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Messages - andy_s

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1
Thanks for this Michael  (oops, Richard) - the body scanning forum does seem to have become rather silent over the last number of years.

Your system is both interesting & very innovative.

2
Face and Body Scanning / Re: Ready made solutions for full body 3D
« on: December 04, 2014, 12:21:55 AM »
That's very impressive solution for cost comparison.

Agree.

It's great to see someone innovating in this field.

Absolutely.

3
Face and Body Scanning / Tether software usage
« on: October 07, 2014, 01:28:50 PM »
A query to those folk using DSLR tether software & studio flash...I just read these posts on the canon point&shoot chdk hack forum (we know those cameras all / mostly have large DOF):

http://chdk.setepontos.com/index.php?topic=11667.msg114638#msg114638
"Clearly querying / manipulating single cams is something that should be improved, and should tied in with permanent serialnumber based camera identification. It shouldn't be terribly hard to make mc:cmd etc operate on a subset of available cameras."

http://chdk.setepontos.com/index.php?topic=11667.msg114642#msg114642
"I will keep your example scripts in mind , in case , specific subnet of cameras should be setup with certain focus/zoom/etc values although i feel the same with what you said..it will be a bit tedious to do so.Lets hope it won't be needed."

Question(s):
If your DSLR's had point&shoot DOF, in what way would you use your tether software? i.e
(i) what settings would you adjust, via tether software, globally (on all cameras)
(ii)  assuming DSLR "on camera" adjustment was not available, what settings would you adjust on individual cameras, by tether software, if "selectable single camera" liveview was available on tether PC monitor ?

4
Python Scripting / Re: Example code for full processin chain
« on: January 23, 2014, 12:40:20 PM »
Yes jmsuomal,

thanks a lot for posting this.

5
Face and Body Scanning / Battery Temperature Terminal as shutter remote
« on: January 19, 2014, 04:40:20 AM »
For those who may be interested in a multi-cam chdk based solution this is interesting:

http://chdk.setepontos.com/index.php?topic=10385.msg109057#msg109057

6
Face and Body Scanning / Re: Face scanner - Prototype
« on: December 16, 2013, 02:29:52 PM »
Thanks Manuel - looking forward to more results.

7
General / Re: Compact Canon CDHK RAW & Lens Distortion
« on: December 16, 2013, 01:43:54 PM »
...then connect the hub to the PC to retrieve images (via Windows Picture Import). This is nice because you can then tag the images to a specific camera number.

I hope to develop a file/directory download interface that is very flexible [including tagging image to the specific camera and maybe directory = customer_number].

Might someone further comment:

why is it nice to relate image to camera ? [is it useful in automation with python for example ?]

fmi:

8
Face and Body Scanning / Re: Face scanner - Prototype
« on: December 15, 2013, 08:30:08 PM »
- Flashes are Yongnuo 560 iii

Hi Mfranquelo, thanks for sharing this - very interesting.

I hadn't really considered this type of flash before - but my memory is that light production period is around 40 ┬Ásec ?

Might you describe how you synchronise them ?
What sort of calculation did you do to decide on quantity ?


Does anybody know if the Yongnuo fit the spiffy gear projector [previously posted somewhere on the forum as http://www.the-digital-picture.com/Reviews/Spiffy-Gear-Light-Blaster.aspx] ?

Does anybody have an idea [to share] how many spiffy's might be needed for whole body capture?

Apologies for vagueness [lazy Sunday post]

9
Face and Body Scanning / Re: Full Body Scanner / aligning of photos
« on: December 11, 2013, 10:03:50 PM »
.... its an early idea, have no time to investigate further will keep you updated

Good stuff Andreas...keep at it  8)

10
Face and Body Scanning / Re: Full Body Scanner / aligning of photos
« on: December 11, 2013, 04:02:55 AM »
... I also thought about an alternative solution to the more expensive 600D's, would be good to compare he two systems...

Hi Andreas,

I [finally :o)] just started some chdk / chdkptp development  see http://chdk.setepontos.com/index.php?topic=6231.msg107865#msg107865 - the shutter release period does seem to be stochastic though so dark[ish] room and long exposure seem likely.

Interested if you might share some further thought on the alternative you mention.

11
Face and Body Scanning / Re: can i use it for people?
« on: October 26, 2013, 12:53:14 PM »
Congratulations Andreas - and the website looks very good !

12
General / Re: What cameras/lenses are preferable for photoscan?
« on: October 15, 2013, 12:52:26 PM »
Found something... I'm not sure if the diaphragm column refers specifically to having a real aperture... But i guess it's a start

http://chdk.wikia.com/wiki/CameraFeatureTable

SX160IS has Manual Focus and aperture

http://chdk.setepontos.com/index.php?topic=9443.msg102555#msg102555

Quote from: reyalp on 06 / July / 2013, 22:37:08
One exception: If the camera has an MF mode, set_focus() should take immediate effect.


That's good to know.  I'll try using my sucky method for setting the focus, but if it get's too frustrating, I'll buy a couple of cameras with support for manual focusing.  The SX150/160 are pretty cheap these days.

[not yet sure about external power]

13
General / Re: What cameras/lenses are preferable for photoscan?
« on: October 14, 2013, 03:12:44 PM »
Hi ikercito, it seems [to me] that you are not talking nonsense.

While this discussion http://www.agisoft.ru/forum/index.php?topic=330.0 didn't end in a particlularly logical conclusion:

"the thesis of the paper is to throw everything [including the kitchen sink] at it"

some comment there may be worth re-visiting.


Also, here's something to be aware of ?

as i'm sure you know http://downloads.agisoft.ru/pdf/photoscan-pro_0_9_0_en.pdf @ page 6:

"...To estimate the field of view for each photo PhotoScan uses the information saved in the EXIF part of each picture. If EXIF data are available you can expect to get the best possible 3D reconstruction. However 3D scene can also be reconstructed in the absence of EXIF data. In this case PhotoScan assumes that the 35mm focal length equivalent equals to 50 mm and tries to align the photos in accordance with this assumption. If the correct focal length value differs significantly from 50 mm, the alignment can give incorrect results or even fail"


http://chdk.setepontos.com/index.php?topic=8613.msg90258#msg90258:

"The EXIF (Tv Av ISO) is not completely accurate in any of these, especially ISO // it's really off sometimes.  For example, I've noticed that if I give shoot -sv=100, the EXIF ISO is 164 and the image is indeed brighter that pressing SHOOT with Canon set to 100.  So there's something weird here too."

"ISO difference is probably "real" vs "market", which I explained at least once before. 100 real -> 164 market is a pretty typical delta. For other parameters, some minor variation between Canon display values and actual values is expected. E.g what displays as 1/125th could really be ~1/128th etc and different values could show up in different places."



PS That whole [long] chdk thread is fascinating - a condensed "War and Peace" e.g the chdk developer in chief says, at one point, in http://chdk.setepontos.com/index.php?topic=8613.msg90969#msg90969:

"I *like* CHDK. I've spent a lot of time on it. It's pretty cool. It would be cool if it's useful for your instrument. All that said, I know the quality of the code, I know much of it was contributed by people with limited programming experience, I know all the crazy unsafe things it does under the hood, and I know that what passes for "QA" is mostly people who don't really know how it's supposed to work trying random stuff on a tiny subset of the supported hardware."

 :-\  :)
 


Edit:
http://chdk.setepontos.com/index.php?topic=9443.msg97933#msg97933:

Placeholder
"Comparing the EXIF data in the JPG and DNG images, I see that the Focal Length is sometimes incorrect in the DNG files.  For example, I took five shots at various zoom levels (from lowest to highest), and I got the following focal lengths recorded in the JPG and DNG files respectively: (5.0, 6.9, 10.7,  24.0, 40.0) and (5.0, 6.9, 10.7, 13.4, 13.4).  The label on the camera states that the focal length goes from 5.0 to 40.0.  I have no idea if this problem is specific to the A4000, or if it is a problem with CHDK in general."

http://chdk.setepontos.com/index.php?topic=8585.msg89924#msg89924:

"...The effect of CHDK overrides on EXIF values isn't very reliable, and varies between cameras and probably camera settings...In some cases, CHDK overrides do not update the regular EXIF, but do update the Canon "maker note" fields..."




Edit:
http://www.agisoft.ru/forum/index.php?topic=330.msg5193#msg5193:

"...The bigger the distance between stereo-pairs, then better the results. With a short basis between pictures the angel for triangulation is small what causes errors(In object direction). I was always using all pictures because I was sure that photoscan is using more Stereo-pairs to estimate one point..."

http://www.agisoft.ru/forum/index.php?topic=330.msg5395#msg5395:

"...Yes, this is generally true, but only to a certain extent. If the distance (viewing angle) between images becomes too large, new problems will appear, mainly related to increasing difficulties of matching features because (a) the changes are too large between images and (b) low incidence angles (i.e. grazing view of objects). In essence, image distance should be neither to small nor too large."

http://www.agisoft.ru/forum/index.php?topic=330.msg5421#msg5421:

"For multiple stereo models, small such measurements can be useful for the validation of measurements with strong intersection geometry. Even though small intersection angles lead to noisy results, models with small base lines should be acquired and used within the surface reconstruction. Since large baseline models have lower image similarity - which is challenging for the matching method, small baseline models are required additionally. Furthermore, highly overlapping imagery leads to high redundancy, which is beneficial for the precision in object space."

14
General / Re: What cameras/lenses are preferable for photoscan?
« on: October 13, 2013, 11:46:06 AM »
Hi Chad - thanks for the battery link...

Edit: this also for remote camera turn on/off http://chdk.setepontos.com/index.php?topic=9271.msg98552#msg98552

"You solder two wires to the power switch or view pictures button and attach them to the relay.
Once this is done you can flick the relay on and off to replicate pressing the button."


In more detail ['Camera 2' description]:

http://www.antthomas.co.uk/webcam/guide.php

15
General / Re: What cameras/lenses are preferable for photoscan?
« on: October 12, 2013, 06:54:50 PM »
Well... Lee is the absolute master in this area, his tips are always words of wisdom.

Not necessarily http://www.agisoft.ru/forum/index.php?topic=1411.msg7106#msg7106 - but I see you posted there already  ;)

Enjoy the rest of the weekend,

Andy.

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