Painting Lighting and Viewing Effects

We present a system for painting how the appearance of an object changes under different lighting and viewing conditions. The user paints what the object should look like under different lighting conditions (dark, partially dark, fully lit, etc.) and (optionally) different viewing angles. The system renders the object under new lighting conditions and a new viewing angle by combining these paintings. We also provide a technique for constructing texture maps directly from the user’s paintings

Results of an observational study on sketching

We present the results of an observational study on sketching. Artists were asked to sketch a small number of objects and comment on how and why they made the marks they did. We summarize these findings, from low-level details on individual marks through the drawing construction order. Based on these observations we provide suggestions for future research directions in 3D sketching

Creating View-dependent Texture Maps

We present a technique for blending multiple images of an object into a single, view-dependent texture map for that object. This technique can be used for image-based rendering, when the object is known, or for “painting” a view-dependent texture map of an object. The technique provides a structured mechanism for combing images at different resolutions, producing a mip-map like structure with the different levels constructed from different images. The user controls the camera angles for which a given image is valid. The technique is also suitable for use on an object that will be animated

Smooth Key-framing using the Image Plane

This paper demonstrates the use of image-space constraints for key frame interpolation. Interpolating in image-space results in sequences with predictable and controlable image trajectories and projected size for selected objects, particularly in cases where the desired center of rotation is not fixed or when the key frames contain perspective distortion changes. Additionally, we provide the user with direct image-space control over {\em how} the key frames are interpolated by allowing them to directly edit the object\u27s projected size and trajectory. Image-space key frame interpolation requires solving the inverse camera problem over a sequence of point constraints. This is a variation of the standard camera pose problem, with the additional constraint that the sequence be visually smooth. We use image-space camera interpolation to globally control the projection, and traditional camera interpolation locally to avoid smoothness problems. We compare and contrast three different constraint-solving systems in terms of accuracy, speed, and stability. The first approach was originally developed to solve this problem [Gleicher and Witken 1992]; we extend it to include internal camera parameter changes. The second approach uses a standard single-frame solver. The third approach is based on a novel camera formulation and we show that it is particularly suited to solving this problem

Smooth Surface Reconstruction using Charts for Medical Data

We present a surface reconstruction technique that constructs a smooth analytic surface from scattered data. The technique is robust to noise and both poorly and non-uniformly sampled data, making it well-suited for use in medical applications. In addition, the surface can be parameterized in multiple ways, making it possible to represent additional data, such as electromagnetic potential, in a different (but related) coordinate system to the geometric one. The parameterization technique also supports consistent parameterizations of multiple data sets

Local Neighborhoods for Shape Classification and Normal Estimation

We introduce the concept of local neighborhoods, a generalization of the one-ring on a mesh to unlabeled 3D data points arising from sampling a 2D surface embedded in 3D. The local neighborhood supports both local shape classification and robust normal estimation. In particular, local neighborhoods out-perform traditional approaches in unevenly sampled, curved regions. We show that the local neighborhood can be used in place of a full mesh structure for applications such as smoothing, moving least-squares reconstruction, and parameterization. Longer version of paper submitted to CAG

Averting Robot Eyes

Home robots will cause privacy harms. At the same time, they can provide beneficial services—as long as consumers trust them. This Essay evaluates potential technological solutions that could help home robots keep their promises, avert their eyes, and otherwise mitigate privacy harms. Our goals are to inform regulators of robot-related privacy harms and the available technological tools for mitigating them, and to spur technologists to employ existing tools and develop new ones by articulating principles for avoiding privacy harms. We posit that home robots will raise privacy problems of three basic types: (1) data privacy problems; (2) boundary management problems; and (3) social/relational problems. Technological design can ward off, if not fully prevent, a number of these harms. We propose five principles for home robots and privacy design: data minimization, purpose specifications, use limitations, honest anthropomorphism, and dynamic feedback and participation. We review current research into privacy-sensitive robotics, evaluating what technological solutions are feasible and where the harder problems lie. We close by contemplating legal frameworks that might encourage the implementation of such design, while also recognizing the potential costs of regulation at these early stages of the technology

Non-Photorealistic Rendering of Algorithmically Generated Trees

This work presents a novel rendering technique inspired by artistic approaches. Instead of trying to recreate the appearance of a traditional medium, such as charcoal or watercolor, this approach is a mixture of both photo-realism and abstraction. Artists use a process of abstraction to provide structural information about subjects that do not have clearly defined shapes, such as groups of leaves in a tree. For example, an artist will first use a color wash to approximate a group of leaves, then add detail on top of parts of this wash to indicate individual leaves. Similarly, we use an abstract shape that approximates the image of leaves clustered at the end of a branch. To prevent oversimplification, we add photo-realistic detail using a blending process. Inter-frame coherence is achieved by smoothly interpolating the abstract shapes as well as by the continuity inherent in the photo-realistically rendered detail

Perceptually Meaningful Image Editing: Depth

We introduce the concept of perceptually meaningful image editing and present two techniques for manipulating the apparent depth of objects in an image. The user loads an image, selects an object and specifies whether the object should appear closer or further away. The system automatically determines target values for the object and/or background that achieve the desired depth change. These depth editing operations, based on techniques used by traditional artists, manipulate either the luminance or color temperature of different regions of the image. By performing blending in the gradient domain and reconstruction with a Poisson solver, the appearance of false edges is minimized. The results of a preliminary user study, designed to evaluate the effectiveness of these techniques, are also presented

Intuitive tools for camera manipulation

We present an image-space camera manipulation widget that sup-ports visualization of the relationship of the camera with respect tothe scene. The form of the widget presents the user with naturalaffordances for camera manipulation. Visual aids such as ghostingof the scene and preview animations are used to acquaint noviceusers with the functions of different parts of the widget. Mousegestures are used to transition between different perspective viewsof the scene in an intuitive way. Finally, we provide a novel methodfor visualizing camera bookmarks