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Video Images (video + image)
Selected AbstractsA Computer-Based Method for Determination of the Cell-Free Layer Width in MicrocirculationMICROCIRCULATION, Issue 3 2006SANGHO KIM ABSTRACT Objectives: The cell-free layer between the erythrocyte column and the vessel wall is an important determinant of hydrodynamic resistance in microcirculatory vessels. The authors report a method for continuous measurement of the width of this layer. Methods: The light intensity of a linear array of pixels perpendicular to the vessel axis is continuously determined from a video image of a microcirculatory vessel. A threshold level based on Otsu's method is used to establish the interface between the cell-free layer and the erythrocyte column. To test the method, video images at 750,4500 frames/s were obtained from venules and arterioles in rat spinotrapezius muscle at normal and reduced arterial pressures before and after induction of erythrocyte aggregation with Dextran 500. The current measurements were compared to manual measurements of the same images. Results: Values obtained by the manual and the new methods were in agreement within the 95% confidence limit by the Bland-Altman analysis and within 90,95% range by the correlation coefficient (R2). The more frequent measurements reveal substantial, rapid variations in cell-free layer width and changes in mean values with alteration of arterial pressure and red cell aggregability. Conclusions: A new, computer-based technique has been developed that provides measurements of rapid, time-dependent variations in the width of the cell-free layer in the microcirculation. [source] Who's in the Mirror?CHILD DEVELOPMENT, Issue 1 2002Nine-Month-Old Infants, Other Discrimination in Specular Images by Four- This research investigated the early determinants of self-other discrimination in infancy. Ninety-six 4- and 9-month-old infants were placed facing a live image either of themselves or of another person (experimenter) mimicking them. The specular image was either contingent (on-line), or contingent with a 2-s delay. After a first 1-min presentation, the video image of either the self or the other was suddenly frozen for 1 min (still-face episode). This was followed by a last minute of live presentation. From 4 months of age, infants appeared to perceive and act differentially when facing the specular image of themselves or the mimicking other. In general, infants tended to smile more, look more, and have more protracted first-look duration toward the mimicking other compared with the self. Developmentally, 9-month-olds showed markedly more social initiatives toward the mimicking other compared with the self during the still-face episode. In all, these results indicate that infants develop self-other discrimination in specular images long before mirror self-recognition, which is typically reported by the second year. Discrimination of the self from other is interpreted as a precursory ability and a perceptual foundation of later conceptual self development. [source] Immersive Integration of Physical and Virtual EnvironmentsCOMPUTER GRAPHICS FORUM, Issue 3 2004Henry Fuchs We envision future work and play environments in which the user's computing interface is more closely integrated with the physical surroundings than today's conventional computer display screens and keyboards. We are working toward realizable versions of such environments, in which multiple video projectors and digital cameras enable every visible surface to be both measured in 3D and used for display. If the 3D surface positions were transmitted to a distant location, they may also enable distant collaborations to become more like working in adjacent offices connected by large windows. With collaborators at the University of Pennsylvania, Brown University, Advanced Network and Services, and the Pittsburgh Supercomputing Center, we at Chapel Hill have been working to bring these ideas to reality. In one system, depth maps are calculated from streams of video images and the resulting 3D surface points are displayed to the user in head-tracked stereo. Among the applications we are pursuing for this tele-presence technology, is advanced training for trauma surgeons by immersive replay of recorded procedures. Other applications display onto physical objects, to allow more natural interaction with them "painting" a dollhouse, for example. More generally, we hope to demonstrate that the principal interface of a future computing environment need not be limited to a screen the size of one or two sheets of paper. Just as a useful physical environment is all around us, so too can the increasingly ubiquitous computing environment be all around us -integrated seamlessly with our physical surroundings. [source] Daily to seasonal cross-shore behaviour of quasi-persistent intertidal beach morphologyEARTH SURFACE PROCESSES AND LANDFORMS, Issue 9 2007S. Quartel Abstract In this study, an intertidal bar and trough system on the beach of Noordwijk, The Netherlands was monitored over a 15-month period in order to examine the daily to seasonal sequential cross-shore behaviour and to establish which conditions force or interrupt this cyclic bar behaviour. The beach morphology (bars and troughs) was classified from low-tide Argus video images based on surface composition. From the classified images, time series of the landward boundary of the bar and of the trough were extracted. The time series of the alongshore-averaged boundary positions described sawtooth motion with a period between 1 and 4 months, comprising gradual landward migration followed by abrupt seaward shifts. The abrupt seaward shift appeared to be a morphological reset induced by storm events, which lasted at least 30 h with a large average root-mean-square wave height (,2 m) and offshore surge level (,0·5 m), and a small trough (<20 m wide) in the pre-storm beach morphology. The time series of the boundary positions exhibited very little longer (seasonal) scale variability, but somewhat larger smaller (daily) scale variability. The bar boundary was found to be more dynamic than the trough boundary. Copyright © 2007 John Wiley & Sons, Ltd. [source] Quality control in laparoscopic cholecystectomy: operation notes, video or photo print?HPB, Issue 3 2001PW Plaisier Background In 1995 the concept of a ,critical view of safety' (CVS) in Calot's triangle was introduced to prevent bile duct injury in laparoscopic cholecystectomy. The aim of this study was to determine the most reliable method for recording CVS. Methods Operation notes, video images and photo prints from 50 consecutive elective non-converted laparoscopic cholecystectomies were analysed. Results Operation notes alone did not suffice to record CVS. As an adjunct, video proved superior to photo print with regard to quality. Nevertheless, photo prints were practically and logistically much easier to produce than video. Moreover, when good quality images were achieved, photo print recorded CVS more conclusively than video. Discussion Operation notes, video and photo print are complementary, and the combination records CVS conclusively in nearly every case. [source] Nonuniform video coding by means of multifoveal geometriesINTERNATIONAL JOURNAL OF IMAGING SYSTEMS AND TECHNOLOGY, Issue 1 2002J.A. Rodríguez This paper presents a control mechanism for video transmission that relies on transmitting nonuniform resolution images depending on the delay of the communication channel. These images are built in an active way to keep the areas of interest of the image at the highest resolution available. In order to shift the areas of high resolution over the image and to achieve a data structure that is easy to process by using conventional algorithms, a shifted foveal multiresolution geometry of adaptive size is used. If delays are too high, the resolution areas of the image can be transmitted at different rates. A functional system has been developed for corridor surveillance with static cameras. Tests with real video images have proven that the method allows an almost constant rate of images per second as long as the channel is not collapsed. A new method for determining the areas of interest is also proposed, based on hierarchical object tracking by means of adaptive stabilization of pyramidal structures. © 2002 John Wiley & Sons, Inc. Int J Imaging Syst Technol 12, 27,34, 2002 [source] Computer-based endoscopic image-processing technology for endourology and laparoscopic surgeryINTERNATIONAL JOURNAL OF UROLOGY, Issue 6 2009Tatsuo Igarashi Abstract Endourology and laparoscopic surgery are evolving in accordance with developments in instrumentation and progress in surgical technique. Recent advances in computer and image-processing technology have enabled novel images to be created from conventional endoscopic and laparoscopic video images. Such technology harbors the potential to advance endourology and laparoscopic surgery by adding new value and function to the endoscope. The panoramic and three-dimensional images created by computer processing are two outstanding features that can address the shortcomings of conventional endoscopy and laparoscopy, such as narrow field of view, lack of depth cue, and discontinuous information. The wide panoramic images show an anatomical ,map' of the abdominal cavity and hollow organs with high brightness and resolution, as the images are collected from video images taken in a close-up manner. To assist in laparoscopic surgery, especially in suturing, a three-dimensional movie can be obtained by enhancing movement parallax using a conventional monocular laparoscope. In tubular organs such as the prostatic urethra, reconstruction of three-dimensional structure can be achieved, implying the possibility of a liquid dynamic model for assessing local urethral resistance in urination. Computer-based processing of endoscopic images will establish new tools for endourology and laparoscopic surgery in the near future. [source] Analysis of video images from a gas,liquid transfer experiment: a comparison of PCA and PARAFAC for multivariate image analysisJOURNAL OF CHEMOMETRICS, Issue 7 2003Stephen P. Gurden Abstract The use of chemical imaging is a developing area which has potential benefits for chemical systems where spatial distribution is important. Examples include processes in which homogeneity is critical, such as polymerizations, pharmaceutical powder blending and surface catalysis, and dynamic processes such as the study of diffusion rates or the transport of environmental pollutants. Whilst single images can be used to determine chemical distribution patterns at a given point in time, dynamic processes can be studied using a sequence of images measured at regular time intervals, i.e. a movie. Multivariate modeling of image data can help to provide insight into the important chemical factors present. However, many issues of how best to apply these models remain unclear, especially when the data arrays involved have four or five different dimensions (height, width, wavelength, time, experiment number, etc.). In this paper we describe the analysis of video images recorded during an experiment to investigate the uptake of CO2 across a free air,water interface. The use of PCA and PARAFAC for the analysis of both single images and movies is described and some differences and similarities are highlighted. Some other image transformation techniques, such as chemical mapping and histograms, are found to be useful both for pretreatment of the raw data and for dimensionality reduction of the data arrays prior to further modeling. Copyright © 2003 John Wiley & Sons, Ltd. [source] Stereoscopic video images for telerobotic applicationsJOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 3 2005Manuel Ferre This article addresses the use of stereoscopic images in teleoperated tasks. Depth perception is a key point in the ability to skillfully manipulate in remote environments. Displaying three-dimensional images is a complex process but it is possible to design a teleoperation interface that displays stereoscopic images to assist in manipulation tasks. The appropriate interface for image viewing must be chosen and the stereoscopic video cameras must be calibrated so that the image disparity is natural for the observer. Attention is given to the calculation of stereoscopic image disparity, and suggestions are made as to the limits within which adequate stereoscopic image perception takes place. The authors have designed equipment for image visualization in teleoperated systems. These devices are described and their performance evaluated. Finally, an architecture for the transmission of stereoscopic video images via network is proposed, which in the future will substitute for current image processing devices. © 2005 Wiley Periodicals, Inc. [source] Diffraction-based automated crystal centeringJOURNAL OF SYNCHROTRON RADIATION, Issue 2 2007Jinhu Song A fully automated procedure for detecting and centering protein crystals in the X-ray beam of a macromolecular crystallography beamline has been developed. A cryo-loop centering routine that analyzes video images with an edge detection algorithm is first used to determine the dimensions of the loop holding the sample; then low-dose X-rays are used to record diffraction images in a grid over the edge and face plane of the loop. A three-dimensional profile of the crystal based on the number of diffraction spots in each image is constructed. The derived center of mass is then used to align the crystal to the X-ray beam. Typical samples can be accurately aligned in ,2,3,min. Because the procedure is based on the number of `good' spots as determined by the program Spotfinder, the best diffracting part of the crystal is aligned to the X-ray beam. [source] A Computer-Based Method for Determination of the Cell-Free Layer Width in MicrocirculationMICROCIRCULATION, Issue 3 2006SANGHO KIM ABSTRACT Objectives: The cell-free layer between the erythrocyte column and the vessel wall is an important determinant of hydrodynamic resistance in microcirculatory vessels. The authors report a method for continuous measurement of the width of this layer. Methods: The light intensity of a linear array of pixels perpendicular to the vessel axis is continuously determined from a video image of a microcirculatory vessel. A threshold level based on Otsu's method is used to establish the interface between the cell-free layer and the erythrocyte column. To test the method, video images at 750,4500 frames/s were obtained from venules and arterioles in rat spinotrapezius muscle at normal and reduced arterial pressures before and after induction of erythrocyte aggregation with Dextran 500. The current measurements were compared to manual measurements of the same images. Results: Values obtained by the manual and the new methods were in agreement within the 95% confidence limit by the Bland-Altman analysis and within 90,95% range by the correlation coefficient (R2). The more frequent measurements reveal substantial, rapid variations in cell-free layer width and changes in mean values with alteration of arterial pressure and red cell aggregability. Conclusions: A new, computer-based technique has been developed that provides measurements of rapid, time-dependent variations in the width of the cell-free layer in the microcirculation. [source] Quantification of Video-Taped Images in Microcirculation Research Using Inexpensive Imaging Software (Adobe Photoshop)MICROCIRCULATION, Issue 2 2000Joachim Brunner ABSTRACT Background: Study end-points in microcirculation research are usually videotaped images rather than numeric computer print-outs. Analysis of these videotaped images for the quantification of microcirculatory parameters usually requires computer-based image analysis systems. Most software programs for image analysis are custom-made, expensive, and limited in their applicability to selected parameters and study end-points. Methods and Result: We demonstrate herein that an inexpensive, commercially available computer software (Adobe Photoshop), run on a Macintosh G3 computer with inbuilt graphic capture board provides versatile, easy to use tools for the quantification of digitized video images. Using images obtained by intravital fluorescence microscopy from the pre- and postischemic muscle microcirculation in the skinfold chamber model in hamsters, Photoshop allows simple and rapid quantification (i) of microvessel diameters, (ii) of the functional capillary density and (iii) of postischemic leakage of FITC-labeled high molecular weight dextran from postcapillary venules. We present evidence of the technical accuracy of the software tools and of a high degree of interobserver reliability. Conclusions: Inexpensive commercially available imaging programs (i.e., Adobe Photoshop) provide versatile tools for image analysis with a wide range of potential applications in microcirculation research. [source] The video images of sleep attacks in Parkinson's diseaseMOVEMENT DISORDERS, Issue 2 2008Masaaki Hirayama MD Abstract We describe a sleep attack, which was induced by taking excessive levodopa and pergolide, in a 73-year-old woman with Parkinson's disease. At the onset of the sleep attack, her head suddenly sagged and sometimes hit the table, but she did not notice these symptoms. Her family noticed that this sleep attack occurred when she began to speak slowly. Her family recorded this attack with a video camera. This sleep attack resolved with control of her medication. This is the first report of video images of a sleep attack due to excessive levodopa and a dopamine agonist. © 2007 Movement Disorder Society [source] Movement disorders associated with encephalitis lethargica: A video compilationMOVEMENT DISORDERS, Issue 1 2006Joel A. Vilensky PhD Abstract Encephalitis lethargica (EL; epidemic encephalitis; von Economo's disease) often presented with a movement disorder, and the motor consequences of postencephalitic parkinsonism (PEP) were characteristic of the chronic sequelae of this condition. PEP was similar to Parkinson's disease but was more variable and had some distinct features such as oculogyric crises. Although two previous publications have included video images of the movement disorders associated with EL and PEP, the sequences presented were typically short, showed only a few patients, and did not include the work of several neurologists who had the foresight to preserve filmed images of their patients. We describe the most complete record of EL and PEP moving images that have been preserved and make them available in edited form. © 2005 Movement Disorder Society [source] Motor patterns and propulsion in the rat intestine in vivo recorded by spatio-temporal mapsNEUROGASTROENTEROLOGY & MOTILITY, Issue 5 2005D. M. Ferens Abstract, We have used spatio-temporal maps derived from video images to investigate propagated contractions of the rat small intestine in vivo. The abdomen, including an exteriorized segment of jejunum, was housed in a humid chamber with a viewing window. Video records were converted to spatio-temporal maps of jejunal diameter changes. Intraluminal pressure and fluid outflow were measured. Contractions occupied 3.8 ± 0.2 cm of intestine and propagated anally at 3.1 ± 0.2 mm s,1 when baseline pressure was 4 mmHg. Contractions at any one point lasted 8.7 ± 0.6 s. Contractions often occurred in clusters; within cluster frequencies were 2.28 ± 0.04 min,1. Pressure waves, with amplitudes greater than about 9 mmHg, expelled fluid when the baseline pressure was 4 mmHg. In the presence ofl -NAME, circular muscle contractions occurred at a high frequency, but they were not propagated. We conclude that video recording methods give good spatio-temporal resolution of intestinal movement when applied in vivo. They reveal neurally-mediated propulsive contractions, similar to those previously recorded from intestinal segments in vitro. The propagated contractions had speeds of propagation that were slower and frequencies of occurrence that were less than speeds and frequencies of slow waves in the rat small intestine. [source] Activation of the prefrontal cortex to trauma-related stimuli measured by near-infrared spectroscopy in posttraumatic stress disorder due to terrorismPSYCHOPHYSIOLOGY, Issue 4 2003Koji Matsuo Abstract To develop a noninvasive method for psychophysiological assessment of posttraumatic stress disorder (PTSD), 34 victims of the Tokyo Subway Sarin Attack in 1995 including 8 diagnosed as PTSD and 12 controls were examined by a multichannel near-infrared spectroscopy (NIRS) system. Hemodynamic response in the prefrontal cortex was monitored during the presentation of trauma-related and control stimuli by video images. Skin conductance response (SCR) was also examined. Oxygenated hemoglobin significantly increased during the trauma-related image in the victims with or without PTSD. Deoxygenated hemoglobin significantly decreased only in victims with PTSD. No significant alteration was found in controls. Significantly enhanced SCR was also observed in the victims with PTSD during trauma-related stimuli. The findings suggest that measurement of cerebral hemodynamic response by NIRS is useful for psychophysiological assessment of PTSD. [source] The range of passive arm circumduction in primates: Do hominoids really have more mobile shoulders?AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 3 2008Lap Ki Chan Abstract Hominoids and lorines are assumed to possess greater shoulder mobility than other primates. This assumption is based on morphological characteristics of the shoulder, rather than on empirical data. However, recent studies have shown that the glenohumeral joint of hominoids is not more mobile than that of other primates (Chan LK. 2007. Glenohumeral mobility in primates. Folia Primatol (Basel) 78(1):1,18), and the thoracic shape of hominoids does not necessarily promote shoulder mobility (Chan LK. 2007. Scapular position in primates. Folia Primatol (Basel) 78(1):19,35). Moreover, lorines differ significantly from hominoids in both these features, thus challenging the assumption that both hominoids and lorines have greater shoulder mobility. The present study aims to test this assumption by collecting empirical data on shoulder mobility in 17 primate species. Passive arm circumduction (a combination of glenohumeral and pectoral girdle movement) was performed on sedated subjects (except humans), and the range measured on the video images of the circumduction. The motion differed among primate species mostly in the craniodorsal directions, the directions most relevant to the animal's ability to brachiate and slow climb. Hylobatids possessed the highest craniodorsal mobility among all primate species studied. However, nonhylobatid hominoids did not have greater craniodorsal mobility than arboreal quadrupedal monkeys, and lorines did not have greater craniodorsal mobility than arboreal quadrupedal prosimians. Nonhylobatid hominoids and lorines had similar craniodorsal mobility, but this was due to a longer clavicle, more dorsal scapula, and lower glenohumeral mobility in the former, and a shorter clavicle, less dorsal scapula, and greater glenohumeral mobility in the latter. This study provides evidence for the reexamination of the brachiation, slow climbing, and vertical climbing hypotheses. Am J Phys Anthropol, 2008. © 2008 Wiley-Liss, Inc. [source] Functional analysis of the gibbon foot during terrestrial bipedal walking: Plantar pressure distributions and three-dimensional ground reaction forcesAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 3 2005Evie Vereecke Abstract This paper gives a detailed analysis of bipedal walking in the white-handed gibbon, based on collected pressure and force data. These data were obtained from four gibbons in the Wild Animal Park, Planckendael, Belgium, by using a walkway with integrated force plate and pressure mat. This is the first study that collects and describes dynamic plantar pressure data of bipedally walking gibbons, and combines these with force plate data. The combination of these data with previously described roll-off patterns of gibbons, based on general observations, video images, force plates, and EMG data, gives us a detailed description of foot function during gibbon bipedalism. In addition, we compare the observed characteristics of hylobatid bipedalism with the main characteristics of bonobo and human bipedalism. We found that gibbons are midfoot/heel plantigrade, and lack the typical heel-strike of other hominoids. The hallux is widely abducted and touches down at the onset of the stance phase, which results in an L-shaped course of the center of pressure. The vertical force curve is trapezoid to triangular in shape, with high peak values compared to humans. The braking component is shorter than the accelerating component, and shortens further at higher walking velocities. Speed has a significant influence on the forefoot peak pressures and on most of the defined gait parameters (e.g., vertical force peak), and it alters the foot contact pattern as well. The investigation of existing form-function relationships in nonhuman primates is essential for the interpretation of fossil remains, and might help us understand the evolution of habitual bipedal walking in hominids. Am J Phys Anthropol, 2005. © 2005 Wiley-Liss, Inc. [source] CCTV on trial: Matching video images with the defendant in the dock,APPLIED COGNITIVE PSYCHOLOGY, Issue 4 2009Josh P. Davis The experiments reported in this paper investigated simultaneous identity matching of unfamiliar people physically present in person with moving video images typical of that captured by closed circuit television (CCTV). This simulates the decision faced by a jury in court when the identity of somebody caught on CCTV is disputed. Namely, ,is the defendant in the dock the person depicted in video'? In Experiment 1, the videos depicted medium-range views of a number of actor ,culprits'. Experiment 2 used similar quality images taken a year previously, some of which showed the culprits in disguise. Experiment 3 utilised high-quality close-up video images. It was consistently found that in both culprit-present and culprit-absent videos and in optimal conditions, matching the identity of a person in video can be highly susceptible to error. Copyright © 2008 John Wiley & Sons, Ltd. [source] | ||||||||||||||||