Scanner
Recently we’ve been using a 3D scanner to assist in our measurements. 3D scanning is not particularly new to New Zealand but it’s not widely used because of the high capital cost of the equipment and the relatively expensive processing software that is required.
The scanner we have been using is a Trimble GX which was made available at no cost for a period of time after the February earthquake (thanks Trimble). Mike spent a week on a training course to learn about operating the scanner in the field and then processing the data. Trimble have a software package called Realworks which we are using to process the data.
The Trimble GX is able to measure 5,000 points per second with an accuracy of 12mm at 100mm. This creates a huge amount of data called a point cloud (basically a list of x, y, z positions and a colour for each point). The processing software can model objects (planes, spheres etc.) from the point cloud which increase the accuracies because it is basically “averaging” the shape to the point cloud.
We’ve been using the software to measure faces of high rise structures and then modelling each face to a plane to measure the tilt. We have also been able to compare each individual point to the average plane which exposes any bumps in a building facade.
The results of the scanning always look stunning – there is so much data that it’s like being at the location. In fact it changes the way you carry out a survey. Normally we capture discrete points such as the top of a kerb or a tree trunk. The scanner is able to capture the whole scene (including the individual leaves of the tree).
Finally, because you can capture so much data, it’s a fantastic way of taking an accurate snapshot of an item. Amongst the data at the training course we came across a scan of the front face of the Cathedral.
Click here to view a video of the point cloud.
As you can see the detail is incredible.
Scanning is ideal for capturing a lot of data very quickly and measuring remote objects. Call us if you have any questions about scanning.