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Article ID: NBR1210 — Created: 25 May 2018 — Reviewed: 13 Jul 2018
I frequently start my uScope, load a slide, and browse to a point of interest. Several minutes later, I return to the uScope to discover that the image has moved from the position I left it. Is this normal operation?
Some image movement is to be expected as the uScope warms up. Thermal expansion occurs when the internal components expand as the unit gets up to temperature. It is most often observed in the first 30 minutes after the uScope is powered on. You should not observe this effect after the unit has been powered on for 30 minutes or more.
The amount of thermal expansion depends on how cold the unit was when the specimen was positioned under the objective. In typical office environments, thermal expansion is approximately 20 microns (about one-fifth the thickness of a sheet of paper). This is about 40 pixels with a 20x objective, 80 pixels at 40x, and 120 pixels at 60x.
This kind of thermal expansion should not affect stitching scanned images.
Extremely cold starting temperatures will have a more pronounced effect on thermal expansion and, therefore, image displacement.