A videogrammetric technique developed at NASA Langley Research Center has been used at five NASA facilities at the Langley and Ames Research Centers for deformation measurements on a number of sting mounted and semisp...
详细信息
ISBN:
(纸本)0819441627
A videogrammetric technique developed at NASA Langley Research Center has been used at five NASA facilities at the Langley and Ames Research Centers for deformation measurements on a number of sting mounted and semispan models. These include high-speed research and transport models tested over a wide range of aerodynamic conditions including subsonic, transonic, and supersonic regimes. The technique. based on digital photogrammetry. has been used to measure model attitude, deformation. and sting bending, In addition, the technique has been used to study model injection rate effects and to calibrate and validate methods for predicting static aeroelastic deformations of wind tunnel models. An effort is currently underway to develop an intelligent videogrammetric measurement system that will be both useful and usable in large production wind tunnels while providing accurate data in a robust and timely manner. Designed to encode a higher degree of knowledge through computer vision, the system features advanced patternrecognition techniques to improve automated location and identification of targets placed on the wind tunnel model to be used for aerodynamic measurements such as attitude and deformation. This paper will describe the development and strategy of the new intelligent system that was used in a recent test at a large transonic wind tunnel.
In this paper we present the results of applying data compression to a three-dimensional object recognition technique based on phase-shift digital holography. Industry-standard lossless data compression algorithms wer...
详细信息
ISBN:
(纸本)0819441856
In this paper we present the results of applying data compression to a three-dimensional object recognition technique based on phase-shift digital holography. Industry-standard lossless data compression algorithms were first applied. Next, lossy techniques based on subsampling, discrete cosine transformation, and discrete Fourier transformation were examined. We used normalized cross-correlation in the object plane as our performance metric. For each hologram tested, we found that as many as 90% of the cosine and Fourier components could be removed, without significant loss in correlation performance.
We present a theoretical study of the recovery of images x from noisy data y by minimizing a regularized cost-function F(x,y)=Ψ(x,y)+αΦ(x), where Ψ is a data-fidelity term, Φ is a smooth regularisation term and ...
详细信息
We present a method to track and recognise shape-changing hand gestures simultaneously. The switching linear model using the active contour model corresponds well to temporal shapes and motions of hands. Inference in ...
详细信息
The goal of this paper is a presentation of the possibilities of the application of syntactic methods to the recognition of the local stenoses of the lumen of coronary arteries, and to the detection of pathological si...
详细信息
The goal of this paper is a presentation of the possibilities of the application of syntactic methods to the recognition of the local stenoses of the lumen of coronary arteries, and to the detection of pathological signs in upper parts of ureter ducts and renal calyxes. An analysis of the correct morphology of these structures is possible thanks to the application of sequence and tree methods from the group of syntactic methods of patternrecognition. In the case of the analysis of coronary artery images, the main objective is a computer-aided early diagnosis of the different forms of cardiac ischemic diseases. In the analysis of kidney radiograms the main goal is the recognition of local irregularities in ureter lumens, and an examination of the morphology of renal pelvis and calyxes.
The purpose of this study is to automate coral reef assessment, that is, to classify coral images into benthic categories from digitized underwater video using a computer-based classifier such that coral reef analysis...
详细信息
ISBN:
(纸本)0933957289
The purpose of this study is to automate coral reef assessment, that is, to classify coral images into benthic categories from digitized underwater video using a computer-based classifier such that coral reef analysis becomes less subjective, less tedious and more precise. Corals exhibit a variety of color, texture and structure which are the visual cues used by marine scientists for their classification. In computer vision, color is a point property of a picture element while texture is a property of an area. Recently, color and texture have been combined as color-texture which is a feature that describes the spatial organization of colors in an area. As inputs to a classifier, we extract color, texture and color-texture descriptors from coral images and measure recognition rates using each feature. Corals are 3D structures and, when imaged, are prone to varying resolutions, perspective projection and lighting conditions. Therefore, an additional objective of this study is to address the problem of illumination, rotation and scale invariance in patternrecognition of underwater images. images were classified into one of five benthic categories: alive coral, dead coral, dead coral with algae, algae and abiotics. Overall, texture was found to be more discriminating than using color alone or color and texture combined. Dead coral was the most successfully recognized class using color features.
In this paper, we propose a method to vectorize Chinese characters in calligraphy documents. Our system can prevent the zigzag phenomena when the characters are enlarged. The system contains two modules: contour segme...
详细信息
Forgery prevention and detection are of great social importance. This paper attempts to apply digital watermarking into forgery prevention. To embed a watermark, the wavelet transformation is first applied to the orig...
详细信息
3D data has many advantages over image data. It is robust to illumination change and does not have a scaling problem caused by distance of an object. Also it can be viewed at various angles. Nowadays with advance of 3...
详细信息
暂无评论