Phong reflection model parameters
Q: Can anyone call me the Phong reflection model parameters for a face image taken for a webcam?
Details:
I am doing 3D reconstruction of 2D images using the 3D Morphable Model as in this article by Vetter and Blanz, 2003 .
There is a cost function that needs to be optimized using the Newton method. I need to give initialization values for Newton's method.
The equation below represents the fog reflection model of an image. Ambient, diffuse, and special components are displayed.
Phong Reflection wiki
Phong parameters: Ks, Kd, Ka, α, Lm, V
I am evaluating the above parameters using Newton's method. The image has a human face and the camera is a webcam.
I gave the following values: Ks = Kd = Ka = 0.6 α = 5 Lm = [0 1 1] V = [0 0 1]
Can anyone comment on the above values and what might be a good initialization value for parameters
My boss had a Siggraph document a few years ago that suggests an online tool that extracts a specific BRDF barcode for a Blinn-Phong model, based on gender, skin type, etc. The tool is available at: http://gvi.seas.harvard.edu/ext/facescanning/index.html
Alternatively you can check the Matusik BRDF database fittings at: http://people.csail.mit.edu/addy/research/ngan05_brdf_supplemental_doc.pdf and pick one BRDF that "looks" like leather (they didn't measure leather, since we used balls).