International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume XXXIX-B3, 2012
XXII ISPRS Congress, 25 August - 01 September 2012, Melbourne, Australia
0 10 20 30 40 S0 60 70 8 90 100 0 10 20 30 40 S0 60 70 80 90 100 0 10 20 30 40 S0 60 70 8 90 10 0 10 220 30 4 S0 6 70 80 90 100
(a) CT, Cones (b) CT, Teddy (c) CT, Venus (d) CT, Tsukuba
% RAC 8 BRD FE
0 888888888888888
(e) CT, P. (f) CT, Pj (b) CT, P»,
Teddy
— Venus Tsukuba -Cones ^^ Teddy — Venus «+ Tsukuba
0 100 200 300 400 500 wo » Ko “a0 1000 1100 120 1x0 1400 1500 0 100 200 200 400 500 P3 "0 800 "500 ^ 1000 100 1x0 1300 1400 1500
(1) Ordered Configurations for P»; (j) Ordered Configurations for P»;
15.0%
14.0%
1309
120% oo
11.0%
10.0%
0 10 20 30 40 SO 60 70 80 90 10 0 10 20 30 40 50 6 70 80 90 100 0 10 20 30 40 50 6&0 70 80 90 100
(k) RT, Cones (1) RT, Teddy (m) RT, Venus (n) RT, Tsukuba
Figure 4: Errors in unoccluded areas for all penalty functions employing census transform examining behavior on the same image (row
one), over different images (row two), stability of configurations across images (row three), and employing rank transform (row four).
ares LU
(a) Left Cones image (b) Ground thruth (OCT Re (d) CT, P», (e) CT, BP; (CT.
E
(g) Left Teddy image (h) Ground Truth (1) CE P. Q CT, P1 (k) CT, P», (D CT, P»,
Figure 5: Disparity maps obtained with optimally parametrized penalty functions for Cones (top row) and Teddy (bottom row).
than for the census transform which is due to the missing spatial comparison, these two functions are plotted with their optimal
information of the rank transform. As with the census transform configuration in Fig. 6 showing an obvious similarity between
P», performs acceptably and P», poorly for an adaptive func- the two functions over x.
tion. However, in opposite to census, P», always outperforms
Py; in 3 cases quite significantly. All functions are similarly 3.2 Simulated Degenerated Images
robust towards parametrization offset as with census (data not
shown). Again, good configurations coincide across all images For the second set of experiments the left input image of the
(data not shown). Cones data set is artificially degraded whereas the right remains
unchanged. Two types of radiometric differences and two types
The error levels obtained with optimally adapted penalty func- of noise are considered:
tions are summarized in Table 1. For the two test images Cones
and Teddy the resulting disparity maps are shown in Fig. 5. Even e Additive white Gaussian noise (AWGN) with SNR = 12 dB
visually highly noticeable, P», introduces a significant amount of e Salt-and-Pepper noise with 14 96 of the image degenerated
errors. Using P5; the small structures in Cones are retained, oth- e Linear brightness (gain) change across the half the image
erwise there is no significant difference between P», and P»;. For e Non-linear brightness (gamma) change
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