NeuroMotive™ User’s Manual
LB-0336 Rev. 1.00
Page 47
Figure 39 - 5x5 Low Pass filter, no Opening filter and no Dilation filter
Figure 40 shows the markers with no low pass filter, no morphological opening filter, and no morphological dilation
filter. As can be seen, this makes the marker shape appear jagged. There is a hole in one of the markers. And a
minimum radius of 4 is no longer small enough to identify one of the markers resulting in the wrong direction being
calculated. In summary, if the markers are very small, both low pass filtering and a morphological opening filter
may remove them. Also remember that a morphological opening filter takes into account the size of the markers,
while low pass filtering takes the hue or luminance value of the neighboring pixels into account.
Figure 40 - no Low Pass filter, no Opening filter, and no Dilation filter