Thank you Kiesel for the links. Unfortunately they are not what I was seeking, because they are dealing with coded targets, which are not used in my case. However, I did some experiments of my own and for the benefit of forum members these are the findings:
- Either with or without the targets masked, after you run initial picture alignment Metashape is capable of detecting non-coded markers residing within the masked areas of the photos used. The software identifies and marks them correctly in space.
- In my case I use four groups of black-on-white targets, each group comprising of four equidistantly placed targets (4x0.5cm black circular targets on white backdrop, equidistantly placed at 1.5cm each from the centre of the other in a 2x2 array), hence there is a total of 16 targets. The four groups are placed at the four edges of each object captured. Since the software recognises the centres of each marker and the distance between any two markers within each group is a constant, placing scale bars and correctly scaling the object becomes very easy either at the start of the procedure or at the end, as it appears that scaling does not affect calculations during point cloud production.
- Only caveat or point to be careful about is that you have to make sure the targets don't move around while shooting, as movement can increase error in the scales or make it impossible for the software to recognise targets altogether.
Hope the above are helpful.
All best,
Cyberworld