Image segmentation refers to the technique and process of partitioning a digital image into multiple segments based on image characteristics so as to extract the object of interest from it. It is a key step from image...Image segmentation refers to the technique and process of partitioning a digital image into multiple segments based on image characteristics so as to extract the object of interest from it. It is a key step from image processing to image analysis. In the mid-1950s, people began to study image segmentation. For decades, various methods for image segmentation have been proposed. In this paper, traditional image segmentation methods and some new methods appearing in recent years were reviewed. Thresholding segmentation methods, region-based, edge detection-based and segmentation methods based on specific theoretical tools were introduced in detail.展开更多
In this paper, the two approximate hypotheses in boundary layer theory p/y=0,2u/x2=0, are reinvestigated and analyzed, while a new approximate hypothesis, p/y =μ2v/y2, is suggested to establish a new expanded boundar...In this paper, the two approximate hypotheses in boundary layer theory p/y=0,2u/x2=0, are reinvestigated and analyzed, while a new approximate hypothesis, p/y =μ2v/y2, is suggested to establish a new expanded boundary layer equation. Its formula of equilibrium of force coincides basically with that of Navier-Stokes equations on the boundary while the applicable range of the boundary layer expansion equation can be extended to the leading edge region. Theoretical analysis and discussion are presented.展开更多
文摘Image segmentation refers to the technique and process of partitioning a digital image into multiple segments based on image characteristics so as to extract the object of interest from it. It is a key step from image processing to image analysis. In the mid-1950s, people began to study image segmentation. For decades, various methods for image segmentation have been proposed. In this paper, traditional image segmentation methods and some new methods appearing in recent years were reviewed. Thresholding segmentation methods, region-based, edge detection-based and segmentation methods based on specific theoretical tools were introduced in detail.
文摘In this paper, the two approximate hypotheses in boundary layer theory p/y=0,2u/x2=0, are reinvestigated and analyzed, while a new approximate hypothesis, p/y =μ2v/y2, is suggested to establish a new expanded boundary layer equation. Its formula of equilibrium of force coincides basically with that of Navier-Stokes equations on the boundary while the applicable range of the boundary layer expansion equation can be extended to the leading edge region. Theoretical analysis and discussion are presented.
