Editing Scanning electron microscope (section)

===3D SEM reconstruction from a stereo pair===
* [[photogrammetry]] is the most metrologically accurate method to bring the third dimension to SEM images.<ref name="Mignot-2018"/> Contrary to photometric methods (next paragraph), photogrammetry calculates absolute heights using [[triangulation (computer vision)|triangulation]] methods. The drawbacks are that it works only if there is a minimum texture, and it requires two images to be acquired from two different angles, which implies the use of a tilt stage. ([[Photogrammetry]] is a software operation that calculates the shift (or "disparity") for each pixel, between the left image and the right image of the same pair. Such disparity reflects the local height).

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File:SEM Stereo Pair.jpg|An SEM stereo pair of [[microfossils]] of less than 1&nbsp;mm in size ([[Ostracoda]]) produced by tilting along the longitudinal axis
File:SEM Stereo pair of micro-fossil (Juxilyocypris schwarzbachi Ostracoda).gif|From this pair of SEM images, the third dimension has been reconstructed by photogrammetry (using [[MountainsMap|MountainsSEM]] software, see next image); then a series of 3D representations with different angles have been made and assembled into a GIF file to produce this animation.
File:3D surface reconstruction from 2 scanning electron microscope images.gif|3D surface reconstruction of a (Ra = 3&nbsp;μm) [[Surface roughness|roughness]] calibration sample (as used to calibrate profilometers), from 2 scanning electron microscope images tilted by 15° (top left). The calculation of the 3D model (bottom right) takes about 1.5 second<ref>Stereo SEM reconstruction using MountainsMap SEM version 7.4 on i7 2600 CPU at 3.4 GHz</ref> and the error on the Ra roughness value calculated is less than 0.5%.
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