FARO Scanner Settings for VTube-LASER

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VTL Computer with Full FARO EDGE.png

This is a guide for FARO scanner setup with VTube-LASER.

Contents

Results from Extensive Research

VTube-LASER has sophisticated analysis tools (like DCF - Dual Cylinder Fit) that can tell operators if the incoming data is reasonably good. Because of these built-in tools, we have discovered some useful operating principles for best practices in FARO scanner setup.

The principles here probably apply to other shapes as well - but we know for sure that they apply to measuring at least cylindrical shaped surfaces.

Vtube-laser v2.8 DCF logo.png

PRINCIPLE 1: LLP Camera Exposure Modes Depend on the FARO Scanner Version

The diagram on the right shows the workable exposure settings that are acceptable with the different versions of FARO scanners when measuring tube shape.

In some cases the older version scanners can use AUTOMATIC modes, but the cylinder calculation is not as reliable in these modes.

For version 2 and version 3 scanners, it is almost impossible to pass the 4-level cylinder fit-test in VTube-LASER 2.8 or newer when scanning tubes. The only solution, in this case, is to use FIXED mode in the FARO Laser Line Probe Control window.

FARO Scanner Settings Illustration.png



PRINCIPLE 2: FIXED Exposure Mode is better than AUTOMATIC Exposure Mode for Reliability

An important principle that we've discovered is that FIXED exposure mode is more reliable than AUTOMATIC exposure mode in returning consistently accurate surface points when measuring a cylinder.

The difference in reliability between FIXED and AUTOMATIC exposure modes depends on the scanner version. With version 6 (the HD blue line scanner), the difference is usually minimal. With older versions, the difference can be more of an issue. Whether or not the difference matters is easily detected and reported by VTube-LASER's DCF - Dual Cylinder Fit feature.

Also, a Cut Plane surface may interfere with the automatic exposure mode if the Cut Plane reflectivity is much different than the tube surface reflectivity. Changing to FIXED exposure mode solves this issue.

Vtube-laser cylinder on cut plane.png



How to Setup FIXED Exposure Mode

To setup FIXED mode for a new tube surface, enter the FARO Laser Line Probe control by pressing VTube-LASER's Scanner Control button at the top of the viewport, then follow these steps:

  1. Set the algorithm to "FIXED".

  2. Aim the scanner at a tube straight and hold the scanner still in that position.

  3. Press the AUTO button. Continue to hold the scanner in this position until the AUTO button re-enables.

When the AUTO button re-enables, then the setup is finished. You can press OK to exit this menu and use these new settings. These values will be stored in the VTube-LASER project file for reuse with this project later.

FARO Laser Line Probe Fixed Mode Setup.png




Two Minor Limitations to FIXED Exposure Mode

Limtation One

The user needs to take the minute to setup the exposure setting for the current material type that is being scanned. (In our experience, no customer has objected to this extra minute of scanner setup time.)

Limitation Two

FIXED mode may not handle parts well that change surface types in the middle of the part. (This is a rare situation in tube fabrication.)



PRNCIPLE 3: Scan Density of 1/16 is Best

Scan Density is set in fractional values. "1/1" means all the points are being transfered to VTube-LASER. "1/16" means a 16th of the total points are being transfered to VTube-LASER.

For measuring tube shapes, a Scan Density of 1/16 is more than enough.

Not only is 1/16 enough density for scanning, it also reduces the calculation time required for VTube-LASER's math engine to calculate the centerline of the cylinders.

Faro llp scan density.png



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