000.07b
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    • pp.927-930
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    • 2000
  • Visual features of lip area play an important role in the visual speech information. We are concerned about correct lip area as region of interest (ROI). In this paper, we propose a robust and fast method for locating the mouth corners. Also, we define a region of interest at mouth during speech. A method, which we have used, only uses the horizontal and vertical image operators at mouth area. This searching is performed by fitting the ROI-template to image with illumination control. Most of the lip extraction algorithms are dependent on luminosity of image. We just used the binary image where the variable threshold is applied. The variable threshold varies to illumination condition. In order to control those variations, the gray-tone is converted to binary image by threshold, which is obtained through Multiple Linear Regression Analysis (MLRA) about divided 2D special region. Thus we obtained the region of interest at mouth area, which is the robust extraction about illumination. A region of interest is automatically extracted.

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THE RELATION BETWEEN MOLECULE AND VISUAL EXTINCTION IN DARK CLOUDS

  • Minn, Y.K.
    • Journal of The Korean Astronomical Society
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    • v.24 no.2
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    • pp.191-215
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    • 1991
  • We have compared the column densities of $H_2CO$, $^{13}CO$, $C^{18}O$, $^{12}CO$, CS, and $HCO^+$ to the visual extinctions derived from star counts in eight dark clouds, L1317, B1, L1551, L1535, L1544, L134, L134N, and B335. We examined the degree of correlation between molecules and extinctions. The contours of $^{13}CO$, $H_2CO$, and CS distributions show an excellent coincidence with those of the visual extinction. Even though the plots of molecule brightness temperature or column density as a function of the visual extinction show a considerable scatter, a good correlation is found between the two quantities. The turnover of the ratios of $^{13}CO$ and $H_2CO$ column densities to the visual extinction at high extinctions observed in several clouds is not apparent in this work. The ratios seem to maintain constant values within the range of $A_V$ we studied. The slopes of the relations between the molecule column density and extinction, and the threshold values of extinction for detection of molecules are comparable to the other works. The cause of the slope difference is discussed. We derived, for the first time, the relations of CS and $HCO^+$ column densities and the visual extinction. The ratio of CS column density to extinction is at least two orders of magnitude lower than the mean value for $^{13}CO$, but the threshold for detection of CS is comparable to that of $^{13}CO$. The ratio of the $HCO^+$ column density to extinction is one to two orders of magnitude lower than the mean ratio for $H_2CO$.

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A study on Development of Precise Orientation control Algorithm of the Mobile Robot Based Vision Technology (비전기술에 의한 모바일 로봇의 정밀 자세 제어 알고리즘 개발에 관한 연구)

  • Sim, Hyun-Seok;Kim, Tae-Gwan
    • Journal of the Korean Society of Industry Convergence
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    • v.18 no.2
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    • pp.129-138
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    • 2015
  • This study describe a new method to control posture and velocity for a wheeled mobile robot using visual feedback control method with a position based visual feedback. To slove the problem of vibration phenomena which were shown in the previous researches using a simple switching function based on a threshold, the proposed visual servo control law introduces the fusion function based on a blending function. The chattering problem and rapid motion of the mobile robot can be eliminated. And we consider the nonlinearity of the wheeled mobile robot unlike the previous visual servo control laws using linear control methods to improve the performances of the visual servo control law. The proposed posture control law using visual servoing is verified by a theoretical analysis and simulation and experimental results.

A Study on an Application of the Protection for the Visual Segment of the Approach Procedure focused on Taean Airport (접근절차의 시계구간 보호 적용 연구 - 태안비행장을 중심으로 -)

  • Kim, Dohyun;Hong, Seung Beom
    • Journal of the Korean Society for Aviation and Aeronautics
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    • v.22 no.2
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    • pp.9-15
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    • 2014
  • 'Visual segment surface' means a surface that extends from the missed approach point of non precision approaches (or the decision altitude location for approaches with vertical guidance and precision approaches) to the threshold to facilitate the identification of and protection from obstacles in this visual segment of the approach. Validation is the necessary final quality assurance step in the procedure design process, prior to publication. The purpose of validation is the verification of all obstacle and navigation data, and assessment of flyability of the procedure. This paper shows how to apply the protection for the visual segment of the approach procedure, and the results of the validation for visual segment surface conducted at an airport.

A study on valid line extraction from visual images (영상 이미지에서의 유효한 Line 추출에 관한 연구)

  • 유원필;정명진
    • 제어로봇시스템학회:학술대회논문집
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    • 1996.10b
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    • pp.273-276
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    • 1996
  • We propose a new method to extract valid lines from a visual image. Unsupervised clustering method is used to assign each line to any of the line groups according to its orientation. During the low-level image processing we use an adaptive threshold method to reduce human supervision and to automate the processing sequence. To reduce the misclassification rate and to suppress the superiors line support regions at the clustering stage, the adaptive threshold method is consistently applied. Performing principal component analysis on each line support region provides an efficient method of obtaining line equation. Finally we adopt the theory of robust statistics to guarantee the quality of each extracted line and to eliminate the lines of poor quality. We present the experimental results to verify our method. With the proposed method, one can extract the lines according to the internal orientation similarities and integrate the whole process into one adaptive procedure.

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Crop Field Extraction Method using NDVI and Texture from Landsat TM Images

  • Shibasaki, Ryosuke;Suzaki, Junichi
    • Proceedings of the KSRS Conference
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    • 1998.09a
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    • pp.159-162
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    • 1998
  • Land cover and land use classification on a huge scale, e.g. national or continental scale, has become more and more important because environmental researches need land cover: And land use data on such scales. We developed a crop field extraction method, which is one of the steps in our land cover classification system for a huge area. Firstly, a crop field model is defined to characterize "crop field" in terms of NDVI value and textual information Textual information is represented by the density of straight lines which are extracted by wavelet transform. Secondly, candidates of NDVI threshold value are determined by "scale-space filtering" method. The most appropriate threshold value among the candidates is determined by evaluating the line density of the area extracted by the threshold value. Finally, the crop field is extracted by applying level slicing to Landsat TM image with the threshold value determined above. The experiment demonstrates that the extracted area by this method coincides very well with the one extracted by visual interpretation.

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Effects of Manual Lymph Drainage on the Activity of Sympathetic Nervous System, Anxiety, Pain, and Pressure Pain Threshold in Subjects with Psychological Stress

  • Kim, Sung-Joong
    • The Journal of Korean Physical Therapy
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    • v.26 no.6
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    • pp.391-397
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    • 2014
  • Purpose: The aim of this study was to investigate the effects of manual lymph drainage (MLD) on the activity of sympathetic nervous system, anxiety, pain and pressure pain threshold in subjects with psychological stress. Methods: Twenty-nine subjects with psychological stress were randomly assigned to experimental (MLD) and control (rest) groups. This study was performed as a controlled, randomized study using spectral analysis of electrocardiographic (ECG) activities, the State-Trait Anxiety Inventory (STAI), Visual Analogue Scale (VAS) and Pressure Pain Threshold (PPT). Results: Heart rate variability differed significantly between the experimental and control groups (p<0.05). Anxiety and pain showed positive change in both group but it were not showed statically differences. The pressure pain threshold in the upper trapezius muscle was increased in the experimental group (p<0.05). Conclusion: These findings indicate that the application of MLD was effective in reducing the activity of the sympathetic nervous system, anxiety, pain, and increasing the PPT.