Line Modules Overview
Line Modules are a specialized type of laser, designed primarily for various types of alignment applications. Machine Vision, a generic term for a broad group of applications, can utilize a variety of schemes for image detection and analysis. Lighting can influence that analysis and lasers are often used to illuminate objects with structured illumination. This can be useful in providing additional information about the objects through image processing. Examples of information that can be obtained include defects, location, dimensions, dents, punctures, and alignment, for example.
When compared to traditional light sources, lasers provide a much higher contrast with the background image providing the computer algorithm with a more precise reference source. As a result, lasers have been widely deployed as structured lighting in many image processing systems. Machine vision line module lasers are typically beam shaped into lines, dots, and other geometric patterns (such as crosses, circles, and grids) and they can come in a wide variety of wavelengths and powers depending on the systems requirements. Each of these geometries has its own unique advantages, but lines tend to be the most commonly used laser shape in modern machine vision technology. Lines are the most popular because if the laser is offset at an angle from the camera, a 3-dimensional image of the object can be reconstructed through a process known as triangulation.
When specifying line modules, the designer needs to understand the required line length, line width or thickness, the distance from laser to object, and whether intensity distribution across the line needs to be uniform. Line length is usually specified as fan angle and can be set to anywhere between 10 and 90 degrees. The line length can be calculated once you know the fan angle and the distance from laser to object. Line width and line thickness can be varied by adjusting the focusing optics. These can be pre-set by the manufacturer for a given object distance or controlled by the customer. You should specify if line module adjustability is an important feature .