Instruction
Manual
SCS1
Series
149
Dividing per three these values and placing them on one single line we will obtain the projection of the
area:
68 73 78 84 96 114
125
133
133
135
The projection consists practically in obtaining an average of the brightness values of an area and
listing them on a line. More image information is thus obtained, respect to considering only the pixels
and a more accurate analysis can be made.
The area is represented as an arrow (and so determining the projection direction) of a specific length
(corresponding to the number of columns) associated to a specific width (number of lines).
When all values are listed along the line, the average intensity flow profile is obtained and the edges
can be tracked.
What is an Edge
:
a variation of the brightness between adjacent pixels, that presents higher values
respect to a specific threshold.
Two different edge types can be found: one due to the transition from a white to a black pixels
(negative edge) and one due to the transition from a black to a white pixel (positive edge).
The following paragraphs offer two different criteria to track and edge and determine the position.
12.7.1.
Threshold detection
The first point is detected following the intensity profile along a specific direction and the intensity
value varies. The point detected will track the edge and its position.
This method is simple and fast but it is very dependent on the lighting used and thus must be
avoided in presence of non-constant lighting, while representing an advantage with back light
sources.
Negative
edge
Positive
edge
Direction
Intensity
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Phone: 800.894.0412 - Fax: 888.723.4773 - Web: www.clrwtr.com - Email: [email protected]
Phone: 800.894.0412 - Fax: 888.723.4773 - Web: www.clrwtr.com - Email: [email protected]
Phone: 800.894.0412 - Fax: 888.723.4773 - Web: www.clrwtr.com - Email: [email protected]
