Combining Shape from Shading and Stereo Depth Maps
This program is packaged in
Stereo algorithms suffer from the lack of
local surface texture due to smoothness of depth constraint, or
local miss-matches in disparity estimates.
Thus, the stereo methods only provide a coarse depth map
which can be associated with a low
pass image of the depth map. On the other hand,
shape from shading algorithms produce better estimates of
local surface areas, but some of them have problems with variable albedo and
Thus, shape from shading
methods produce better detailed depth information, and
can be associated with the high pass image of the
depth map image.
In order to compute a better depth map,
we present a method for integrating the high frequency
information from the shape from shading
and the low frequency information from stereo.
In this paper, we present a method for integrating the high frequency
information from the shape
from shading, and the low frequency information from
the stereo in order to
produce a better depth map.
Our method is motivated by the
human vision system, and follows Hall and Hall's model.
The proposed algorithm is very simple, takes about .7 seconds for
a 128 x 128 image on a
Sun SparcStation-1, is non-iterative, and
does not use any thresholds. The results obtained with
a variety of
synthetic and real images are discussed.
The quality of depth obtained by integrating shading and stereo is
compared with the ground truth (range image) using average surface
gradient error measure, and improvement ranging from 30% to 50%
over stereo, and from 65% to 98% over shading is demonstrated.
What's In It?
Program1 name : combine
Input images :
mozart-sh.rimg : depth map from shading
mozart-st.rimg : depth map from stereo
bread-sh.rimg : depth map from shading
bread-st.rimg : depth map from stereo
Depth.rimg : combined result
L.rimg : Low freq. info of Hall's Model
H.rimg : High freq. info. of Hall's Model
combine-depth.ascii : ascii data file of the combined
result (for 3-D plotting)
Program2 name : lambert
Input image : depth map (range image)
Light source direction (any)
Output : `lambert.iimg' Gray level image created using
the lambertian reflectance model.
Program3 name : disp3
This will display the images with the
extensions .rimg and .iimg to the screen of a
SUN spark station.
Program4 name : stereo
Barnard's stereo algorithm.
The Technical Report
The algorithm is described in Technical Report tech25.ps.gz