Geometric anticipation: assisting users in 2D layout tasks

We describe an experimental interface that anticipates a user's intentions and accommodates predicted changes in advance. Our canonical example is an interactive version of ``magnetic poetry'' in which rectangular blocks containing single words can be juxtaposed to form arbitrary sentences or ``poetry.'' The user can rearrange the blocks at will, forming and dissociating word sequences. A crucial attribute of the blocks in our system is that they anticipate insertions and gracefully rearrange themselves in time to make space for a new word or phrase. The challenges in creating such an interface are three fold: 1) the user's intentions must be inferred from noisy input, 2) arrangements must be altered smoothly and intuitively in response to anticipated changes, and 3) new and changing goals must be handled gracefully at any time, even in mid animation. We describe a general approach for handling the dynamic creation and deletion of organizational goals. Fluid motion is achieved by continually applying and correcting goal-directed forces to the objects. Future applications of this idea include the manipulation of text and graphical elements within documents and the manipulation of symbolic information such as equations

Geometric anticipation: assisting users in 2D layout tasks

We describe an experimental interface that anticipates a user's intentions and accommodates predicted changes in advance. Our canonical example is an interactive version of ``magnetic poetry'' in which rectangular blocks containing single words can be juxtaposed to form arbitrary sentences or ``poetry.'' The user can rearrange the blocks at will, forming and dissociating word sequences. A crucial attribute of the blocks in our system is that they anticipate insertions and gracefully rearrange themselves in time to make space for a new word or phrase. The challenges in creating such an interface are three fold: 1) the user's intentions must be inferred from noisy input, 2) arrangements must be altered smoothly and intuitively in response to anticipated changes, and 3) new and changing goals must be handled gracefully at any time, even in mid animation. We describe a general approach for handling the dynamic creation and deletion of organizational goals. Fluid motion is achieved by continually applying and correcting goal-directed forces to the objects. Future applications of this idea include the manipulation of text and graphical elements within documents and the manipulation of symbolic information such as equations

Direct HDR Capture of the Sun and Sky

We present a technique for capturing the extreme dynamic range of natural illumination environments that include the sun and sky, which has presented a challenge for traditional high dynamic range photography processes. We find that through careful selection of exposure times, aperture, and neutral density filters that this full range can be covered in seven exposures with a standard digital camera. We discuss the particular calibration issues such as lens vignetting, infrared sensitivity, and spectral transmission of neutral density filters which must be addressed. We present an adaptive exposure range adjustment technique for minimizing the number of exposures necessary. We demonstrate our results by showing time-lapse renderings of a complex scene illuminated by high-resolution, high dynamic range natural illumination environments

Assembling the Sculptures of the Parthenon

e light onto the casts with the video projector. Because of the efficiency of the system, we were able to scan over 440 linear feet of frieze, 52 metopes, and both pediments in just five days with a team of four people, totaling nearly 2,200 individual scans. Our calibration process involved scanning a flat checkerboard grid pattern in several orientations, allowing us to solve for the distortion characteristics and the relative orientations of the camera and projector. We developed methods for extracting these calibrations using HDRShop and Matlab, and then streamlined the process into a single Windows application. Given such calibration parameters and a scan of a sculpture, the 3D structure of the visible surface is triangulated. We found it was faster to remove undesirable geometry in the 2D camera image space before the scans were converted to 3D meshes. For this we developed a program that allows the user to view the scanned surface normals and mask out specific regions