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Topics - Tyler J

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Face and Body Scanning / Canon 600D/1100D or other?
« on: May 27, 2015, 12:28:04 PM »

I want to experiment with DSLR.
I can get a 1100D for 220€ or a 600D for 350€ both with a 15-58 lens.

Should I invest in the 600D or the mesh/texture gain would be very little?
Do you know a better DSLR (500€ naked max).


Face and Body Scanning / Best depth filtering for human heads?
« on: April 28, 2015, 12:37:01 AM »

I'm experimenting with depth filtering, however trying various combination will take 2 weeks.
I'm working with 21 picture, only the face.

Is there a depth filtering that always suits human heads? or is it pictures quality dependant?

Experimenting with :

no alignment optimisation
   no removal of bad sparse point
   removal of bad sparse point
      medium dense cloud
      high dense cloud
      very high dense cloud
         agressive depth filtering
         mild depth filtering
         moderate depth filtering
         depth filtering disabled

Done so far
no alignment optimisation
removal of bad sparse point
very high agressive dense cloud
high mesh

comparaison will come

each step take me one day or more


Face and Body Scanning / Mask unfocused area?
« on: July 01, 2014, 03:35:19 PM »

I I have XXX pictures of a face, and sometimes some part are out of focus,
example, side pictures right eye in focus, left eye unfocused.

Would I get better result by masking the lef eye?



I have 21 Coolpix L27 and 9 times out of 10 I have 2 of them (never the same) which
are out of focus.
2 of them are focusing on the the cameras which are behing the subject.

This can be solved by doing 10 scan and 1 of them should be OK.
The user guide say that the camera focus on the center of the image, here it's clearly focused on a corner.


recently I made a 3d face scanner based on 21 point and shoot cameras.
21 coolpix l27, this was a bad choice, I did not know that low end cameras
did not allow settings such as ISO or shutter speed to be set.
Canon camera would have allowed it through firmware hacking and unfortunatly
there is no community based around nikkon point and shoot camera firmware hacking.

I modified the cameras so they could be triggered and made my own power adapters.

That being said, I'm having good result using the "auto" mode force to macro
which in the end always uses the macro scene.
In this mode the white balance can be set, i've set it to "flash" as I'm using cool white lighting.
however shutter speed and ISO is choosen by the camera. I lowered the exposure to -0.7
and each camera takes a shot with a 1/25 shutter speed and and ISO value betwen 80 and 120.

lowering exposure to -2 ensure an ISO of 80 but the lighting required to get a good picture
will hurt the eyes of the subject (lighting is constant)

pictures are being taken in the dark, only the lighting of the scanner is present,
it's composed of 7 30cm cool white led strip with transparent paper to diffuse the light.
CRI seems to be good enought, however I can see reflection on the subjects (is this a problem?)

Here is the scanner, heigh can be set and distance from the head too.

Here is my problem, subject1 is "perfectly" modelized, I can only align half of the pictures
for subject 2 so I get half a face.

subject 1

subject 2

Why this difference? here is a link for the hi-res pictures of subject 2 :
dropbox link
As you can see 19 of them are sharp, 2 of them are not focused on the face (one is focused on it's shirt, one on it's hairs)
removing the 2 bad pictures does the same thing, only half of the face is aligned.

what do you think about the orientation?
Vertical may be a bad solution, at first I tought that by maximizing the
face area in the pictures would generate more data.

But in the end only 1 third of the face is in focus.

by putting them horizontally I get only a piece of the face but it's all in focus.

Any idea why?


Ps : if someone here has a service manual please PM me :D I'd love to make a board capable of intercepting communication from the microcontroller in order to set ISO and shutter speed.

General / Is there a minimum resolution for photoscan?
« on: April 28, 2014, 11:02:07 AM »

I trie to do a webcam based scan it did not match anything.
After I downsized with paint a set of photos taken with regular cameras to
2Mpix and it did not match any of them.

At their standard size (18Mpix) there is no problem.

So I was wondering, is there a minimum resolution for photoscan?


General / Rig calibration.
« on: January 30, 2014, 12:27:21 PM »

let's say I have a 30 sphere camera rig.
can I photograph a sphere like this to get good alignment.

[see attachment]

Then replace the detected camera one by one by pictures of the actual object I want to scan?
(Since the cameras are not moving)

General / should I see the whole object with all camera? can I zoom?
« on: January 28, 2014, 12:07:42 PM »

In case of a head scan, with 30 camera for example.
Should the whole head be visible on all the pictures or can I zoom and take only a part to maximise information about the head?
Since a lot of pictures will overlap.

Can I zoom? and by that I mean, can I have a different level of zoom on each camera or should it be the same for all of them?


General / Head scan, lightning and best position.
« on: January 25, 2014, 06:38:27 PM »

Recently I did some experimentation with a Coolpix L27, taking 21 pictures, and a silicone mask stuffed with t-shirts.
Contrary to my belief I got some very good result :

Moving to live humans I plan to get 30 of them however I do not have a lightning system yet.
Since I have little to no knowledge of photography I don't want to buy stuff that won't be of use.

My main idea is to use 30 3W warm white LED, one on each camera (light intensity will be adjustable).
warm white can be corrected with the white balance and it's cheaper than natural light led.
but since I'm making a sphere around the head each camera will "see" 15 leds, woudn't this make a bad pictures?

How could I evenly light a human head?

also would it help to make a 15 stereo pair camera sphere rather than a 30 camera sphere.

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