36184486
Image-Based Surface Detail Transfer
We present a novel technique, called Image-Based Surface Detail Transfer, to transfer geometric details from one surface to another with simple 2D image operations. The basic observation is that, without knowing its 3D geometry, geometric details (local deformations) can be extracted from a single image of an object in a way independent of its surface reflectance, and furthermore, these geometric details can be transferred to modify the appearance of other objects directly in images. We show examples including surface detail transfer between real objects, as well as between real and synthesized objects.
15783652
Low bit-rate video streaming for face-to-face teleconference
Face-to-face video teleconferencing is very important for real time communication. Current teleconferencing applications use standard video codecs, such as MPEG 1/2/4, for the compression of face video. Either a high bandwidth is required for high quality video transmission, or the transmitted face video is blurred at low bitrates. We present a system for real-time coding of face video at low bit-rate. There are two main contributions. First, we improve the technique of long term memory prediction by selecting frames into the database in an optimal way. A new frame is selected into the database only when it is significantly different from those frames which are already in the database. In this way, the database can cover a wider range of images. Second, we incorporate prior knowledge about faces into the long term memory prediction framework. The prior knowledge includes: (1) facial motions are repetitive such that most of them can be reconstructed from multiple reference frames; (2) different components of the face and the background can tolerate different levels of error because of different perceptual importance. Experiments show that, at similar PSNR, the proposed system works much faster and achieves better visual quality than the standard H.264/JVT codec.
215894941
Geometry-Driven Photorealistic Facial Expression Synthesis
Expression mapping (also called performance driven animation) has been a popular method for generating facial animations. A shortcoming of this method is that it does not generate expression detail...
5771284
Face relighting with radiance environment maps
A radiance environment map pre-integrates a constant surface reflectance with the lighting environment. It has been used to generate photo-realistic rendering at interactive speed. However, one of its limitations is that each radiance environment map can only render the object, which has the same surface reflectance as what it integrates. We present a ratio-image based technique to use a radiance environment map to render diffuse objects with different surface reflectance properties. This method has the advantage that it does not require the separation of illumination from reflectance, and it is simple to implement and runs at interactive speed. In order to use this technique for human face relighting, we have developed a technique that uses spherical harmonics to approximate the radiance environment map for any given image of a face. Thus we are able to relight face images when the lighting environment rotates. Another benefit of the radiance environment map is that we can interactively modify lighting by changing the coefficients of the spherical harmonics basis. Finally we can modify the lighting condition of one person's face so that it matches the new lighting condition of a different person's face image assuming the two faces have similar skin albedos.
10848842
Vision Guided Circumnavigating Autonomous Robots
In this paper, we propose a system for vision guided autonomous circumnavigation, allowing robots to navigate around objects of arbitrary pose. The system performs knowledge-based object recognition from an intensity image using a canonical viewer-centred model. A path planned from a geometric model then guides the robot in circum-navigating the object. This system can be used in many applications where robots have to recognize and manipulate objects of unknown pose and placement. Such applications occur in a variety of contexts such as factory automation, underwater and space exploration, and nuclear power station maintenance. We also define a canonical-view graph to model objects, which is a viewer-centred representation.
16579361
A Theory of Reactive Components
We present a theory of reactive components. We identify a component by its provided services, and specify the individual services by a guarded-design, which enables one to separate the responsibility of clients from the commitment made by the component, and model the behaviour of a component by a set of failures and divergences. Protocols are introduced to coordinate the interactions between a component and its environment. We adopt the notion of process refinement to formalise the substitutivity of components, and provide a complete proof method based on the notion of simulations. We also study the algebraic properties of component combinators.
2458786
High Performance Embedded Route Lookup Coprocessor for Network Processors
Embedded Route Lookup Coprocessors (RLCs) are attractive for their potential in building high-performance Network Processors. But compared with conventional lookup schemes, it always imposes more severe restrictions on table size and power consumption, which poses challenge in the state of art. In this paper, we propose a novel lookup mechanism, Compounded CAM with Optimized Bitmap Compression (CCAM-OBC), which employs different lookup methods for prefixes of different length ranges, so as to combine the benefits of CAMs and bitmap compressed tries. With this scheme, table size, power consumption and update complexity are all well optimized while very high lookup throughput is achieved, which makes it a perfect solution to embedded RLC. For a real-life 130K-prefix route table, the implemented prototype performs more than 100 Million Packets Per Second (MPPS) with only 24KB TCAM, 48KB BCAM and 251KB SRAM. Furthermore, each update needs only 2 memory accesses averagely.
5196479
Odd Wheels in Graphs
For k?1 the odd wheel of 2k+1 spokes, denoted by W2k+1, is the graph obtained from a cycle of length 2k+1 by adding a new vertex and joining it to all vertices of the cycle. In this paper it is shown that if a graph G of order n with minimum degree greater than 7n/12 is at least 4-chromatic then G contains an odd wheel with at most 5 spokes.
7502395
Dynamic image sequence analysis using fuzzy measures
In this paper, we present an image understanding system using fuzzy sets and fuzzy measures. This system is based on a symbolic object-oriented image interpretation system. We apply a simple, powerful three-dimensional (3-D) recursive filter to tracking moving objects in a dynamic image sequence. This filter has a time-varying 3-D frequency-planar passband that is adapted in a feedback system to automatically track moving objects. However, as objects in the image sequence are not well-defined and are engaged in dynamic activities, their shapes and trajectories in most cases can be described only vaguely. In order to handle these uncertainties, we use fuzzy measures to capture subtle variations and manage the uncertainties involved. This enables us to develop an image understanding system that produces a very natural output. We demonstrate the effectiveness of our system with complex real traffic scenes.