Master Thesis - Fachbereich Informatik

128 CHAPTER 5. RESULTS AND EVALUATION
computation and tracking. The last group contains all remaining operations that are not
considered by any of the groups before.
Manythousandsofframeshavebeentimedwithandwithouttubesinthevisualfield
of the camera. The results of the performance evaluation can be found in Figure 5.22. It
turns out that the processing of a measurable frame requires 17.8ms on average. Thus,
all images at a capture rate of 50fps (i.e. a new image is acquired every 20ms) can be
processed.
The dominant part of the processing is consumed by edge detection and template matching
where the later is mostly expensive. 82% of the total processing time is needed for
this step on average, although the number of pixels considered is highly restricted by the
local ROIs. The undistortion operation is the second most expensive operation with 10%
followed by the length computation and tracking with 4%. The profile analysis, thougth as
fast heuristic to locate a tube roughtly, is proven to be very fast with only 0.29ms/frame.
The remaining 3% represent operations such as image conversions, copying or drawing
functions to visualize the detection results. The later could be saved at production if
visualization is not required.
If the profile analysis detects a non measurable frame, the template matching is not
performed. Thus, the remaining time could be used for different side operations in future,
e.g. to save logging information or to run certain self control mechanisms. Such mechanisms
could check whether the illumination is still bright enough or if the camera position
has changed for example.