Contour Display Research Articles

Real-time 3D echocardiographic transilluminated imaging combined with artificially intelligent left atrial appendage measurement for atrial fibrillation interventional procedures.

Aims: This study investigated the feasibility and accuracy of real-time three-dimensional (3D) echocardiographic transilluminated imaging (TrueVue Glass) in left atrial appendage (LAA) anatomical morphology and artificial intelligence (AI)-assisted 3D automated LAA measurement (3D Auto LAA) software in the preoperative evaluation of LAA occlusion (LAAO) in patients with atrial fibrillation (AF). Method and results: Thirty-seven patients with AF were selected. Two-dimensional (2D) and real-time 3D transesophageal echocardiography (RT3D-TEE) were performed preoperatively, using conventional 3D, the new 3D TrueVue Glass mode, and cardiac computed tomography angiography (CCTA) to assess and type the morphology of LAA. Physiological parameters were measured using traditional 2D and 3D manual (3D Manual LAA), 3D Auto LAA, and CCTA. TrueVue Glass for LAA outer contour display was compared with CCTA. Comparisons were based on correlation and consistency in measuring the maximum diameter (LZ max), minimum diameter (LZ min), area (LZ area), and circumference (LZ cir) of LAA landing zone (LZ). Times and variabilities were compared. The concordance rate for external shape of LAA was 97.14% between TrueVue Glass and CCTA. 3D Auto LAA and 3D Manual LAA have a stronger correlation and higher consistency in all parameters. 3D Auto LAA showed higher intra- and interobserver reproducibility and allowed quicker analysis (p < 0.05). LAAO was performed in 35 patients (94.59%), and none of which had serious adverse events. Conclusion: TrueVue Glass is the first non-invasive and radiation-free visualization of the overall external contour of LAA and its adjacent structures. 3D Auto LAA simplifies the measurement, making the preoperative assessment more efficient and convenient while ensuring the accuracy and reproducibility. A combination of the two is feasible for accurate and rapid assessment of LAA anatomy and physiology in AF patients and has practical application in LAAO.

An Image Saliency Detection Method Based on Combining Global and Local Information

In the field of computer vision, image saliency target detection can not only improve the accuracy of image detection but also accelerate the speed of image detection. In order to solve the existing problems of the saliency target detection algorithms at present, such as inconspicuous texture details and incomplete edge contour display, this paper proposes a saliency target detection algorithm integrating multiple information. The algorithm consists of three processes: preprocessing process, multi-information extraction process, and fusion optimization process. The frequency domain features of the image are calculated, the algorithm calculates the frequency domain features of the image, introduces power law transform and feature normalization, improves the frequency domain features of the image, saves the information of the target region, and inhibits the information of the background region. On three public MSRA, SED2, and ECSSD image datasets, the proposed algorithm is compared with other classical algorithms in subjective and objective comparison experiments. Experimental results show that the proposed algorithm can not only accurately and comprehensively extract significant target regions but also retain more texture information and complete edge information while satisfying the human visual experience. All evaluation indexes are significantly better than the comparison algorithm, showing good reliability and adaptability.

Indoor Wireless Network Coverage Area Optimization

The presence of interference has a significant impact on wireless network connections indoors. Because of the effects of multipath propagation, such as reflection, refraction, and scattering of radio waves by the structure of the building, the sent signal can usually be received in free space or via more than one pathway, and the consequence might be a phenomenon known as multipath fading. For different results, propagation models have been identified, which provide the propagation features of the initial evaluation. There are two types of wireless propagation models: empirical and theoretical models that deal with coverage, overlapping channels, and wireless network performance. The planning system was set out using a practical and theoretical approach. Furthermore, this comparison may aid in determining the accuracy of survey measures in the context of indoor wireless monitoring and provide an estimate of the breadth and performance of wireless networks in the form of a new topology with contour presentation. Layout plan optimization The typical RSSI of a Wi-Fi system ranges from -40 dBm to -55 Dbm, with a power of 17-18 Dbm, and is applied to channels 1 through 11 non-overlapping in the design of networks with multiple APs that are nearby. The new topology represents the optimization outcomes, accompanied by a contour display and dispersed over the region.

Five-Year Development and Usage Outcomes of eContour, a Web-Based Interactive Contouring Atlas

<h3>Purpose/Objective(s)</h3> The delivery of safe and effective radiation therapy relies on accurate target delineation, particularly in the era of highly conformal treatment techniques. Contouring resources can improve accuracy but are fragmented and underused. We report the 5-year development and usage outcomes of a free, online, easily accessible web-based interactive contouring atlas. <h3>Materials/Methods</h3> <b>eContour</b> (https://econtour.org) was developed using modern web technologies, including HTML5, Python, and an interpreted computer programming language, to interactively display images and contours from real patient cases. The viewer has standard tools for image manipulation, contour display, image overlays, and radiation dose distribution. Information from evidence-based guidelines and clinical pearls are summarized and presented next to each case. Mixpanel software was used to collect web usage statistics, including user demographics, geography, and case views. <h3>Results</h3> In the first 5 years of operation (February 1, 2016 to February 1, 2021), a total of 22,889 users registered on eContour. Users represented a total of 146 countries, with the largest cohort from the United States (7,096, 31%). Other countries with > 700 registered users included Spain, India, Brazil, China, and Russia. The majority of registered users (58%) reported their profession as physicians, including 10,869 practicing radiation oncologists (47%) and 2,583 resident physicians (11%). There are 3,107 users who identified as physicians and were geographically within the US. The remaining users identified as radiation therapists (10%), dosimetrists (10%), medical physicists (8.7%), and medical students (6.6%). As of February 2021, a total of 65 cases have been developed covering 9 disease sites. The most commonly viewed disease site was head and neck (23% of all case views), followed by gynecological, gastrointestinal, and breast cancer. The most commonly viewed cases include pre-operative rectal cancer, head and neck organs-at-risk, and intact prostate cancer. Over 5 years, usage of <b>eContour</b> has increased both in terms of total users and case views. Total users have grown > 600% since 2017; 3,613 (2017), to 12,248 (2019), to 22,889 cumulative total users (2021). In the fourth quarter of 2020, <b>eContour</b> averaged 1,018 case views per weekday. Since the onset of the COVID pandemic, usage of <b>eContour</b> has accelerated. Annual case views increased 56% year-over-year from 2019 to 2020 (147,846 to 230,304 views) as compared to essentially stable from 2018 to 2019 (144,769 to 147,846). <h3>Conclusion</h3> With approximately 5,000 radiation oncologists in the US, we estimate 60% of US radiation oncologists are registered users. Growth in users and web site traffic over the first 5 years of <b>eContour</b> show its strong potential to increase the use of evidence-based contouring information at the point of care.

Research on the Method of Displaying the Contour Features of Image to the Visually Impaired on the Touch Screen.

Conveying image information to the blind or visually impaired (BVI) is an important means to improve their quality of life. The touch screen devices used daily are the potential carriers for BVI to perceive image information through touch. However, touch screen devices also have the disadvantages of limited computing power and lack of rich tactile experience. In order to help BVI to access images conveniently through the touch screen, we built an image contour display system based on vibrotactile feedback. In this paper, an image smoothing algorithm based on convolutional neural network that can run quickly on the touch screen device is first used to preprocess the image to improve the effect of contour extraction. Then, based on the haptic physiological characteristics of human beings, this paper proposes a method of using the improved MH-Pen to guide the BVI to perceive image contour on the touch screen. This paper introduces the extraction and expression methods of image contours in detail, and compares and analyzes the effects of the subjects' perception of image contours in two haptic display modes through two types of user experiments. The experimental results show that the image smoothing algorithm is useful and necessary to help obtain the main contour of the image and to ensure the real-time display of the contour, and the contour expression method based on the motion direction guidance helps the subjects recognize the contour of the image more effectively.

INTERACTIVE VISUALIZATION OF PROBABILITY AND CUMULATIVE DENSITY FUNCTIONS

The probability density function (PDF), and its corresponding cumulative density function (CDF), provide direct statistical insight into the characterization of a random process or field. Typically displayed as a histogram, one can infer probabilities of the occurrence of particular events. When examining a field over some two-dimensional domain in which at each point a PDF of the function values is available, it is challenging to assess the global (stochastic) features present within the field. In this paper, we present a visualization system that allows the user to examine two-dimensional data sets in which PDF (or CDF) information is available at any position within the domain. The tool provides a contour display showing the normed difference between the PDFs and an ansatz PDF selected by the user and, furthermore, allows the user to interactively examine the PDF at any particular position. Canonical examples of the tool are provided to help guide the reader into the mapping of stochastic information to visual cues along with a description of the use of the tool for examining data generated from an uncertainty quantification exercise accomplished within the field of electrophysiology.

Fully automatic three‐dimensional quantitative analysis of intracoronary optical coherence tomography

Quantitative analysis of intracoronary optical coherence tomography (OCT) image data (QOCT) is currently performed by a time-consuming manual contour tracing process in individual OCT images acquired during a pullback procedure (frame-based method). To get an efficient quantitative analysis process, we developed a fully automatic three-dimensional (3D) lumen contour detection method and evaluated the results against those derived by expert human observers. The method was developed using Matlab (The Mathworks, Natick, MA). It incorporates a graphical user interface for contour display and, in the selected cases where this might be necessary, editing. OCT image data of 20 randomly selected patients, acquired with a commercially available system (Lightlab imaging, Westford, MA), were pulled from our OCT database for validation. A total of 4,137 OCT images were analyzed. There was no statistically significant difference in mean lumen areas between the two methods (5.03 + or - 2.16 vs. 5.02 + or - 2.21 mm(2); P = 0.6, human vs. automated). Regression analysis showed a good correlation with an r value of 0.99. The method requires an average 2-5 sec calculation time per OCT image. In 3% of the detected contours an observer correction was necessary. Fully automatic lumen contour detection in OCT images is feasible with only a select few contours showing an artifact (3%) that can be easily corrected. This QOCT method may be a valuable tool for future coronary imaging studies incorporating OCT.

The Perception of Moving Subjective Contours by 4-Month-Old Infants

We investigated whether 4-month-old infants are capable of perceiving illusory contours produced by the Kanizsa-square display, first introduced by Prazdny (1983, Perception & Psychophysics 34 403-404), which tests whether a viewer perceives the illusory contour in the absence of brightness contrast (illusory brightness). Because the illusory square appears to move across the computer screen and infants are attracted to motion, this display holds their interest. In experiment 1, 4-month-old infants were tested for their ability to distinguish between a continuously moving illusory square and a continuously moving control display in which the pacman elements were rotated so that the perception of subjective contours did not occur. Data analysis revealed a significant preference for the subjective contour display. In experiment 2, habituation-dishabituation was used with 4-month-old infants. They were tested for their ability to discriminate between the illusory Kanizsa square that continuously moved back and forth and an illusory square which changed positions randomly. Although the infants did not show differences in dishabituation as a function of the habituation display, they looked significantly longer at the continuously moving display.

The VSOP 5 GHz Continuum Survey: The Prelaunch VLBA Observations

We have imaged with milliarcsecond resolution at 5 GHz 374 strong flat-spectrum radio sources north of declination -44° using the VLBA in 1996 June. The source sample was compiled from the source list for the VLBI Space Observatory Programme (VSOP) Survey Program. About 250 of the sources observed with the VLBA had correlated flux densities ≥0.3 Jy on the longest VLBA baseline and these sources are currently being observed with VSOP at 5 GHz. This paper presents the results from the VLBA prelaunch observations: the correlated flux density dependence with u-v distance; the contour display of the images; the model fit parameters for each radio component; and improved positions for 62 sources. Comparisons and extensive cross-referencing with other major VLBI surveys are also given.

Implications of Spatial Distribution of Insect Populations in Storage Ecosystems

Integrated management of storage pests requires understanding storage ecosystems and accurately monitoring pest population levels. Geostatistical techniques for spatial analysis provide a powerful tool to assist in biological interpretation of sample counts and trip captures of insects, as well its interpretations of physical measurements such as grain temperature and moisture content. Contour analysis is 3-step process. Data are first posted to a map of sample points; then a denser grid of data points is generated by interpolation (using one of several algorithms) and contours (lines joining points with equal values) are drawn at some fixed interval. This provides a contour display, showing the value of the variable at all points on the surface represented by the sample points. The utility of this method in stored-product protection is illustrated by a series of studies based on data sets for stored corn. These include comparison of spatial distribution of species and species interactions; analysis of temporal changes in distribution, precision targeting, and evaluation of control measures; interpretation of trap cattch; examination of physical variables and interactions of insects with the physical environment; and analysis of goodness of fit of contour surfaces to the data. The utility of techniques such as grid subtraction and construction of probability contours is demonstrated.

Integrated simulation, error assessment, and tool path correction for five-axis NC milling

A system of algorithms is presented for material removal simulation, dimensional error assessment, and automated correction of five-axis numerically controlled (NC) milling tool paths. The methods are based on a spatial partitioning technique that incorporates incremental proximity calculations between milled and design surfaces. Hence, in addition to real-time animated five-axis milling simulation, milling errors are measured and displayed simultaneously. Using intermediate error assessment results, a reduction-of-intersection-volume algorithm is developed to eliminate gouges on the workpiece via tool path corrction. A similar technique is implemented for detection and elimination of unexpected collisions between the tool assembly and the workpiece. These combined algorithms provide efficient, accurate, and automatic assessment and correction of five-axis milling tool paths. Finally, the view dependency typical of previous spatial partitioning based NC simulation methods is overcome by a contour display technique that generates parallel planar contours to represent the workpiece, thus enabling dynamic viewing transformations without reconstruction of the entire data structure.

The stereotactic operating microscope: accuracy refinement and clinical experience.

Accuracy of a stereotactic operating microscope, by which imaging data may be superimposed on the operative field without a stereotactic frame, has been most limited by the resolution of imaging information. Using newer algorithms and pilot pole calibration of the digitizer, an error in registration of 2 mm and in contour display of 3 mm has been demonstrated. Greatest utility of the system clinically has been in providing navigational guidance to small lesions undergoing resection.

Perceptual organization and apparent brightness in subjective contour figures.

According to a number of theories subjective contours arise from brightness contrast and/or assimilation. The apparent brightness gradients generated by these effects are assumed to give rise to the perception of contours delineating the gradients. A study is reported in which naive observers were shown a subjective contour display and asked to report what they saw. They were then asked to judge whether the center or the surround of the display appeared brighter. Subjects whose reports indicated that they had seen the subjective contour figure showed an overwhelming preference for the center of the display being brighter than the surround. However, subjects who did not see the subjective contour figure did not differ significantly in their selection of the center over the surround. This finding presents difficulties for any theory which derives subjective contours from the apparent brightness difference.

A contour display generation algorithm for VLSI implementation

Recent articles have discussed the current trend towards designing raster graphics algorithms into VLSI chips. The purpose of these design efforts is to capture some of the real-time animation capability found in vector graphics systems. Currently, real-time vector graphics animation is limited primarily to operations involving coordinate transformations. In order to enhance this animation capability, frequently encountered vector graphics algorithms that require the high speed, parallel computation capability of VLSI must be identified. Real-time contour display generation from grid data is one such algorithm. This paper describes the specifics of a contour display generation algorithm, the architectural framework of a processor that performs this algorithm and the architectural requirements of such a processor. The contouring algorithm is based on a data structure, the contouring tree, whose regularity and amenability for parallel computation make it an ideal candidate for VLSI. The architectural framework for a contouring processor chip that performs this algorithm for the real-time environment of interactive graphics is discussed, particularly the issues of memory size and data distribution. A model of the contouring process is created in order to determine the necessary physical parameters of the contouring processor in this architectural framework. Conclusions are drawn concerning the feasibility of producing a VLSI chip that performs this contouring algorithm.

Regional left ventricular wall movement in hypertrophic cardiomyopathy.

Left ventriculograms of 20 patients with hypertrophic cardiomyopathy were digitised frame by frame and analysed using a contour display. Abnormalities of regional wall movement were present in 17, and included an abnormal sequence of inward movement during systole (13), regional delay in the onset of inward movement (10), and an abnormal dispersion of peak velocities (5). Diastolic wall movement was disturbed in 13, because of abnormal peak velocities in 7 and regional asynchrony in 6. Abnormal wall movement during the two isovolumic periods was rare in hypertrophic cardiomyopathy, unlike ischaemic heart disease. These disturbances may reflect underlying structural abnormalities.

936. Technique for a contour display of photoemission uniformity: C D Hollish and R J Hertei,Rev Scient Instrum, 45 (11), 1974) 1336–1339

936. Technique for a contour display of photoemission uniformity: C D Hollish and R J Hertei,Rev Scient Instrum, 45 (11), 1974) 1336–1339

Technique for a contour display of photoemission uniformity

A contour plotter has been designed to display the sensitivity uniformity of photocathodes in quantized format on the Z axis of an oscilloscope. An optical scanner, synchronously driven by the oscilloscope X-Y deflection signals is used to raster scan the photocathode with a focused light beam. Sensitivity, resolution, and scanning time are sufficient to use the plotter to monitor sequential processing steps for photocathodes in demountable, ultrahigh vacuum systems. A general description of the contour plotter system and a detailed circuit description are given. An example relating to cesium uniformity on a III-V photocathode is presented to illustrate the use of the contour plotter.

Lineprinter display of digital scintiscans.

Lineprinter display of digital scintiscan data is becoming more common due to the wider availability of computer facilities. The basic method of presentation is in the form of a contour map, using symbols to represent areas of different count rates.This paper evaluates various types of contour display and suggests criteria for choosing the optimum type for a given scanning situation.

Voice prints in laryngeal disease.

The scientific merit of sound spectrography has been well established for the study of vocal pathology. Contour display spectrography provides even better visualization of the vocal spectrum. Voice prints permit an objective evaluation of the acoustic correlates of hoarseness, and suggest a valuable new technique for the acoustic identification of different laryngeal diseases.

A Modern Approach to Sound Spectrograph Instrumentation

A new sound spectrograph has been developed that features direct analysis from a prerecorded tape plus several new features that facilitate ease of operation and provide a higher degree of reliability and consistency. The design uses a tape scanner that repeats any 2.5-sec segment of tape for spectrographic analysis, and includes an automatic tape-advance mode for producing contiguous spectrograms. The basic model features only a single type of display—namely, the wide-band “bar” display for applications in areas where visual pattern matching and speech therapy are desirable. The typical wide-band analyzing-filter bandwidth of 300 Hz has been found to be ideally suited where visual comparisons of speech sounds are desired. This display is also useful for pattern studies of heart sounds, mechanical and industrial sounds, underwater sounds, etc. One of the several new design improvements to be described is the ability to mark single-line frequency calibration marks across the entire spectrogram. All of the features presently included in the standard spectrograph, namely the choice of filter bandwidth, frequency shaping, contour display, amplitude cross sectioner, and frequency scale expansion, can be added depending on the requirements of the user.