Any type will do as long as it has bristles left and you never intend to brush your teeth with it ever again.
For this example, I'm using "Snazaroo classic colours" black face paint as it's PH neutral and is very easily removed.There are other coating sprays out there but we have found this is the easiest to apply and importantly remove later. Available from David this is very fine grain powder that will stick to most surfaces but more importantly can easily be removed after the scan.For this tutorial, I'm using a Canon 100d with a 35mm prime lens. CameraĪny camera will do but if you want the best results a DSLR with manual exposure ISO and aperture control is best, failing that a point and shoot with manual controls. So the first stage is to prepare the tools and equipment that you will need. A highly polished transparent glass bowl, a photogrammetry nightmare if ever there was one.
For this example, I've chosen the hardest possible subject. But is the only way to really get good scan data from such an object using photogrammetry. I realise that the techniques in this tutorial might not be suitable for all objects such as high-value items that the owner might not take to kindly to having sprayed with matting powder or historical artefacts. There is only really one way around the problem and that is to coat the surface with something that will scan. In this tutorial, I'm going to show you a fast and relatively non-destructive way to scan almost any reflective surface. A few people have expressed the opinion that using a polarising filter on the camera lens will help in some way, whilst it will help to remove unwanted reflections the surface will still contain little or no detail and therefore will not scan well.
Anything that is there will be confused by reflections and refractions within the surface of the glass. So an object like the glass bowl we are going to use for this example will have little to no surface detail for the software to pick up on.
Photogrammetry works by defining exact positions of reference points on a given surface. One question I see rising time and time again is “how do I scan shiny or reflective objects with photogrammetry” The answer is, you can't, it's impossible to scan a / transparent / reflective or very shiny objects using photogrammetry without some kind of surface preparation or complicated projection technique. 3D Scanning Reflective Objects With Photogrammetry
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