Key to Good Color – Lighting
If you’ve ever seen a 3D scanning setup, you might have noticed that the person being scanned is surrounded with lights. This isn’t just a prop to make it look cool.
Different Light Angles ruin merging colors
Because 3D Scanning involves take different 3D Snapshots and merging them together, each shot is taken at a different angle and these different angles are merged together. When there is directional light being shined on an object, that object will have a higher contrast at different areas depending on the angle you are looking at it. To put it in an example- depending the angles, the brightest spot on a bald guy’s head will appear to move around as you walk around them while you look at that spot.
How this affects 3D Scanning
Here is an example of two 3D snapshots merged.
First, the color images looked like this:
Once merged together they looked like this:
You may notice above the right eyebrow, there is a white splotch. Also the neck has some splotches as well. This is because of 2 things-
- Different lighting conditions cause the hardware brightness/contrast in the Kinect to adjust, meaning the entire color image is altered to accommodate a different lighting condition.
- Different angles of light cause the brightness to be different at different spots of the surface.
Current Work Arounds
Well, the standard practice is to just have better controlled lighting conditions, so no matter what angle you take the image from, there is uniform lighting. This seems to be done with either LED Strips or Defused lighting.
We are considering to test this is a photography studio, to see if the lighting provided would be enough to handle this problem.