PC-based Imaging Research Articles

Initial experiments of a 128-channel FPGA and PC-based ultrasound imaging system for teaching and research activities.

Although widely employed in medical diagnostic applications, most of the available commercial ultrasound (US) scanners do not always fit the needs of research users. Access to raw US data, portability, flexibility and advanced user control are essential features to explore alternative biomedical signal and imaging processing algorithms. In this paper, we present the initial results of a reconfigurable, cost-effective and modular 128-channel FPGA and PC-based US system, specifically designed for teaching and medical imaging research. The proposed system exploits the advantages of the MD2131 (Microchip Technology Inc.) beamformer source driver to generate arbitrary waveforms and the analog front-end AFE5805 (Texas Instruments Inc.) to obtain the maximum flexibility and wide data access to the various US data streams. Two applications involving plane wave excitation and delay-and-sum (DAS) beamforming are discussed. The results show that the open platform can help biomedical students and researchers to develop and evaluate different imaging strategies for medical US imaging and nondestructive testing (NDT) techniques, among other applications.

Volumetric real-time imaging using a CMUT ring array

A ring array provides a very suitable geometry for forward-looking volumetric intracardiac and intravascular ultrasound imaging. We fabricated an annular 64-element capacitive micromachined ultrasonic transducer (CMUT) array featuring a 10-MHz operating frequency and a 1.27-mm outer radius. A custom software suite was developed to run on a PC-based imaging system for real-time imaging using this device. This paper presents simulated and experimental imaging results for the described CMUT ring array. Three different imaging methods--flash, classic phased array (CPA), and synthetic phased array (SPA)--were used in the study. For SPA imaging, two techniques to improve the image quality--Hadamard coding and aperture weighting--were also applied. The results show that SPA with Hadamard coding and aperture weighting is a good option for ring-array imaging. Compared with CPA, it achieves better image resolution and comparable signal-to-noise ratio at a much faster image acquisition rate. Using this method, a fast frame rate of up to 463 volumes per second is achievable if limited only by the ultrasound time of flight; with the described system we reconstructed three cross-sectional images in real-time at 10 frames per second, which was limited by the computation time in synthetic beamforming.

A compact PC-based X-ray imaging system

A compact, portable PC-based X-ray imaging system has been developed based on a 2D silicon microstrip sensor and particle physics readout electronics. The sensor is housed in a specially built hybrid, which also hosts the front-end electronics. The control and the readout electronics used are based on the standard PCI and PMC architectures and were originally developed for High Energy Physics Experiments. The use of PCI based electronics and the development of the control software for the PC-Linux platform led to a compact, portable, low cost imaging system. The system was initially tested and evaluated with beta particles from a 90Sr radioactive source, gamma rays from an 241Am radioactive source and cosmic rays, and it displayed consistent response. It was then operated using a compact X-ray machine with Mo tube and images of various targets were reconstructed offline using the ROOT data analysis package.

A PC-based discrete tomography imaging software system for assaying radioactive waste containers

A PC-based discrete tomography imaging software system for assaying radioactive waste containers for use in facilities in Mexico has been developed. The software system consists of three modules: (i) for reconstruction transmission tomography, (ii) for reconstruction emission tomography, and (iii) for simulation tomography. The Simulation Module is an interactive computer program that is used to create simulated databases for input to the Reconstruction Modules. These databases may be used in the absence of physical measurements to insure that the tomographic theoretical models are valid and that the coding accurately describes these models. Simulation may also be used to determine the detection limits of the reconstruction methodology. A description of the system, the theory, and a demonstration of the systems capabilities is provided in the paper. The hardware for this system is currently under development.

PC-based ultrasound imaging system with microminiaturized electronics

Indications for and applications of diagnostic ultrasound have expanded dramatically over the past two decades. Although new ultrasound imaging techniques have been developed and brought to clinical practice, to date, ultrasound machines have employed proprietary, closed system architectures. This approach can slow innovation and increase product costs, both undesirable, given the need for health-care cost containment even as demand for ultrasound imaging continues to expand. In contrast, the Terason family of ultrasound systems features an open, PC-based architecture that allows Terason to leverage the rapid development cycles and economies of the PC industry with respect to display, storage, and transmission of ultrasound data. The Terason approach replaces some “traditional” hardware using software running on commercially available PCs, which reduces cost and increases flexibility. This is in conjunction with Terason’s patented CDP integrated circuit technology, which allows production of an ultrasound system that provides a full range of high-quality fully digital imaging (including B-mode, color flow, and spectral Doppler) at substantially lower cost, size, and power consumption than traditional approaches. Further, Terason’s PC-based approach allows for integration of third-party medical solutions, such as 3D rendering, data analysis, and report-generating software and provides reliable options for both data storage and transmission, facilitating telemedicine applications. Additionally, the open architecture supports external communication with other applications running on the same host computer. This facilitates system integration with other medical applications where real-time noninvasive imaging is desired, including radiation therapy planning and treatment, minimally invasive and robotic surgery techniques, and catheter introduction for diagnostic and therapeutic angiography. Terason’s open, PC-based system architecture in combination with CDP integrated-circuit technology provides significant cost, size, and portability advantages as compared with “traditional” ultrasound systems without compromising features or performance.

Pc-Based Imaging System for Color Cell Identification and Scoring

Abstract Pathologists, microbiologists and cytologists are very interested to automatically identify and quantify the sperms, cells or nucleus in the cellular level images. Complexities like voluminous data sets, variability in data sets, millions of colors, and different kinds of artifacts make the detection and quantification process very difficult. This paper is an attempt to design a sophisticated cellular diagnostic system based on color image processing, mathematical morphology and connected components based on run length encoding. This system runs on Windows ‘98/NT PC platform, in Visual C++, 6.0 environment using three different architectures: Single document interface, multiple document interface and dialog based applications. The system takes around 1.5 seconds per image of 512 x 484 square pixels using high speed threading architecture written on the on 400 MHz Pentiumll processor. The system has an accuracy of 95%. The software has been validated tested on NASA and machine vision real world images.

Identification and Measurement of Convolutions inCotton Fiber Using Image Analysis

An image analysis procedure was developed to quantify morphological characteristics of convolutions in individual cotton fibers without pre-tensioning or orientation requirements. The image of each fiber was captured by a PC-based color imaging system using a conventional microscope. Ends of individual cotton fibers were glued on a microscope slide without any tension or straightening. A modified watershed technique was implemented to identify individual convolution segments, which were defined as sections of the fiber bordered by two neighboring convolutions. Length, area and perimeter of each convolution segment were measured directly from the image. Average width, shape factor and number of convolution segments in mm were calculated from the measured parameters. Performance of the image analysis algorithm was compared with visual inspection for number and position of convolution segments in three different varieties of cotton. Image analysis results agreed with visual inspection in 89.6% of the tested images.

A PC-Based Near Real-Time Ultrasonic Imaging System for Flaw Characterization

Abstract This paper presents the description of a PC-based ultrasonic imaging system which generates three types of pulse-echo ultrasound images, namely, A-scan, B-scan, and C-scan, almost in real time. The system has pulser-receiver circuitry employing a single ultrasonic probe working as both the transmitter and the receiver. The generated ultrasound signal is transferred to a PC-AT using the A/D conversion facility of a digital storage oscilloscope where it is processed for target echoes with their amplitude and location. Thereafter, this information is correlated to provide a particular type of image. The probe positioning for the images is accomplished by a motorized mechanical system made up of two stepping motors. This developed ultrasonic imaging system is fully automatic, user-friendly, and operator independent.

CHARACTERIZING CONVOLUTIONS IN COTTON FIBER AND THEIR EFFECTS ON FIBER STRENGTH

An image analysis procedure was developed to quantify several morphological parameters of convolutions inindividual cotton fibers. The image of each fiber was captured by a PC-based color imaging system using a conventionalmicroscope. A modified watershed technique was implemented to identify individual convolutions in a single fiber. Length,area, and perimeter of each convolution segment were measured directly from the image. Average width, shape factor andnumber of convolution segments were calculated from the measured parameters. The tensile strengths of individual fiberswere measured by Mantis Single Fiber Tensile Tester. By measuring convolution characteristics of cotton fiber nondestructively,the image analysis allowed us to study relationship between convolution characteristics and tensileproperties of a single fiber.

A non-invasive, three-dimensional, diagnostic laser imaging system for accurate wound analysis

A PC-based laser imaging system has been developed that can accurately image and analyse three-dimensional (3D) surfaces in healing wound tissue. The device consists of a laser diode and sensor mounted to a motorized, bi-directional, X - Y table. The laser measures the distance to the wound surface as the X - Y table moves over the wound. The laser beam diameter is and can measure distances as small as . The distance information from the laser is used to produce the 3D image and to calculate the volume of the wound. The accuracy of this device is demonstrated by measuring rubber model wounds of 0.5, 1 and 2 ml. The per cent error for the 0.5 and 1 ml model wounds was less than 1 per cent and approximately 4 per cent for the 2 ml model. Studies were done in which full-thickness wounds were made on rats and monitored over a two week period. The rats were scanned five times during this period and the wound area and volumes calculated. The laser measurements are compared to measurements using saline and wound thickness multiplied by wound area. Keywords: volume, surface area, non-invasive, laser imaging, wound healing

Electron Spectroscopic Imaging of Organic Compounds Using PC-Based Energy Sequence Imaging Software

We have designed, characterised and tested Windows based software packages for rapid elemental microanalysis using a sequence of energy filtered transmission electron microscopic images which combines electron spectroscopic imaging with electron energy loss spectroscopy (Image-EELS). Image sequences containing up to 45 images of 512 × 512 pixels were recorded rapidly over an appropriate range of the energy spectrum for an analysis of boron, nitrogen, titanium and fluorine. Energy loss information was extracted from local variations in the energy loss spectrum with good energy resolution (5 eV) and a spatial resolution of 2 nm for the determination of the relative concentration of elements within a region of interest by grey level integration in consecutive images of an energy loss sequence, using the least mean squares method to calculate the parameters for an A.e −r back-ground model. The methods were used to define the optimum collections conditions and practical limitations of the system for qualitative and semi-quantitative elemental analysis relevant to biological specimens. Qualitative elemental analysis of images from Lowicryl HM23- embedded ultra-thinsection of a boric acid polymer showed that boron was not distributed evenly. Semi-quantitative elemental analysis of the fluorine-containing organic polymer Nafion suggested a linear relationship between fluorine energy loss intensity, image area and specimen thickness. These techniques were applied to an examination of the reaction between purified RNA and the novel titanium-containing anti-cancer agent MKT-4, showing that ratios calculated from the cumulative electron energy loss intensity increase within regions of interest as a function of grey level intensity for titanium and nitrogen are directly proportional to the incubation concentration of the drug with RNA. Expression of data in this way is shown to be a useful indicator of the relative drug distribution within specific intracellular compartments of human cancer cells incubated with MKT-4 in vitro

A PC-based imaging system for automated platelet identification.

In this communication, a PC-based imaging system was developed for automatically identifying fluorescence-labeled individual platelets adherent to protein-coated surface under flow conditions. It is to eliminate the laborious and time-consuming task, and the subjective error of manual measurements. Based upon the features of adherent platelets, three passes of the image processing were developed for platelet identification. From the results, 90-95% accuracy could be routinely obtained. The platelet distribution and other related parameters could be easily extracted and investigated.

Surface quality assessment using computer vision methods

An assessment of surface quality in turned and milled specimens is made utilizing a PC-based digital imaging system. Two different methods of surface finish measurement are examined and compared. The first approach, as pioneered by Luk and Huynh, utilizes the intensity histogram of the surface image to characterize surface roughness and quality. Changes in the statistical descriptors of the histogram serve to quantify the surface finish. A second method utilizes the two-dimensional Fast Fourier Transform of the digitized surface image. The magnitude and frequency information obtained from the FFT are used as measurement parameters of the surface finish. Advantages and disadvantages of these two methods are discussed and compared.

Surface quality assessment using computer vision methods

An assessment of surface quality in turned and milled specimens is made utilizing a PC-based digital imaging system. Two different methods of surface finish measurement are examined and compared. The first approach, as pioneered by Luk and Huynh, utilizes the intensity histogram of the surface image to characterize surface roughness and quality. Changes in the statistical descriptors of the histogram serve to quantify the surface finish. A second method utilizes the two-dimensional Fast Fourier Transform of the digitized surface image. The magnitude and frequency information obtained from the FFT are used as measurement parameters of the surface finish. Advantages and disadvantages of these two methods are discussed and compared.

A PC-based 3D imaging system: Algorithms, software, and hardware considerations

Three-dimensional (3D) imaging in medicine is known to produce easily and quickly derivable medically relevant information, especially in complex situations. We intend to demonstrate in this paper, that with an appropriate choice of approaches and a proper design of algorithms and software, it is possible to develop a low-cost 3D imaging system that can provide a level of performance sufficient to meet the daily case load in an individual or even group-practice situation. We describe hardware considerations of a generic system and give an example of a specific system we used for our implementation. Given a 3D image as a stack of slices, we generate a packed binary cubic voxel array, by combining segmentation (density thresholding), interpolation, and packing in an efficient way. Since threshold-based segmentation is very often not perfect, object-like structures and noise clutter the binary scene. We utilize an effective mechanism to isolate the object from this clutter by tracking a specified, connected surface of the object. The surface description thus obtained is rendered to create a depiction of the surface on a 2D display screen. Efficient implementation of hidden-part removal and image-space shading and a simple and fast antialiasing technique provide a level of performance which otherwise would not have been possible in a PC environment. We outline our software emphasizing some design aspects and present some clinical examples.

A Microcomputer-Based Imaging System for the Visualization of Fluid Displacements

Summary This paper describes a PC-based imaging workstation that PC-based imagingworkstation that uses a video camera and appropriate computer hardware andsoftware to digitize, display, and store images of fluid flow patterns in realtime. The system includes image-processing software so that the digital imagescan be quantitatively analyzed. Introduction Flow-visualization experiments have been used for many years to study fluidflow phenomena. For example, flow-visualization phenomena. For example, flow-visualization studies in EOR research have greatly increased ourunderstanding of the phenomenon of viscous fingering. In these phenomenon ofviscous fingering. In these studies, the fluid flow fields were made visiblewith transparent models and colored fluids or by exploiting the contrast in therefractive indices of the fluids and the models. An important step in a flow-visualization experiment is the acquisition ofpermanent records of the fluid flow field for subsequent study. In the abovestudies, permanent records of the visualized flow were in the form ofphotographs, videotapes, or movies. Unfortunately, images recorded onphotographs or on film are not easily amenable photographs or on film are noteasily amenable to quantitative analyses. What is needed is animage-acquisition technique that captures the images in digital form. Suchimages can then be easily analyzed with computer image-processing techniques. The availability of low-cost, high-resolution, microcomputer graphics deviceshas now made such a digital image-acquisition system affordable. The objective of this study was to develop a low-cost, high-resolution, microcomputer-based imaging workstation for the acquisition of digital imagesin flowvisualization studies. This paper describes our imaging workstation andpresents example images of displacement phenomena obtained with it. Hardware Fig. 1 shows the major components of the flow-visualization imagingworkstation. The imaging system consists of a video camera, a transparent modelpacked with a porous medium, and a microcomputer outfitted with animage-digitizing board, a high-resolution graphics-adapter board, a colorgraphics monitor, a monochrome monitor, and a graphics printer. Our workstation was configured around an IBM PC-AT TM having 1 megabyterandom access memory and 20 megabytes of hard disk for image storage. The 4-bitimage digitizer is capable of capturing and digitizing images every 0.5 secondsinto 16 gray scales with a resolution of 640 columns by 400 rows of pictureelements (pixels). The 16 gray scales are numbered from 0 (black) to 15(white). The digitizer, which plugs into one of the PC expansion slots, isplugs into one of the PC expansion slots, is an electronic circuit board thataccepts analog signals from a video camera and converts them into digitalimages. To take advantage of the digitizer's high resolution, we used ahigh-resolution graphics board that exactly matches it. The graphics boardaccepts digital data from the computer memory, converts the data to analogsignals, and sends the signals to the graphics monitor for display. We used the IBM color monitor for image display, and to enter commands, weincorporated a monochrome monitor and keyboard into the configuration. Withthis arrangement, we can see the entered commands on the monochrome monitorwhile the processed image is displayed on the color monitor. For hard copies of the images, we used a paint-jet color-graphics printercapable of printing images in 16 colors from a palette printing images in 16colors from a palette of 256 at a resolution of 90 dots per inch. Images can beprinted on paper or on transparency film. Images were captured with a black and white video camera. However, we alsoconfigured the system for a color camera by installing a color-filter board toconvert the color signal into a black-and-white signal to minimize noise. Thevideo camera, which plugs directly into the digitizer board, plugs directlyinto the digitizer board, converts the light intensities from the object to beimaged into analog signals for the digitizer. Our flow-visualization experiments were conducted in a 40 × 40 × 0.32-cm [16x 16 × 0.13-in.] transparent lucite model, packed with 30/35-mesh glass beads. Designed to simulate a quarter five-spot flood pattern, it had a porosity of38% and a permeability of about 20 darcies. The model can be used without theporous medium to study fluid flow in a Hele-Shaw cell. JPT P. 558

A PC-Based Interactive Imaging System Designed for INSAT Data Analysis and Monsoon Studies

A PC-based interactive image processing system has been developed for aiding the analysis of Indian Geosynchronous Satellite (INSAT) data for Asian monsoon studies. In view of its diminutive stature, the system has been given the name “MIDGET,” for a Micro-based Image Display and Graphics Enhancement Tool. Various analysis procedures involving INSAT data and other monsoon datasets are described in conjunction with the MIDGET system. These include the use of the system for monitoring monsoon evolution and the behavior of organized tropical storms, analysis of low-frequency intraseasonal oscillations, diagnostic studies of cloudiness, retrieval of monsoon precipitation and its relationship to satellite cloudiness, and statistical prediction of monsoon cloud bands associated with low-frequency intraseasonal fluctuations of monsoon rainfall. The system is designed as a workstation terminal in a supercomputer environment. The basic virtue of this system is that it is an inexpensive approach for generating a high-resolution video time-lapse of large satellite datasets in an interactive environment familiar to PC users. The motivation for developing this system derives from a new source of Indian satellite data that has been made available to United States scientists through archive holdings at the National Center for Atmospheric Research.