image registration forms the basis of many computervision tasks. the Lucas-Kanade image registration algorithm is known to efficiently solve the sub-problem of rigid image registration. It is therefore often used in ...
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We present an algorithm for estimating dense image correspondences. Our versatile approach lends itself to various tasks typical for video post-processing, including image morphing, optical flow estimation, stereo rec...
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We consider here a change detection problem: to find regions of change on a test image with respect to a reference image. Unlike the state-of-the-art change detection and background subtraction algorithms that compute...
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ISBN:
(纸本)9781424442195
We consider here a change detection problem: to find regions of change on a test image with respect to a reference image. Unlike the state-of-the-art change detection and background subtraction algorithms that compute only local (pixel location-based) changes, we propose to minimize a novel region-based energy functional based on Bhattacharya coefficient involving histograms of image features. the optimization of the proposed energy functional simply consists of two very efficient searches if a crude segmentation such as a bounding box around the region of change is sufficient. Also, it allows variational optimization via level set-based curve evolution for supervised binary image labeling. the framework is demonstrated to cope well with considerable camera motion and shafts of objects between the test and the reference images. We illustrate encouraging results on finding bounding box around abnormality from brain MRI, object detection for maritime surveillance, and segmenting oil-sand particles from conveyor belt images.
As vision algorithms mature with increasing inspiration from the learning community, statistically independent pseudo random number generation (PRNG) becomes increasingly important. At the same time, execution time de...
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ISBN:
(纸本)9781424442195
As vision algorithms mature with increasing inspiration from the learning community, statistically independent pseudo random number generation (PRNG) becomes increasingly important. At the same time, execution time demands have seen algorithms being implemented on evolving parallel hardware such as GPUs. the Mersenne Twister (MT) [7] has proven to be the current state of the art for generating high quality random numbers, and the Nvidia provided software for parallel MT is in widespread use. While execution time is important, development time is also critical. As processor cardinality changes, a foundation for generating simulations that will vary only in execution time and not in the actual result is useful;otherwise the development time will be impacted. In this paper we present an implementation of the Lagged Fibonacci Generator (LFG) considered to be of quality equal [7] to MT on the GPU. Unlike MT LFG has this important processor-cardinality agnostic capability that is - as the number of processing resources changes, the overall sequence of random numbers remains the same. this feature notwithstanding, our basic implementation is roughly as fast as the parallel MT;an in-memory version is actually 25% faster in execution time. Both parallel MT as well as parallel LFG show enormous speedup over their sequential counterparts. Finally, a prototype particle filter tracking application shows that our method works not just in parallel computing theory, but also in practice for vision applications, providing a decrease of 60% in execution time.
Diabetic retinopathy is one of the major causes of blindness. However diabetic retinopathy does not usually cause a loss of sight until it has reached an advanced stage. the earliest sign of the disease are microaneur...
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ISBN:
(纸本)9781424442195
Diabetic retinopathy is one of the major causes of blindness. However diabetic retinopathy does not usually cause a loss of sight until it has reached an advanced stage. the earliest sign of the disease are microaneurysms (MA) which appear as small red dots on retinal fundus images. Various screening programmes have been established in the UK and other countries to collect and assess images on a regular basis, especially in the diabetic population. A considerable amount of time and money is spent in manually grading these images, a large percentage of which are normal. By automatically identifying the normal images, the manual workload and costs could be reduced greatly while increasing the effectiveness of the screening programmes. A novel method of microaneurysm detection from digital retinal screening images is proposed. It is based on filtering using complex-valued circular-symmetric filters, and an eigen-image, morphological analysis of the candidate regions to reduce the false-positive rate. We detail the imageprocessing algorithms and present results on a typical set of 89 image from a published database. Our method is shown to have a best operating sensitivity of 82.6% at a specificity of 80.2% which makes it viable for screening. We discuss the results in the context of a model of visual search and the ROC curves that it can predict.
In this paper, we present a general framework for solving the shape from shading problem for a class of surfaces called implicit surfaces by applying image synthesis techniques from computergraphics. the method relie...
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In this paper, we present a general framework for solving the shape from shading problem for a class of surfaces called implicit surfaces by applying image synthesis techniques from computergraphics. the method relies on iterative synthesis of images from object descriptions in order to minimize an error function. the technique is illustrated in detail for quadric surfaces, withthe ellipsoid as the specific example. the advantage of this approach is that reconstructing the shape of objects from shading is possible even under very general imaging conditions.
this volume constitutes the thoroughly refereed post-conference proceedings of the 7th International conference on Curves and Surfaces, held in Avignon, in June 2010. the conference had the overall theme: "Repres...
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ISBN:
(数字)9783642274138
ISBN:
(纸本)9783642274121
this volume constitutes the thoroughly refereed post-conference proceedings of the 7th International conference on Curves and Surfaces, held in Avignon, in June 2010. the conference had the overall theme: "Representation and Approximation of Curves and Surfaces and Applications".
the 39 revised full papers presented together with 9 invited talks were carefully reviewed and selected from 114 talks presented at the conference. the topics addressed by the papers range from mathematical foundations to practical implementation on modern graphicsprocessing units and address a wide area of topics such as computer-aided geometric design, computergraphics and visualisation, computational geometry and topology, geometry processing, image and signal processing, interpolation and smoothing, scattered data processing and learning theory and subdivision, wavelets and multi-resolution methods.
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