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Image Pair (image + pair)
Selected AbstractsRoad Infrastructure Data Acquisition Using a Vehicle-Based Mobile Mapping SystemCOMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING, Issue 5 2006Gi-Hong Kim The mobile mapping system that integrates the global positioning system (GPS), the inertial navigation system (INS), and digital cameras has been developed to collect data on position and attributes of road infrastructure. The vehicle-based mobile mapping system works by having the GPS and INS record the position and attitude data, and digital cameras take road images. The stereovision system can determine the position of objects that are visible on the image pair in the global coordinate system with GPS and INS data. As field data acquisition is a very expensive task, a mobile mapping system offers a greatly improved solution. In this study, we successfully created a road infrastructure map with mobile mapping technology and proposed automatic algorithms for detecting and identifying road signs from road images. The proposed detection algorithm includes line and color region extraction processes and uses the Hopfield neural networks. The identification algorithm uses seven invariant moments and parameters that present geometric characteristics. With this combined method, we could successfully detect and identify road signs. [source] Effect of bone chip orientation on quantitative estimates of changes in bone mass using digital subtraction radiographyJOURNAL OF PERIODONTAL RESEARCH, Issue 3 2003André Mol Objectives:, To assess the effect of the orientation of arbitrarily shaped bone chips on the correlation between radiographic estimates of bone loss and true mineral loss using digital subtraction radiography. Methods:, Twenty arbitrarily shaped bone chips (dry weight 1,10 mg) were placed individually on the superior lingual aspect of the interdental alveolar bone of a dry dentate hemi-mandible. After acquiring the first baseline image, each chip was rotated 90 degrees and a second radiograph was captured. Follow-up images were created without the bone chips and after rotating the mandible 0, 1, 2, 4, and 6 degrees around a vertical axis. Aluminum step tablet intensities were used to normalize image intensities for each image pair. Follow-up images were registered and geometrically standardized using projective standardization. Bone chips were dry ashed and analyzed for calcium content using atomic absorption. Results:, No significant difference was found between the radiographic estimates of bone loss from the different bone chip orientations (Wilcoxon: P > 0.05). The correlation between the two series of estimates for all rotations was 0.93 (Spearman: P < 0.05). Linear regression analysis indicated that both correlates did not differ appreciably ( and ). Conclusion:, It is concluded that the spatial orientation of arbitrarily shaped bone chips does not have a significant impact on quantitative estimates of changes in bone mass in digital subtraction radiography. These results were obtained in the presence of irreversible projection errors of up to six degrees and after application of projective standardization for image reconstruction and image registration. [source] User-Controllable Color TransferCOMPUTER GRAPHICS FORUM, Issue 2 2010Xiaobo An This paper presents an image editing framework where users use reference images to indicate desired color edits. In our approach, users specify pairs of strokes to indicate corresponding regions in both the original and the reference image that should have the same color "style". Within each stroke pair, a nonlinear constrained parametric transfer model is used to transfer the reference colors to the original. We estimate the model parameters by matching color distributions, under constraints that ensure no visual artifacts are present in the transfer result. To perform transfer on the whole image, we employ optimization methods to propagate the model parameters defined at each stroke location to spatially-close regions of similar appearance. This stroke-based formulation requires minimal user effort while retaining the high degree of user control necessary to allow artistic interpretations. We demonstrate our approach by performing color transfer on a number of image pairs varying in content and style, and show that our algorithm outperforms state-of-the-art color transfer methods on both user-controllability and visual qualities of the transfer results. [source] Three-dimensional representation of curved nanowiresJOURNAL OF MICROSCOPY, Issue 3 2004Z. HUANG Summary Nanostructures, such as nanowires, nanotubes and nanocoils, can be described in many cases as quasi one-dimensional curved objects projecting in three-dimensional space. A parallax method to construct the correct three-dimensional geometry of such one-dimensional nanostructures is presented. A series of scanning electron microscope images was acquired at different view angles, thus providing a set of image pairs that were used to generate three-dimensional representations using a matlab program. An error analysis as a function of the view angle between the two images is presented and discussed. As an example application, the importance of knowing the true three-dimensional shape of boron nanowires is demonstrated; without the nanowire's correct length and diameter, mechanical resonance data cannot provide an accurate estimate of Young's modulus. [source] | ||||||||||