The hough transform can detect straight lines and

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Unformatted text preview: ithin an image. The Hough transform can detect straight lines and curves (object borders) if their analytic equations are known. It is robust in recognition of occluded and noisy objects. Faculty of Engineering Robotics Technology MECH 4041 19 B.Eng (Hons.) Mechatronics S. Venkannah Mechanical and Production Engineering Department The generalized Hough transform can be used if the analytic equations of the searched shapes are not available; the parametric curve (region border) description is based on sample situations and is determined in the learning stage. While forming the regions from complete borders is trivial, region determination from partial borders may be a very complex task. Region construction may be based on probabilities that pixels are located inside a region closed by the partial borders. Such methods do not always find acceptable regions but they are useful in many practical situations. Region based image segmentation: Region Growing: Instead of partitioning an image, a region grower begins at one position in the image (often the top left corner) and attempts to grow each region until the pixels being compared are too dissimilar to the region to add them. Usually a statistical test is performed to decide if this is the case. Haralick proposed a region growing technique, which assumes that a region is a set of connected pixels with the same population mean and variance. Region growing is a collection of segmentation techniques in which pixels are grouped in regions called grid elements based on attribute similarities. Defined region can then be examined as to whether they are independent or can be merged to other regions by means of an analysis of the difference in their average properties and spatial connectiveness. To differentiate between the objects and the background, assign 1 for any grid element occupied by an object and 0 for background elements. It is common practice to use a square sampling grid with pixels spaced equally along each side of t...
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This document was uploaded on 03/12/2014 for the course MECHANICAL 214 at University of Manchester.

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