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Flower Garden stereo-pair. a) original left-eye image, b) original right-eye image, c) unprocessed interlaced stereo-pair, d) interlaced stereo-pair after translation and cropping.
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Eye strain is often experienced when viewing a stereoscopic image pair on a flat display device (e.g., a computer monitor). Violations of two relationships that contribute to this eye strain are: 1) the accommodation/convergence breakdown and 2) the conflict between interposition and disparity depth cues. We describe a simple algorithm that reduces...
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... first stereoscopic sequence examined, Flower Garden, was obtained from a monoscopic sequence with almost entirely horizontal camera motion. The left-and right-eye image sequences are the same monoscopic sequence delayed with respect to one another by two frames. The left-and right-eye images of the tenth stereo-pair of this sequence are shown in Figs. 3a and 3b, respectively. The line interlaced version of this stereo-pair, shown in Fig. 3c, illustrates the large negative disparity of the foreground tree. In fact, all image points in this stereo-pair have negative disparity, which make viewing of this sequence very difficult. A minimum disparity value of -12 pixels was calculated from the ...
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... with almost entirely horizontal camera motion. The left-and right-eye image sequences are the same monoscopic sequence delayed with respect to one another by two frames. The left-and right-eye images of the tenth stereo-pair of this sequence are shown in Figs. 3a and 3b, respectively. The line interlaced version of this stereo-pair, shown in Fig. 3c, illustrates the large negative disparity of the foreground tree. In fact, all image points in this stereo-pair have negative disparity, which make viewing of this sequence very difficult. A minimum disparity value of -12 pixels was calculated from the estimated disparity histogram for this image pair, and the resulting interlaced ...
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... the foreground tree. In fact, all image points in this stereo-pair have negative disparity, which make viewing of this sequence very difficult. A minimum disparity value of -12 pixels was calculated from the estimated disparity histogram for this image pair, and the resulting interlaced image after horizontal translation and cropping is shown in Fig. 3d. The foreground tree now appears to lie on the screen surface, with the rest of the scene behind the screen. While no formal human factors experiments were conducted, the raw and processed images were shown to approximately seven viewers, all of whom agreed that the pro- cessed imagery was much easier to view, and produced less ...
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... The problem is aggravated in geo-virtual reality systems, such as Digital Earth browsers, as these environments are usually so vast in territory that the parallax is always large. To alleviate this problem, the disparity of the images needs to be maintained under some level (McVeigh, Siegel, and Jordan 1996) and changes in the disparity need to be gentle (Kim, Kane, and Banks 2012). Geo-virtual reality systems rely on s3D visualization. ...
Due to advances in rendering techniques and hardware capability, stereoscopic 3D (s3D) visualization is becoming increasingly common in daily life. However, this does not change the fact that stereo effects and visual comfort depend greatly on how the related parameters are controlled during the production of the s3D images. In geo-virtual reality systems, which are important browsers for Digital Earth, the maintenance of these parameters is deeply related to the navigation process. Therefore, the navigation method in such systems requires special care. This paper presents a new flying method based on a Cubemap structure. The method defines a Vehicle model and modifies the original Cubemap structure by adding a front view camera during the navigation; it allows the users to fly through a virtual geographic environment with automatic speed control, smooth collision resolution, and dynamic adjustment of the s3D-related parameters. A user test was conducted to compare this new method with the original method based on the Cubemap structure. The results show that the new method performs better than the former one for it provides a convenient interaction experience with improved stereoscopic effect, and diminishes visual discomfort.
... Displaying the raw images in the HMD as they are captured would cause confusion and eye strain. 44 For this reason, the images are rectified using image processing techniques, prior to displaying them in the HMD. Moreover, they are displayed in the HMD full screen, which in principle allows for an improved detailed perception. ...
This paper describes and evaluates the use of a head-mounted display (HMD) for the teleoperation of a field robot. The HMD presents a pair of video streams to the operator (one to each eye) originating from a pair of stereo cameras located on the front of the robot, thus providing him/her with a sense of depth (stereopsis). A tracker on the HMD captures 3-DOF head orientation data which is then used for adjusting the camera orientation by moving the robot and/or the camera position accordingly, and rotating the displayed images to compensate for the operator's head rotation. This approach was implemented in a search and rescue robot (RAPOSA), and it was empirically validated in a series of short user studies. This evaluation involved four experiments covering two-dimensional perception, depth perception, scene perception, and performing a search and rescue task in a controlled scenario. The stereoscopic display and head tracking are shown to afford a number of performance benefits. However, one experiment also revealed that controlling robot orientation with yaw input from the head tracker negatively influenced task completion time. A possible explanation is a mismatch between the abilities of the robot and the human operator. This aside, the studies indicated that the use of an HMD to create a stereoscopic visualization of the camera feeds from a mobile robot enhanced the perception of cues in a static three-dimensional environment and also that such benefits transferred to simulated field scenarios in the form of enhanced task completion times.
... However, the cameras in the robot's frontal body are prone to misalignment, due to mechanical vibration. Displaying the raw images in the HMD as they are captured would cause confusion and eye strain [13] . For this reason , the images are rectified using image processing techniques , prior to displaying them in the HMD. ...
This paper proposes an alternative approach to common teleoperation methods found in search and rescue (SAR) robots. Using a head mounted display (HMD) the operator is capable of perceiving rectified images of the robot world in 3-D, as transmitted by a pair of stereo cameras onboard the robot. The HMD is also equipped with an integrated head-tracker, which permits controlling the robot motion in such a way that the cameras follow the operator's head movements, thus providing an immersive sensation to him. We claim that this approach is a more intuitive and less error prone teleoperation of the robot. The proposed system was evaluated by a group of subjects, and the results suggest that it may yield significant benefits to the effectiveness of the SAR mission. In particular, the user's depth perception and situational awareness improved significantly when using the HMD, and their performance during a simulated SAR operation was also enhanced, both in terms of operation time and on successful identification of objects of interest.
... When viewing a stereo pair on a flat screen, the right and left eye converge as if portions of the image are located at different distances, yet they continue to focus on the plane of the screen. This breakdown in the normal accommodation/convergence relationships is a known cause of eyestrain, and the severity of the strain is related to the disparity of the stereo images [3], [4]. The view interpolation method can be used to overcome this problem [5] and can also be used for multiview image compression. ...
This paper proposes a mesh-based representation method for the disparity map of stereo images. The proposed method is designed to concentrate mainly on applications of view interpolation and stereo image compression. To obtain high image quality in the view interpolation and compression of stereo images, we formulate the view-interpolation error and prediction error. In the formulation, the view-interpolation and prediction errors depend not only on the accuracy of the disparity map, but also on the gradient of the stereo images. The proposed representation method for the disparity map is based on a triangular mesh structure, which minimizes the formulated interpolation and prediction errors. The experimental results show that the proposed method yields higher quality view-interpolated images and also has better performance in stereo image compression than the conventional methods.
... Eye strain is attributed to a number of factors including the type of displays, content, and the constant vergence/accommodation adjustments in the human eye. There has been work on developing algorithms that attempt to reduce the strain on the eye when watching 3D videos [6]. The long term studies are necessary to understand the effects of 3D viewing on the eye strain and human vision. ...
This paper explores the challenges opportunities in developing and deploying 3D TV services. The 3D TV services can be seen as a general case of the multi-view video that has been receiving significant attention lately. The keys to a successful 3D TV experience are the availability of content, the ease of use, the quality of experience, and the cost of deployment. Recent technological advances have made possible experimental systems that can be used to evaluate the 3D TV services. We have developed a 3D TV prototype and have currently conducting our first user study to evaluate the quality and experience. These experiences have allowed us to identify challenges and opportunities in developing 3D TV services.
... Researchers have attempted to compensate for accommodation-convergence separation using numerous methods, including adjusting the disparity of the scene on-the-fly to place fixated objects onto the screen surface (zero parallax) using eye tracking 26,31 , simply limiting the range of disparities presented in the stereoscopic media (avoiding negative parallax), employing large user to screen distances, and by adjusting physical lenses to attempt to recreate natural blur effects. Blohm et al proposed synthetic DOF system (which they referred to as DOI -depth of interest) to make stereoscopic viewing more comfortable, selectively blurring regions of the image displaced from the fixation depth, confirming the efficacy of this approach by gathering feedback from human test subjects 1 . ...
Spatial contrast sensitivity varies considerably across the field of view, being highest at the fovea and dropping towards the periphery, in accordance with the changing density, type, and interconnection of retinal cells. This observation has enabled researchers to propose the use of multiple levels of detail for visual displays, attracting the name image foveation. These methods offer improved performance when transmitting images across low-bandwidth media by conveying only highly visually salient data in high resolution, or by conveying more visually salient data first and gradually augmenting with the periphery. For stereoscopic displays, the image foveation technique may be extended to exploit the additional acuity constraint of the human visual system caused by the focal system: limited depth of field. Images may be encoded at multiple resolutions laterally taking advantage of the space-variant nature of the retina (image foveation), and additionally contain blur simulating the limited depth of field phenomenon. Since optical blur has a smoothing effect, areas of the image inside the high-resolution fovea, but outside the depth of field may be compressed more effectively. The artificial simulation of depth of field is also believed to alleviate symptoms of virtual simulator sickness resulting from accommodation-convergence separation, and reduce diplopia.
... Several approaches have been proposed to reduce the discomfort caused by large disparities. For example, we can restrict the disparity in the image to a limited range by controlling camera convergence and separation appropriately or by increasing viewing distance so that objects with large disparities do not appear in the scene when the stereoscopic video is viewed 5,6 . These approaches are simple, but we cannot apply the former method to images that have already been captured. ...
Current binocular stereoscopic displays cause visual discomfort when the objects with large disparities are present in the scene. With this technique, the improvement of visual comfort has been reported by blurring far background and foregrounds in the scene. However, this technique has a drawback of degrading overall image quality. To lesson visual discomfort caused by large disparities while maintaining high-perceived image quality, we use a novel disparity-based asymmetrical filtering technique. Asymmetrical filtering, which refers to the filtering applied to the image of one eye only, has been showen to maintain the sharpness of a stereoscopic image, provided that the amount of filtering is low. Disparity-based asymmetrical filtering usese the disparity information in a stereoscopic image for controlling the severity of blurring. We investigated the effects of this technique on stereoscopic video by measuring visual comfort and apparent sharpness. Our results indicate that disparity-based asymmetrical filtering does not always improve visual comfort but it maintains image quality.
... Conversely, when looking at a stereoscopic display, the eyes accommodate on the plane of the screen but converge based on the parallax between the left and right viewpoint images. This breakdown of the habitually accustomed accommodation/ convergence relationship is a well-documented cause for eye strain [8]. The level of discomfort is highly individual and can be reduced with practice. ...
One of the most remarkable features of the human visual system is the ability to perceive three-dimensional depth. This phenomenon is primarily related to the fact that the binocular disparity causes two slightly different images to be projected on the retinas. The images are fused by the human brain into one three-dimensional view. Various stereoscopic display systems have been devised to present computer generated or otherwise properly produced images separately to the eyes resulting in the sensation of stereopsis. A stereoscopic visual communication system can be conceived by arranging two identical video cameras with an appropriate inter-ocular separation, encoding the video signals and transporting the resultant data over a network to one or more receivers where it is decoded and properly displayed. The requirements for realising such a system based on Internet technology are discussed in this paper and in particular a transport protocol extension is proposed. The design and implementation of a prototype system is discussed and some experiences from using it are reported.
... Conversely, when looking at a stereoscopic display, the eyes accommodate on the plane of the screen but converge based on the parallax between the left and right viewpoint images. This breakdown of the habitually accustomed accommodation/ convergence relationship is a well-documented cause for eye strain [8]. The level of discomfort is highly individual and can be reduced with practice. ...
One of the most remarkable features of the human visual system is the ability to perceive three-dimensional depth. This phenomenon is primarily related to the fact that the binocular disparity causes two slightly different images to be projected on the retinas. The images are fused by the human brain into one three-dimensional view. Various stereoscopic display systems have been devised to present computer generated or otherwise properly produced images separately to the eyes, resulting in the sensation of stereopsis. A stereoscopic visual communication system can be conceived by arranging two identical video cameras with an appropriate interocular separation, encoding the video signals and transporting the resultant data over a network to one or more receivers where it is decoded and properly displayed. The requirements for realising such a system based on Internet technology are discussed and in particular a transport protocol extension is proposed. The design and implementation of a prototype system is discussed and some experiences from using it are reported
This paper presents an efficient method for adjusting the 3D depth of an object including as much as a whole scene in stereo 3D images by utilizing a virtual fronto-parallel planar projection in the 3D space perceived by a viewer. The proposed method just needs to establish object correspondence instead of the accurate estimation of the disparity field or point correspondence. We simulate the depth adjustment of a 3D point perceived by a viewer through a corresponding pair of points on the stereo 3D images by moving the virtual fronto-parallel plane on which the left and right points are projected. We show that the resulting transformation of image coordinates of the points can be simply expressed by three values of a scale factor and two translations that depend on one parameter for the depth adjustment. The experimental results demonstrate the feasibility of the proposed approach that yields less visual fatigue and smaller 3D shape distortion than the conventional parallax adjustment method. The overall procedure can be efficiently applied to each frame of a stereo video without causing any artifact.
