Machine vision technology has widespread acceptance and use in production floor applications. While the majority of these applications are in 2-D space, the availability of systems and components providing 3-D information has grown significantly. Although 3-D imaging in machine vision applications has been around for many years, with expanding technology and shrinking costs the use of 3-D imaging is becoming much more common for a widening scope of applications. Since this subset of machine vision technology may be less familiar to many, a broader understanding of the fundamentals may reveal more ways 3-D machine vision may be used for automated inspection and guidance. In this tutorial, we will provide an overview of some of the key concepts, techniques and uses of 3-D machine vision.
Our eyes (being a “stereo imaging pair”) perceive visual data in three dimensions, and we use that data intuitively to make decisions. A machine vision camera, however, processing a planar, 2-D image is significantly more limited in the data available for decision making. Essentially a machine vision system with a 2-D image must rely exclusively on brightness, contrast and only X, Y and rotational position relative to the camera. It is very valuable when a machine vision application can take advantage of additional data like that available in a 3-D view, such as the height of an object or even the height of every point in the image. Difficult inspections that may require multiple cameras or precision part presentation may be simplified with the availability of 3-D data. Other applications such as automated guidance of motion and location or measurements of objects in 3-D space fundamentally require 3-D information.