- Thanks to all the readers of In the Scan for helping us to achieve a Google PageRank of 4.
- Laser trackers are capable of accuracies which are an order of magnitude better than scanners.
- This allows them to be used to establish the accurate location of targets for laser scanner calibration.
First of all thanks to all the readers of In the Scan for helping us achieve a Google PageRank of 4 in the first 2 months of blogging. My 18 year old son has been advising me on SEO – Search Engine Optimization, so I want to also thank him for his help in achieving this important recognition. It takes a lot of work to establish an online community, so whenever you can contribute or pass the word on it is greatly appreciated.
I had a very enlightening conversation about laser trackers with a fellow member of the ASTM E57.04 Data Interoperability subcommittee last week. First he explained how they operate, which is similar in concept to a robotic total station in that the instrument is capable of finding the reflector automatically. Once located the instrument is capable of making very accurate 3D measurements.
My friend hires a laser tracking consulting firm to establish the 3D dimensions of his test range targets. He then checks the calibration of his scanners against the laser tracker supplied coordinates, which he considers to be “truth”.
One of the initial challenges of using the hand held laser tracker reflector was how to compensate for the offset from it to the center of the target. The solution was an extension device attached to the back of the reflector of a known length that could be added to the measured range. Reminds me of some of the early issues with EDM’s – electronic distance meter. The first one I used was built by Hewlett Packard. You had to take the theodolite or transit off the tripod to mount the EDM. They were heavy and bulky, but they sure beat the heck out of using a 200 foot steel tape, and plumb bobs.
HP had the early lead in the EDM and survey computer/software market, but the company pulled the plug on the survey product group in the mid-80’s. I heard some comments about their being too many laser scanning hardware vendors last week. It will be interesting to see how things shake out.
