The shape and area of the vortex are important indicators to judge the effect of chemical liquid spraying and crop pollination by agricultural plant protection UAV. However, the traditional way of extracting the vorte...
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The shape and area of the vortex are important indicators to judge the effect of chemical liquid spraying and crop pollination by agricultural plant protection UAV. However, the traditional way of extracting the vortex related data through manual methods without an adaptive mechanism is complicated and inefficient. In order to solve this problem, the vortex image is preprocessed by adaptive iterative binarization and mean filtering. Then, the convex hull algorithm combined with Edge function is applied to the pre-processed image to extract the specific shape of vortex image and further calculate its area. Experimental results show that this method can be used to extract the vortex shapes and calculate the vortex area under different experimental conditions without manual intervention. Compared with the results of vortex area obtained via the manual extraction method, this method reported the average absolute error rate of 2.84%, the RMSE of 0.2903, and the correlation coefficient of 0.9965, indicating that the proposed method is more applicable to reveal the actual state of the vortex. A standardized extraction method was established to provide a standard for future vortex image research. The method in this paper lays a scientific foundation for the real-time tracking research of agricultural plant protection UAV and vortex.
An important issue in database (DB) systems is responding to different users' queries in an acceptable time. To do this, we should define different queries based on users' real needs and we should consider sui...
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An important issue in database (DB) systems is responding to different users' queries in an acceptable time. To do this, we should define different queries based on users' real needs and we should consider suitable solutions. In this article, we express a new query called 'boundary query' which is used for achieving an overall view of a subject in the DB. This query does not return all query answers but it returns boundary values that cover all answers for the related query. In this article, we map a DB environment to a vector space based on necessary attributes. Then we implement the proposed method, and based on the results, we observe that the proposed method's run time is acceptable for huge DBs.
Currently, tuberculosis (TB) remains one of the major threats to people's health. Specifically, the problem of under-segmentation due to adhesion of pulmonary tuberculosis lesions to the pleura is a thorny problem...
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ISBN:
(纸本)9783031097263;9783031097263
Currently, tuberculosis (TB) remains one of the major threats to people's health. Specifically, the problem of under-segmentation due to adhesion of pulmonary tuberculosis lesions to the pleura is a thorny problem in image segmentation. In this paper, An effective lung parenchyma patching method is proposed, which is composed of an improved convex hull algorithm with non-uniform rational B-splines. Our method is mainly divided into three parts. First, the temporal image processing method is used to preliminarily segment the lung parenchyma. Then, the lesion area was discriminated based on the convex hull algorithm and discrete point derivative frequency. Finally, the NURBS fitting method is introduced to complete the fitting of the defect contour. According to our experimental results, the completed lesion contour blends naturally with the original lung contour. Compared with some existing algorithms, our method performs better.
Virtual maintenance based on virtual reality has been developed recent years, yet the relation between qualitative analysis and quantitative analysis has not been built. In this paper, a calculation method of operatio...
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ISBN:
(纸本)9781538609187
Virtual maintenance based on virtual reality has been developed recent years, yet the relation between qualitative analysis and quantitative analysis has not been built. In this paper, a calculation method of operational domain of virtual maintenance based on convex hull algorithm is proposed. First, a hierarchical skeleton mathematical model based on the physiological characteristics of human skeletal structure is given to digitalize the virtual human body. Second, the motion equation of human posture is built based on the model of skeleton joint chain and the offset matrix of default skeleton posture. Finally, convex hull algorithm is used to calculate the operational domain of virtual maintenance. The proposed method is validated using realtime data collected by the Noitom's motion-capturing device. The experiment result has testified the method can provide an effectively quantitative analysis for operational domain of virtual maintenance.
Conventional convex hull algorithm determines the smallest convex polygon that contains the analyzed shape. The article presents a modification of this algorithm, which allows us to select the concavity to detect. In ...
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ISBN:
(纸本)9783037856116
Conventional convex hull algorithm determines the smallest convex polygon that contains the analyzed shape. The article presents a modification of this algorithm, which allows us to select the concavity to detect. In contrast to the typical convex hull algorithm, the data are analyzed in portions. This paper proposes the use of this modified algorithm for the defects detection on medical images. Two types of images were used: micro-computer tomography images of dental root canals filled with sealer and magnetic resonance images of a patient hand with rheumatoid arthritis. Those images contained some defects that needed to be measured. Prepared algorithm greatly facilitated this process by supporting the user in the segmentation process. The achieved results were positively evaluated by experts - doctors: rheumatologists and endodontists.
A fast algorithm for computing the convexhull of a set of distinct points or an arbitrarily shaped object in the Cartesian discrete plane is presented in this paper. A sequence of points is first extracted from the i...
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A fast algorithm for computing the convexhull of a set of distinct points or an arbitrarily shaped object in the Cartesian discrete plane is presented in this paper. A sequence of points is first extracted from the input image. These points form a non-self-intersecting polygon. Then, a cross-product rule is used to check the convexity of the polygon and compute the convexhull from it.
Computing the convexhull of a point set is requirement in the GIS applications. This paper studies on the problem of minimum convexhull and presents an improved algorithm for the minimum convexhull of planar scatte...
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Computing the convexhull of a point set is requirement in the GIS applications. This paper studies on the problem of minimum convexhull and presents an improved algorithm for the minimum convexhull of planar scattered point set. It adopts approach that dividing the point set into several sub regions to get an initial convexhull boundary firstly. Then the points on the boundary, which cannot be vertices of the minimum convexhull, are removed one by one. Finally the concave points on the boundary, which cannot be vertices of the minimum convexhull, are withdrew. Experimental analysis shows the efficiency of the algorithm compared with other methods.
To ensure the safety of honeycomb sandwich structures (HSS), ongoing research focuses on developing guided wave (GW)-based monitoring techniques for detecting, localizing, and quantifying damage(s). While substantial ...
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To ensure the safety of honeycomb sandwich structures (HSS), ongoing research focuses on developing guided wave (GW)-based monitoring techniques for detecting, localizing, and quantifying damage(s). While substantial progress has been made in damage detection and localization, further work is needed to improve localization of multiple damages and assess their extent. This study introduces a multi-stage GW-based technique to identify the shape and size of multiple damages in HSS through both experimental and numerical investigations. Initially, damage quadrants are identified using a probability-based signal difference coefficient algorithm. Next, a convex hull algorithm determines the boundary of each damage. The technique is demonstrated on six cases with multiple different damages of varying sizes, shapes, and orientations. Finally, the distinctiveness of this technique lies in its ability to quantify multiple damages through both geometric area measurement and using the Intersection over Union (IoU) metric.
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