Electromechanical 3D Optoelectronic Scanners: Resolution Constraints and Possible Ways of Improvement

Abstract

Non-Contact optoelectronic 3D measurement is a rapidly growing field. Three-Dimensional Non-Contact Measurement Technologies are very common for research due to multiple practical applications expecting for its benefits. Many fields are using in any way 3D measurements or shape recognition, some of them there are vision assisted assembly in various branches of industry, autonomous mobile robots navigation, structural health monitoring, micro surfaces inspections, precise automated surgery, etc. In this chapter it is expedient to mention and briefly cross-compare the following emerging technologies for 3D measurements: laser scanners, lasers based on conoscopy holography technology and 3D cameras. Laser scanners: Most contemporary non-contact 3D measurement devices are based on laser range scanning. The simplest devices (Fischer, 2007) are based on the laser triangulation technique. This is an active stereoscopic technique in which the distance of the object is computed by means of a directional light source and a video camera. The CCD camera’s 2D array captures the image of surface profile and digitizes all data points along the laser disadvantage of this method is that a single camera collects only a small percentage of the reflected energy. The amount of the collected energy can be drastically increased by trapping the entire reflection cone, thus significantly increasing the precision and reliability of the measurements. Lasers based on Conoscopic Holography technology: Conoscopic Holography is a simple implementation of a particular type of polarized light interference process based on crystal optics. In the basic interference set-up, a point of light is projected onto a diffuse object. This point creates a light point, which diffuses light in every direction. In a conoscopic system, a complete solid angle of the diffused light is analyzed by the system. The measurement