Both 3DPM and 3D Stereo can be used.
The 105° FOV of 3DPM tips allow a wider scene to be viewed and measured from a given distance than 3D Stereo (50 or 60° FOV dependent on tip used).
3D Stereo may provide better results than 3DPM in compressors having shiny blades and liner.

Position the probe tip as close as possible to the target surface.
Images must have at least 50% overlap. Too little overlap often results in failed or inaccurate stitching.
Surface must have unique details that look similar from one image to the next.
Surfaces that have a shiny or reflective appearance that changes as the probe tip moves position can be problematic. Increasing overlap can help.
Avoid excessive (c.20°) rotation steps between image captures.
Avoid excessive (c.30%) magnification steps between image captures.
Clean data helps – minimize MTD. Use Green or Yellow 3DPM tip where possible.
Always check registration or stitching quality before proceeding and measuring.

During the capture and subsequent stitching of images, it is possible to intermittently check the registration or quality of stitch before proceeding and capturing more images or subsequent measurement assessment.
This is an important process to ensure accuracy of measurements on stitched images.
Watch surface details while using ‘Next/Previous Image’
If well registered, surface details will move very littlebetween images
If poorly registered, details will shift.

3D stitching options on the Mentor Visual iQ+ VideoProbe