Rockwell Automation 5370-CVIM2 Module - Manual (Page 327)

5 Chapter Chapter 7
Inspection Tools
7–89
Quad
A quad “shape” image tool consists of two separate windows: a quadrilateral
AOI, and a rectangular “destination.” The quad AOI provides a means of
reshaping the contents of the original image.
The image appearing in the quadrilateral AOI is transformed according to the
shape of the AOI and the aspect ratio of the destination. Each point in the
AOI is “mapped” into a corresponding point in the destination. The quad
image tool can be used to rotate an image, rescale an image (make larger or
smaller), or change the aspect ratio.
Figure 7.72 illustrates this concept by using the image of a square grid where
the image plane is not perpendicular to the camera. The resulting grid is
trapezoidal, and the AOI is positioned around the grid.
The squared destination shows the resulting “quad” image.
Figure 7.72 Example: Image Tool With Quad “Shape”
AOI
Destination
The effect of the quad image tool, in this example, is to stretch the upper part
of the original image horizontally, but not the bottom part. Note that the grid
lines are essentially at right angles, but the bottom “squares” of the grid are
slightly higher than the top squares because the quad shape does not
compensate for perspective distortion.