A typical runway holding position sign detection and
recognition scenario is shown in the following figures. Figure
3 shows the original input image. Figure 4 shows the detected
sign after top-hat filtering and median filtering. Figure 5
displays the runway information on the original image frame.
223 images obtained from the ground operation of an aircraft
are tested using this method and the result is shown in Table
I. We can see that the detection has high recall yet relatively
low precision. It is caused by the algorithm picking up similar
objects (color and shape) in the vicinity including light box,
aircraft painting and wind sock. The overall accuracy is 95.1%.