Rotating blades on helicopters experience reverse flow under high advance ratio conditions. Here, reverse flow is characterized by the flow traveling from the sharp trailing edge to the blunt leading edge. Uncertainty in the blade aerodynamic loads under these conditions has been a limitation during the design of high-speed rotorcraft. In this work, we hypothesize that the reverse flow over a y...

Three model problems were examined to assess the diiculties involved in using a hybrid scheme coupling ow computation with the the Ffowcs Williams and Hawkings equation to predict noise generated by v ortices passing over a sharp edge. The results indicate that the Ffowcs Williams and Hawkings equation correctly propagates the acoustic signals when provided with accurate ow information on the i...

This paper presents a method for extracting blur/sharp regions of interest (ROI) that benefits of using a combination of edge and region based approaches. It can be considered as a preliminary step for many vision applications tending to focus only on the most salient areas in low depth-of-field images. To localize focused regions, we first classify each edge as either sharp or blurred based on...

A study is made to detect human eye from a color face image (in RGB space) using Harris corner detector and Sobel edge operator. Morphological operation like dilation and erosion are also applied to make the edge of the eyes sharp and prominent. This study is found to yield 90.47% eye detection rate which is comparable with the same obtained by other standard algorithm. Keywords-RGB color image...

Given a graph G on n vertices with maximal degree d, form a random subgraph Gp by choosing each edge of G independently with probability p. Strengthening a classical result of Margulis we prove that if the edge connectivity k(G) satisfies k(G) À d/ log n, then the connectivity threshold in Gp is sharp. This result is asymptotically tight.

Edges are important visual features, providing many cues to the three-dimensional structure of the world. One of these cues is edge blur. Sharp edges tend to be caused by object boundaries, while blurred edges indicate shadows, surface curvature, or defocus due to relative depth. Edge blur also drives accommodation and may be implicated in the correct development of the eye's optical power. Her...

An image is considered as a set of pixels that are connected in such a manner to form a boundary between two disjoints regions. Typically, the edge detection approach goes through the segmentation process by segmenting an image into regions of discontinuity. Hence it is a technique for marking sharp intensity changes. In this paper, it presents the Ant Colony Optimization based mechanism to com...

Motion Blur is one of the common artifacts in digital photographing. With the population of handheld camera and smart phone, image deblurring becomes an important problem. RichardsonLucy algorithm is well-known deconvolution algorithm. But the ringing artifacts usually appear while the estimated point spread function is not accurate. In this paper, we proposed an improved Richardson-Lucy deconv...

Edge is a boundary between two homogeneous regions. Edge detection is a preprocessing step in image analysis. It is a most difficult task in image processing. Edge in an image are with strong intensity contrast. A jump in intensity from one pixels to the very next, which effects in the quality of the picture. A quality of picture is characterized by the sharp discontinuities in an image. Hence ...

We study theoretically light propagations at the zigzag edge of a honeycomb photonic crystal consisting of dielectric rods in air, analogous to graphene. Within the photonic band gap of the honeycomb photonic crystal, a unimodal edge state may exist with a sharp confinement of optical fields. Its dispersion can be tuned simply by adjusting the radius of the edge rods. For the edge rods with a g...