466097
Merging artificial objects with marker-less video sequences based on the interacting multiple model method
Inserting synthetic objects into video sequences has gained much interest in recent years. Fast and robust vision-based algorithms are necessary to make such an application possible. Traditional pose tracking schemes using recursive structure from motion techniques adopt one Kalman filter and thus only favor a certain type of camera motion. We propose a robust simultaneous pose tracking and structure recovery algorithm using the interacting multiple model (IMM) to improve performance. In particular, a set of three extended Kalman filters (EKFs), each describing a frequently occurring camera motion in real situations (general, pure translation, pure rotation), is applied within the IMM framework to track the pose of a scene. Another set of EKFs,one filter for each model point, is used to refine the positions of the model features in the 3-D space. The filters for pose tracking and structure refinement are executed in an interleaved manner. The results are used for inserting virtual objects into the original video footage. The performance of the algorithm is demonstrated with both synthetic and real data. Comparisons with different approaches have been performed and show that our method is more efficient and accurate.
14489674
Automatic lyrics alignment for Cantonese popular music
From lyrics-display on electronic music players and Karaoke videos to surtitles for live Chinese opera performance, one feature is common to all these everyday functionalities temporal: synchronization of the written text and its corresponding musical phrase. Our goal is to automate the process of lyrics alignment, a procedure which, to date, is still handled manually in the Cantonese popular song (Cantopop) industry. In our system, a vocal signal enhancement algorithm is developed to extract vocal signals from a CD recording in order to detect the onsets of the syllables sung and to determine the corresponding pitches. The proposed system is specifically designed for Cantonese, in which the contour of the musical melody and the tonal contour of the lyrics must match perfectly. With this prerequisite, we use a dynamic time warping algorithm to align the lyrics. The robustness of this approach is supported by experiment results. The system was evaluated with 70 twenty-second music segments and most samples have their lyrics aligned correctly.
35666520
Automatic Lyrics Alignment on Popular Music
188431
A fast and robust simultaneous pose tracking and structure recovery algorithm for augmented reality applications
A robust simultaneous pose tracking and structure recovery algorithm based on the Interacting Multiple Model (IMM) for augmented reality applications is proposed in this paper. A set of three extended Kalman filters (EKFs), each describes a frequently occurring camera motion in real situations (general, pure translation, pure rotation), is applied within the IMM framework to track the pose of an object. Another set of EKFs, one filter for each model point, is used to refine the positions of the model features in the 3D space. The filters for pose tracking and structure refinement are executed in an interleaved manner. The results are used for inserting virtual objects into the original video footage. The performance of the algorithm is demonstrated with both synthetic and real data. Comparisons with different approaches have been performed and show that our method is more efficient and accurate.
33091738
SHAPES: A Novel Approach for Learning Search Heuristics in Under-Constrained Optimization Problems
Although much research in machine learning has been carried out on acquiring knowledge for problem-solving in many problem domains, little effort has been focused on learning search-control knowledge for solving optimization problems. This paper reports on the development of SHAPES, a system that learns heuristic search guidance for solving optimization problems in intractable, under-constrained domains based on the Explanation-Based Learning (EBL) framework. The system embodies two new and novel approaches to machine learning. First, it makes use of explanations of varying levels of approximation as a mean for verifying heuristic-based decisions, allowing heuristic estimates to be revised and corrected during problem-solving. The provision of such a revision mechanism is particularly important when working in intractable and under-constrained domains, where heuristics tend to be highly over-generalized, and hence at times will give rise to incorrect results. Second, it employs a new linear and quadratic programming-based weight-assignment algorithm formulated to direct search toward optimal solutions under best-first search. The algorithm offers a direct method for assigning rule strengths and, in so doing, avoids the need to address the credit-assignment problem faced by other iterative weight-adjustment methods.
13460900
Reconstruction of sculpture from its profiles with unknown camera positions
Profiles of a sculpture provide rich information about its geometry, and can be used for shape recovery under known camera motion. By exploiting correspondences induced by epipolar tangents on the profiles, a successful solution to motion estimation from profiles has been developed in the special case of circular motion. The main drawbacks of using circular motion alone, namely the difficulty in adding new views and part of the object always being invisible, can be overcome by incorporating arbitrary general views of the object and registering its new profiles with the set of profiles resulting from the circular motion. We describe a complete and practical system for producing a three-dimensional (3D) model from uncalibrated images of an arbitrary object using its profiles alone. Experimental results on various objects are presented, demonstrating the quality of the reconstructions using the estimated motion.
12936831
On designing an experiment to evaluate a reverse engineering tool
The Rigi reverse engineering system is designed to analyze and summarize the structure of large software systems. Two contrasting approaches are available for visualizing software structures in the Rigi graph editor. The first approach displays the structures through multiple, individual windows. The second approach, simple hierarchical multi-perspective (SHriMP) views, employs fisheye views of nested graphs. The paper describes the design of an experiment to evaluate these alternative user interfaces. Various results from a preliminary pilot study to test the experiment design are reported.
28636461
A Superimposed Codeword Indexing Scheme for Handling Sets in Prolog Databases
While there has been growing interest in the use of Prolog for database applications, the size of these applications is limited by the capabilities of current Prolog systems for handling disk resident clauses. A major impediment is the inordinate amount of time required for retrieval and urujication of clauses from a large set stored on disk. Indexing is commonly used in conventional database systems to achieve fast data access to large sets of records. However, the use of variables and non-atomic arguments such as complex structures which may exist in a Prolog clause render conventional indexing strategies unsuitable. To overcome this, several indexing schemes have been developed. The Superimposed Codewor< plus Mask Bits (SCW+MB) is one such scheme which is eficient and relatively simple to implement. Sets which are finite lists consisting only of constant terms are useful structures for advanced database systems. Existing indexing schemes for Prolog databases, including SCW+MB, cannot handle sets. In this paper, a modified SCW+MB matching algorithm which can handle set arguments is proposed. Two hardware approaches, based on existing machines namely CURE-FSl and CAFS, for implementing the modified algorithm are suggested.
7622452
Tracking based motion segmentation under relaxed statistical assumptions
We present a novel and efficient motion segmentation and tracking algorithm that follows the shift and align paradigm. We introduce two statistical tests to evaluate the similarity of aligned image pixels or patches and we use them to determine the spatial extend of each segment. The one statistical test is fast and accurate when the noise is moderate and the other employs a sophisticated noise model involving the Mahalanobis distance to handle correlated noise. Direct computation of the Mahalanobis distance is prohibitively expensive so we apply the Sherman-Morrison-Woodbury identity and amortization to reduce the cost by several orders of magnitude. We tested both versions of the algorithm on a variety of image sequences (indoor and outdoor, real and synthetic, constant and varying lighting, stationary and moving camera, one of them with known ground truth) with very good results.