41677043
Unknown object grasping using statistical pressure models
Grasping is one of the most fundamental and challenging tasks in robotics. Applications range from space missions (e.g., collection of rock samples) to industrial automation. In this work, we use a camera mounted on the end-effector of a manipulator to grasp an unknown object in the workspace. A novel deformable contour model is used to determine plausible grasp axes of the target object. Potential grasp point pairs are generated, ranked based upon measurements taken from the contour, and a vision-guided grasp of the object using the highest ranked grasp point pair is executed. Several experimental results are presented.
5822992
Active Deformable Models Using Density Estimation
This paper introduces a new approach to active deformable models. The paper starts with a brief review of the relevant approaches. We then use the Expectation Maximization and Parzen Window techniques to develop a more robust formulation for pressure snakes. The generic nature of the proposed model allows it to perform well on complex colored images. We show, by several examples, the enhanced performance of the snake under the new formulation, compared to the performance of other known snake formulations.
42411588
Computer vision issues during eye-in-hand robotic tasks
Our previous work has introduced the framework of controlled active vision that provides a bridge between computer vision and control theory. This paper presents some of the computer vision techniques that were employed in order to detect targets, automatically select features, measure feature displacements, and evaluate measurements during the various applications of the controlled active vision framework. We experimented with a lot of different techniques, but the most robust proved to be the sum-of-squared differences (SSD) optical flow technique. Search optimizations and dynamic pyramiding are proposed in order to provide real-time performance. In addition, several techniques for the evaluation of the measurements are presented. One important characteristic of these techniques is that they can also be used for the selection of features for tracking in conjunction with several numerical criteria that guarantee the robustness of the servoing. These techniques are important aspects of our work since they can be implemented either on-line or off-line. The paper concludes with results from the application of these techniques to real images.
14452564
Eye Tracking Using Active Deformable Models
Developing a robust, non-intrusive, inexpensive eye tracker is quite a challenge in the computer vision field. This paper introduces a new eye tracking approach based on an enhanced formulation of the statistical pressure snakes. Using a head-mounted camera, to eliminate the effect of head movements, we can detect and track the eye pupil robustly. Experimental results on video sequences for normal and blinking eyes are presented with high accuracy.
25855174
General Principles for Performance Oriented Design
2858208
New Software Performance AntiPatterns: More Ways to Shoot Yourself in the Foot
Performance antipatterns document common software performance problems as well as their solutions. These problems are often introduced during the architectural or design phases of software development, but not detected until later in testing or deployment. Solutions usually require software changes as opposed to system tuning changes. This paper presents three new performance antipatterns and gives examples to illustrate them. These antipatterns will help developers and performance engineers avoid common performance problems.
13422329
Performance Engineering Models of CORBA-based Distributed-Object Systems
Systems using distributed object technology offer many advantages and their use is becoming widespread. Distributed object systems are typically developed without regard to the locations of objects in the network or the nature of the communication between them. However, this approach often leads to performance problems due to latency in accessing remote objects and excessive overhead for communication. Thus, it is important to provide support for early assessment of the performance characteristics of such systems. This paper presents extensions to the software performance engineering process and its associated models for assessing distributed object systems, and illustrates with a case study.
2552665
From UML models to software performance results: an SPE process based on XML interchange formats
The SPE process uses multiple performance assessment tools depending on the state of the software and the amount of performance data available. This paper describes two XML based interchange formats that facilitate using a variety of performance tools in a plug-and-play manner thus enabling the use of the tool best suited to the analysis. The Software Performance Model Interchange Format (S-PMIF) is a common representation that is used to exchange information between (UML-based) software design tools and software performance engineering tools. On the other hand, the performance model interchange format (PMIF 2.0) is a common representation for system performance model data that can be used to move models among system performance modeling tools that use a queueing network model paradigm. This paper first defines an XML based S-PMIF based on an updated SPE meta-model Then it demonstrates the feasibility of using both the S-PMIF and the PMIF 2.0 to automatically translate an architecture description in UML into both a software performance model and a system performance model to study the performance characteristics of the architecture. This required the implementation of some extensions to the XPRIT software in order to export UML models into the S-PMIF and a new function in the SPEED software to import S-PMIF models, which are also described. The SPE process and an experimental proof of concept are presented.
6988052
QSEM: Quantitative Scalability Evaluation Method
While scalability is important to today's software applications, few organizations understand how to quantitatively evaluate their software's scalability. This paper describes the Quantitative Scalability Evaluation Method, QSEM. QSEM uses straightforward measurements to quantify the scalability of a software application. The results provide an understanding of the application's scalability that makes it possible to extrapolate behavior to larger configurations with confidence. The seven steps of the QSEM method are described and illustrated with a case study.