Operation of the Triangulation Sensor
A triangulation sensor measures objects by imaging the intersection of a uniform planar light source and an object. The sensor projects a sheet of light through a measurement area. The 3D sensorvision system captures this area at an angle, out of the plane of the sheet. When an object passes through the sheet, a laser stripe appears on the object's visible surface, which is imaged onto the detector. The software reduces the image data to a representative profile. Profiles are combined into a point cloudrange image which contains 3D information (height, volume, etc).
The properties of the major elements of the system determines the sensitivity and accuracy of the measurement. The light source is a laser with a large divergence in one axis (20 - 40 degrees) and minimal divergence and extent in the perpendicular axis. Since the object plane is angled relative to the camera, you have to position the camera sensor to achieve optimal focus across the field.
When the 3D sensorvision system reads the image from the system, the image is then processed to
- Detect the line and determine its location
- Calibrate the line's position
- Assemble the calibrated profile data
Note: There are certain image distortions that derive from the fact that the 3D sensorvision system has a fixed-point aspect, has a lens, and the object is moving under the unit. However, In-Sight Vision SuiteVisionPro uses the calibrated profile data from the 3D sensorvision system (factory calibrated in manufacturing). As a result, the point cloudrange image does not show unwanted optical effects.