Figure 6

Changes of the z-position of the thorax of agent 58 during abdominal flipping. (a) the z-value during a shimmering episode (the same as displayed in Figure 6, w₂), computed by stereo tracking; the grid ranges from +1 (away from the comb) to -1 mm (towards the comb) (ordinate), and refers to 600 ms (abscissa, see horizontal bar); the rows refer to nine successive frames starting with frame 15 (frame 0, not displayed here, refers to the first in a sequence of 40 images which featured the respective wave event at agent 58, see Figure 6); (b,c) the pairs of left and right stereo images; (d) detailed cut of agent 58 from the left camera image (inverted luminance); (e) contour display of agent 58 extracted from d, with abdomen (black), thorax (red) and head (white). The yellow full circles mark the z-value of the thorax in (a) and the thorax position in (b-e). Note that the abdominal flipping started already when the thorax of the agent moved towards the comb, represented by the negative transient in (a). Within 100 ms the abdomen was thrown upwards at more than 90°, which can be seen in the respective images in the projection of the abdomen with the shortening and curving effect (d,e). From frame 20 onwards the abdominal flipping declined and the thorax was pushed by a strong force away from the comb (a).