2910253
Registration and integration of textured 3-D data
In general, multiple views are required to create a complete 3-D model of an object or of a multi-roomed indoor scene. In this work, we address the problem of merging multiple textured 3-D data sets, each of which corresponds to a different view of a scene or object. There are two steps to the merging process: registration and integration. To register, or align, data sets we use a modified version of the Iterative Closest Point algorithm; our version, which we call color ICP, considers not only 3-D information, but color as well. We show that the use of color decreases registration error by an order of magnitude. Once the 3-D data sets have been registered we integrate them to produce a seamless, composite 3-D textured model. Our approach to integration uses a 3-D occupancy grid to represent likelihood of spatial occupancy through voting. In addition to occupancy information, we store surface normal in each voxel of the occupancy grid. Surface normal is used to robustly extract a surface from the occupancy grid; on that surface we blend textures from multiple views.
16190492
Noise Estimation from a Single Image
In order to work well, many computer vision algorithms require that their parameters be adjusted according to the image noise level, making it an important quantity to estimate. We show how to estimate an upper bound on the noise level from a single image based on a piecewise smooth image prior model and measured CCD camera response functions. We also learn the space of noise level functions how noise level changes with respect to brightness and use Bayesian MAP inference to infer the noise level function from a single image. We illustrate the utility of this noise estimation for two algorithms: edge detection and featurepreserving smoothing through bilateral filtering. For a variety of different noise levels, we obtain good results for both these algorithms with no user-specified inputs.
47117010
Stylizing 2.5-D video
In recent years considerable interest has been given to non-photorealistic rendering of photographs, video, and 3D models for illustrative or artistic purposes. Conventional 2D inputs such as photographs and video are easy to create and capture, while 3D models allow for a wider variety of stylization techniques, such as cross-hatching. In this paper, we propose using video with depth information (2.5-D video) to combine the advantages of 2D and 3D input. 2.5-D video is becoming increasingly easy to capture, and with the additional depth information, stylization techniques that require shape information can be applied. However, because 2.5-D video contains only limited shape information and 3D correspondence over time is unknown, it is difficult to create temporally coherent stylized animations directly from raw 2.5-D video. In this paper, we present techniques for processing 2.5-D video to overcome these drawbacks, and demonstrate several styles that can be created using these techniques.
2096181
Video editing using figure tracking and image-based rendering
We describe a new approach to video editing based on the semi-automatic segmentation of video into multiple layers and the composition of layers using image-based rendering. Using figure tracking and background motion estimation, we can segment a moving figure and reconstruct the background. Using geometrically-correct pixel reprojection, layers can be composited on the basis of the geometry of the underlying scene and the position of a virtual camera. We have implemented a prototype editing system called SpliceWorld.
44673585
Characterization of Errors in Compositing Panoramic Images
A panoramic image has a 360° horizontal field of view, and it can provide the viewer the impression of being immersed in the scene. A panorama is created by first taking a sequence of images while rotating the camera about a vertical axis. These images are then projected onto a cylindrical surface before being seamlessly composited. The cross-sectional circumference of the cylindrical panorama is called thecompositing length. This work characterizes the error in compositing panoramic images due to errors in some of the intrinsic parameters. The intrinsic camera parameters that are considered are the camera focal length and the radial distortion coefficient. We show that the error in the compositing length is more sensitive to the error in the camera focal length. Especially important is the discovery that the relative error in compositing length is always smaller than the relative error in the focal length. This means that the error in focal length can be corrected by iteratively using the composited length to compute a new and more correct focal length. Thiscompositing approach to camera calibrationhas the advantages of not requiring both feature detection and separate prior calibration.
40596005
Survey of image-based representations and compression techniques
We survey the techniques for image-based rendering (IBR) and for compressing image-based representations. Unlike traditional three-dimensional (3-D) computer graphics, in which 3-D geometry of the scene is known, IBR techniques render novel views directly from input images. IBR techniques can be classified into three categories according to how much geometric information is used: rendering without geometry, rendering with implicit geometry (i.e., correspondence), and rendering with explicit geometry (either with approximate or accurate geometry). We discuss the characteristics of these categories and their representative techniques. IBR techniques demonstrate a surprising diverse range in their extent of use of images and geometry in representing 3-D scenes. We explore the issues in trading off the use of images and geometry by revisiting plenoptic-sampling analysis and the notions of view dependency and geometric proxies. Finally, we highlight compression techniques specifically designed for image-based representations. Such compression techniques are important in making IBR techniques practical.
14227015
Towards an Efficient Semantic Prefetching for Location Based Services
Location-Based Services(LBSs) in a wireless location-aware network are public and personal services intended to be available for users. It is important to support Location Dependent Data(LDD) that users want to get to their moving location properly. If we get many LDD in a local device, the communication cost increased by frequent connections can remarkably reduce. General prefetching scheme make it possible to send data to mobile clients in advance. But, after analyzing queries fixed to users’ interests in current location, it is difficult to support proper data in LBSs. Therefore, we propose a Semantic Prefetching scheme to efficiently prefetch LDD and semantic description through servers with large scale data. Also, with our semantic prefetching scheme for LDD in LBSs, we propose a new cache management scheme to manage data needed by mobile users. A performance study shows efficiency of these schemes when compared to traditional semantic cache scheme.
17977437
Technology independent arbitrary device extractor
This paper presents the technology independent arbitrary device specification language and device extraction algorithm used in our layout extractor iLEX. Device models specified in the device specification language are converted to graphs, and subgraph isomorphism is used to extract device instances in given layouts. Finally, experimental data are provided to show the capability of our device extraction algorithms.
5789613
ILLIADS: a new fast MOS timing simulator using direct equation-solving approach
By using a direct equation solver of a new MOS circuit primitive with piecewise-linear approximation of electrical waveforms, ILLIADS has been shown to be significantly superior to existing fast MOS timing simulators in both accuracy and speed. For simulation of medium-size digital circuits containing a few hundred transistors (n), ILLIADS has already achieved an O(n), about 3n or more, speedup over SPICE with error less than 3%. The sizes of circuits ILLIADS can handle is not limited by this method and the speedup is expected to grow with the circuit size. The possibility of generating false waveforms caused by merging of parallel transistors is reduced. A modified waveform relaxation algorithm is used to handle circuits with feedbacks as demonstrated through simulation of a ring oscillator and a updown counter.
1671645
Domino logic synthesis minimizing crosstalk
Based on the new concept of crosstalk immunity set (CIS), procedures to minimize capacitive cross-coupling effects are developed for domino logic circuit. The nets in a crosstalk immunity set are free from crosstalk effects for any combination of input vectors. New algorithms for CIS identification and minimization are proposed to maximize the chance of crosstalk minimization in routing step. Our routing algorithm augmented with CIS information searches for optimal solution to minimize maximum crosstalk the circuit would experience. Experimental results show that the reduction of maximum crosstalk is up to 30% with CIS-augmented routing.
5947702
Fast timing simulation of transient faults in digital circuits
Transient fault simulation is an important verification activity for circuits used in critical applications since such faults account for over 80% of all system failures. This paper presents a timing level transient fault simulator that bridges the gap between electrical and gate-level transient fault simulators. A generic MOS circuit primitive and analytical solutions of node differential equations are used to perform transistor level simulation with accurate MOS-FET models. The transient fault is modeled by a piecewise quadratic injected current waveform; this retains the electrical nature of the transient fault and provides SPICE-like accuracy. Detailed comparisons with SPICE3 show the accuracy of this technique and speedups of two orders of magnitude are observed for circuits containing up to 2000 transistors. Latched error distributions of the benchmark circuits are also provided.