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About the Matching Cursors
For each cursor you place on the left image during stereo measurement,
the system places a matching cursor on the right image for use in
triangulation.
You must place each left cursor on an image point (a pixel) that has
sufficient surrounding detail to differentiate it from its neighboring
pixels. If the neighboring pixels look the same as the point you choose —
especially the pixels to the point’s left and right, for example, pixels along
a smooth horizontal line — the system cannot accurately place the
matching cursor. When there is enough differentiating detail, the “match
strength” is high (meaning that the generated match point clearly
matches better than its neighboring pixels — the system’s confidence in
the match is high). But if there is not enough detail, the match strength is
low (meaning that the generated point and its neighboring pixels match
almost equally well — the match may be correct, but the system’s
confidence in the match is low).
For every matching cursor, the system calculates a match strength
value between <0> (lowest confidence) and <5> (highest confidence).
If too little detail is present, the system simply does not generate a
matching cursor. Whenever possible, try to achieve a match strength
of at least <3>. If you cannot achieve this level, try capturing another
image with less glare or more image details. (Adjust the tip orientation
or image brightness.)
Even when match strength is <5>, and especially when the match
strength is lower, you need to verify that the matching cursor appears
to be placed properly. A matching cursor that is off by just one pixel can
significantly impact measurement accuracy.
Repositioning a Matching Cursor
Note:
Misplaced matching cursors most likely occur when the
measurement area contains a repeating pattern. Generally, the best
results are achieved by leaving the matching cursors exactly where
the system places them.
Move the matching cursor to the correct position.
When you stop moving the cursor, the system optimizes the match
position. Each manually corrected matching cursor is indicated by the
absence of a match strength number.
