1 Columbia University
2 Princeton University
3 NVIDIA Corporation
We introduce a layered, heterogeneous spectral reflectance model for human skin. The model captures the inter-scattering of light among layers, each of which may have an independent set of spatially-varying absorption and scattering parameters. For greater physical accuracy and control, we introduce an infinitesimally thin absorbing layer between scattering layers. To obtain parameters for our model, we use a novel acquisition method that begins with multi-spectral photographs. By using an inverse rendering technique, along with known chromophore spectra, we optimize for the best set of parameters for each pixel of a patch. Our method finds close matches to a wide variety of inputs with low residual error. We apply our model to faithfully reproduce the complex variations in skin pigmentation. This is in contrast to most previous work, which assumes that skin is homogeneous or composed of homogeneous layers. We demonstrate the accuracy and flexibility of our model by creating complex skin visual effects such as veins, tattoos, rashes, and freckles, which would be difficult to author using only albedo textures at the skin’s outer surface. Also, by varying the parameters to our model, we simulate effects from external forces, such as visible changes in blood flow within the skin due to external pressure.
Craig Donner, Tim Weyrich, Eugene d’Eon, Ravi Ramamoorthi, Szymon Rusinkiewicz.
ACM Transactions on Graphics (Proc. SIGGRAPH Asia), Vol. 27, No. 5, pp. 140:1–140:12, Singapore, 2008.Craig Donner, Tim Weyrich, Eugene d’Eon, Ravi Ramamoorthi, and Szymon Rusinkiewicz. A layered, heterogeneous reflectance model for acquiring and rendering human skin. ACM Trans. on Graphics (Proc. SIGGRAPH Asia 2008), 27(5):10:1–10:12, 2008.Donner, C., Weyrich, T., d’Eon, E., Ramamoorthi, R., and Rusinkiewicz, S. 2008. A layered, heterogeneous reflectance model for acquiring and rendering human skin. ACM Trans. on Graphics (Proc. SIGGRAPH Asia 2008) 27, 5, 10:1–10:12.C. Donner, T. Weyrich, E. d’Eon, R. Ramamoorthi, and S. Rusinkiewicz, “A layered, heterogeneous reflectance model for acquiring and rendering human skin,” ACM Trans. on Graphics (Proc. SIGGRAPH Asia 2008), vol. 27, no. 5, pp. 10:1–10:12, 2008.
This work was supported in part by the NSF (grants IIS 03-25867, CCF 03-47427, CCF 04-44916, CCF 05-41259, CCF 07-01775, and CCF 07-02580), a Sloan Research Fellowship, and an ONR Young Investigator award N00014-07-1-0900. We also acknowledge generous equipment donations by NVIDIA. Many thanks are due to Ryan Overbeck for help in creating parameter maps, and to Xiaojuan Ma for assistance in scanning skin patches. Thank you also to Paul Matts for invigorating discussions and allowing the use of skin cross-section images. We acknowledge the helpful and constructive comments from the Tiggraph and SIGGRAPH reviewers. The ear is a section of a high-resolution scanned model by XYZRGB, the palm model is provided generously to the community by Ma et al. , and the hand model is a part of the AIM@Shape Repository.