Real-Time Runway Detection for Infrared Aerial Image Using Synthetic Vision and an ROI Based Level Set Method

We present a new method for real-time runway detection embedded in synthetic vision and an ROI (Region of Interest) based level set method. A virtual runway from synthetic vision provides a rough region of an infrared runway. A three-thresholding segmentation is proposed following Otsu’s binarization method to extract a runway subset from this region, which is used to construct an initial level set function. The virtual runway also gives a reference area of the actual runway in an infrared image, which helps us design a stopping criterion for the level set method. In order to meet the needs of real-time processing, the ROI based level set evolution framework is implemented in this paper. Experimental results show that the proposed algorithm is efficient and accurate.

Morphology and Tensile Behavior of 2024 Al Alloy Objects Fabricated by Uniform Droplet Spraying Deposition

A metal rapid prototyping technique, uniform droplet spraying, is utilized to fabricate 2024 Al alloy objects. Molten droplets are generated by drop-on-demand mode and deposited onto a zigzag moving substrate, which produces objects with different side surfaces. The tensile strength of the deposited specimen is 180.5 MPa, with elongation to fracture of ~8.2%. The fracture surface of deposited specimen presents two regions, namely, rough region and smooth region. The smooth region initially cracks under tension load, and the rough region presents many elongated dimples, indicating a ductile shear fracture. This unique tensile behavior could be attributed to weak metallurgical bonding between droplets and the special movement of substrate.

Fracture Behavior of Organic Silicon Rubber at Different Extension Rate

Fracture behavior of organic silicon rubber at the extension rate of 100, 300, 500 and 700 mm/min at room temperature was studied in this paper. The fracture surface morphology was observed by scanning electron microscopy (SEM). Effects of different extension rate on the tensile strength tensile fracture behavior and mechanism were investigated. The results showed that fracture of the organic silicon rubber was composed by flat region and rough region, while the rough region was relatively small. With the increasing extension rate, the area of flat region enlarged while rough region decreased, and the secondary cracks appeared when the extension rate reached critical value. The relationship of the tensile strength and elongation with the extension rate were similar, both of which rised and then droped as the extension rate increased, and further studies were needed for the fracture mechanism.

Tensile Fracture Characteristics of Polysulfide Sealants Immersed in Oil

In this paper, the morphology characteristic of tensile test fracture of polysulfide sealants immersed in oil for different time was observed through scanning electron microscopy. Combined with the performance data of tensile test, the effect of oil immersion time on the properties and fracture behavior of sealant was studied. The results show that the fracture of polysulfide sealants includes rough region and flat region. After being immersed in oil, the area of rough region diminishes and the roughness of fracture decreases. Within 168h, oil immersion time has little effect on the tensile strength and elongation of sealants.

Foreground Extraction Based on Dual-Camera System

This paper presents an automatic foreground segmentation algorithm for stereo image pair captured by a dual-camera system. Being different from the monocular image, binocular images contain the disparity map between the stereo image pair. For the disparity map is computationally expensive, our approach adopts the residual image with spatial displacement ( , ) to segment the initial trimap automatically. From the residual image, rough region of foreground is clustered as the initial trimap of GrabCut algorithm. Compared with a rectangular region, the calculated trimap is more accurate. After running GrabCut algorithm, the images are segmented into foreground and background layers that comprises of the front objects and back environment. Experimental segmentation results with the original images captured by the dual-camera system indicate that our approach is efficient and promising.

Impact of Surface Roughness on Compressor Cascade Performance

This paper presents an experimental investigation of roughness effects on aerodynamic performance in a low-speed linear compressor cascade. Equivalent sandgrain roughnesses of 12 μm, 180 μm, 300 μm, 425 μm, and 850 μm have been tested. In nondimensional terms, these roughnesses represent compressor blade roughnesses found in actual gas turbines. Downstream pressure, velocity, and angle have been measured with a five-hole probe at 0.3 chord downstream of the blade trailing edge. For the tested roughnesses of 180 μm, 300 μm, 425 μm, and 850 μm, the axial velocity ratio across the blade row decreases by 0.1%, 2.1%, 2.5%, and 5.4%, respectively. For the same cases, the exit flow angle deviation increases by 24%, 38%, 51%, and 70%, respectively. Finally, the mass-averaged total pressure loss increases by 12%, 44%, 132%, and 217%, respectively. Also, the loss increases more rapidly in the transitionally rough region. Thus, among the three parameters, the loss responds most sensitively to changes in compressor blade roughness.

Rough Entropy Clustering Algorithm in Image Segmentation

Clustering understood as a data grouping technique represents fundamental procedures in image processing. The present chapter’s concerns are combining the concept of rough sets and entropy measures in the area of image segmentation. In this context, comprehensive investigations into rough set entropy based clustering image segmentation techniques have been performed. Segmentation presents low-level image transformation routines concerned with image partitioning into distinct disjoint and homogenous regions. In the area of segmentation routines, threshold based algorithms and clustering algorithms most often are applied in practical solutions when there is a pressing need for simplicity and robustness. Rough entropy threshold based segmentation algorithms simultaneously combine optimal threshold determination with rough region approximations and region entropy measures. In the present chapter, new algorithmic schemes RECA in the area of rough entropy based partitioning routines have been proposed. Rough entropy clustering incorporates the notion of rough entropy into clustering models, taking advantage of dealing with some degree of uncertainty in analyzed data. RECA algorithmic schemes performed usually equally robust compared to standard k-means algorithms. At the same time, in many runs they yielded slightly better performances making possible future implementation in clustering applications.

Structure and Properties of Epoxy Resin/Poly (aryl ether ketone) Blends Cured with 4,4'-Diaminodiphenylmethane

The study on bisphenol A epoxy resin (EP)/4,4'-Diaminodiphenylmethane (DDM) system modified with poly(aryl ether ketone) (PEK-C) by the method of melt blending process is reported. The microscopic phase structure and morphology of impact fractured surface were observed by SEM, the phenomenon of microscopic phase separation and heat resistance property were studied by DMA. The results showed that PEK-C can disperse in the blends in the form of nanometer size (<100nm) particles or in the form of molecular size when the content of PEK-C lower than 10%, and the nano-particles are uniformly dispersed in the blends. The rough region of impact fractured surface with PEK-C modified sample is larger and more obvious, which indicated that toughness of the blends has been improved. The modified system has microscopic phase separation characteristics with higher content of PEK-C, as the same observed result of SEM, the glass transition temperature (Tg) of the blends moves towards higher temperature with the increasing content of PEK-C and the property of heat resistance has been improved.