Multi-sensor ring configurations for 3D line profile sensors
The introduction of Firmware 5.0 has increased the multi-sensor networking capability for Gocator 3D line profile sensors from LMI Technologies. Since many scanning applications require shape data for 360º of a part, multi-sensor ring configurations can now be set up for full cross sectional visualisation.
The new multi-sensor ring layout, complements the existing Gocator multi-sensor networking capabilities by allowing the entire object shape to be inspected and target features measured from all sides. As the part moves through the sensor ring, a 3D point cloud of the entire circumference of the part is acquired with full data preservation on object sides and overhanging areas. Data is “stitched” into a complete 3D model to provide accurate volume measurement.
All sensors in the ring network are aligned to a common coordinate system in order to determine relative position using a known shape. Setting this up is done by an enhanced new 6 degrees of freedom simple alignment process. Simply by passing through the ring a known polygon target, each angular corner is aligned between the sensors so the smart sensor can then calculate each sensor’s position and transform data into a common coordinate system. This transformation is carried out automatically for every 3D point produced by the sensor.
Measurements can be made using the new Profile Closed Area tool provided in Firmware 5.0. This allows cross sectional area measurements to be made on profiles as the object moves through the sensor ring, from which the volume can be calculated.
For portioning applications where the target object must be cut according to its total weight, the weight of the object can be determined from its volume and density. Scripting can be used to accumulate the areas from the profiles acquired as the object moves through the sensor ring and trigger downstream control decisions to activate cutters the target weight is reached.
There are a number of other Gocator multi-sensor networking configurations. Two or more sensors can be mounted side by side to measure large objects that are wider than a single sensor’s field of view. Sensors mounted opposite each other can determine true object thickness when the object cannot be referenced to a known surface like a conveyor. Sensors mounted at an angle to an object can eliminate shadowing effects.
Source: Control Engineering Europe - All Articles