Reynold J. Bailey

Subtle gaze direction

This article presents a novel technique that combines eye-tracking with subtle image-space modulation to direct a viewers gaze about a digital image. We call this paradigm subtle gaze direction. Subtle gaze direction exploits the fact that our peripheral vision has very poor acuity compared to our foveal vision. By presenting brief, subtle modulations to the peripheral regions of the field of view, the technique presented here draws the viewers foveal vision to the modulated region. Additionally, by monitoring saccadic velocity and exploiting the visual phenomenon of saccadic masking, modulation is automatically terminated before the viewers foveal vision enters the modulated region. Hence, the viewer is never actually allowed to scrutinize the stimuli that attracted her gaze. This new subtle gaze directing technique has potential application in many areas including large scale display systems, perceptually adaptive rendering, and complex visual search tasks.

Improving search task performance using subtle gaze direction

A new experiment is presented which demonstrates the usefulness of an image space modulation technique called Subtle Gaze Direction (SGD) for guiding the user in a simple searching task. SGD uses image space modulations in the luminance channel to guide a viewers gaze about a scene without interrupting their visual experience. The goal of SGD is to direct a viewers gaze to certain regions of a scene without introducing noticeable changes in the image. Using a simple searching task we compared performance using no modulation, using subtle modulation and using obvious modulation. Results from the experiments show improved performance when using subtle gaze direction, without affecting the users perception of the image. Results establish the potential of the method for a wide range of applications including gaming, perceptually based rendering, navigation in virtual environments and medical search tasks.

Search task performance using subtle gaze direction with the presence of distractions

A new experiment is presented that demonstrates the usefulness of an image space modulation technique called subtle gaze direction (SGD) for guiding the user in a simple searching task. SGD uses image space modulations in the luminance channel to guide a viewers gaze about a scene without interrupting their visual experience. The goal of SGD is to direct a viewers gaze to certain regions of a scene without introducing noticeable changes in the image. Using a simple searching task, we compared performance using no modulation, using subtle modulation, and using obvious modulation. Results from the experiments show improved performance when using subtle gaze direction, without affecting the users perception of the image. We then extend the experiment to evaluate performance with the presence of distractors. The distractors took the form of extra modulations, which do not correspond to a target in the image. Experimentation shows, that, even in the presence of distractors, more accurate results are returned on a simple search task using SGD, as compared to results returned when no modulation at all is used. Results establish the potential of the method for a wide range of applications including gaming, perceptually based rendering, navigation in virtual environments, and medical search tasks.

Subtle gaze manipulation for improved mammography training

We use the Subtle Gaze Direction technique (SGD) to guide novices as they try to find abnormalities in mammograms. SGD works by performing image-space modulations on specific regions of the peripheral vision to attract attention. Gaze is monitored and modulations are terminated before they are scrutinized with high-acuity foveal vision. This approach is preferred to overt techniques which permanently alter images to highlight areas of interest. SGD is used to guide novices along the scanpath of an expert radiologist. We hypothesized that this would increase the likelihood of novices correctly identifying irregularities. Results reveal that novices who were guided in this manner performed significantly better than the control group (no gaze manipulation). Furthermore, a short-term post-training lingering effect was observed among subjects guided using SGD. They continued to perform better than the control group once the training was complete and gaze manipulation was disabled.

Guiding attention in controlled real-world environments

The ability to direct a viewers attention has important applications in computer graphics, data visualization, image analysis, and training. Existing computer-based gaze manipulation techniques, which direct a viewers attention about a display, have been shown to be effective for spatial learning, search task completion, and medical training applications. In this work we extend the concept of gaze manipulation beyond digital imagery to include controlled, real-world environments. We address two main challenges in guiding attention to real-world objects: determining what object the viewer is currently paying attention to, and providing (projecting) a visual cue on a different part of the scene in order to draw the viewers attention there. Our system consists of a pair of eye-tracking glasses to determine the viewers gaze location, and a projector to create the visual cue in the physical environment. The results of a user study show that we can effectively direct the viewers gaze in the real-world scene. Our technique has applicability in a wide range of instructional environments, including pilot training and driving simulators.

Evolutionary spectral co-clustering

Co-clustering is the problem of deriving sub-matrices from the larger data matrix by simultaneously clustering rows and columns of the data matrix. Traditional co-clustering techniques are inapplicable to problems where the relationship between the instances (rows) and features (columns) evolve over time. Not only is it important for the clustering algorithm to adapt to the recent changes in the evolving data, but it also needs to take the historical relationship between the instances and features into consideration. We present ESCC, a general framework for evolutionary spectral co-clustering. We are able to efficiently co-cluster evolving data by incorporation of historical clustering results. Under the proposed framework, we present two approaches, Respect To the Current (RTC), and Respect To Historical (RTH). The two approaches differ in the way the historical cost is computed. In RTC, the present clustering quality is of most importance and historical cost is calculated with only one previous time-step. RTH, on the other hand, attempts to keep instances and features tied to the same clusters between time-steps. Extensive experiments performed on synthetic and real world data, demonstrate the effectiveness of the approach.

Using texture synthesis for non-photorealistic shading from paint samples

This paper presents several methods for shading meshes from scanned paint samples that represent dark to light transitions. Our techniques emphasize artistic control of brush stroke texture and color. We first demonstrate how the texture of the paint sample can be separated from its color gradient. We demonstrate three methods, two real-time and one off-line, for producing rendered, shaded images from the texture samples. All three techniques use texture synthesis to generate additional paint samples. Finally, we develop metrics for evaluating how well each method achieves our goal in terms of texture similarity, shading correctness and temporal coherence.

Directing gaze in narrative art

Narrative art tells a story, either as a moment in an ongoing story or as a sequence of events unfolding over time. In many works of art separate panels within the same frame are used to depict the sequence of events. Often, there is no clear delineation between these panels, or any indication of the optimal viewing order. To improve visual literacy we propose using Subtle Gaze Direction (SGD) to direct the viewers gaze across an image in a manner which reveals the story. SGD uses small image space modulations in the luminance channel to guide a viewers gaze about an image without disrupting their normal visual experience. Using a simple ordering task we compared performance using no modulation and using subtle modulation with the correct order of narrative episodes as intended by the artist. Results from experiments show improved performance when SGD is employed. This experiment establishes the potential of the method as an aid to visual navigation in images where the viewing order is unclear.

Tabletop Computed Lighting for Practical Digital Photography

We apply simplified image-based lighting methods to reduce the equipment, cost, time, and specialized skills required for high-quality photographic lighting of desktop-sized static objects such as museum artifacts. We place the object and a computer-steered moving-head spotlight inside a simple foam-core enclosure and use a camera to record photos as the light scans the box interior. Optimization, guided by interactive user sketching, selects a small set of these photos whose weighted sum best matches the user-defined target sketch. Unlike previous image-based relighting efforts, our method requires only a single area light source, yet it can achieve high-resolution light positioning to avoid multiple sharp shadows. A reduced version uses only a handheld light and may be suitable for battery-powered field photography equipment that fits into a backpack.

The Real Effect of Warm-Cool Colors

Abstract The phenomenon of warmer colors appearing nearer in depth toviewers than cooler colors has been studied extensively by psy-chologists and other vision researchers. The vast majority of thesestudies have asked human observers to view physically equidistant,colored stimuli and compare them for relative depth. However, inmost cases, the stimuli presented were rather simple: straight col-ored lines, uniform color patches, point light sources, or symmet-rical objects with uniform shading. Additionally, the colors usedwere typically highly saturated. Although such stimuli are use-ful in isolating and studying depth cues in certain contexts, theyleave open the question of whether the human visual system oper-atessimilarlyforrealisticobjects. Thispaperpresentstheresultsofan experiment designed to explore the color-depth relationship forrealistic, colored objects with varying shading and contours.CR Categories: I.4.8 [Image Processing and Computer Vision]:Scene Analysis—Depth CuesKeywords: depth perception, depth cues, warm-cool colors