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Development of a novel mechatronic system for mechanical weed ...

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5.1.3 Results <strong>of</strong> the robustness test<br />

Results and discussion<br />

The robustness test showed that there is no significant difference between the<br />

estimated size <strong>of</strong> the plants in the darkness, by daylight and artificial illumination<br />

neither <strong>for</strong> the detection with RGB sensor nor <strong>for</strong> the detection with laser<br />

sensor. Table 5.1 and Table 5.2 contain the mean values <strong>of</strong> estimated plant<br />

sizes from experiments, conducted without change in sensor setting and<br />

repeated 10 times <strong>for</strong> every variation <strong>of</strong> the illumination intensity and number <strong>of</strong><br />

allowed FALSE values in the plant pattern. The estimated size can vary from<br />

the measured diameter <strong>of</strong> the plant, but the estimated size stays uni<strong>for</strong>m<br />

regardless the illumination intensity change. Tables containing the mean values<br />

<strong>of</strong> the estimated plant sizes <strong>for</strong> every variation <strong>of</strong> the illumination intensity and<br />

number <strong>of</strong> allowed FALSE values in the plant pattern with calculated standard<br />

deviation <strong>of</strong> the estimated values <strong>for</strong> both <strong>of</strong> sensors are given in appendix (see<br />

Table 9.1, Table 9.3, Table 9.5, Table 9.7, Table 9.9 and Table 9.11).<br />

More obvious confirmation <strong>of</strong> the detection <strong>system</strong> applicability can be observed<br />

by analysing the estimated centre positions <strong>of</strong> the plants. Table 5.3 and Table<br />

5.4 contain the mean values <strong>of</strong> estimated plant centre positions from<br />

experiments, conducted without change in sensor setting and repeated 10 times<br />

<strong>for</strong> every variation <strong>of</strong> the illumination intensity and number <strong>of</strong> allowed FALSE<br />

values in the plant pattern. Tables containing the mean values <strong>of</strong> the estimated<br />

centre positions <strong>for</strong> every variation <strong>of</strong> the illumination intensity and number <strong>of</strong><br />

allowed FALSE values in the plant pattern with calculated standard deviation <strong>of</strong><br />

the estimated values <strong>for</strong> both <strong>of</strong> sensors are given in appendix (see Table 9.2,<br />

Table 9.4, Table 9.6, Table 9.8, Table 9.10 and Table 9.12).<br />

The maximum deviation <strong>of</strong> the estimated centre positions from the plant<br />

measured centre positions, detected by RGB sensor, was 31 mm, whereby<br />

50% <strong>of</strong> the samples were inside the interval 0 to 5 mm and 90% <strong>of</strong> the samples<br />

were inside the interval 0 to 16,9 mm. For the laser sensor, the maximum<br />

deviation <strong>of</strong> the estimated centre positions from the plant measured centre<br />

positions was 25 mm, whereby 50% <strong>of</strong> the samples were inside the interval 0 to<br />

3 mm and 90% <strong>of</strong> the samples were inside the interval 0 to 6.9 mm.<br />

65

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