Motion Parallax in Stereo 3D: Model and Applications

Binocular disparity is the main depth cue that makes stereoscopic images appear 3D. However, in many scenarios, the range of depth that can be reproduced by this cue is greatly limited and typically fixed due to constraints imposed by displays. For example, due to the low angular resolution of current automultiscopic screens, they can only reproduce a shallow depth range. In this work, we study the motion parallax cue, which is a relatively strong depth cue, and can be freely reproduced even on a 2D screen without any limits. We exploit the fact that in many practical scenarios, motion parallax provides sufficiently strong depth information that the presence of binocular depth cues can be reduced through aggressive disparity compression. To assess the strength of the effect we conduct psycho-visual experiments that measure the influence of motion parallax on depth perception and relate it to the depth resulting from binocular disparity. Based on the measurements, we propose a joint disparity-parallax computational model that predicts apparent depth resulting from both cues. We demonstrate how this model can be applied in the context of stereo and multiscopic image processing, and propose new disparity manipulation techniques, which first quantify depth obtained from motion parallax, and then adjust binocular disparity information accordingly. This allows us to manipulate the disparity signal according to the strength of motion parallax to improve the overall depth reproduction. This technique is validated in additional experiments

GazeStereo3D: seamless disparity manipulations

Producing a high quality stereoscopic impression on current displays is a challenging task. The content has to be carefully prepared in order to maintain visual comfort, which typically affects the quality of depth reproduction. In this work, we show that this problem can be significantly alleviated when the eye fixation regions can be roughly estimated. We propose a new method for stereoscopic depth adjustment that utilizes eye tracking or other gaze prediction information. The key idea that distinguishes our approach from the previous work is to apply gradual depth adjustments at the eye fixation stage, so that they remain unnoticeable. To this end, we measure the limits imposed on the speed of disparity changes in various depth adjustment scenarios, and formulate a new model that can guide such seamless stereoscopic content processing. Based on this model, we propose a real-time controller that applies local manipulations to stereoscopic content to find the optimum between depth reproduction and visual comfort. We show that the controller is mostly immune to the limitations of low-cost eye tracking solutions. We also demonstrate benefits of our model in off-line applications, such as stereoscopic movie production, where skillful directors can reliably guide and predict viewers' attention or where attended image regions are identified during eye tracking sessions. We validate both our model and the controller in a series of user experiments. They show significant improvements in depth perception without sacrificing the visual quality when our techniques are applied

Virtual viewpoint three-dimensional panorama

Conventional panoramic images are known to provide for an enhanced field of view in which the scene always has a fixed appearance. The idea presented in this paper focuses on the use of the concept of virtual viewpoint creation to generate different panoramic images of the same scene with three-dimensional component. Three-dimensional effect in a resultant panorama is realized by superimposing a stereo-pair of panoramic images

HiddenGazeStereo: Hiding Gaze-Contingent Disparity Remapping for 2D-Compatible Natural 3D Viewing

Stereoscopic 3D displays (S3D), the most popular consumer display devices for 3D presentation, have a few problems that degrade the natural visual experience, such as unnatural relationships between eye vergence and accommodation, and severe image blurring (ghost) for viewers without stereo glasses. To simultaneously solve these problems, we combine gaze-contingent disparity remapping with Hidden Stereo in a manner that mutually compensates for their respective shortcomings. Gaze-contingent disparity remapping can reduce the vergence-accommodation conflict by shifting the disparity distribution around the gaze position to be centered on the display plane. Hidden Stereo can synthesize 2D-compatible 3D stereo images that do not produce any ghosting artifacts when the images for the two eyes are linearly fused. Thus, by using our new gaze-contingent display, while one viewer with glasses enjoys natural 3D content, many other glassless viewers enjoy clear 2D content. To enable real-time synthesis, we accelerate Hidden Stereo conversion by limiting the processing to each horizontal scanline. Through a user study using a variety of 3D scenes, we demonstrate that Hidden Stereo can effectively hide disparity information to glassless viewers despite the dynamic disparity manipulations. Moreover, we show that our method can alleviate the limitation of Hidden Stereo --the narrow reproducible disparity range-- by manipulating the disparity so that the depth information around the gaze position is maximally preserved

Multimodal Stereoscopic Movie Summarization Conforming to Narrative Characteristics

Video summarization is a timely and rapidly developing research field with broad commercial interest, due to the increasing availability of massive video data. Relevant algorithms face the challenge of needing to achieve a careful balance between summary compactness, enjoyability, and content coverage. The specific case of stereoscopic 3D theatrical films has become more important over the past years, but not received corresponding research attention. In this paper, a multi-stage, multimodal summarization process for such stereoscopic movies is proposed, that is able to extract a short, representative video skim conforming to narrative characteristics from a 3D film. At the initial stage, a novel, low-level video frame description method is introduced (frame moments descriptor) that compactly captures informative image statistics from luminance, color, optical flow, and stereoscopic disparity video data, both in a global and in a local scale. Thus, scene texture, illumination, motion, and geometry properties may succinctly be contained within a single frame feature descriptor, which can subsequently be employed as a building block in any key-frame extraction scheme, e.g., for intra-shot frame clustering. The computed key-frames are then used to construct a movie summary in the form of a video skim, which is post-processed in a manner that also considers the audio modality. The next stage of the proposed summarization pipeline essentially performs shot pruning, controlled by a user-provided shot retention parameter, that removes segments from the skim based on the narrative prominence of movie characters in both the visual and the audio modalities. This novel process (multimodal shot pruning) is algebraically modeled as a multimodal matrix column subset selection problem, which is solved using an evolutionary computing approach. Subsequently, disorienting editing effects induced by summarization are dealt with, through manipulation of the video skim. At the last step, the skim is suitably post-processed in order to reduce stereoscopic video defects that may cause visual fatigue

Stereoscopic image stitching with rectangular boundaries

This paper proposes a novel algorithm for stereoscopic image stitching, which aims to produce stereoscopic panoramas with rectangular boundaries. As a result, it provides wider field of view and better viewing experience for users. To achieve this, we formulate stereoscopic image stitching and boundary rectangling in a global optimization framework that simultaneously handles feature alignment, disparity consistency and boundary regularity. Given two (or more) stereoscopic images with overlapping content, each containing two views (for left and right eyes), we represent each view using a mesh and our algorithm contains three main steps: We first perform a global optimization to stitch all the left views and right views simultaneously, which ensures feature alignment and disparity consistency. Then, with the optimized vertices in each view, we extract the irregular boundary in the stereoscopic panorama, by performing polygon Boolean operations in left and right views, and construct the rectangular boundary constraints. Finally, through a global energy optimization, we warp left and right views according to feature alignment, disparity consistency and rectangular boundary constraints. To show the effectiveness of our method, we further extend our method to disparity adjustment and stereoscopic stitching with large horizon. Experimental results show that our method can produce visually pleasing stereoscopic panoramas without noticeable distortion or visual fatigue, thus resulting in satisfactory 3D viewing experience

Human factors and performance considerations of visual spatial skills in medical context tasks

In the medical field, stereoscopic applications are present in diagnosis, pre-operative planning, minimally invasive surgery, instruction, and training. The use of stereoscopic applications has afforded new ways to interact with patient data, such as immersive virtual environments. This increased usage of stereoscopic applications also raises many basic research questions on human perception and performance. Current studies show mixed results on the benefits of stereoscopic applications with regards to general performance. The benefits depend on the specific task as well as the application domain. The work presented here attempts to answer the general question: How would adding the stereopsis depth cue affect the performance of visual spatial tasks in a medical context? Visual spatial tasks are needed in medicine to understand the relationships between shapes and organs for a variety of activities in patient diagnosis and treatment. The general research question was decomposed into specific hypotheses and three studies were conducted to study them. These studies measured performance of a visual spatial computer task using medical imaging data. Participants assessed the relative positions of three different objects located inside a 3D volumetric representation of a patient\u27s anatomy. The first study consisted of static views and recognition of the position of color objects. The second study consisted of static views using gray objects. The third study consisted of animated views of color objects. In all three studies the task was basically the same: To select which of two objects was closest to a reference object. In all three studies participants were first and second year medical students. Thirty-four participants completed the first study. The results of this study showed some emerging patterns in which the stereoscopic display condition had a positive benefit on performance. The stereoscopic condition had a positive effect on performance for the most difficult cases but did not yield higher results under every case and condition. The second study, completed by 44 participants, showed the stereoscopic condition had a positive benefit on performance in 20 out of the 40 tasks completed. These 40 tasks were divided into four cases, with varying degrees of difficulty, depending on the distances between the objects being judged (i.e. cylinders in this study). At distances between 5-15 mm, the stereoscopic condition yielded statistically significant higher performance. At other distance ranges, while stereopsis showed improvement it was not statistically significant. Thirty-one participants completed the third study. These participants completed a visual spatial task with the addition of an animation to the volume. This allowed the representation to be viewed from multiple angles before the task was completed. Overall the stereoscopic condition had a benefit in performance over the monoscopic condition. As in the previous studies tasks that had the objects between 5 - 15 mm apart had higher performance in the stereoscopic condition. Females performance in the stereoscopic condition was higher and statistically significant than for the monoscopic condition. Participants over 25 years also had a statistically significant higher performance under the stereoscopic condition. It was also observed that the stereoscopic condition did not outperform the monoscopic one in every condition. The results of these studies show that, in general, stereopsis has a positive benefit in performance for visual spatial tasks in medical contexts. This benefit certainly has a relationship with the difficulty of the task as well as age and gender. These initial insights are a step into further work to help generate design guidelines when developing stereoscopic applications

Novel haptic interface For viewing 3D images

In recent years there has been an explosion of devices and systems capable of displaying stereoscopic 3D images. While these systems provide an improved experience over traditional bidimensional displays they often fall short on user immersion. Usually these systems only improve depth perception by relying on the stereopsis phenomenon. We propose a system that improves the user experience and immersion by having a position dependent rendering of the scene and the ability to touch the scene. This system uses depth maps to represent the geometry of the scene. Depth maps can be easily obtained on the rendering process or can be derived from the binocular-stereo images by calculating their horizontal disparity. This geometry is then used as an input to be rendered in a 3D display, do the haptic rendering calculations and have a position depending render of the scene. The author presents two main contributions. First, since the haptic devices have a finite work space and limited resolution, we used what we call detail mapping algorithms. These algorithms compress geometry information contained in a depth map, by reducing the contrast among pixels, in such a way that it can be rendered into a limited resolution display medium without losing any detail. Second, the unique combination of a depth camera as a motion capturing system, a 3D display and haptic device to enhance user experience. While developing this system we put special attention on the cost and availability of the hardware. We decided to use only off-the-shelf, mass consumer oriented hardware so our experiments can be easily implemented and replicated. As an additional benefit the total cost of the hardware did not exceed the one thousand dollars mark making it affordable for many individuals and institutions