Joined: Aug 22, 2007 Posts: 3 Location: London, UK
Posted: Thu Aug 23, 2007 4:30 pm Post subject:
I've investigated this problem for some time and even written a few not particularly successful algorithms to do this.
The fundamental problem and thing to understand is laser scanning is good for capturing surfaces but it is indiscriminate and does not do a good job of capturing edges. This is because edges tend to be rather thin and occupy a very very small area of the overall view.
Drawings usually represent edges, silhouettes or boundaries and not surfaces, think about how you would draw a cylinder for example. Edges usually have to be re-constructed from scan data since they are not present. This is better done by eye than by any automated system, it is also fairly subjective and requires a great deal of judgement - none of which an algorithm can emulate very easily.
I suppose it would be possible to develop a 'learning' system that learned as you draw and would slowly start to take over. I'll leave this for someone else to do!
The only exception IMHO are organic forms such as rock faces or some historic buildings. These respond better to automated drawing. _________________ Faraz Ravi
Pointools | High Performance Point Cloud Software
www.pointools.com
When you say line drawings do you mean isometric drawing of pipelines and the such?
If so, point clouds are "dumb data". Laser scanners don't know what it is scanning, all it knows is where points are in 3D space. There is no way to automatically (with the press of a button) extract iso's or P&ID info from a point cloud. The laser scanner doesn't know line-number's, fluid codes or component data.
How ever there are ways of modeling the data and extracting it to a CAD package.
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