A 3D imager uses a triangulation method to measure the 3D coordinates of points on an object. The 3D imager usually includes a projector that projects onto a surface of the object either a pattern of light in a line or a pattern of light covering an area. A camera is coupled to the projector in a fixed relationship, for example, by attaching a camera and the projector to a common frame. The light emitted from the projector is reflected off of the object surface and detected by the camera. Since the camera and projector are arranged in a fixed relationship, the distance to the object may be determined using trigonometric principles. Compared to coordinate measurement devices that use tactile probes, triangulation systems provide advantages in quickly acquiring coordinate data over a large area. As used herein, the resulting collection of 3D coordinate values or data points of the object being measured by the triangulation system is referred to as point cloud data or simply a point cloud.
There are a number of areas in which existing triangulation scanners may be improved, including improved thermal stability and cooling, improved geometries for detecting problems or automatically correcting scanner compensation parameters, improved rejection of background lighting, reduced effect of cooling fan vibration, optimized illumination projection levels, improved ways to measure relatively large objects with relatively high accuracy and high resolution in a relatively short time, improved methods of registering an array of 3D imagers, and a structure configured to simplify proper alignment of 3D imagers to a part-under-test.
Accordingly, while existing triangulation-based 3D imager devices that use photogrammetry methods are suitable for their intended purpose, the need for improvement remains.