3Dvisionlab: Equipment
Laboratory for Optical 3D Metrology and Computer Vision

by observing a given scene from two distinct perpectives, one can extract depth information from the shift of certain image points. The human eye uses the same principle.

In order to cleary identify a point in two images (s.c. correspondence problem), the surface of an object will be encoded with a series of fringe patterns. Capturing this sequence with two cameras enables this technique to uniquely identify the pixel coordinates of one point in both images and therefore calculate the point coordinates in three dimensional space through triangulation. This enables a high resolution measurement of object surfaces, which can be used for nominal/actual dimensions comparsion, or in order to digitize machined parts without the need of a technical drawing.

Light cut is a 3D metrology technique. The technique is based on triangulation which can be used to calculate three dimensional surface information. Typically a light cut system is composited of a laser, which projects a line on a test object and a camera at a certain angle relativ to the LASER, which captures an image of the LASER line.

Time of flight is a term for a measuring distances by determining the travel time of light pulses. By sending out light pulses and measuring the time between emission and detection of the reflected light pulses, the distance between the object and the sensor can be calculated due to the fixed speed of light.

A time of flight camera will acquire a two dimensional projection of a given scene. With the calculated height information a three dimensional point cloud is generated. Due to the relative high frame rates of such cameras, they can be used for object detection and collision prevention for driverless car operation.

Laser scanning is a secondary application of the time of flight method, where big objects such as geographic features or big buildings are scanned point by point.

Light field technology is an image acquisition technique, where additionally to the intensity distribution the angle of incidence of light is recorded. This additional information can be used to reconstruct three dimensional surface information or to change the focus position and depth of field of a image. Apart from camera arrays and various specialized acquisition techniques the light field camera offers a compact solution for light field image acquisiton in industrial environments.

2D visual inspection is the most basic method for optical metrology in industrial environments. Visual inspection means, that a conventional two dimensional image will be acquired from a work piece and analysed in order to trigger an action from a machine. Therefore all components (camera, objetive, illumination, acquisition hardware) have to be perfectly matched in order to reliably solve the metrology problem, (e.g. dimensional metrology, thread inspection, ...)

Our lab has the equipment to implement and test even complex 2D visual inspection methods. From image to decision!

New optical metrology methods can be researched and developed by using the comprehensive assortment of experiment equipment. The focus not only lies in two and three dimensional image acquisiton but also in the development of new image processing algorithms.