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Topics - Andrew

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1
Python Scripting / Python scripts collection?
« on: April 13, 2014, 09:30:33 PM »
I use Photoscan Standard edition - looking at feature list (considering my needs) I just couldn't find justification for upgrade. When looking at "Python scripting support" line I assumed it meant basically a more advanced and open alternative to "Batch Process" feature, but every now and then I read it can do lots more, hence my question: are any useful scripts included in Pro demo installation package? Or maybe there is some repository of useful scripts available? Or at least a list of what some more advanced scripts can accomplish? I think more insight into this can help push me and many other over the edge to upgrade.

-Andrew

2
General / Accuracy of masking from low/med quality model
« on: March 31, 2014, 01:14:36 PM »
I read recommendations of masking photos from model on more than one occasion on this forum, but whenever I tried the workflow (align unmasked photos first, build low/med quality mesh and use it to generate masks for photos), there would be enough imprecisions in the mask to scare me away from using this feature. Mask encompassing some of the background is not the end of the world, but often mask would clip tip of the nose, or edge of ears etc.

And so, my questions are:

- where do these imprecisions in masking from model come from? Could it be that masks are generated for undistorted photos but the resulting mask is displayed over original photo that still carries optical distortions? In this case, mask could actually be perfect even if it appears to be off.

- does Photoscan respect photo masks down to pixel precision? Or is there some threshold that causes PS to scan for points even if they fall just slightly behind mask edge?

Cheers,
Andrew



3
Hopefully you guys find it interesting what we're cooking up here using Photoscan. Some interactive scan samples included in the article.

http://www.theastronauts.com/2014/03/visual-revolution-vanishing-ethan-carter/

Cheers,
Andrew

4
Feature Requests / Adding new photos to existing chunk
« on: December 01, 2013, 03:05:36 PM »
Adding new photos and aligning them to already existing aligned chunk does not seem to work, could that be made possible?

Every now and then, after grabbing photos and aligning them in Photoscan I realize I didn't get enough coverage of some area, or I messed up cam settings and some photos are unusable. Ideally I would like to take additional photos and just add them to existing chunk, just align those new photos to the previously aligned ones. This could easily save hours, as usually hundreds of photos are just fine and I only need to add a couple new ones.

-Andrew

5
I have quite a lot experience with PS Standard Edition (and I'm really quite happy with results!), but I keep wondering - can Professional Edition enhance reconstruction quality even further?

I know it can help streamline process with ability to scale/orient meshes properly and with broad Python scripting capabilities, but I am curious about features that refine/optimize reconstruction - do these only make sense for DEM applications or will they also result in more precise/smoother reconstructions of human faces and such?

Perhaps anyone can share screengrabs from same dataset processed with and without ProEdition-specific features?

-Andrew

6
General / Photoscan texture generation vs DOF
« on: September 04, 2013, 01:30:31 PM »
When acquiring complex sets of shapes, I often end up grabbing some parts in perfect focus while other parts are blurred by DOF (too close or too far from focal plane). However, I always make sure that every square inch of my project is perfectly sharp on at least a couple of photos.

Problem is, Photoscan doesn't always use these sharp photos for texture generation. I try to mask out DOF areas by hand, but on larger datasets this becomes tedious.

Questions:

1. Is there any way of knowing which photo photoscan used to texture selected area?
2. PS ver 1.0.0 has this 'Estimate image quality' feature to quantify image sharpness (or perhaps it quantifies other qualities of a photo?), does this mean PS can/could use this data to pick sharpest photo parts for texturing?
3. Could it be possible to use image quality data to automatically (with adjustable tolerance) mask out blurred areas in photos?

-Andrew

7

Nikon D3200 seems to be the camera of choice these days, replacing Canon 600D, with main rationale behind it being price advantage over 600D, but also, to quote Lee on FB, "These things are as quick as gunslingers! Very fast and perfect sync compared to 600D's".

Now, I understand the price factor all too well, but speed? Can anyone (Lee? :)) explain what that means specifically with respect to 3D scanning?

With devices like Shutter Cell/Camera Axe/Multi Flash Plus, one can precisely synchronize cameras with flash units, no matter how big the shutter lag is (btw. D3200s shutter lag is larger than D600s), as long as shutter lag is consistent. To me both D3200 and 600D seem to have consistent shutter lags but I didn't have time/means to do very precise tests yet - I can only confirm they are both light years ahead of old Canon 550D.

So:

1) Is D3200's shutter lag much more consistent than 600Ds?

2) Are there any other important speed/synch factors I am missing?

3) Isn't D3200 a tad soft for precise 3D reconstruction? Does sharpening photos help?


Oh, just to be clear, this is all for internal indie studio use, I am not about to offer scanning services and poach anyone's business :) Also, I only do occasional scans so convenience (battery bay doors blocked by camera mount etc.) are of secondary importance, although it would be nice to hear all known pros and cons.

Thanks in advance!
Andrew

8
Face and Body Scanning / Synchronizing different DSLR cameras
« on: July 04, 2013, 05:23:16 PM »
I just bought Camera Axe with Multi Flash Plus to solve different shutter lags on different camera models I have laying around (old Canon 550D, two 600D's, Nikon D3200 and Nikon D7100).

I set all cameras to Manual mode, set all zoom lenses to Manual Focus, made sure all cameras use same settings (ISO 100, F5,6, same WB), disabled any image altering shenanigans (like Active-Dlighting and some such), pointed all cameras at digital stopwatch and triggered them all simultaneously with Camera Axe/Multi Flash. I used no stobe lights to keep things simpler.

What I expected was evidence of consistent (down to 1-3ms) shutter lag, letting me adjust trigger times on Multi-Flash Plus unit, to achieve near-perfect sync.

To my surprise, I only observed consistent shutter lag on Nikon D7100 and Canon 550D. The two 600Ds would either sync perfectly with 550D or be quicker by 43ms, while Nikon D3200 would either sync perfectly with 550D or be slower, curiously by the same 43ms value.

All camera settings look the same, but perhaps there is something I'm missing, something that causes D3200 and 600Ds to sometimes pause and think before taking photos? Any ideas?

Cheers,
Andrew

9
Face and Body Scanning / Broad DOF vs image softening due to high f-stop
« on: February 28, 2013, 11:11:52 AM »
Fellow Photoscanners,

I am curious as to your findings about sweet spot for optimum quality of photos, both for building geometry and generating textures. Specifically, while scanning large (human) subjects, higher f-stop helps keep everything in perfect focus, at the price of per-pixel sharpness. On a typical Canon (crop) 55mm lenght (EF-S 18-55 kit lens), would you go f16 and higher? Is broader DOF worthy of softening images overall?

Cheers,

Andrew

10
Hi there!

I am about to start building a lighting setup for scanning props and eventually people.

Will greatly appreciate any and all advice about what works and what doesn't :)

One of my options would be this: http://www.fsfoto.pl/en/zestaw-oswietlenia-ciaglego-2x85w.html - sorry for weird (for most of you anyway) language - this is essentially twin 85 watt bulbs (continuous, not flash), with 90cm silver reflective umbrellas. One from lower angle and one from above (max 2,1m).
- Does that seem bright enough?
- Would three sets of these suffice or would I need four?
- What about getting those bright bulbs and reflective silver in my shots, would I be better off using semi-transparent light-scattering umbrellas instead? Or some ceiling/floor lighting setup to avoid lights behind photographed subject in my shots entirely?
- Maybe I am better off with non continuous, flash lighting? (although I'd rather avoid having synching issues)

Thanks in advance!

Andrew

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