• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.4
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• pp.37-42
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• 2018

With advancements in digital image production technology, the branch of stereoscopic image technology has also been undergoing active development. Accordingly, research and development on cutting-edge display products for mounting stereoscopic images are currently being pursued. There are various problems that can occur when viewing 3D images. Because viewers feel visual fatigue while perceiving the depth of the images provided via an artificial method, a negative human factor such as visual fatigue has become one of the most prominent concerns, especially as it is a factor that affects the ongoing maintenance of 3D images. Therefore, by identifying the factors affecting the depth of the graphic images provided in 2D images, and subsequently using this information to develop an image processing method, we conducted depth-related experiments and analysed them under the assumption that stereoscopic images could be reproduced without visual fatigue. Thus, we analysed the most significant factors related to depth and verified the interactions by performing depth-related factors-based ANOVA variance analysis by differentially applying the texture, colour temperature, and contrast ratio to graphic images. We determined the significance of the factors related to depth and proposed a method to improve depth based on an analysis of the results of the experiments conducted in this study.

• ETRI Journal
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• v.26 no.6
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• pp.597-604
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• 2004

In stereoscopic television, there is a trade-off between visual comfort and 3-dimensional (3D) impact with respect to the baseline-stretch of a 3DTV camera. It is necessary to adjust the baseline-stretch at an appropriate the distance depending on the contents of a scene if we want to obtain a subjectively optimal quality of an image. However, it is very hard to obtain a small baseline-stretch using commercially available cameras of broadcasting quality where the sizes of the lens and CCD module are large. In order to overcome this limitation, we attempt to freely control the baseline-stretch of a stereoscopic camera by synthesizing the virtual views at the desired location of interval between two cameras. This proposed technique is based on the stereo matching and view synthesis techniques. We first obtain a dense disparity map using a hierarchical stereo matching with the edge-adaptive multiple shifted windows. Then, we synthesize the virtual views using the disparity map. Simulation results with various stereoscopic images demonstrate the effectiveness of the proposed technique.

• Journal of Broadcast Engineering
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• v.19 no.2
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• pp.205-214
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• 2014

Minimization of visual fatigue is important for production of high quality stereoscopic 3D contents. Vertical disparity of stereo images occurred during contents production is considered as the main factor of visual fatigue. To ensure correct stereoscopy vertical disparity needs to be eliminated. In this paper, a method for automated image alignment was proposed for Stereoscopic 3D contents generation and post-processing steps. The proposed method consists of two parts: rectification for image alignment and camera motion detection. The proposed method showed that its rectification performance was the most superior among the existing methods tested and that camera motion detection had a success rate of 98.35%. Through these evaluations, we confirmed that the proposed method can be effectively applied to 3D contents production.

• Journal of Broadcast Engineering
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• v.16 no.4
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• pp.584-595
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• 2011

Recently, RGB images and depth maps have been supplied to academic fields. The depth maps are utilized to the generation of stereoscopic images in the diverse formats according to the users' preference. A variety of methods that use depth maps have been introduced so far. One of applications is a medical field. In this area, the improvement of the perceptual quality of 2D medical images has gained much interest. In this paper, we propose a novel scheme that expands the conventional method to 3D stereoscopic image, thereby achieving the perceptual depth quality improvement as well as 3D stereoscopic perception enhancement at the same time. For this, contrast transformation as well as depth darkening are proposed and their performance is validated through the subjective test. Subjective experiments peformed for stereoscopic enhancement as well as visual fatigue validate that the proposed method achieves better 3D perception than the usage of the original stereoscopic image and suggests the limitation in terms of the visual fatigue.

• Journal of Korean Ophthalmic Optics Society
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• v.19 no.3
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• pp.363-369
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• 2014

Purpose: Three-dimensional (3D) displays are very useful in many fields, but induce physical discomforts in some people. This study is to assess symptom type and severity of asthenopia with their habitual distance corrective spectacle (HDCS) and their binocular vision corrective spectacle lenses (BVCSL) in people who feel physical discomforts. Methods: 35 adult subjects (ages $32.2{\pm}4.4$ yrs) were pre-screened out of 98 individuals to have the highest symptom/asthenopia scores following 65 minutes of 3D television viewing with HDCS. These 35 individuals were then retested symptom/asthenopia scores during they watched 3D television for 65 minutes at a distance of 2.7 m with wearing BVCSL of horizontal, vertical or base down yoked prisms. A 4-point symptom-rating scale questionnaire (0=no symptom and 3=severe) was used to assess 11 symptoms (e.g., blur, diplopia, etc.) related to visual fatigue/visual discomfort. Distance and near lateral phoria were measured using Howell phoria card and vertical phoria were measured using Maddox rod. Symptoms induced by watching 3D TV were compared between wearing HDCS and BVCSL. Results: Asthenopia in watching 3D TV with wearing BVCS was significantly lower than wearing HDCS at 5, 25, 45, and 65 minutes (all p < 0.001, paired t-tests). In only refractive error power correction power group, all asthenopia was not significantly different between HDCS and BVCSL (all $p{\geq}0.05$, paired t-tests). In prism correction groups for binocular imbalance, symptoms of asthenopia, however, was significantly lower for when wearing BVCSL than when wearing HDCS (all p < 0.05). Conclusions: Correction of phoria/vergence-based binocular vision imbalance can reduce asthenopia during 3D television viewing. An individual with binocular vision imbalance need corrected/compensated glasses with appropriate prisms prior to prolonged viewing of 3D television displays to reduce asthenopia/visual fatigue.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.125-128
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• 2013

The reason why visual fatigue occurs while watching 3D TV is because the left/right images of the fixed disparity are played. This paper proposes a measuring method of pupil distance and the 3D location of a viewer using stereo camera modules, and a reflection method of the data into 3D TV.

• Science of Emotion and Sensibility
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• v.12 no.2
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• pp.169-180
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• 2009

The present study have investigated the effect of the characteristics of stereoscopic images and viewing environment on visual fatigue. We manipulated the speed of stereo images with motion-in-depth and viewing distance, which were used as representative variables of the characteristics of stereo image and viewing environment, respectively. Visual fatigue was evaluated with use of a subjective questionnaire which is consisting of 5 different and independent factors: "Eye pain", "Visual stress," "Nauseousness", "Body stiffness", and "Blurriness". In general, when viewing time increased from 10 minutes to 20 and 40 minutes, observers felt severe visual fatigue. Among other factors, only the factor score of "Nauseousness" was significantly increased as the speed of object moving in depth became faster. When viewing distance was increased, the score of "Blurriness" was decreased. These results suggest that different kind of the visual fatigue might be induced depending on characteristics of the stereo images and viewing environment.

• Journal of Information Display
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• v.8 no.4
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• pp.23-26
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• 2007

A natural 3D image is considered by many people to be next-step in evolution of displays. This paper introduces autostereoscopic 3D of 60-view number, which is made using slanted lenticular lens array and LCD of 15.1 inch diagonal size and 3200 by 2400 pixel numbers and presents the results of our prototype. Due to its large view number, smooth motion parallax is observed and the visual fatigue is reduced.

• Journal of Broadcast Engineering
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• v.18 no.1
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• pp.66-76
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• 2013

Although there has been much advance in the development of 3D displays of various purpose, 3D contents are not yet so used as expected in those displays. One well-known obstacle in the enjoyment of 3D contents is visual fatigue, but another major issue is image distortion of 3D contents. In the previous research, Shin, Li, & Kim (2012) reported systematic linear relationship between screen disparity and size perception of a simple object whose retinal size was constant across different disparities. In this research, we intended to generalize the previous finding by using various 3D stimuli in the test of the relationship between screen disparity and size perception of those stimuli. Consistent with previous findings, our data indicated that size perception linearly changes as a function of screen disparity and the linearity was observed in all stimuli types we used in this research. We described the empirical relationship between screen disparity and size perception in the form of prediction function for size perception in which visual angle is the predictor. This function will be very useful in the creation of 3D contents as one can make reasonable predictions on the to-be-perceived size of an object being filmed using screen disparity of their camera setting.

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.11
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• pp.74-85
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• 2012

In this paper, we propose a optical property correction technique for a low-cost heterogeneous stereoscopic camera. Three main optical properties of a stereoscopic camera are zoom, focus, and DOF(depth of field). The difference or mis-match of these properties between two stereoscopic videos are the main causes of the visual fatigue to human eyes. The proposed correction technique reduces the difference of the optical properties between the stereoscopic videos and produces high-quality stereoscopic videos. To correct the zoom difference, a LUT(look-up table) is established to match the zoom ratio between the stereoscopic videos. To correct the DOF difference, the magnitude of image edge is measured and the lens iris is changed to control the DOF of the camera. A vertical-type stereoscopic rig is developed for the experiments of the optical property correction. Based on the experimental results, we find that a low-cost heterogeneous stereoscopic camera can be implemented, which can yield low visual fatigue to human eyes.