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Author Topic: Face scanning and macro  (Read 5931 times)

Mfranquelo

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Face scanning and macro
« on: December 03, 2013, 01:40:36 PM »
I have some questions regarding to face scanning id love to discuss / share some thoughts about this with all of you:

- Ive recently made a first prototype with good scanning results, however it is too big at the moment. (it is a semi circular frame of 80 cm radius) with 6 cameras mounted onto it.
This is the source of my problem, i need this system to be smaller. So here go all my questions:

1. At the moment the cameras are positioned at 80cm from the subject so i get "proper" DOF (its around 17cm) lenses are 50mm prime. f13. Im using continuos light using high luminance fluorescents.

2. Since i need this system to be smaller, (like 50 cm radius for example) DOF will of course decrease.
I can probably stop down to f20 but difraction will blur my entire scan producing a low amount of matching points -> more noise.

3. 50mm lens allows me to focus at a minimun distance of 45cm so 50cm is OK, however this is not the main issue.

4. Ive calculated 80cm (which is the radius of this prototype) it is so to fill the frame of the sensor.
If i build a new one at 50cm the face will fill too much of the face leaving un-scanned parts. So i may have to change to 35mm lens.

5. The main problem i see here is the DOF, does anybody have experience / thoughts / ideas scanning with macro photography ? How could i overcome DOF ?

* Maybe playing with cameras focusing different parts of the face ?
* Maybe increasing the number of cameras focused at different / overlaping parts of the face ?

- Ill post a very quick preview of the 3d render i did before the prototype so you can understand better what im saying:

All ideas or thoughts are welcome!

Manuel Franquelo.






maddin

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Re: Face scanning and macro
« Reply #1 on: December 03, 2013, 02:49:10 PM »
A question and a comment:

- What cameras are you using?

- Keep in mind that faces distort a little when people lie down; nut sure you want that?

Martin

Mfranquelo

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Re: Face scanning and macro
« Reply #2 on: December 03, 2013, 06:39:10 PM »
Im using Canon 700d (i didn?t buy canon 600d because they have less FPS / time between shutters is larger)

- Thats not a problem as of now. However i understand what you mean.