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Author Topic: Smooth skin issues and results  (Read 2436 times)

viper_0711

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Smooth skin issues and results
« on: November 09, 2013, 08:08:42 PM »
Hi,

see anyone have some insights or similar experience:

i have been scanning a couple of friends' face as test, using my 12 canon rig with a fixed setup of a few 600W flash and f11, iso100. 1/125sec shutter, with cross-polarization setup.

after a few test, im quite convinced that people with smoother skin to less smooth skin/larger pores results in HUGE quality differences:
(not any racial discussion, purely experimental findings) my samples includes Caucasian and Chinese men and girls(without make-up), each group of above contains 2-3 person as samples.
results shows quite clearly that Caucasian men group always produces the highest quality even if i try higher ISO, dimmer flash lights. whereas Caucasian girls (usually with smoother skin than men) producer nosier quality. and Chinese man produces an obviously even noiser result, while chinese young girls produces worst very noisy results. An exception is if i scan a chinese elderly, which producer really nice details with least noise.

reading and trying myself about how Pscan works, i thin kit definitely has to do with different level of skin contrast/ pattern clarity, etc.

i must say visually the causian men scans can withstand full screen head with pleasant looking detail/low noise, while the chinese girls i have to zoom out up to only 1/3 of screen in order to have same "visual quality". such a huge difference.

Then i tried projecting noise pattern (which i need to use lower ISO and wider aperature, slower shutter, sacrifice texture, not ideal), results:
the already high quality Caucasian men scans do not gain significant higher quality results, while others gain increasing level of detail/lower noise, from cauasian girl < chinese men < chinese girls. the latter ones gain huge quality difference and catch up with the caucasian men scans. and this results catch up with the above flash only quality.

but there comes another frustration of acquiring usable texture...

this frustrates me, because i wish to test scan friends of different nationality. While my caucasian men friends are all good without projection noise, others are suffer lower quality, especially chinese groups scans are unacceptable quality without projection.

I tried splitted scan (but i have to manually switch off the flash at the time of projection, and change settings from smartshooter to send to the 12 cameras. this manual work takes me at least 3 seconds , and i suppose this is totally not ideal to ask the subject ot stay still for 3 seconds or above to introduce movement.

i have read this thread repeatedly :
http://www.agisoft.ru/forum/index.php?topic=1324.0
and yet i cant find an ideal way...

any advises?

thanks