Photogrammetry can simply be defined as the measurement of photographs. It is a process that largely depends on camera positioning around the given subject and light control to create high resolution details of skin and clothing. The scanning can be used for capturing data for various projects including face replacements and CG characters. With so many variables to control, photogrammetry scanning can be overwhelming. There is just too much trial and errors involved to achieve best practices but with a few helpful tips, it is very possible to achieve accuracy and top quality with the process.
Tip 1 – Think about overlapping coverage. When building your setup, you should use as many cameras as possible so you are able to reduce or minimize manual cleanup later. Enough coverage translates into very decent recreation and you will also rarely miss any information when you use enough cameras so manual cleanup is very minimal.
Tip 2 – Put in measures to minimize distortions. When there are distortions, it is given that your system will have issues aligning the images. The fact is that most Photogrammetry systems come with a lens that helps reduce images, but it is always a much better choice to try and minimize it in-camera. Use tools that match with the camera format that you are using to get the best results every time.
Tip 3 – Mask out the background to dramatically improve overall quality of generated mesh and post processing time. It is a process that can be time consuming, especially when you need to go through every single picture but it pays off in the end. If manual masking is something you would rather avoid, then you can use systems that offer automatic masking feature to achieve a clean background. It also helps to tie cables together and eliminating any junk from the frame, especially when using a camera rig.
Tip 4 – Focus on more resolution when operating. You can use as much as necessary from your sensor because the more the resolution you can achieve then the more detailed your mesh is going to be. Try every way not to waste a single pixel if you can actually use it for quality benefits.
Tip 5 – Remember that lighting remains key in all kinds of photography. To increase depth of filed and eliminate photo noise, keep your aperture small and ISO as low as you can. But because doing so will definitely decrease amount of light that you get to work with, ensure that you have other light sources to substitute. Consider using flashes over continuous lighting that are less efficient, less color accurate and expensive for that matter. Flashes keep talent comfortable and enough lit unlike continuous lights that can produce heat leaving enclosed rig hot.
Tip 6 – Pay attention to photo orientation. It is factor that plays a huge role in accuracy of projects and it needs to be accurate for every camera position. Increase number of well-positioned points to improve orientation quality. These points should take up a greater percentage of photograph area.