Current Issue : January - March Volume : 2014 Issue Number : 1 Articles : 4 Articles
Lens distortion practically presents in a real optical imaging system causing nonuniform geometric distortion in the images and\r\ngives rise to additional errors in the vision measurement. In this paper, a planar-dimensions vision measurement method is\r\nproposed by improving camera calibration, in which the lens distortion is corrected on the pixel plane of image.The method can\r\nbe divided into three steps: firstly, the feature points, only in the small central region of the image, are used to get a more accurate\r\nperspective projection model; secondly, rather than defining a uniformmodel, the smoothing spline function is used to describe the\r\nlens distortion in the measurement region of image, and two correction functions can be obtained by fitting two deviation surfaces;\r\nfinally, ameasurementmethod for planar dimensions is proposed, in which accurate magnification factor of imaging system can be\r\nobtained by using the correction functions. The effectiveness of the method is demonstrated by applying the proposed method to\r\nthe test of measuring shaft diameter. Experimental data prove that the accurate planar-dimensions measurements can be performed\r\nusing the proposed method even if images are deformed by lens distortion....
Wireless capsule endoscopy (WCE) enables a physician to diagnose a patient�s digestive system without surgical procedures.\r\nHowever, it takes 1-2 hours for a gastroenterologist to examine the video. To speed up the review process, a number of analysis\r\ntechniques based on machine vision have been proposed by computer science researchers. In order to train a machine to\r\nunderstand the semantics of an image, the image contents need to be translated into numerical form first. The numerical form\r\nof the image is known as image abstraction. The process of selecting relevant image features is often determined by the modality\r\nof medical images and the nature of the diagnoses. For example, there are radiographic projection-based images (e.g., X-rays and\r\nPET scans), tomography-based images (e.g., MRT and CT scans), and photography-based images (e.g., endoscopy, dermatology,\r\nand microscopic histology). Each modality imposes unique image-dependent restrictions for automatic and medically meaningful\r\nimage abstraction processes. In this paper, we review the current development of machine-vision-based analysis of WCE video,\r\nfocusing on the research that identifies specific gastrointestinal (GI) pathology and methods of shot boundary detection....
We propose an innovative approach for human activity recognition based on affine-invariant shape representation and SVMbased\r\nfeature classification. In this approach, a compact computationally efficient affine-invariant representation of action shapes\r\nis developed by using affine moment invariants. Dynamic affine invariants are derived from the 3D spatiotemporal action volume\r\nand the average image created fromthe 3D volume and classified by an SVM classifier. On two standard benchmark action datasets\r\n(KTH andWeizmann datasets), the approach yields promising results that compare favorably with those previously reported in the\r\nliterature, while maintaining real-time performance....
The research reported in this paper focuses on the modeling of Local Binary Patterns (LBPs) and presents an a priori model where\r\nLBPs are considered as combinations of permutations. The aim is to increase the understanding of the mechanisms related to the\r\nformation of uniform LBPs. Uniform patterns are known to exhibit high discriminative capability; however, so far the reasons for\r\nthis have not been fully explored.We report an observation that although the overall a priori probability of uniform LBPs is high,\r\nit is mostly due to the high probability of only certain classes of patterns, while the a priori probability of other patterns is very\r\nlow. In order to examine this behavior, the relationship between the runs up and down test for randomness of permutations and\r\nthe uniform LBPs was studied. Quantitative experiments were then carried out to show that the relative effect of uniform patterns\r\nto the LBP histogram is strengthened with deterministic data, in comparison with the i.i.d. model. This was verified by using an\r\na priori model as well as through experiments with natural image data. It was further illustrated that specific uniform LBP codes\r\ncan also provide responses to salient shapes, that is, to monotonically changing intensity functions and edges within the image\r\nmicrostructure....
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