# Finding Corners

VisionPro defines a corner as the intersection of two line segments. To use a Find Corner tool, you must know the approximate location of the line segments that define the corner you wish to find in the image. You specify the number of calipers to use, the same number for both line segments, and the tool then distributes the calipers along the expected line segments. The expected lines you specify should be close to the actual lines you wish to find in the image.

You also specify the geometry and run-time parameters that are used by all the calipers of both line segments. The Find Corner tool spaces the calipers evenly along both of the expected line segments you supply. You can use only one of the two line segments to specify these parameters. You can specify only the position of the other line segment.

The same parameter setting considerations apply to the line segments of the finding corners as to that of Finding Lines.The following figure shows the edge points found after the tool runs calipers on an image:

The found edge points are then applied to the Fit Line tool which fits two infinite length lines to the two set of points and the corner they define:

The infinite length lines shown in the previous figure are shortened to line segments using projections of the expected lines. The projections of the lines are performed the same way as in the case of the Find Line tool. The following figure shows the found line segments and the corner.