Standard PC Platform Research Articles

Open portable platform for hearing aid research

The NIDCD has recently funded a number of projects to develop portable signal processing tools that enable real-time processing of the acoustic environment. The overarching goal is to provide a large group of researchers with the means to efficiently develop and evaluate, in collaborative multi-center environments, novel signal processing schemes, individualized fitting procedures, and technical solutions and services for hearing apparatus such as hearing aids and assistive listening devices. We report on the specific goals and results of two such projects. In one of them (R01DC015429), an open source software platform for real-time runtime environments is developed: The open Master Hearing Aid (openMHA). It provides an extendible set of algorithms for hearing aid signal processing and runs under Linux, Windows, and Mac operating systems on standard PC platforms and on small-scale ARM-based boards. An optimized version of openMHA is provided for the companion SBIR project (R44DC016247), which is a portable, rigid, versatile, and wearable platform featuring an ARM Cortex®-A8 processor. The resulting Portable Hearing Aid Community Platform consists of both hardware elements to provide the advanced desired functionality and software routines to provide for all the features that researchers may need to develop new algorithms.

Characterization of runtime resource usage from analysis of binary executable programs

This paper introduces a methodology for characterizing the runtime resource demands of a computer program from the analysis of its binary executable file. Categorization of applications according to the kind of resources required during execution – such as CPU and memory usage – is a sough-after piece of knowledge for the aims of computer system design and management. Conventional techniques available for this purpose include white-box static source code analysis and profile matching based on historical execution data. The former tends to be challenging in face of complex software architectures and requires access to the source code; the latter is dependent on the availability of reliable past data and on the selection of features yielding effective correlations with resource usage. The alternative data mining approach proposed in this paper avoids those difficulties by manipulating binary executable files. The method combines techniques from information theory, complex networks and phylogenetics to produce a hierarchical clustering of a set of executable files, which can be used to infer potential similarities in terms of runtime resource usage. The paper introduces the method's rationales and presents results of its application to characterize CPU and IO usages of benchmark applications executed on a standard PC platform. Essays carried out over a set of 80 programs from varying sources yielded numerically significant evidences that the prediction of resource usage similarity obtained by the approach is consistent with experimentally measured runtime profile.

Continuous penetration depth computation for rigid models using dynamic Minkowski sums

We present a novel, real-time algorithm for computing the continuous penetration depth (CPD) between two interpenetrating rigid models bounded by triangle meshes. Our algorithm guarantees gradient continuity for the penetration depth (PD) results, unlike conventional penetration depth (PD) algorithms that may have directional discontinuity due to the Euclidean projection operator involved with PD computation. Moreover, unlike prior CPD algorithms, our algorithm is able to handle an orientation change in the underlying model and deal with a topologically-complicated model with holes. Given two intersecting models, we interpolate tangent planes continuously on the boundary of the Minkowski sums between the models and find the closest point on the boundary using Phong projection. Given the high complexity of computing the Minkowski sums for polygonal models in 3D, our algorithm estimates a solution subspace for CPD and dynamically constructs and updates the Minkowski sums only locally in the subspace. We implemented our algorithm on a standard PC platform and tested its performance in terms of speed and continuity using various benchmarks of complicated rigid models, and demonstrated that our algorithm can compute CPD for general polygonal models consisting of tens of thousands of triangles with a hole in a few milli-seconds while guaranteeing the continuity of PD gradient. Moreover, our algorithm can compute more optimal PD values than a state-of-the-art PD algorithm due to the dynamic Minkowski sum computation.

Smart Camera Based on Embedded HW/SW Coprocessor

This paper describes an image acquisition and a processing system based on a new coprocessor architecture designed for CMOS sensor imaging. The system exploits the full potential CMOS selective access imaging technology because the coprocessor unit is integrated into the image acquisition loop. The acquisition and coprocessing architecture are compatible with the majority of CMOS sensors. It enables the dynamic selection of a wide variety of acquisition modes as well as the reconfiguration and implementation of high-performance image preprocessing algorithms (calibration, filtering, denoising, binarization, pattern recognition). Furthermore, the processing and data transfer, from the CMOS sensor to the processor, can be operated simultaneously to increase achievable performances. The coprocessor architecture has been designed so as to obtain a unit that can be configured on the fly, in terms of type and number of chained processing stages (up to 8 successive predefined preprocessing stages), during the image acquisition process that can be defined by the user according to each specific application requirement. Examples of acquisition and processing performances are reported and compared to classical image acquisition systems based on standard modular PC platforms. The experimental results show a considerable increase of the achievable performances.

Reality Augmentation for Medical Procedures: System Architecture, Single Camera Marker Tracking, and System Evaluation

Augmented Reality is an emerging technology that seeks to enhance a user's view by overlaying graphical information. We developed a prototype AR system geared for medical applications. It is built around a stereoscopic head-mounted display of the video-see-through variety. The newest generation of this prototype system exhibits high performance on a standard PC platform. Stereoscopic video images are augmented with medical graphics in real-time at 30 frames per second and with XGA (1024× 768) resolution. The system provides a compelling AR perception: the graphics appears firmly anchored in the scene--there is no time lag between video and graphics or any apparent jitter of the graphics. With the head-mounted display, the user has a natural and direct access to understanding the 3D structure of the scene, based on both stereo and kinetic depth cues. In the present paper, we describe in detail the architecture and several features of the AR prototype system. Head tracking is accomplished with a single-camera system, with the dedicated tracker camera placed on the head-mounted display. This configuration is the foundation of achieving a high-accuracy graphics overlay. We are now exploring the use of the prototype system for a variety of medical applications. This paper gives an overview over the pre-clinical tests that we have performed for interventional guidance. Overall, the feedback has been very positive and encouraging, and we are continuing to work towards realizing the clinical potential of the technology.

A hybrid condensed finite element model with GPU acceleration for interactive 3D soft tissue cutting

AbstractTo meet the requirement of computer‐aided medical operations, apart from the real‐time deformation, it is also necessary in the design to simulate the tissue cutting and suturing in a surgery simulation. In this paper, we present a model on topology change and deformation of soft tissue, referred to as the hybrid condensed finite element model, based on the volumetric finite element method. The most important advantage of our model is its ability to achieve an interactive frame rate for the topology change in surgical simulation on standard PC platform. This is achieved through two innovations. One is to apply the condensation technique, by fully calculating the volumetric deformation in the operation part while only calculating the surface nodes in the non‐operation part. Secondly, the major calculation work in the Conjugate Gradient solver for cutting and deformation is migrated from the CPU to the contemporary GPU to promote the calculation. Test examples have been given to show the feasibility and efficiency of the model. Copyright © 2004 John Wiley & Sons, Ltd.

Efficient volumetric ray casting for isosurface rendering

While volume rendering is becoming more widely used in medical applications, it is still difficult to generate a good-quality image interactively without expensive hardware when the size of the dataset is quite large. For interactive rendering of a large dataset, we present an acceleration method, image–space bounding surface. Using an image–space bounding surface, the isosurface ray casting is accelerated by avoiding unnecessary volume traversals. Image–space bounding surface can be interactively handled by polygon-rendering hardware even in a conventional personal computer. Two optimization techniques, LF-minmax map and memory bricking, are also employed to efficiently render isosurfaces. This paper also shows that the algorithm can be extended to multiple isosurfaces rendering. The experimental results show that the algorithm generates a good-quality image of a large dataset interactively on a standard PC platform.

The design of a real-time engineering flight simulator for the rapid prototyping of avionics systems and flight control systems

This paper describes the design of a real-time flight simulator, which is based on a modular architecture of PCs coupled by Ethernet. The simulator is required to provide a rapid prototyping environment to support the design and evaluation of avionics systems and flight control systems. Methods are described to ensure real-time implementation of the equations of motions using a standard PC and the provision of real-time graphics to simulate aircraft displays using SVGA. The paper includes analysis of the performance of the flight modelling methods and the simulation of aircraft displays. The paper concludes that high fidelity flight models and aircraft displays can be implemented using standard PC platforms and Ethernet cards, if attention is given to the design of the simulator architecture. The resultant simulator provides a rapid prototyping environment, standardising on the packet format and low-level packet protocols of Ethernet,

Starting the codes that solve ordinary differential equations

This article presents a method to compute the initial conditions which are induced by smooth or jump commands into the processes modeled by nonlinear differential equations. The knowledge of such starting states is usually needed before running numerical programs that solve initial value problems on digital computers. The proposed technique, which is based on an extension of a graph method, permits the transient analysis of nonlinear systems just at the instant t = 0+. For the purpose of illustration, a mechanical process is analyzed on an standard PC platform. © 1999 John Wiley & Sons, Inc. Comput Appl Eng Educ 7: 196–202, 1999

Visual routines for real-time monitoring of vehicle behavior

Low-cost, purely visual modules are presented, which are able to reliably perform real-time computation of kinematic quantities relevant for the navigation of commercial vehicles moving along highways or motorways. Taking as input a video stream of b/w images coming from a standard camera mounted aboard the vehicle, the modules return instantaneous measurements for the speed of the vehicle, its lateral position in the lane, and the distance from the preceding vehicle. The modules, which are designed to work in real-time on standard PC platforms, have been tested under typical working conditions. Preliminary results are reported and discussed.

An image enhanced, knowledge based expert system for maintenance trouble shooting

This paper describes the results of a successful effort to develop a vehicle trouble-shooting expert system which has imaging capability integrated into its knowledge base. The system is used to diagnose maintenance problems in the electrical/hydraulic subsystem of a D-900 Derrick. Video information required to effectively execute this diagnostic task is obtained through the use of a TARGA image capture board in a standard PC platform. This paper contains a discussion of the general use of imaging in this context along with a description of the expert system incorporating this capability. A summary of several design and implementation issues that emerged during the research is also included.