Papers by Author: Andrzej Sioma

Abstract: This paper discusses the subject of filtering range images constructed using vision systems. Construction of a range image using the laser triangulation method LTM is burdened by noise resulting from the specificity of the adopted method. This method uses structural illumination, usually in the form of a laser line from the object illumination. The image of the object is captured by a camera, whereupon the laser line image is transformed into height profiles, which are then used to construct a range image of the object. Yet, such images fail to describe the entire surface of the object, due to occlusion. Occlusion of image fragments occurs in two forms. The first one stems from the impossibility to fully illuminate all surfaces of the object, due to occlusion of the laser lines. The second form occurs when the surface is illuminated properly, but the image of this surface cannot be captured by the camera. In both cases, there is an occlusion which usually results from the shape of the object. This paper describes the method of backfilling the data in undefined areas of range images caused to the phenomenon of occlusion. It suggests a method of defining the direction of data backfilling, identification of undefined areas, as well as methods of calculating and backfilling height differences at undefined spots. The purpose of these transformations is to prepare the image for measurement and control tasks. Select examples are presented with the results of image transformation using the developed data backfilling method.

Abstract: Ropes, including steel wire ropes, are the essential component of the kinematic chains in many passenger and cargo transport systems. Their condition also determines the level of operational safety of those devices. The article is devoted to discussion of methods of assessing the condition of steel wire ropes. The paper discusses magnetic and visual methods. Both methods are used obligatorily to assess ropes employed in rope transport systems. The most significant advantages of the magnetic method and the capabilities of modern methods of analysis of signals obtained from such studies are described. An important part of this article is showing how to determine the geometrical parameters of ropes during a routine evaluation of the degree of wear. The second part of the article presents new methods of determining and recording the geometrical parameters of ropes based on vision systems. The original method of determination of those parameters described herein is complementary to the currently used methods of assessment of the wear of both steel wire ropes and the increasingly more common synthetic fibre ropes. The method is based on the analysis of vision signals. Images of rope surface are created using 3D technology. The article presents some results of research based on which it is possible to identify the geometric dimensions of ropes as well as defects on the surface of those ropes. Such identification is possible on a digital image of a projection of rope surface.

Abstract: In robotic systems navigation, it is necessary to determine the direction, in which the local coordinate system of a robot is to be turned in regards to the reference, global system. That direction from mathematical point of view is the rotation along one axis of the reference system, such that the reference system coincides with the local system associated with the body, which direction is defined. There is an assumption that the rotations along two other axes do not exist or they were taken into account in the calculations. A question appears: what is the measurement of the direction based on The answer to that question is provided by nature [1, , because it has already solved this problem long ago. In migratory species such as birds, bees and fish, evolved magnetoreception abilities which allow an animal to detect the magnetic field of Earth. These abilities enable such organisms to navigate in space. In many devices magnetic field sensors called magnetometers are already used. However, magnetic measurements are subject to many kinds of distortions and errors. This paper shows a practical approach to a robot navigation problem.

Abstract: This article is devoted to the methods of image analysis used in three-dimensional vision systems. Based on a sample set of 3D images, their defects resulting from the adopted three-dimensional image construction technique are discussed. Those defects are discussed in relation to the following parameters: speed of the vision system, power of the laser, laser mode, laser arrangement relative to the vision system sensor and relative to the tested surface. To illustrate the cases discussed, images showing the effects of selected parameters on the quality of mapping of the tested object onto a three-dimensional image were presented. The next part of the article discusses methods of range image filtering that removes or reduces the importance of defects of the adopted method in any control and measuring tasks. Particular attention is given to methods of removing data described as missing data.

Abstract: Water and underwater vehicles are driven by propellers. Various models use propellers with 2 to 7 blades with either fixed or controllable pitch. Another known solution are water-jet propellers. Water is sucked from the front of the vehicle and ejected through a nozzle at the rear. A propeller is usually the water pumping component. This paper presents the design of a novel type of water-jet propeller, inspired by the way animals move in the aquatic environment. It discusses the mechanisms of propeller operation and its structural solutions. It also presents theoretical simulation studies and actual studies on a real object, which enabled assessment of the propellers parameters.

Abstract: This paper discusses a visual method of measuring the geometric parameters of ropes and evaluating their wear based on measurements of a three-dimensional rope model. The 3D model is created using the method of laser triangulation. Selection of appropriate geometry of camera and laser lighting arrangement allows collection of the height profile of the observed rope surface in the selected cross-section and, subsequently, building of a 3D model. The resulting model is a representation of the actual dimensions of the rope and allows determination of the parameters describing its basic geometric dimensions and condition of rope surface. Determination of those values and parameters allows estimation of the degree of rope wear. The article discusses issues related to resolution of the vision system, resolution of laser beam analysis, and resolution relating to the measurement of the height profile on the surface of the rope. Based on the model constructed in such a way, measurements are presented in order to assess the dimensional parameters and surface defects in sample rope structures. Based on tests and analyses of the three-dimensional model, a range of inspection tasks using 3D vision systems is indicated.

Abstract: This paper discusses a visual method of measuring the geometric parameters of elements produced by electrodynamic stamping. This paper presents also electrodynamic method which is an unconventional machining technology, which complements the capabilities of traditional technologies, in particular as regards the formation of metal elements with low-profile dies of complex shape. The article discusses issues related to resolution of the vision system, resolution of laser beam analysis, and resolution relating to the measurement of the height profile on the surface of the product. Based on the model constructed in such a way, measurements are presented in order to assess the dimensional parameters. Based on tests and analyses of the three-dimensional model, a range of inspection tasks using 3D vision systems is indicated.