  Dawn spacecraft orbited Vesta for more than one year and collected a huge
volume of multispectral, high-resolution data in the visible wavelengths with
the Framing Camera. We present a detailed disk-integrated and disk-resolved
photometric analysis using the Framing Camera images with the Minnaert model
and the Hapke model, and report our results about the global photometric
properties of Vesta. The photometric properties of Vesta show weak or no
dependence on wavelengths, except for the albedo. At 554 nm, the global average
geometric albedo of Vesta is 0.38+/-0.04, and the Bond albedo range is
0.20+/-0.02. The bolometric Bond albedo is 0.18+/-0.01. The phase function of
Vesta is similar to those of S-type asteroids. Vesta's surface shows a
single-peaked albedo distribution with a full-width-half-max ~17% relative to
the global average. This width is much smaller than the full range of albedos
(from ~0.55x to >2x global average) in localized bright and dark areas of a few
tens of km in sizes, and is probably a consequence of significant regolith
mixing on the global scale. Rheasilvia basin is about 10% brighter than the
global average. The phase reddening of Vesta measured from Dawn Framing Camera
images is comparable or slightly stronger than that of Eros as measured by the
Near Earth Asteroid Rendezvous mission, but weaker than previous measurements
based on ground-based observations of Vesta and laboratory measurements of HED
meteorites. The photometric behaviors of Vesta are best described by the Hapke
model and the Akimov disk- function, when compared with the Minnaert model,
Lommel-Seeliger model, and Lommel- Seeliger-Lambertian model. The traditional
approach for photometric correction is validated for Vesta for >99% of its
surface where reflectance is within +/-30% of global average.
