Photogrammetry and Reverse Engineering 1

[trumpetman]

We are a Tool & Die Company looking to get into scanning or photogrammetry to collect data (pt cloud information)in order to do hard cutting on our tools as well as keep our CAD data up to date. I have recently been introduced to Photogrammetry or Photo Imagery which can also be used in inspection which would be an asset to us.
Any info would be greatly appreciated

 

[HDS]

Please, provide some more information on the photogrametry systems you are looking at.

 

[RCDLtd]

I use the data from both a GOM scanner and a Laser scanner on a Farro arm, each have their pros and cons.

My experience is that the results from the GOM scanner carried the least "noise" and the registraion of one scan to the next adjacent scan was the most accurate. The Laser scanner is quicker to setup and can be used in a wider range on environments.

Be aware though that the scanner is only half the story, you need to consider what software you'll use to process the cloud data. Data sets of 2 - 4 million points are not uncommon with 3D scans which can cause most CAD systems trouble with handling them.

The scans will need "processing", you'll want to remove any "noise" in the scan to ensure accuracy of the data, and your likely to need to join adjacent scans together accurately if the area you wish to scan cannot be captured in a single hit. Once the scan is clean you then need to be able to run some sort of diagnosis to compare the scan to surface data you used to cut the tool.

I've used both Imageware and ICEM for cloud manipulation and each has it's role. Imageware probably has the edge for inspection purposes and cleaning up the scan, whereas ICEM has the edge for Reverse Engineering. I used Alias StudioTools a few years ago, but at the time it's scan module wasn't up to the same level as the other two - that may have changed now though.

These applications are quite expensive and I know there are cheaper options now available but I don't have experience of these.

 

[amorrison]

This stuff has been around for 15 yrs but as far as I know never seemed to catch on for general use.

Trying photogrammetry in rec.crafts.metalworking got some 5 year old hits.
Google has some theory items available.
Maybe some good stuff here

http://www.geodetic.com/Downloadfiles/Basics of Photogrammetry.pdf

 

[plasgears]

Some trivia info:

Photogrammetry first found application in map making using rectified overlapping aerial photos. Many years ago I visited the headquarters of government mapmaking in Alexandria VA, and I found the process fascinating.

Using twin projector cameras and polaroid viewers, the operator would scribe around the film where the image appeared to be intersecting and projecting above the working elevation. Successive intersections at higher elevations were drawn of contour lines.

The "mapping" definition of mechanical parts would follow the same logic except the process now is no doubt computerized using lasers.

 

[onyx01]

I have experience in three different laser scanners, all of which had pro's and con's associated with them. It comes down to what you will use it for. It appears that you want to collect data for validation of tooling and reverse engineering from tools. IMHO use a laser digitizer, like a Farro or Sharnoa (if still around). These gather points on a surface in a linear method (like a CNC toolpath). You would have to still sort the points with some software, and for this Imageware is hard to beat.

I successfully reverse engineered many tools and parts using this method. It is not a quick and automatic process, even with the software, but the software is about 90% of the package. Talk to more users and gather information and before purchasing a unit really do your homework.

Brandon Jacobsen
Product Design Engineer - Catia

 

[amorrison]

For < $3000 you can get a hobbiest digitizer system.

http://www.maxnc.com/