Dear Dmitry,
Thank you for your detailed response. This will help me configure equipment that is most efficient for processing image collections with PhotoScaner. I am presently in the field, internet access is intermittent, and access to new hardware impossible. When I return to the US, I'll be looking into installing PhotoScaner on a high end Win64. I've got a pair of machines in my lab that would be perfect. In the mean time, I seem to be able to regularly process collections of >30 4 megapixel images. I'm considering downsampling a little more to see if that will permit more images to be included in the collections. In the mean time I have been working with the following process:
Select 25-30 images that are on a single "flight line" and process these images. Once the mesh and photo texture is created, I export this as a ply file. Then I process the next 25-30 images. I often leave an overlap of 2-5 images to ensure that both sections will have enough common form to permit co-registration.
When I open a pair of ply files created from different image sub-sets the scale in the two models looks "pretty close". In VRMesh Studio, I use a manual registration routine and then perform a global registration between the two sections. I've not tried registering two sections in MeshLab, but this is on my list of things to try.
The ability to process 100 images with 64 bit OS would be fantastic. That would significantly reduce the number of sections that have to be registered.
Do you have any suggestions to ensuring that the scale is similar in different sets of sub-collections? Given the way I place targets, I can't always be sure there are two separate known points for setting scale. If there are processing parameters that would help ensure common scale across sub-sets of a larger collection, I would be very interested to learn about this.
Thanks again, I've already been getting good use out of PhotoScan.