Figure 10. Translation dx, dy on reference track 1.
Figure 11. Disparity dzx on reference track 2
The tests on the eight tracks contains 70 image pairs each,
resulting in a total distance of 700 mm for each test. The data
are analyzed using a 51×51 pixel window corresponding to
approximate 40×40 mm at height 450 mm. The error and
variance of the measurement in driving direction of robot (ydirection)
are presented in Table I.
In total 5.6 m on various surfaces using 560 stereo pairs,
the variance is measured to 0.040 mm which means 99.7% of
the measurements are found within 0.60 mm. The variance
measured includes both the manual positioning of the lathe
carriage, and the error of the visual odometry system. Fig. 12
shows plots for the disparities measured and calculated
traveled distance for the test on sugar beet sawed on uneven
soil.