We compute discrete convex hulls in 2D grey-level images, where we interpret grey-level values as heights in 3D landscapes. For these 3D objects, using a 3D binary method, we compute approximations of their convex hulls. Differently from other grey-level convex hull algorithms, producing results convex only in the geometric sense, our convex hull is convex also in the grey-level sense.

BACKGROUND Plaster casts of individual patients are important for orthodontic specialists during the treatment process and their analysis is still a standard diagnostical tool. But the growing capabilities of information technology enable their replacement by digital models obtained by complex scanning systems. METHOD This paper presents the possibility of using a digital camera as a simple i...

Image recognition is one of the most important field in image processing that in recent decades had much attention .Due to expansion of related fields with image processing and various application of this science in machine vision, military science, geography, aerospace and artificial intelligence and lots of other aspects, out stand the importance of this subject.One of the most important aspe...

LET K C R3 be a simple closed curve, and K be its convex hull. In [l], Almgren and Thurston define the (oriented) convex hull genus of K to be the minimal genus of an (oriented) surface contained in g and bounded by K. They give examples showing that even if K is unknotted both the orientable and non-orientable convex hull genus of K may be arbitrarily large. In 43 of this paper we show that th...

In this paper, a new Hough transform is proposed to detect lines with geometric meanings. the standard transform, are parameterized by length and orientation of normal vector from origin line. The parameter space presented in polar coordinate system. Geometric measurements such as distance angle not suitable due inconsistency axes. To deal problem, which carried out bounded Cartesian developed....

Suppose you are given a number of points in a plane and want to have those lines that each contain a large number of the given points. The Hough transform is a computerized procedure for that task. It was invented by Paul Hough (1962), originally to find the trajectories of subatomic particles in a bubble chamber, and it has even been patented. Nowadays, adaptations of the Hough transform are u...

This paper presents a new O(nlog(n)) algorithm for computing the convex hull of a set of 3 dimensional points. The algorithm first sorts the point in (x,y,z) then incrementally adds sorted points to the convex hull using the constraint that each new point added to the hull can 'see' at least one facet touching the last point added. The reduces the search time for adding new points. The algorith...

This paper proposes a new algorithm for 2-D object detection called Randomized Generalized Hough Transform (RGHT). It combines the Generalized Hough Transform (GHT) with the Randomized Hough Transform (RHT). Our algorithm can detect arbitrary objects of various scales and orientations in graylevel images. We also demonstrate RGHT’s advantage of high speed, low storage requirement, high accuracy...

In optical character recognition and document image analysis skew is introduced in coming documented image. Which degrade the performance of OCR and image analysis system so to detection and correction of skew angle is important step of preprocessing of document analysis. Many methods have been proposed by researchers for the detection of skew in binary image documents. The majority of them are...