Image Acquisitionand Proces

Displaying Images 83
FIGURE 4.37 Vision window tools palette — multiple tools demonstration.
Polygon (Tool 5): The example above includes a demonstration of the polygon
tool — the n-sided polygon begins with a left mouse click, and each
subsequent side is deÞned by the next mouse click. The polygon is then
closed to the Þrst point with a double click.
Free (Tool 6): As its name suggests, this tool allows the user to draw a
freehand ßat-sided region in the image. The Þrst point is deÞned by left
clicking, as are subsequent vertices. Double clicking will close the ROI.
Annulus (Tool 7): An annulus is the area between two concentric sliced
circles. This tool is useful when analyzing parts like spanners, and terminal
clamps. The two circles are initially created with a left click drag (Þrst click
deÞnes the center of the circles, and the second deÞnes the radius of the
outer circle), and then the slice and radius of the inner circle is deÞned by
dragging the appropriate ROI handles.
Zoom and Pan (Tools 8 and 9): These tools allow the user to manipulate
the way an image is displayed, by either magnifying a portion of the image,
to moving within the image. Zoom and pan are very useful when the user
needs to observe small areas of a large image, zooming in and then moving
the viewable area to adjacent areas.
Broken and Free-Hand Lines (Tools 10 and 11): As you can see from
Figure 4.38, broken and free lines allow the user a free way of deÞning
open and closed ROIs. The broken line creates a line as the user draws
(click and drag to create the region), which is useful to trace features in
the image, whereas the free line joins the last point deÞned with the Þrst,
creating a closed region.
Rotated Rectangle (Tool 12): The rotated rectangle tool is very useful when
a rectangular ROI is required, but the part’s acquired image is not exactly
aligned with the coordinate system of the image acquisition system. The
user can Þrst draw the rectangle, and then rotate it by moving one of the
ROI’s rotation handles.