Frame Grabber Card Research Articles

A study on the laser marking process of stainless steel

A Q-switched Nd:YAG laser was used in the laser marking process of stainless steel. The influence of the pulse frequency of the laser beam on the mark depth, width and mark contrast have been studied in this paper. The mark contrast is the ratio of the apparent brightness between the mark and unmarked areas which shows the clearance degree of the mark. An optical microscope, scanning electron microscope and surface profile instrument were used to measure the effects of pulse frequency on the mark depth and width. An image-analysis system with a frame-grabber card and a charged-couple-device (CCD) was used to measure mark contrast. It has been found that the mark depth, width and mark contrast depend on the interaction process of the laser beam and the material, which was influenced dramatically by the pulse frequency. The pulse frequency of the laser has a significant effect on the mark quality. There is maximum mark depth when the pulse frequency is about 3 kHz, while mark width almost keeps constant at different pulse frequency. With the pulse frequency increasing, evaporation of material becomes less, and at the same time oxidization becomes more significant, which leads to the improvement of mark contrast. The highest mark contrast could be obtained when the pulse frequency of laser was about 8 kHz.

Equidimensional Fractal Maps for Indirect Estimation of Deformation Damage in Nonuniform Aircraft Alloys

This article describes the surface relief formation on Al single-crystal plates (sensors) with orientation {100}〈001〉 that were rigidly attached to weld specimens of aircraft alloy 2024 T351 during fatigue loading. Taking into account the nonuniform structure of the weld alloy, we located sensors in different zones of the weld specimens to receive information about the sites of strain localization and probability of destruction. The qualitative and quantitative information about the sensor relief was extracted by the online method automated on the basis of a stereomicroscope with a charge-coupled device (CCD) camera attached to a personal computer by a video adapter and frame-grabber card. The quantitative and qualitative relief parameters are shown to correlate with the deformation prehistory of the weld specimens. Panoramic views were created and used for fractal analysis of deformation relief. Spatial distributions of information fractal dimension on the sensor surface for different numbers of cycles were plotted in the shape of contour lines with equal values (equidimensional maps). Equidimensional maps for sufficiently large sensors allow us to find strain localization sites in specimens and monitor their evolution in an online regimen.

The St. Gallen digital ophthalmological imaging system

Digital photography has many advantages over the conventional method. At present commercially available digital ophthalmological imaging systems utilise only a fraction of the advantages of this technique and some of them have fundamental conceptional problems. Images of a fundus camera, a slit lamp and a scanning laser ophthalmoscope were digitised using digital and video cameras and/or frame grabber cards. Digital images and movies were recorded via a personal computer. The image recording software was developed using an imaging library and open source software. The recorded images and video sequences were processed with three different commercially available programme packages. The images were archived in a around-the-clock accessible database. Our digital imaging system is capable to record normal and high resolution slit lamp images, colour fundus images in normal resolution, Fluorescein angiography images in normal and high resolution, digital simultaneous ICG and Fluorescein videoangiograms (without compression) and high resolution macro images. Different functions, e.g., contrast enhancement are integrated in the image capture software. Most of the parameters of the image acquisition are individually adaptable. The digital image archive supports multiple image and video formats. Using standard software and hardware components an imaging system can be constructed featuring functions usually not available in commercial ones. Since the system is adaptable, recording of images with a wide variety of parameters, e.g., for measurements for scientific experiments, is possible.

An online monitor system for high energy photon beams

An apparatus and corresponding software for optimization of photon beams during the beam development phase and for monitoring during experiments is described. The system consists of a scintillator positioned in the beam, an image intensifier and a highly sensitive CCD camera. The CCD camera is read out and controlled by a PC via a frame-grabber card. Software control of the camera and a graphical interface have been developed. The intensity as well as the position of the beam can be constantly supervised online.

VIEWER: a program for visualising, recording, and analysing animal behaviour

In order to determine the influence of environmental interventions, medical substances, drugs, or diseases on an animal, it is a common to observe the behaviour of the animal in the open field or in other environments. Changes in animal behaviour can be the first indicators for an influence of a substance or an intervention on the organism and certain kinds of behavioural changes can permit speculations about the underlying physiological mechanisms. Behavioural properties which are of interest in this respect are movement parameters such as velocity or direction, activity patterns, spatial distribution and occurrence of several types of standard behaviours of an animal. Observation of simple behaviours such as determining the average activity level can help to detect general changes of the internal state of an animal, while changes in complex behaviours may point to specific influences of a substance or an intervention. Our system ‘ VIEWER’ uses a microcomputer (IBM-compatible PC running windows 95, windows 98, windows NT, or windows 2000), a low budget framegrabber card (e.g. WinTV, Hauppauge) and a standard black-and-white video camera (if necessary with infrared sensitivity). The software records the position of the animal online with a sample rate of up to 25 frames/s. After identification of the animal in the arena, animal location and orientation with respect to time is determined. In addition, movement velocity and direction, general activity level, and several other behavioural parameters which can include complex behavioural patterns are processed online. Data are presented as graphics and/or tables. Results may also be exported into those programs that are capable of importing graphics (wmf or bmp format) or ASCII-files. VIEWER offers an inexpensive, fast and easy way for analysing simple and complex behaviours of many species of animals in a variety of behavioural situations.

Applications of visible CCD cameras on the Alcator C-Mod tokamak

Five 7 mm diameter remote-head visible charge-coupled device (CCD) cameras are being used on Alcator C-Mod for several different diagnostic purposes. All of the cameras’ detectors and optics are placed inside a magnetic field of up to 4 T. Images of the cameras are recorded simultaneously using two three-channel color framegrabber cards. Two CCD cameras are used typically to generate two-dimensional emissivity profiles of deuterium line radiation from the divertor. Interference filters are used to select the spectral line to be measured. The local emissivity is obtained by inverting the measured brightnesses assuming toroidal symmetry of the emission. Another use of the cameras is the identification and localization of impurity sources generated by the ion cyclotron radio frequency (ICRF) antennas, which supply the auxiliary heating on Alcator C-Mod. The impurities generated by the antennas are identified by correlating in time the injections seen at the cameras with measurements made with core diagnostics. Fibers whose views aligned with the camera views and whose outputs are coupled to a visible spectrometer are also used to identify the species of the impurities injected.

A Low Cost Configuration for Internetwork Telemicroscopy

Abstract Advances in internetwork data transmission rates and reductions in the cost of imaging components and applications have facilitated real-time sharing of video, still images, and microscope operating systems with collaborators or observers at remote locations. Specialized direct and web-based systems for transmission electron microscopy have been described previously. However, in order to develop a generic and flexible means of sharing live images and data from light, scanning electron, and transmission electron microscope instruments, a telemicroscopy system was configured using readily available components and software that can be adapted for use with most common computer operating and networking systems. Figure 1 diagrams the general configuration used in our laboratory. Input devices can include inexpensive desktop digital or analog video cameras, specialized fast or slow scan CCD cameras, and the analog video-screen signal generated by scanning electron microscopes. For transmission through TCP/IP networks, analog signals must be digitized with a frame grabber card.

Automated optical liquid film thickness measurement method

A nonintrusive, automated, optical film thickness measurement technique has been developed to be used with a wide range of fluids and flow configurations. In this method, light is reflected from the surface of a liquid film flowing over a transparent wall. This reflected light generates an image on the outside of the wall which is captured and digitized using a charge coupled device camera and framegrabber card in a desktop computer. The image is processed to determine the positions of the reflected light rays, with which the film thickness is calculated. The entire process is automated, allowing for the collection of 600 data points in about 4 min using a personal computer with a 486 microprocessor. Film thicknesses on the order of 0.01 mm may be determined using inexpensive components, with the possibility of greater precision using more advanced imaging equipment. An automated calibration procedure allows for the determination of the necessary physical parameters, so the index of refraction of the test fluid or the test section wall need not be known a priori. Static liquid measurements agree to within 2.2% of measurements made using the needle-contact method. Film thickness data are presented for both round and square test sections operating under annular, two-phase flow conditions with air and water.

An automated spring balance for kinetic gravimetric sorption of gases and vapors in polymers

A method for automation of a McBain-type spring balance using a charge coupled device camera, a computer equipped with a frame-grabber card, and National Institutes of Health Image software is presented. This balance is used to study the sorption and transport of small molecules in polymeric materials. Kinetic gravimetric sorption data of acetone uptake in a random copolymer of 50 wt % poly(ethylene terephthalate) and 50 wt % poly(ethylene 2,6-naphthalate) at 35 °C are provided to illustrate the utility of the method. The diffusion coefficients determined from the cathetometer and camera experiments are 1.1±0.2×10−12 and 1.0±0.2×10−12 cm2/s, respectively. At an acetone partial pressure of 5.4 cm Hg, the equilibrium acetone uptake was 1.47±0.15 g acetone/100 g polymer using the cathetometer to determine spring extension and 1.52±0.15 g acetone/100 g polymer when the camera was used to determine mass uptake of acetone by the polymer. The camera-based balance was determined to be sensitive to weight changes as small as ±1 μg.

CCD camera modeling and simulation

In this paper we propose a modeling of an acquisition line made up of a CCD camera, a lens and a frame grabber card. The purpose of this modeling is to simulate the acquisition process in order to obtain images of virtual objects. The response time has to be short enough to permit interactive simulation. All the stages are modelised: in the first phase, we present a geometric model which supplies a point to point transformation that provides, for a space point in the camera field, the corresponding point on the plane of the CCD sensor. The second phase consists of modeling the discrete space which implies passing from the continous known object view to a discrete image, in accordance with the different orgin of the contrast loss. In the third phase, the video signal is reconstituted in order to be sampled by the frame grabber card. The practical results are close to reality when compared to image processing. This tool makes it possible to obtain a short computation time simulation of a vision sensor. This enables interactivity either with the user or with software for the design/simulation of an industrial workshop equipped with a vision system. It makes testing possible and validates the choice of sensor placement and image processing and analysis. Thanks to this simulation tool, we can control perfectly the position of the object image placed under the camera and in this way, we can characterise the performance of subpixel accuracy determining methods for object positioning.

Software tools for 4D live cell microscopy

The Integrated Microscopy Resource has developed a trio of Macintosh-based software tools which allow the user to collect digital 4D microscopy (3D over time) of live cells. To demonstrate the program, high-resolution Nomarski DIC images were collected from an inverted microscope using a video camera. The output of the camera can be averaged and contrast-enhanced before the resulting signal is digitized using a framegrabber card installed in a Macintosh computer (Figure 1). Collection, subsequent processing, and analysis of the resulting data sets are handled by the following three software tools:4D Acquisition Software - This IMR-designed software system is based on the popular shareware image processing program “NIH-Image” (author Wayne Rasband, NIH) and controls the actual image acquisition through a series of graphic user interfaces. A framegrabber card, a stage drive motor, and an illumination shutter are manipulated to allow the imaging of either a single focal-plane of the specimen over time, or the acquisition of 3-dimensional volumes at each timepoint. After selecting the top and bottom of the sample, the user can specify the number of focal planes to acquire, the increment for the focus motor between focal planes, the number of timepoints to collect, and a file format in which to save the images. The software will automatically move through the sample from the top to the bottom gathering images of each focal plane as it goes. The result is a stack of images representing the 3D structure of the sample. The software will wait a defined amount of time and the process will be repeated for as many timepoints as the user has designated.

Direct measurement of diffusion rates in enzyme crystals by video absorbance spectroscopy

In order to directly observe the structure of enzyme intermediate complexes that form during turnover, one must ensure the homogeneous and complete accumulation of the intermediate during the collection of diffraction data. In the case of steady-state Laue experiments, the accumulation of the intermediate is dictated by the rate of substrate diffusion throughout the crystal, compared with the rate of turnover and disappearance of a rate-limited catalytic intermediate. This paper describes a simple quantitative method for measuring substrate diffusion and binding within an enzyme crystal. The set-up consists of a light source, specific bandpass filters, a crystallographic flow cell, a syringe pump, a charge-coupled-device color video camera and a workstation with a frame-grabber card for collection and digitization of images and subsequent processing of data. By this technique, any diffusion and binding process in a protein crystal leading to a visible absorbance shift may be accurately monitored and quantified during data collection. This method offers the crystallographer an inexpensive and simple alternative to the use of a single-crystal microspectrophotometer to measure the relatively slow process of diffusion.

Quantization of surface rust by using laser imaging techniques

Laser speckle interferometry 1,2 and image processing 3,4 have been used to detect and quantize the rust build-up on metal surfaces under water. Speckle information from the sample metal surface was captured by a CCD camera and a frame grabber card. Software techniques were used to convert the image data files into ASCII files in an appropriate format. Three-dimensional surface plots were generated to define the numerical values for the amout of rust build-up.

Optical recognition of motor vehicle license plates

A system for the recognition of car license plates is presented. The aim of the system is to read automatically the Italian license number of a car passing through a tollgate. A CCTV camera and a frame grabber card are used to acquire a rear-view image of the vehicle. The recognition process consists of three main phases. First, a segmentation phase locates the license plate within the image. Then, a procedure based upon feature projection estimates some image parameters needed to normalize the license plate characters. Finally, the character recognizer extracts some feature points and uses template matching operators to get a robust solution under multiple acquisition conditions. A test has been done on more than three thousand real images acquired under different weather and illumination conditions, thus obtaining a recognition rate close to 91%. >

Calibration of a laser range-finding coordinate-measuring machine

An automated, self-calibrating, active-laser-triangulation 3-D surface-measuring system has been designed and built for the acquisition of surface coordinate information. The system is driven by a 50-MHz 80486-based PC/AT computer controlling a laser, a CCD camera, a frame-grabber card, and an encoded motor-driven positioning system. A novel self-calibration procedure is executed in a matter of seconds with the use of a standard sphere and a flat plane. Data acquisition rates of 750 points/s are obtained with an overall system accuracy of ± 0.12 mm using a 75-mm compound lens. Resolutions for the system, using the 75-mm lens, are 480 parts per image width of field in the x axis, 0.6 im in the y axis, and 4096 parts per depth of field in the z axis. The system operates at a standoff of 30 cm, a depth of view of 7 cm, and a width of field of view of 4.5 cm in the close plane and 6 cm in the far plane. The theory and design of the system are presented along with the derivation and implementation of the calibration equations, followed by results of the system's application, and a brief discussion on ways of improving accuracy, resolution, and data acquisition rates.

The Bright Future of Digital Imaging in Scanning Electron Microscopy

Abstract One of the major advancements applied to scanning electron microscopy (SEM) during the past 10 years has been the development and application of digital imaging technology. Advancements in technology, notably the availability of less expensive, high-density memory chips and the development of high speed analog-to-digital converters, mass storage and high performance central processing units have fostered this revolution. Today, most modern SEM instruments have digital electronics as a standard feature. These instruments, generally have 8 bit or 256 gray levels with, at least, 512 X 512 pixel density operating at TV rate. In addition, current slow-scan commercial frame-grabber cards, directly applicable to the SEM, can have upwards of 12-14 bit lateral resolution permitting image acquisition at 4096 X 4096 resolution or greater.

The pluviospectrometer: classification of falling hydrometeors via digital image processing

Characteristic properties of precipitation as intensity, raindrop size distribution, velocity of raindrops and morphology of the hydrometeors (especially snow flakes) are important parameters for the atmospheric scavenging processes. In order to measure these parameters without any disturbance, optical methods are suitable. The Pluviospectrometer is a new optical device that has been developed to classify raindrops and other hydrometeors by means of digital image processing at a low cost level. Using a commercial video system and a personal computer equipped with a frame grabber card, it is possible to measure raindrops size distributions automatically. For rain drops the considered size range reaches from 0.1 mm to 6.0 mm. There is the possibility to modify this measuring range by using different camera optics for example to analyse snowflake structures in the submillimetre range. To get high quality pictures of falling hydrometeors a special illumination unit has been developed on the principle of projection illumination. The image acquisition system is composed to meet the requirements given by the characteristics of the falling raindrops. The analysing image processing software measures the sizes of the objects and separates them into different size classes. At present only a few raindrop size distributions have been analysed. They show a behaviour similar to the corresponding Marshall-Palmer distributions, but droplets with size below 0.3 mm seem to be underestimated significantly by the approximation of Marshall and Palmer. A comparison of the rainfall rate calculated from the drop size distributions to values measured by an Ombrometer hasn't been satisfying in all cases considered. In principle there is the possibility for more sophisticated hydrometeor analysis with the Pluviospectrometer. Future developments may allow analysis of the velocities of fall or snowflake classification.

The bright future of digital imaging in scanning electron microscopy

One of the major advancements applied to scanning electron microscopy (SEM) during the past 10 years has been the development and application of digital imaging technology. Advancements in technology, notably the availability of less expensive, high-density memory chips and the development of high speed analog-to-digital converters, mass storage and high performance central processing units have fostered this revolution. Today, most modern SEM instruments have digital electronics as a standard feature. These instruments, generally have 8 bit or 256 gray levels with, at least, 512 × 512 pixel density operating at TV rate. In addition, current slow-scan commercial frame-grabber cards, directly applicable to the SEM, can have upwards of 12-14 bit lateral resolution permitting image acquisition at 4096 × 4096 resolution or greater. The two major categories of SEM systems to which digital technology have been applied are:In the analog SEM system the scan generator is normally operated in an analog manner and the image is displayed in an analog or "slow scan" mode.

The use of image analysis for spore counts of white-rot fungi

An improved method has been developed for the determination of fungal spore counts using a haemocytometer. The method uses a personal computer with a frame grabber card and commercial imaging software. Semi-automation using an iterative programming technique was implemented to count the spores produced byPhanerochaete chrysosporium. Rapid and reliable counts were achieved using image processing.

Surface tension by pendant drop: I. A fast standard instrument using computer image analysis

An improved method has been developed for the determination of surface and interfacial tensions from primary drop shape data. In addition, wetting angles of sessile drops may be determined. The method has been built around a commercial pendant drop instrument and an IBM-compatible PC with a frame grabber card. In order to differentiate the drop profile, a filter routine using a local threshold and interpolation technique has been developed that is combined with an edge-tracing algorithm. The program for calculation of surface tension is divided into two parts. The first part is based on the traditional optical method and uses inflection of the drop profile. By means of several polynomial interpolations and curve fitting of theoretical profiles, the form factor β and surface tension γ are determined. The second part of the calculation utilizes the above values as a first estimate and then performs a further optimalization of γ by comparison between experimental and theoretical Young—Laplace profiles. With a PC AT with a 80287 mathematical coprocessor the measurements take about 5 s and the reproducibility is typically 0.01–0.03 mN/m for a wide range of known liquids.