Workflow
--------

3D scans:

- save foo.pix and foo.stl (as text)
- copy foo.* from lab:~/scan to ws:/home/n9/scans
- visualize foo.stl with MeshLab and generate snapshot
- crop snapshot00.png with gimp and save as foo.png
- ./bz foo
- git commit

Pictures:

- take picture
- run gimp
- rotate, crop, contrast-correct (Colors > Curves)
- scale to 50% (Image > Scale Image)
- add Image > Image Properties > Comment "From IMG_nnnn"
- File > Export As foo.jpg
- mv foo.jpg pics/large/
- ./smallpics
- git commit


Correcting for the shape of the scanning needle
-----------------------------------------------

Needle shape:
- tip diameter: 80 um
- cone length: ~ 7 mm
- cone diameter: 1 mm

Correction for needle shape at an edge (vertical drop):

z' = measured depth (larger values are deeper)
z = real depth
x = distance from edge
r = cone diameter / 2
d = cone diameter
a = (d - tip diameter) / cone length / 2 = 0.066

x < 0:		z' = z
x < 0 < r:	z' = z + r - sqrt(r^2 - x^2)
x > r:		z' = z + r + (x - r) / a
x > d / 2:	not applicable

In gnuplot syntax:

a=.92/7/2
plot x < 0 ? 0 : x < r ? r-sqrt(r*r-x*x) : r+(x-r)/a