algorithms, the geometrical properties such as size, shape, and orientation, of objects can also be investigated by ultrasonic imaging methods. An inherent problem with ultrasonic detection is the conflict between signal-to-noise ratio and resolution. If good resolution is to be obtained, the transmitted pulse cannot be long in duration. If short ultrasonic pulses are used, their energy is smal...

To extract features from digital images, it is useful to be able to find simple shapes (straight lines, circles, ellipses, etc.). In order to achieve this goal, one can be able to detect a group of pixels that are on a straight line or a smooth curve. That is what a Hough transform is supposed to do. Since the Hough transform is a special case of Radon transform then line detection process is a...

We introduce the concept of a constrained pointed pseudo-triangulation TG of a point set S with respect to a pointed planar straight line graph G = (S,E). For the case that G forms a simple polygon P with vertex set S we give tight bounds on the vertex degree of TG.

It is shown that if a planar straight line graph (PSLG) with n vertices in general position in the plane can be augmented to a 3-edge-connected PSLG, then 2n−2 new edges are enough for the augmentation. This bound is tight: there are PSLGs with n ≥ 4 vertices such that any augmentation to a 3-edge-connected PSLG requires 2n− 2 new edges.

It is shown that every connected planar straight line graph with n ≥ 3 vertices has an embedding preserving augmentation to a 2-edge connected planar straight line graph with at most b(2n − 2)/3c new edges. It is also shown that every planar straight line tree with n ≥ 3 vertices has an embedding preserving augmentation to a 2-edge connected planar topological graph by adding at most bn/2c edge...

We propose a method of conveyor belt longitudinal tear dynamic line edge detection based on CCD digital image processing. CCD camera captured video frames of conveyor belt at a certain frequency, we first applied median noise filtering and binarization to preprocessing the motion images of conveyor belt on the condition that they were not degenerative. Then Canny edge detection operator detecte...

Let G be a cycle-free connected straight-line graph with predefined edge lengths and fixed order of incident edges around each vertex. We address the problem of deciding whether there exists a simple polygon P such that G is the straight skeleton of P . We show that for given G such a polygon P might not exist, and if it exists it might not be unique. For the later case we give an example with ...

Autonomous vehicles require highly reliable navigation capabilities. For example, a lane-following method cannot be applied in an intersection without lanes, and since typical lane detection is performed using a straight-line model, errors can occur when the lateral distance is estimated in curved sections due to a model mismatch. Therefore, this paper proposes a localization method that uses G...

Simplification of given polygons has attracted many researchers. Especially, finding circular and elliptical structures in images is relevant in many applications. Given pixel chains from edge detection, this paper proposes a method to segment them into straight line and ellipse segments. We propose an adaption of Douglas-Peucker’s polygon simplification algorithm using circle segments instead ...