I recently digged a lot into 3D Scanning and PBR Material scanning and was very curious about all those "Material Scanner" but I never found out if you can actually scan a specular map. Everything is usally a Normal with diffuse and maybe translucency. The only Scanner I found were they claim to be able to scan everything was here https://www.muravision.com/ but this looks a lot out of my Budget. I want to create more of a DIY version like this one I found in a old Substance Blog (https://store.substance3d.com/blog/your-smartphone-material-scanner)
So does anyone have a clue what to do to capture Specular maps or is it more a guess which you create afterwards by hand and hope that it meets the real attributes.