Visual Servoing for Beating Heart Surgery - Visual Servoing via Advanced Numerical Methods - page 100

(c)

(a) (b)

Fig. 6.8 The pattern is occluded by a finger or a part of the pattern is high lighted

Fig. 6.9 The topic surface is bended and twisted

Fig. 6.10 Tracking results

First some preliminary results will be shown. The first results show the robust-
ness of the algorithm with respect to partial occlusion and to illumination changes
in the template. The selected template (Figure 6.8(a)) is first occluded by a finger
(Figure 6.8(b)), and then enlightened by an additional torch (Figure 6.8(c)). We re-
mark that the tracking of the template is achieved correctly even when the above
disturbances are applied. The tracking area is 64 × 64 pixels and the image process-

ing is 120 fps.
The second preliminary results show the robustness against the object shape
change. The algorithm assumes that the object is planar. However it can be tracked
even if the surface is slightly bent or twisted. Figure 6.9 shows the results. The track-
ing area is 144

× 128 pixels and the image processing is 30 fps. If the deformation