标题: Micro-geometric Modeling of Human Face Skis for Cosmetic Analysis [打印本页] 作者: 彬彬 时间: 2012-1-3 10:18 标题: Micro-geometric Modeling of Human Face Skis for Cosmetic Analysis 1 Introduction
Condition of skin is an important factor for the impression of faces.
Well-cared skins give shiny and beautiful impression, while dry and
rough skins loss the gloss and therefore they are less attractive.
These differences often attribute to the difference of their microgeometry.
Such micro-geometry of human skins consists of furrows
forming a mesh, ridges surrounded by the furrows, and pores.
Many of pores exist at intersections between furrows. We observed
that widths of pores are approximately proportional to their depths.
Most of existing works on impression analysis of human skins are
based on images of real photographs. However, this approach is
often very expensive: we need to ask many people to take photographs
of their skins to gather various conditions of skin images.
In contrast, we attempt to use images of computer-synthesized skins
for impression analysis of various conditions of skins while controlling
ridges, pores, and furrows independently. Human skin representation
is an important technique for entertainment movie production,
and skin modeling is therefore an active research topic.
This paper presents a technique for micro-geometry simulation of
human skins. The technique first generates pores forming a pattern
of a well-aligned triangular grid. It then divides the skin region by
applying the Delaunay triangulation algorithm to connect the pores.
It treats the triangles as ridges, and the edges as furrows. Finally,
the technique divides the pattern into a finer triangular mesh, so that
it can finely represent 3D geometry of pores, ridges, and furrows.
2 Geometric modeling of skin structure
We captured micro-geometry of real human skins to discuss and
design the modeling technique. We subjectively observed skins in
the following three conditions which are especially important for
cosmetics analysis:
[1: Well-cared skin] Furrows are continuous. Ridges are regularly
aligned, equally-sized, and roundly.
[2: Dry skin] Ridges are flat but regularly aligned. However, furrows
are so depthless that patterns are unclear.
[3: Pore-expanded skin] Pores are not only large but also deep.
Based on the above observation, we concluded that the following
parameters should be controllable while representing microgeometry
of skins:
Pore: radius, depth, and randomness of positions.
Ridge: heights, and randomness of heights.
Furrow: depths, widths, and directional dependency.
We aimed to develop a 3D modeling technique so that we can generate
various skins by freely controlling the above parameters. The
technique first generates patterns of pores, ridges, and furrows, applying
Delaunay triangular meshing. It then tessellates the patterns
into fine triangular polygons.
Figure 1(Upper-left) shows an illustration of processing flow of the
pattern generation, including generation of pores, ridges, and furrows.
The technique first generates a set of pores so that they form
a pattern of a well-aligned triangular grid. Here, it controls radii,
depths, and positions of pores based on the predefined parameters.
mihayu, mami, itot)@itolab.is.ocha.ac.jp