Wenglor B50 - Find Line

115
Smart Camera / Vision-Sensor / 1D-/2D-Code-Scanner / OCR Reader
11.10.2.1. Find Line
Objective
Detect an edge.
Procedure
First of all, activate the function in the toolbar. After the tool Find Line has been acti-
vated, a line can be defined. The first click specifies the starting point, and the second
click the end point of the sought after line.
Search rays are generated perpendicular to this line. In accordance with the selected
settings for edge polarity, find by and edge width, as well as positive and negative
gradient threshold, an edge is searched for on each of these search rays (see section
11.4.3.1). These detected edges form a scatter plot through which only a single line
is drawn, for which the clearance to the scatter plot is as small as possible. Individual
points may be detected as outliers and ignored during the next iteration step (renewed
best-fit calculation). This best-fit calculation is executed as many times as selected
under fitting iterations.
Property
The following settings/results are displayed:
Edge Polarity Expected Brightness Characteristics
Either
Both bright to dark and dark to bright transi-
tions are searched for.
Bright to Dark
Only bright to dark transitions are searched
for.
Dark to Bright
Only dark to bright transitions are searched
for.
Find by This parameter can be used to specify which of the detected edges
will be used on the search line.
Best Score
If several edge transitions are detected on the
search line, the transition with the greatest con-
trast is selected.
First Score
If several edge transitions are detected on the
search line, the first transition in the search direc-
tion is selected.
Last Score
If several edge transitions are detected on the
search line, the last transition in the search direc-
tion is selected.
Edge Width
(px)
The setting Edge Width controls the sensitivity of brightness chang-
es.
Note:
• An Edge Width of 3 pixels represents the highest sensitivity in con-
trast in the image.
• An Edge Width of 9 pixels smoothes the gray profile to ignore the
noise.