Appearance of Woven Cloth

The appearance of a particular fabric is produced by variations in both large-scale reflectance and small-scale texture as the viewing and illumination angles change across the surface. This thesis presents a study of the reflectance and texture of woven cloth that aims to identify and model the most important optical features of cloth appearance. New measurements are reported for a range of fabrics including natural and synthetic fibers as well as staple and filament yarns. A new scattering model for woven cloth is introduced that describes the reflectance and the texture based on an analysis of specular reflection from the fibers. Unlike data-based models, our procedural model requires no image data. It can handle a wide range of fabrics using a small set of physically meaningful parameters that describe the characteristics of the fibers, the geometry of the yarns, and the pattern of the weave. The model is validated against the measurements and by comparisons to high-resolution video of the real fabrics

Haptic cueing of a visual changedetection task: Implications for multimodal interfaces

This study is part of an ongoing program designed to investigate the integration of visual and haptic information in the context of multimodal interfaces. With the current experiments, we study whether haptic cues can be used to redirect spatial attention in a visual task where an observer is asked to detect a change between two scenes. Subjects were asked to look at visual scenes consisting of rectangular horizontal and vertical elements of equal sizes. Their task was to detect an orientation change in one of the elements. Prior to this visual task, the subject was tapped on the back at one of four locations by a vibrotactile stimulator. It was found that reaction time to detect a visual change decreased significantly when the location of the tactor coincided with the quadrant of the visual scene where the changing element occurred. It was also found that reaction time increased when the location of the tactile stimulation did not coincide with the visual quadrant where change occurred. These results have implications for designers of multimodal interfaces where a user can benefit from haptic attentional cues in order to detect and process information in a small area within a large and complex visual display

Perceptually Based Tone Mapping of High Dynamic Range Image Streams

This paper presents a new perceptually based tone mapping operator that represents scene visibility under timevarying, high dynamic range conditions. The operator is based on a new generalized threshold model that extends the conventional threshold-versus-intensity (TVI) function to account for the viewer’s adaptation state, and a new temporal adaptation model that includes fast and slow neural mechanisms as well as photopigment bleaching. These new visual models allow the operator to produce tone-mapped image streams that represent the loss of visibility experienced under changing illumination conditions and in high dynamic range scenes. By varying the psychophysical data that the models use, we simulate the differences in scene visibility experienced by normal and visually impaired observers. Categories and Subject Descriptors (according to ACM CCS): I.3.3 [Computer Graphics]: Picture/Image Generation