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Author Topic: Here I go again..8bit, 16bit, 32..  (Read 7973 times)

bmc130

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Here I go again..8bit, 16bit, 32..
« on: May 27, 2014, 10:51:36 AM »
I've asked this question before and try and re read some post about Agisoft handles bit depths.

So when using 16bit tiffs and save out texture as tiff they are converted to 8bit, does that mean that my 16bit tiffs are converted to 8bit in Agisoft? or will I keep my range saving out my tiffs to exr? or will it be the same like converting my 8bit to 32bit when saving?

To get the higher bits workflow all the way do I have to use EXR all the way in agisoft?

Will the saving 16bit tiffs be fixed?

David Cockey

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Re: Here I go again..8bit, 16bit, 32..
« Reply #1 on: May 27, 2014, 10:21:27 PM »
Previous thread on this topic:  http://www.agisoft.ru/forum/index.php?topic=308.0

On January 5, 2014 Alexey Pasumansky said:
Yes, I mean that PhotoScan uses all the information of the image without any conversion to the 8-bit.
Version 1.0.0 Build 1795 is now the standard release

On January 20, 2014 Alexey Pasumansky said:
16-bit tiffs on input really produce 8-bit texture output. So the only way to overcome this problem is to convert the original images to 32-bit, it will result in 32-bit output.

We will consider to possibility of fast implementation from 16-bit input to 16-bit output for texture generation, but it will take some time.

I did not find any updates since then from Alexey Pasumansky on 16-it for texture generation.

bmc130

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Re: Here I go again..8bit, 16bit, 32..
« Reply #2 on: May 27, 2014, 10:35:52 PM »
Yes this is the only information I found as well David.

What confuses me a little is, are 16bits input in Agisoft still 16/32bits when saved out as exr, or have the inputs tiff files already been converted to 8bit and then converted back to 32 exr?

On the other hand it might be better as said to save out exr's all the way to be on the safe side. Exr files are usually smaller than tiffs which is good..but it adds one extra step in production for me since Adobe Camera Raw doesnt save out exr, I first have to save out tiffs then batch save them to exr in photoshop..

Marcel

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Re: Here I go again..8bit, 16bit, 32..
« Reply #3 on: May 28, 2014, 07:51:14 AM »
I think 16 bit files only make sense if your scene has a lot of dynamic range. Most scenes would be fine with properly exposed 8 bit files (slight overexposed when shooting) . Unless you need 16 bit textures in you pipeline ofcourse.

I've tried 16 bit files but didn't notice any difference in scan quality.

The filesize of EXR is smaller,  but memory use is the same as Tiff files. I did a project with 200+ 36MP files in HDR,  and memory use even for generating the Dense Cloud was over 80GB. (doing scans with HDR images is something I cannot recommend, too much to go wrong).

bmc130

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Re: Here I go again..8bit, 16bit, 32..
« Reply #4 on: May 28, 2014, 09:38:39 AM »
The only reason for 16 bit is because I need to go that way for pipeline workflow, otherwise I would gladly gone with jpg.

It would have been a easy fix if Agisoft would allowed to replace photos when just generating textures. But using the standard version I dont know of any easy way to batch switch from .tif to .exr without doing it manually photo by photo..

It's only for texture reasons I want the 16/32 bit not for generating mesh.

Marcel

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Re: Here I go again..8bit, 16bit, 32..
« Reply #5 on: May 28, 2014, 12:18:22 PM »
Why not use 16 bit tiffs then? Adobe camera Raw can export them directly, and you can switch between 8 bit and 16 bit tiffs (same   filename/extension so you can just rename folders).

Filesizes will be bigger,  but only by 2 times (if you have a lot of projects you'll need a NAS anyway :) )

bmc130

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Re: Here I go again..8bit, 16bit, 32..
« Reply #6 on: May 28, 2014, 12:35:14 PM »
Yes Marcel, that would do it, but my main concern is when I get the 16Bit tiffs in Agisoft are they converted to 8Bit? The only reason right now I would like to get the EXR's in Agisoft is just IF Agisoft is automaticlly convert them to 8bit.

Alexey Pasumansky

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Re: Here I go again..8bit, 16bit, 32..
« Reply #7 on: May 28, 2014, 01:54:27 PM »
Hello bmc130,

If you require to have HDR texture you need to convert input files to 32bit images, otherwise (even with 16-bit imagery) the resulting texture will be 8-bit image.

But during processing stages like camera alignment and geometry reconstruction the full range will be used.
Best regards,
Alexey Pasumansky,
Agisoft LLC

bmc130

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Re: Here I go again..8bit, 16bit, 32..
« Reply #8 on: May 28, 2014, 02:16:04 PM »
Ok then I know Alexey, thanks! Will this ever be fixed so you actually can save out 16bits as well with out having to do the extra step and convert my tiffs to 32bit?