Rockwell Automation 5370-CVIM2 Module - Manual (Page 171)

Chapter 6
Reference Tools
6–12
Filter Function
The filter function is active only when the binary gaging mode is selected. It
is described in Chapter 8, Threshold, Filters, and Morphology, under the
Binary Filter heading.
Line Width Selection
The Gage Width selection menu provides five preset line widths, as shown
in Figure 6.10. The default line width selection is “1.”
Figure 6.10 The Line Width Selection Menu
The “width” of the reference line axis is stated in pixels; thus, for example,
an X–axis reference line 150 pixels long will be eight pixels wide if “8” is
selected. (The line’s appearance on the screen, however, does not change
with different width selections: It always appears as a single–width line.)
When a width of “1” is selected, the pixels along the length of the reference
line axis are evaluated only according to the threshold and filter settings, for
a binary axis, or the kernel and threshold settings, for a gray scale axis.
When a width of “2” or more is selected, the pixels across the width of the
axis (at each point on the axis) are averaged first, after which the average
value is evaluated according to the threshold or threshold/filter settings as
described above.
The averaging works like this: At each point along a reference line axis, the
brightness values (from 0 to 255) of all pixels across the width of the axis are
summed, then divided by the width. For example, if you selected a width of
8, and the pixels across the width at one point along the axis were 145, 148,
150, 156, 167, 164, 172, and 170, the sum (1272) divided by 8 equals 159,
the average brightness value across the axis at that point. The value “159” is
then evaluated according to the threshold and filter settings. In this example,
if a binary threshold were set to 160, the average brightness value would be
on the low side of the threshold even though several of the pixels at that point
across the axis were higher than 160.