Stereo Measurements - GE Mentor Visual iQ User Manual

Stereo Measurements

Stereo measurements require the use of StereoProbe measurement tips to capture
stereoscopic images of a target — two pictures of the same target from two different
angles. To measure the target, the Visual iQ uses triangulation based on these two
side-by-side images. You can take stereo measurements on a frozen image or on a
recalled image, provided the recalled image was acquired with a StereoProbe. The
Stereo Measurement process includes (see following sections for details):
Step 1 – Attaching a calibrated Stereo Tip
Step 2 – Capturing an acceptable view with a suitable Stereo Index.
Step 3 – Identifying the attached optical tip, selecting desired measurement type and
placing measurement cursors.
Step 4 – Properly positioning the Matching Cursors
Achieving a Suitable Image for Making Stereo Measurements
For maximum accuracy in any type of stereo measurement, you must begin by
positioning the stereo tip carefully. To position the probe tip (before freezing) for a
Stereo Measurement Image:
Visibility—The feature must be fully visible on both sides of the screen.
Tip-to-target proximity—The tip must be as close as possible to the target while
keeping it in focus.
Minimal glare—Minimize glare by adjusting the viewing angle and the image
brightness in the areas where you will be placing cursors. Small glare speckles do not
present a problem, but larger glare areas may appear in different positions on the
two sides, causing false matches.
Vertical orientation—If measuring distance between lines or across a circle, the
image is oriented so that you can place cursors at left and right edges of the
item to be measured — not at top, bottom or diagonal points. The system needs
differentiated details to the left and right of each cursor to accurately place the
matching cursors in horizontal relationship to the left-side cursors.
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The images above represent good and bad image capturing techniques when
stereo measurements will be made. Both images were captured for length
measurement across the slot.
About the Stereo Index
The stereo index is a number that indicates the amount of magnification during stereo
measurements. The higher the stereo index, the greater the magnification, the more
accurately you can place the measurement cursors and the more accurate your results.
When taking stereo measurements, you magnify the image not by zooming but by
moving the optical tip as close as you can to the target. The stereo index can be turned
ON or OFF and the minimum value (below which it flashes) can be altered.
learn about adjusting the Stereo Index Limit and other Measurement Settings.
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07/30/2014