sample 58
tree bark, anisotropic
from what kind of tree? i don't know!

it's a reasonably flat piece but not completely flat, as is 
visible in the images. I nailed it to the wooden holder but the 
nails were visible so i hid the nails with 2 small pieces of 
tree bark. Puzzle for Kristin: can you see where? I don't think you can. 

aperture: 1 tick before 4
zoom: maximum
parameters: z=330 p=19 l=175
roll angles: 90 0

because the bark is not flat there is a gap between the grid 
and the sample of 5 or 6 mm in the middle and lower row. Upper 
row is not usable. This also made setting the parameters a bit 
of a guess, but i tried to correct for this gap (although at 
other parts of the sample the chosen values are not correct of 
course)

didn't grab millimeter paper, would be white

the bark is not vertically centered on the holder, i center on 
the holder by zooming out.

By looking at the images i noticed that what you see at high 
angles is bark oriented towards the camera, so not the flat 
part. These images may not be as useful as other sets, we have 
to keep that in mind. They show the structure of tree bark very 
nicely though.

THIS IS ABOUT SAMPLE 56

the harddisk that i stored these images on was indeed not 
errorfree. Two files 56b01-50.bmp and cca56-4.bmp were not 
backed up on tape 13a but i was able to recover them and they 
are included on tape 13b (though in the data directory and not 
in the data\sample56 directory. I also kept copies of these 
files on the fixed hard disk. the validation datat for these 
two files is 2695-3bea and 83ec-2b44 (not included in 
sample56.val).

the hard-disk with errors will no longer be used.

I also noticed that the validation data for sample 0, 1 and 2 
is missing (we didn't do that at that time) and for sample 23, 
24 and 25 it went wrong (runned the program on the wrong 
hard-disk, files are empty). Also forgot to copy logfiles 53 
and 54, have to retrieve those from tape (although i have 53 
because i mailed it to Kristin).