Vertical Projection Research Articles

Phase velocities of gravity waves in the solar photosphere

Space-time variations of pressure in the solar photosphere are reproduced based on the results of observations in the Fe I line. Local internal gravity waves (IGWs) are isolated by means of proper filtering. A method of determination of the phase velocities of IGWs based on 1D observations is developed. Horizontal and vertical projections of the phase velocities of isolated IGWs with different periods are determined. It is shown that the phase velocity of an IGW decreases significantly with a decrease in oscillation frequency. The horizontal wavelengths of gravity waves with periods ranging from 5 to 60 minutes are commensurable with the granulation scales. The dispersive properties of gravity waves are studied.

Robust and fast pedestrian detection method for far-infrared automotive driving assistance systems

Despite considerable effort has been contributed to night-time pedestrian detection for automotive driving assistance systems recent years, robust and real-time pedestrian detection is by no means a trivial task and is still underway due to the moving cameras, uncontrolled outdoor environments, wide range of possible pedestrian presentations and the stringent performance criteria for automotive applications. This paper presents an alternative night-time pedestrian detection method using monocular far-infrared (FIR) camera, which includes two modules (regions of interest (ROIs) generation and pedestrian recognition) in a cascade fashion. Pixel-gradient oriented vertical projection is first proposed to estimate the vertical image stripes that might contain pedestrians, and then local thresholding image segmentation is adopted to generate ROIs more accurately within the estimated vertical stripes. A novel descriptor called PEWHOG (pyramid entropy weighted histograms of oriented gradients) is proposed to represent FIR pedestrians in recognition module. Specifically, PEWHOG is used to capture both the local object shape described by the entropy weighted distribution of oriented gradient histograms and its pyramid spatial layout. Then PEWHOG is fed to a three-branch structured classifier using support vector machines (SVM) with histogram intersection kernel (HIK). An off-line training procedure combining both the bootstrapping and early-stopping strategy is introduced to generate a more robust classifier by exploiting hard negative samples iteratively. Finally, multi-frame validation is utilized to suppress some transient false positives. Experimental results on FIR video sequences from various scenarios demonstrate that the presented method is effective and promising.

SU-D-144-02: Four-Dimensional Cone Beam CT for a Small Animal Image Guided Radiation Therapy System Without Use of An External Respiratory Monitoring System

Purpose: To develop four‐dimensional cone beam CT for an image guided radiation system for small animals without the use of external respiration monitoring systems. Methods: Nine mice were scanned using the cone beam CT capabilities of an X‐Rad 225Cx system. The mice were anesthetized with 1.5 to 3% isoflurane and scanned (60 kVp and 4 mA) at a sampling rate of 15 fps and gantry rotation rate of 0.5 rpm to yield a total of approximately 1800 975×975 projection images. The projections were used to obtain a respiratory signal using a modified Amsterdam Shroud method. Inspirations appeared approximately as vertical lines in the Amsterdam Shroud image due to the small ratio of inspiration to expiration times in mice anesthetized with isoflurane. The locations of these lines were extracted using vertical edge detection, dilation and projection onto one dimension. Four‐dimensional cone beam CT images (voxel size 0.1 × 0.1 × 0.3 mm) were then obtained using these peak inspirations to sort the projections into 6 phases. The peak inspirations of two mice were manually extracted from the projections to test the peak extraction method. Results: 4D CBCT images were successfully created for each mouse with minimal streak artifacts. Some blurring in the initial phase was seen due to the sharpness of the inspiration peak. The peak finding algorithm determined the peaks correctly to within an average of 0.7 and 0.4 projections for the first and second mouse, respectively. 82% and 89% of the projections were sorted into the correct phase bin for the two mice. Conclusion: The four‐dimensional CBCT method developed here can be used to analyze lung motion in mice and assist in preclinical targeted radiation therapy studies.

An Application for Stereo Vision based Vehicle/Obstacle Detection for Driver Assistance

A stereo vision based vehicle/obstacle detection system has been proposed that generates alarms when vehicles/obstacles are detected in vicinity of near/mid region. Numerous techniques have been applied to detect vehicles/obstacles using a forward facing monocular camera mounted inside a vehicle. This paper presents a methodology for vehicle/obstacle detection using high resolution stereo camera. Stereo cameras are calibrated; stereo images are undistorted and rectified using stereo calibration parameters. Stereo disparity image is then generated using stereo matching algorithm. To localize vehicles/obstacles, search space reduction forms a preliminary step by eliminating sky region retaining only road regions on which vehicles/obstacles are embedded. Periodic peaks in the histogram of stereo disparity image are used as a cue in vehicle/obstacle detection process. Line profiles corresponding to each periodic peak are extracted using vertical strokes. Statistical features are extracted and analyzed for each line profiles to determine the presence/absence of vehicles/obstacles. If vehicles/obstacles are detected in a line profile, then bounding box of blobs are detected using vertical projection technique. Blobs detected from all the gray level profiles are merged together and connected component analysis is applied to count the number of vehicles/obstacles. Color mapping of vehicles/obstacles detected are done to indicate the presence of vehicles/obstacles in near region or mid region thereby generating appropriate alarms.

Vehicle Speed Detection Based on Video at Urban Intersection

In order to obtain the average speed of vehicle at plane intersection on urban traffic, an algorithm of average speed measurement based on the video is proposed in this study. Video is captured against the motion of the vehicle by the camera which is mounted on the cross bar at the intersection. The detection zone is set between the stop line and the pedestrian road. These methods of background difference, shadow removal and region filling of morphology are applied to detection zone. Then, method of vertical projection is employed to the obtained binary image, judging whether the vehicles exist in the detection region by vertical projection diagram and calculating the total frames that the vehicle drive into and depart out the detection region. The instantaneous velocity is obtained by using the frame rate of the camera and the width of the detection region and then to calculate the mean velocity.

Analisi della copertura forestale in ambiente alpino: metodi di stima a confronto

Forest canopy analysis in the Alpine environment: comparison among assessment methods. Forest canopy is an important ecological feature of forest stands and can be expressed as Leaf Area Index (LAI) or canopy cover percentage. LAI is the ratio between leaf area and ground area (m2 m-2) and it can be measured using an angle of 180°. Instead, the canopy cover is the percentage of forest area occupied by the vertical projection of tree crowns; consequently, LAI expresses the canopy closure rather than the canopy cover. This paper focuses on the estimation of LAI and canopy cover percentage in 54 sampling points randomly distributed over the main forest types of Trentino (beech forests, Scots pine forests, Norway spruce forests and European larch forests). The main purpose was the analysis of relationship between LAI and canopy cover percentage, the latter measured with two different techniques: visual estimation and estimation using the spherical densiometer. In the last part of the paper, LAI data collected in the four main forest types of Trentino are compared with values reported in the literature for the same forest types.

Temporal and spatial distribution of GPS-TEC anomalies prior to the strong earthquakes

Earthquakes are one of the most destructive and harmful natural disasters, especially in recent years, the 2008/5/12 Wenchuan M7.9 earthquake, the 2011/3/11 Tohoku M9.0 earthquake and the 2012/4/11 Sumatra M8.6 earthquake have caused a significant impact to the human life. In this paper, we make a study of the temporal and spatial distribution of the Global Positioning System Total Electron Content (GPS TEC) anomalies prior to the three strong earthquakes by the method of statistical analysis. Our results show that the pre-earthquake ionospheric anomalies are mainly positive anomalies and take the shape of a double-crest structure with a trough near the epicenter. The ionospheric anomalies do not coincide with the vertical projection of the epicenter of the subsequent earthquake, but mainly localize in the near-epicenter region and corresponding ionospheric anomalies are also simultaneously observed in the magnetic conjugate region prior to the three earthquakes. In addition, the amplitude and scale-size of the ionospheric ΔTEC are different with the magnitude of the earthquake, and the horizontal scale-size of the greatest anomalies before the Tohoku M9.0 earthquake is ∼30∘ in longitude and ∼10∘ in latitude, with the maximum amplitude of TEC disturbances reaching ∼20 TECu relative to the background. The peak of anomaly enhancement usually occurs in the afternoon to sunset (i.e. between 14:00 and 18:00 local time) which lasts for approximate 2 hours. Possible causes of these anomalies are discussed, and after eliminating the effect of solar activities and magnetic storms it can be concluded that the detected obvious and regular anomalous behavior in TEC within just a few days before the earthquakes is related with the forthcoming earthquakes with high probability.

Complexity results for reconstructing binary images with disjoint components from horizontal and vertical projections

The problem of reconstructing a special class of binary images from their horizontal and vertical projections is considered. We present a general framework for analyzing the worst case complexity of this task if the image consists of more than one pairwise disjoint component. Applying the presented technique we analyze the complexity of reconstructing canonical hv-convex binary images. We also present parameterized complexity results on general and so-called glued hv-convex images. Moreover, we study how our results are related to the reconstruction of permutation matrices from four projections.

Targeted Cranial Bone Transport Distraction Is Enhanced Using a Novel Device

Targeted Cranial Bone Transport Distraction Is Enhanced Using a Novel Device

Cuneiform Symbols Recognition Based on K-Means and Neural Network

Cuneiform is the ancient writing systemin the world. But, there is no clear interest recognition cuneiform symbol, despite its importance. This research interested in building an algorithm for cuneiform symbol recognition. Firstly, the Sumerian texts were entered through the scanner and make some initial preprocessing operations such as segmentation for the purpose of cutting the text and getting a cuneiform symbol. Then, features were extracted for each symbol by using vertical and horizontal projections, centre of gravity, and connected component. Because of the large number of cuneiform symbols, the similar symbols are clustered by K-means algorithm, then multilayer neural networks are used to classify the symbol within the same cluster. The proposed algorithm gave good results.

Anomalous variation in GPS TEC prior to the 11 April 2012 Sumatra earthquake

On 11 April 2012, a strong earthquake of magnitude Ms8.6 occurred near the west coast of Northern Sumatra, Indonesia. In this paper, we investigated the morphological characteristics of anomalous variations in Global Positioning System Total Electron Content (GPS TEC) prior to the earthquake by the method of the statistical analysis. It was found the TEC anomaly was firstly decreased, then, it became more enhanced, finally, it decreased, the peak of anomaly enhancement arose from 13:00–17:00 LT on April 5 lasted for ∼4 hours and the anomalous ionospheric regions extended to ∼40∘ in longitude and ∼20∘ in latitude, its location did not coincide with the vertical projection of the epicenter, but lies at the north and south of the geomagnetic equator, meanwhile, corresponding ionospheric anomalies are also observed in the magneto conjugate region. Potential causes of these results are discussed,eliminating the ionospheric anomalies that may be caused by solar activities and magnetic storms, it can be concluded that the observed obvious anomalous variation in GPS TEC on April 5 were possibly related to the earthquake.

The Reconstruction of Polyominoes from Horizontal and Vertical Projections and Morphological Skeleton is NP-complete

Reconstruction of binary images from their projections is one of the main tasks in many image processing areas, therefore determining the computational complexity of those problems is essential. The reconstruction complexity is highly dependent on the requirements of the image. In this paper, we will show that the reconstruction is NP-complete if the horizontal and vertical projections and the morphological skeleton of the image are given, and it is supposed that the image is 4-connected.

An Empirical Study of Reconstructing hv-Convex Binary Matrices from Horizontal and Vertical Projections

The reconstruction of hv-convex binary matrices (or equivalently, binary images) from their horizontal and vertical projections is proved to be NP-hard. In this paper we take a closer look at the difficulty of the problem. We investigate different heuristic reconstruction algorithms of the class, and compare them from the viewpoint of running-time and reconstruction quality. Using a large set of test images of different sizes and with varying number of components, we show that the reconstruction quality can depend not only on the size of the image, but on the number and location of its components, too. We also reveal that the reconstruction time can also be affected by the number of the so-called switching components present in the image.

Bilateral Orbital Dysmorphology in Unicoronal Synostosis

Orbital dysmorphology is believed to cause ipsilateral ocular abnormalities in unicoronal synostosis. Recently, there has been increasing evidence of visual problems in the contralateral eye. The purpose of this study was to explore morphology of both the ipsilateral and contralateral unicoronal synostosis orbit. Demographic data and computed tomographic information were recorded. Three-dimensional computed tomographic renderings were created digitally and analyzed (SurgiCase). Craniometric analysis was conducted for orbital volume, horizontal and vertical orbital cone angle, orbital depth, and corneal projection. Twenty-one unicoronal synostosis infants and 10 matched controls were examined. The orbital volume ratio between ipsilateral and contralateral sides was 93.8 ± 5.3 in unicoronal synostosis infants and 99.3 ± 2.1 (p = 0.001) in the control group. The horizontal orbital cone angle of the contralateral eye was significantly greater than that of both the ipsilateral side (p < 0.0001) and the control orbits (p = 0.0011, p = 0.0004). The vertical cone angle of the ipsilateral eye was significantly greater than that of the ipsilateral (p < 0.0001) and control orbits (p = 0.0326, p = 0.0030). There was no difference in orbital depth between ipsilateral and contralateral orbits. The ipsilateral globe projected 27 percent farther past the orbital aperture than the contralateral side. There was no difference between right and left orbits of a control in any analysis. In addition to ipsilateral orbital deformity, the contralateral orbit is highly dysmorphic. As orbital asymmetry may underlie visual abnormalities, future reconstructive efforts may necessitate bilateral correction. Risk, II.

Subsurface temperature of the onshore Netherlands: new temperature dataset and modelling

AbstractSubsurface temperature is a key parameter for geothermal energy prospection in sedimentary basins. Here, we present the results of a 3D temperature modelling using a thermal-tectonic forward modelling method, calibrated with subsurface temperature measurements in the Netherlands. The first step involves the generation of a coherent dataset of temperature values for the calibration of the model. In the Netherlands, most of the available measurements (98.8%) are BHT measurements and therefore need to be corrected from the thermal perturbation created during drilling. The remaining 1.2% is composed of DST measurements, which closely resemble the formation temperature (i.e., ±5 °C). The resulting dataset, after correction, gives a total number of 1293 values in 454 wells. Included in this dataset are 412 highly reliable values corrected with the Instantaneous Cylinder Source (ICS) method and 829 values of a lower reliability corrected with the AAPG method. In addition to the corrected values, 52 DST values in 26 wells are available from the Dutch subsurface. The average thermal gradient of this whole dataset is 31.3 °C/km with a surface temperature of 10.1 °C. The second step in the modelling process was the generation of a 3D forward model that focuses on calculating the temperature distribution of the sedimentary basin fill, taking into account the basin evolution of the past 20 Myrs and thermal properties and processes of the whole lithosphere. From the 3D thermal model, we extracted 2D cross sections across well locations to compare model temperatures with calibration data. Furthermore, we present vertical profiles, isodepth maps and temperature projection on geological layers, to discuss the relationship between temperature and geology. Anomalies in this relationship can have several causes and include: 1) the extreme thermal conductivity and complex geometry of the Zechstein salt; 2) enhanced radiogenic heat production of the upper crust due to magmatic intrusions. In addition, our model supports earlier findings that shallow hydrothermal convection in highly permeable sediments can effectively lower thermal conductivity and temperatures in shallow sediments.

Shadow removal with background difference method based on shadow position and edges attributes

This article presents a shadow removal algorithm with background difference method based on shadow position and edges attributes. First, a novel background subtraction method is proposed to obtain moving objects. This method mainly includes three parts, namely detecting the moving regions approximately by calculating the inter-frames differences of symmetrical frames and counting the static index of each probable moving point; modeling for background by the statistics of brightness information and updating this model combining motion templates; then extracting moving objects and its edges. Second, based on the above processing, we suppress shadows in the HSV color space first, then the direction of shadow is determined by shadow edges and positions combining with the horizontal and vertical projections of the edge image, respectively, the position of the shadow is located accurately through proportion method, the shadow can be removed finally. Experimental results indicate that the proposed method is easy to be realized and can determine the direction of the shadow adaptively, then eliminate the shadow and extract the whole moving object accurately, especially when the chrominance invariant principle is ineffective.

Partner Selection for Partnering Mode Based on Vertical Projection Method

Selecting excellent partnering partners is crucial for project implementation．In view of the drawbacks of traditional methods which only consider the rigid index such as business index, technical data and management data, this paper establishes an evaluation system which considers soft level index and is appropriate for the project of partnering mode. From this system, this paper sets up a comprehensive evaluation mode for partners’ selection based on the entropy and vertical projection method. This mode provides a simple and scientific new way for selecting excellent partnering partners.

Formulation of consistent nonlinear restoring stiffness for dynamic analysis of tension leg platform and its influence on response

Shortcomings of the traditionally used nonlinear restoring stiffness of TLPs, i.e. unrealistically high stiffness of horizontal motions, their uncoupling and secant formulation are pointed out. Therefore, new consistent restoring stiffness is derived. The platform is considered as a rigid body moored by flexible pretensioned tendons. Global horizontal low frequency motions (surge, sway and yaw) with large amplitudes as a result of dominant second order wave excitation and small stiffness, and vertical local motions (heave, roll and pitch) of higher frequency and small amplitudes excited by the first order wave forces, are distinguished. Hence, horizontal displacements represent position parameters in analysis of vertical motions. First, the linear restoring stiffness, which consists of the tendon conventional axial stiffness, the tendon geometric stiffness and the platform hydrostatic stiffness, is established. Then it is extended to large displacements resulting in new secant restoring stiffness. It depends on surge, sway and yaw displacements and is the same in any horizontal direction. Also, the tangent stiffness, which gives more accurate results, is derived. Heave is defined as vertical projection of axial tendon vibrations and platform tangential oscillations, which are analyzed in their natural moving coordinate system. Inertia force due to setdown, as a slave d.o.f. of the master horizontal motions, is taken into account in the dynamic equilibrium equations. As a result the complete tangential stiffness matrix of horizontal and vertical motions includes 7 d.o.f. The known secant restoring stiffness matrices are compared with the new one and noticed differences are discussed. All theoretical contributions are illustrated by relatively simple numerical example.

Polygonal estimation of planar convex-set perimeter from its two projections

This paper deals with the problem of extracting qualitative and quantitative information from few tomographic projections of an object without reconstructing this object. It focuses on the extraction of quantitative information, precisely the border perimeter estimation for a convex set from horizontal and vertical projections. In the case of a multiple reconstruction, lower and upper bounds for the perimeter are established. In the case of a unique reconstruction, we give conditions and a method for constructing an inscribed polygon in a convex set only from the convex-set projections. An inequality on border perimeter is proved when a convex set is included in another one. The convergence of the polygon perimeter, when the number of vertices increases, is established for such polygons.

Identification of the Hook on Investment Casting Shell Line Based on Machine Vision

In this paper, the idea identify the hook on investment casting shell line based on machine vision has been proposed. According to the characteristic of the hook, we do the image acquisition and preprocessing, we adopt Hough transform to narrow the target range, and find the target area based on the method combining the level projection and vertical projection, use feature matching method SIFT to do the image matching. Finally, we get the space information of the target area of the hook.