HDevelop User's Manual

110 CHAPTER 5. PROGRAM EXAMPLES
90
"wood_cells.dat"
80
70
60
Anzahl
50
40
30
20
0 100 200 300 400 500 600 700 800 900
Position
Figure 5.16: Cell wall proportion in growth direction in percent
character. Thus the number is transformed into a string. Finally, the proportion of the cell wall
(in percent) is concatenated to the string. At this it is important that the first or second value
of the expression is a string, so that the following numbers are converted into strings. Here ·
denotes the concatenation of characters instead of the addition of numbers.
5.9 Region Selection
File name: Ý׺Ú
This example explains how to handle single iconic objects. In contrast to numerical data, where
many different functions may be executed on parameter positions (see chapter 3.5), iconic objects
may only be handled by using HALCON operators. The most important operators to select
and combine iconic objects are shown in this example.
The task is to search the eyes of the mandrill in figure 5.17.
This is a simple task. First, we extract the bright parts by a thresholding. Then we have to
examine the connected components according to their shape and size to select the eyes. At this,
you could use the operator ×ÐØ ×Ô and get a fast program of five lines that processes the
task. For demonstration purpose we use a kind of “low level” version instead: every region is
extracted separately and examined afterwards. If it conforms to a given shape, it is added to a
result variable.
HDevelop / 2000-11-16