• Journal of the Institute of Electronics Engineers of Korea SP
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• v.48 no.6
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• pp.77-87
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• 2011

In this paper, we propose a disparity correction technique to reduce the inherent visual discomfort while watching stereoscopic videos. The visual discomfort must be solved for commercial 3D display systems to provide natural stereoscopic videos to human eyes. The proposed disparity correction technique consists of horizontal and vertical disparity corrections. The horizontal disparity correction is implemented by controlling the depth budget of stereoscopic video using the geometric relations of a stereoscopic camera system. In addition, the vertical disparity correction is implemented by using a feature-based stereo matching algorithm. Conventional vertical disparity corrections have been done by only using camera calibration parameters, which still cause systematic errors in vertical disparities. In this paper, we minimize the vertical disparity as small as possible by using a feature-based correction algorithm. Through the comparisons of conventional feature-based correction algorithms, we analyze the performance of the proposed technique.

• Journal of Korean Ophthalmic Optics Society
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• v.19 no.4
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• pp.539-550
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• 2014

Purpose: This research was designed to figure out if there are changes based on types of vergence fixation disparity curve after optical correction and vision training to for people with steep slope of forced vergence fixation disparity curve and symptoms. Methods: For 30 subjects out of 91 subjects, who have steep slopes of fixation disparity curve examined with Wesson Fixation Disparity Card and symptoms about steep slope of fixation disparity curve, proper vision training was offered for 5 weeks. Results: After Vision training for 30 people with the symptoms of type I, II, III, IV for 5 weeks, slope of fixation disparity curve was significantly changed (p=0.013), and the results of binocular vision test and subjective symptoms were also significantly improved. Conclusions: Vision training can not only affect the change of fixation disparity curve, but also relieve the symptoms. Fixation disparity curve has lots of visual function information of the subject and can be suggested as a guideline for prescribing.

• Journal of the Institute of Convergence Signal Processing
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• v.6 no.3
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• pp.112-119
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• 2005

In this paper, a model of neural circuit was proposed, which abstracts the depth information in two images gotten from right and left retinas. The proposed neural circuit corresponds to binocular stereo vision based on psychologic and physiological knowledge, and we examine a restoration method of three-dimensional surface. In case of drawing a disparity based on characteristics of images, we can not abstract the depth information correctly if resemblant characteristics are repeated on the boundary region of an object. A binocular disparity is decided in a model of neural circuit by abstraction, synthesis, and correction of a disparity. And we propose a method which restores three-dimensional shape by correcting a depth information, and also restores a three-dimensional surface by mapping a left input image on the restored three-dimensional shape. And we confirmed that the computation time for disparity abstraction can be greatly reduced through the simulation.

• Journal of Korean Ophthalmic Optics Society
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• v.9 no.1
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• pp.93-104
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• 2004

In order to have a comfortable vision without any asthenopia in work place, it is very necessary to make a complete binocular correction in addition to the perfect correction of refractive deficits. For this, At first, the exact understanding of the required corrective value of the existing angular ametropia(associated phoria) is needed. The fact likely seems fact that a correction of refractive deficits could not to be reached with single optotype, the corrections of angular ametropia(associated phoria) with single optotype is impossible. The reason is that a most ametropia(associated phoria) is accompanied with the fixation disparity. To make a perfect measurement of ametropia(associated phoria), at least, 3 kinds of optotype is essential. This fact could be explained by stating the fusional stimulus in the binocular refraction tests on each eye. If these types of three tests have not practical practice. The most of many cases may result in undercorrection.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.42 no.4 s.304
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• pp.13-20
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• 2005

In this paper, we propose new smoothing filters, i.e., occluding patterns that can accurately correct disparities of occluded areas in the estimated disparity map. An image is composed of several layers and each layer presents similar disparity. Furthermore, the distribution of the estimated disparities has a specific direction around the boundary of the occlusion, and this distribution presents the different direction with respect to the left- and the right-based disparity map. However, typical smoothing filters, such as mean filter and median filter, did not take into account those characteristic. So, they can decrease some error, but they cannot guarantee the accuracy of the corrected disparity. On the contrary, occluding patterns can accurately correct disparities of occluded areas because they consider both the characteristic that occlusion occurs and the characteristic that disparities of the occlusion are ranged, from estimated disparity maps with respect to the left and the right images. We made experiments on occluding patterns with some real stereo image set, and as a result, we can correct disparities of occluded areas more accurately than typical smoothing filters did.

• Journal of Chest Surgery
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• v.30 no.1
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• pp.83-87
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• 1997

Taussig-Bing anomaly is infrequently associated with interrupted aortic arch and size discrepancy of great arteries makes it difficult to undergo arch reconstruction and arterial switch operation. A 20-day old male infant was admitted with the diagnosis of Taussig-Bing anomaly with type B Interrupted aortic arch. Multi-organ failure, due to the diminution of ductal flow, was stabilized after 3 weeks of prostaglandin El and controlled ventilatory support. The surgical correction consisted of VSD closure, arterial swtich and extended aortic arch reconstruction. The marked disparity between the hypoplastic ascending aorta and the dilated main pulmonary artery was overcome by constructing distal neoaorta using both native ascending and descending aortic tissue. The patient was extubated on postoperative 2nd day Postoperative catheterization showed no left ventricular outflow obstruction, no intracardiac shunt, and no incompetence of neoaortic valve.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.6
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• pp.3208-3229
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• 2017

Rectification is an essential procedure for simplifying the disparity extraction of stereo matching algorithms by removing vertical mismatches between left and right images. To support real-time stereo matching, studies have introduced several look-up table (LUT)- and computational logic (CL)-based rectification approaches. However, to support high-resolution images, the LUT-based approach requires considerable memory resources, and the CL-based approach requires numerous hardware resources for its circuit implementation. Thus, this paper proposes a multi-level accumulation-based rectification method as a simple CL-based method and its circuit implementation. The proposed method, which includes distortion correction, reduces addition operations by 29%, and removes multiplication operations by replacing the complex matrix computations and high-degree polynomial calculations of the conventional rectification with simple multi-level accumulations. The proposed rectification circuit can rectify $1,280{\times}720$ stereo images at a frame rate of 135 fps at a clock frequency of 125 MHz. Because the circuit is fully pipelined, it continuously generates a pair of left and right rectified pixels every cycle after 13-cycle latency plus initial image buffering time. Experimental results show that the proposed method requires significantly fewer hardware resources than the conventional method while the differences between the results of the proposed and conventional full rectifications are negligible.

• Journal of Chest Surgery
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• v.21 no.1
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• pp.184-190
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• 1988

The treatment of aortic aneurysm of ascending aorta has been fraught with difficult surgical problems. For the most part, these were resolved in 1968 with the introduction of a technique of total replacement of ascending aorta and reimplantation of the coronary arteries by Bentall and De Bono. This technique however, with all of its advantages, caries a certain problems. In chronic dissecting aneurysms, there is frequently a marked disparity in circumference between the true and false lumen distally. Distal perfusion is directed into both the true and false lumens by removing segment of the septum between the two lumens and constructing the distal graft anastomosis is to the outer layer of aortic adventitia. The distal false lumen, aortic branches and fenestrations have matured and healed in most cases. And importantly, major aortic tributaries may be solely dependent on the false lumen for perfusion. We are presenting two cases of chronic dissecting aneurysm of ascending aorta with aortic regurgitation, who have good result by surgical correction of so-called Bentall procedure with maintenance of blood flow directed into both true and false lumen.

• Wind and Structures
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• v.27 no.6
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• pp.369-380
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• 2018

In this research work, nonlinear thermal buckling behavior of functionally graded (FG) plates is explored based a new higher-order shear deformation theory (HSDT). The present model has just four unknowns, by using a new supposition of the displacement field which enforces undetermined integral variables. A shear correction factor is, thus, not necessary. A power law distribution is employed to express the disparity of volume fraction of material distributions. Three kinds of thermal loading, namely, uniform, linear, and nonlinear and temperature rises over z-axis direction are examined. The non-linear governing equations are resolved for plates subjected to simply supported boundary conditions at the edges. The results are approved with those existing in the literature. Impacts of various parameters such as aspect and thickness ratios, gradient index, type of thermal load rising, on the non-dimensional thermal buckling load are all examined.

• Journal of Korean Society on Water Environment
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• v.24 no.6
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• pp.793-800
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• 2008

Recently domestic drinking water industry has recognized membrane-based technology as a promising alternative for water treatment. To ensure successful application of membrane processes, the integrity of membrane systems should be maintained. According to US EPA guidance, the pressure decay test based on the bubble point theory is recommended to detect any membrane defection of which size is close to the smallest diameter of Cryptosporidium oocysts, $3{\mu}m$. Proper implementation of the pressure decay test is greatly affected by initial test pressure, and the interpretation of the test results is associated with upper control limit. This study is conducted to investigate various factors affecting determination of initial test prtessure and upper control limit, including membrane-based parameters such as pore shape correction factor, surface tension and contact angle, and system-based parameters, such as volumetric concentration factor and total volume of system. In this paper, three different hollow fibers were used to perform the pressure decay test. With identical initial test pressure applied, their pressure decay tendency were different from each other. This finding can be explained by the micro-structure disparity of those membranes which is verified by FESEM images of those membranes. More specifically, FESEM images revealed that three hollow fibers have asymmetry, deep finger, shallow finger pore shape, respectively. In addition, sensitivity analysis was conducted on five parameters mentioned above to elucidate their relation to determination of initial test pressure and upper control limit. In case of initial pressure calculation, the pore shape correction factor has the highest value of sensitivity. For upper control limit determination, system factors have greater impact compared to membrane-based parameters.