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Our model approximates heterogeneous light transport in skin
through the inter-scattering of light between layers. Shown are
hand-drawn spatially-varying parameter maps of two
scattering layers, and of an infinitesimally thin absorbing layer
between them. The maps have been scaled in intensity (10x for melanin,
20x for hemoglobin) to show detail. Given this simple input, our method renders
heterogeneous and volumetric effects that cannot be simulated
using previous methods.
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![](\"$img\") ";
/*/
echo "\n";
echo " $text ";
echo " | ";
/**/
}
?>
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Example skin patch reconstructions
(a,b,d,e,h,i)
Caucasian, skin type III: bridge of the nose (a),
freckle on arm (b) slight acne on arm (d), forehead (e),
stronger acne on arm (h), scar on edge of the hand (i).
(c,g)
African, skin type V:
exterior lower arm (c) (artifact due to hair),
wrinkles at posterior side of wrist (g).
(f) Caucasian, skin type II, exterior lower arm.
(j) Asian-subcontinental, skin type IV, scar on back of hand.
(k,l) Caucasian, red-haired, skin type I:
exterior (k) and interior (l) lower arm.
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\n";
echo "![](\"coeff-plots/$label.jpg\") | \n";
for ($i=0; $i<4; $i++)
echo "![](\"coeff-plots/$img[$i]-$str.jpg\") | \n";
echo "![](\"coeff-plots/bar-$str.jpg\") \n";
echo " | \n";
}
function write_table($size, $img) {
write_row($size, $img, "epidermis-eumel", "ee");
write_row($size, $img, "epidermis-phmel", "ep");
write_row($size, $img, "epidermis-beta", "eb");
write_row($size, $img, "epidermis-hemo", "eh");
write_row($size, $img, "dermis-hemo", "dh");
write_row($size, $img, "residual", "r");
}
?>
| (a) | (b) | (c) | (d) |
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Chromophore concentrations as derived from our measurements,
corresponding to patches in Figure to the left, (a--d).
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Abstract
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.
Downloads
[ Paper
preprint ]
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Note that ACM Portal will have the official version of the paper.
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