화면 시차로부터 지각되는 3D 컨텐츠의 입체시 깊이

감기택(Keetaek Kham) 한국방송·미디어공학회 2016 방송공학회논문지 Vol.21 No.1

This study was investigated whether the perceived depth was changed depending on the measurement methods. In the method of direct comparison, virtual object with one of the various binocular disparities was presented in the frontal space with LEDs which were used for depth estimation for a binocular stimulus, while in the method of indirect comparison, visual object was presented in the frontal space but the LEDs were placed rightward at the angle of 45 degree from the mid-sagittal line. In these experimental setup, the depth of binocular stimulus was directly matched that of LED in direct comparison condition. In indirect comparison condition, however, observer estimated the depth of binocular stimulus, turned ones head rightward to the array of LEDs and turned on the LED which was supposed to be the same depth as binocular stimulus. Additionally, it was investigated whether the perceived depth was different depending on observers stereo acuity. The results showed that perceived depths measured in the direct comparison were more similar to the depth predicted from geometry than those in the indirect comparison, and that the perceived depths from observers with high stereo acuity were similar to the predicted depth from geometry those from observers with low stereo acuity. These results indicated that stereoscopic depths of the binocular stimuli would vivid and compelling when binocular stimuli was simultaneously presented with real objects in the same visual space, like a mixed reality.

3D TV 시청 환경에서 수렴 훈련에 의한 시각적 불편감의 감소

감기택(Keetaek Kham),전현민(Hyunmin Jeon) 한국방송·미디어공학회 2013 방송공학회논문지 Vol.18 No.5

The present study investigated whether convergence training in which has an effect on reducing visual discomfort in viewing 3D TV. The stereoscopic depth of 3D training stimulus was gradually increased while maintaining individual visual discomfort at a minimum value. Participants were randomly assigned into one of three groups: a control group and two training groups. For both training groups, all procedure and the disparity range of training stimuli were the same except the order of the disparities of training stimuli. One of the two different training procedure was provided: gradual change or random change of the disparities of training stimulus. Training itself was very effective so that convergence fusional range was improved after three sessions of training with intervals of two weeks. In order to evaluate the effect of convergence training on visual discomfort, the subjective visual discomfort in 3D TV viewing was measured before and after training sessions using questionnaire. The results showed that a significant reduction in visual discomfort was found after training only in the group of gradual change. These results demonstrated a repeated convergence training might be helpful in reducing the visual discomfort in 3D TV environment.

두 위치 오류 현상의 직접적인 비교

감기택(Keetaek Kham) 한국인지과학회 2007 인지과학 Vol.18 No.3

회전 운동 잔여 효과의 확산 현상

감기택(Keetaek Kham) 한국인지과학회 2005 인지과학 Vol.16 No.1

워터 마크 잡음 탐지에 미치는 디지털 영상의 밝기와 대비의 효과

감기택(Keetaek Kham),문호석(Ho-Seok Moon),유헌우(Hun-Woo Yoo),정찬섭(Chan-Sup Chung) 한국인지과학회 2005 인지과학 Vol.16 No.4

표면 요소의 시선방향에 의한 동일시선 상에 놓여있는 표면의 입체시 깊이 변화

감기택(Keetaek Kham) 한국인지과학회 2004 인지과학 Vol.15 No.4

비순응 영역으로의 운동 잔여효과의 번짐에 미치는 삼차원 깊이 불연속의 효과

감기택(Keetaek Kham) 한국인지과학회 2010 인지과학 Vol.21 No.1

운동자극에 오랫동안 노출된 이후 해당 자극이 제시된 망막상의 영역에 제시된 정지 자극은 운동 자극의 방향과는 반대방향으로 움직이는 것으로 지각되는 운동 잔여효과(motion aftereffect: MAE)가 발생한다. 본 연구에서는 운동순응에 의해 발생된 운동 잔여효과가 인접 비순응 영역에까지 번져나가는 현상이 양안 시차에 의해 깊이가 다른 표면에서도 발생하는 지를 살펴보았다. 동심원의 고리부분에만 운동순응을 시킨 후, 실험 1에서는 양안 시차에 의한 경사 표면을 중앙 비순응 영역에 제시했고 실험 2에서는 양안시차에 의해 깊이가 다른 정면평행 표면(fronto parallel plane)을 중앙 비순응 영역에 제시하였다. 경사 표면인 경우 주변 순응영역과 깊이가 동일한 비경사조건에서의 MAE지속시간과 유사한 반면, 깊이가 다른 정면 평행 표면에서는 동일 깊이 조건보다 MAE 지속시간은 줄어들었지만 완전히 사라지지는 않았다. 이러한 결과는 MAE의 번짐 현상이 깊이 불연속 정보에 의해 영향 받는다는 것을 보여줄 뿐만 아니라 양안정보가 합치된 이후에도 발생될 수 있음을 시사한다. The stationary image appears to move after we view a moving stimulus for a long time. The motion aftereffect(MAE) can spread to an adjacent region if there is no contrast discontinuity between two regions. In this study, it is investigated whether a phenomenon of MAE spreading to an adjacent non adapting area is affected by the depth discontinuity defined by binocular disparity. In the first experiment a disparity defined slanted pattern was presented in an unadapted region, and in the second experiment, a disparity defined pattern with a different depth was presented on the fronto-parallel plane. Although MAE duration in the condition with slanted pattern was not different from that in the non-slanted pattern condition, MAE durations in the pattern presented on pronto-parallel plane was vividly reduced, but not completely disappeared. These results suggest that a phenomenon of MAE spreading might be affected by depth discontinuity, and could be occurred after binocular information converges.

3D 환경에서 가보 영상을 이용한 입체 시력 검사도구의 개발

감기택(Keetaek Kham) 한국방송·미디어공학회 2015 방송공학회논문지 Vol.20 No.6

Many studies tried to develop a 3D display based stereo test as a substitute for the conventional stereo test. Although many 3D monitor based stereo tests have various advantages over the conventional stereo tests with printed stimuli, they have a crucial limitation in manipulating disparity. The least value for disparity manipulation is one pixel, which is too big to screen the normal stereo acuity in pc environment with a short viewing distance. In this explorative study, a Gabor image was employed as a test stimulus, because its position can be manipulated by changing its phase information, which allows sub-pixel manipulation for disparity. Instead of employing the methods of the conventional stereo tests where measurement was made only once for each of a wide range of disparity values, 10 replications were administrated for each of 6 disparity levels. The results from the test using Gabor images were compared with those using random dot stimulus because the latter stimulus was exactly the same as that of the conventional stereo test. The correlation coefficient between two tests was found to be moderate. After one month later, the whole test was repeated in the same settings. The correlation coefficient between test and retest results from Gabor images was found to be as high as that from a random dot stimulus, implying high test-retest reliability. These results suggest that a Gabor stimulus could be used as a test stimulus for the valid and reliable stereo test, even in the limited condition, such as 3D environment with a short viewing distance and a condition for evaluating the stereo acuity very precisely.

동공간 거리가 입체시 지각에 미치는 영향

감기택(Keetaek Kham),이주환(Ju-Hwan Lee) 한국인지과학회 2003 인지과학 Vol.14 No.3

색채 - 운동 오결합에서 삼차원 표면배열의 효과

감기택(Keetaek Kham) 한국인지과학회 2010 인지과학 Vol.21 No.1

색상이 다른 점들이 서로 반대 방향으로 움직이는 무선점 자극을 중앙 영역에 제시하고, 주변 영역에는 이와 반대의 색상을 가진 무선점 자극을 제시하면 주변영역에 있는 점들의 속성은 중앙 영역에 있는 점들의 속성과 동일하게 지각되는 색상-운동 오결합 현상이 발견된다. 본 연구에서는 이러한 오결합이 중앙영역과 주변영역이 동일한 깊이 표면을 구성하지 못하는 상황에서도 여전히 발생하는 지를 알아보기 위해 실험 1에서는 주변영역의 점들을 중앙영역과는 다른 깊이에 제시하였고 실험 2에서는 주변영역의 점들을 주어진 깊이 범위 내에서 무선적으로 변화시켰다. 두 실험 결과 중앙과 주변영역의 점들이 동일 깊이에 제시된 조건과 비교해 볼 때 두 영역이 동일한 표면을 형성하지 못할 때 오결합 정도는 약화되었지만 완전히 사라지지는 않았다. 이러한 결과는 운동정보에 의한 표면뿐만 아니라 양안시차에 의한 표면정보가 오결합 과정에 영향을 주는 것을 보여준다. If color and motion direction of random dots in the central region was combined in opposite fashions with those of random dots in the peripheral region, the color of dots with a particular direction in the peripheral region is perceived as that of dots in the central region, known as color-motion mis-binding phenomenon. In the present study, it is investigated whether mis-binding would happen even if the central and peripheral region do not have a common three-dimensional surface. In the first experiment, the dots in the peripheral were presented in a different depth plane with use of binocular disparity, and in the second experiment the disparity of dots in the peripheral region was randomly selected from a given range. The results showed that the magnitude of mis-binding was weakened, but not completely disappeared even when two regions did not have a common 3D surface. These results indicate that the surface information from motion and stereodepth may influence in the process of color-motion mis-binding.