Messages

91

General / Re: Decreasing Dense Point Cloud Rendering Time

« on: February 23, 2015, 01:00:31 PM »

If the plan is to run scans at Medium or High then there is no need for a render farm. My computer is a i7 4930K@ 3.4Ghz with an AMD R9 290 GPU, and it takes about 4 hours for a point cloud with 250+ million points (50 large photos at Ultra setting).

The Dense Cloud processing depends mostly on the GPU.  A fast GPU will speed it up a lot (a dual GPU a bit more). The second half of the Dense Cloud reconstruction (depth map filtering) depends on the CPU, so the CPU also needs to be fast. Dual CPUs aren't necessarily much faster for big projects. Clock speed is very important.

Don't rely on the Anandtech benchmarks too much. The benchmark is using a very small project so the results are a bit skewed. For big projects that run multiple hours the performance might be different.

To run Photoscan in a Renderfarm you need Pro licenses for each computer, in which case the licenses equal the costs for the computers. If you are doing relatively small projects it's much better to just get a fast computer.

92

General / Re: Best F-stop?

« on: February 16, 2015, 09:27:25 PM »

A Depth of Field calculator can be very useful to get an idea how big your 'sharp' zone is:

http://www.cambridgeincolour.com/tutorials/dof-calculator.htm

For example with a full frame camera:

50mm lens @F11 and focussed at 2 meter distance = 1 meter depth of field
35mm lens @F11 and focussed at 2 meter distance = 3 meter depth of field
200mm lens @F11 and focussed at 2 meter distance = 0.06 meter  depth of field

Try downloading a DOF calculator app on your phone (there are several available for free), it will give you a good idea on what to expect when you are photographing a certain subject.

Diffraction degrades image quality from F8.0 and higher, but Igor is correct that the extra sharpness you gain from a deeper depth of field is usually more important than the sharpness lost due to diffraction. Diffraction is very subtle, and blur from depth of field is usually not. I would try to keep the F-stop at around F11 unless you really need the extra depth of field.

For perfect quality scans, be extra super picky about image quality. And I mean extra SUPER picky, because even the slightest blur can cause noise in your scans. Examine your shots at 400% and if you even have the slightest doubt that it's blurred then dump the shot.

93

General / Re: 8000 EUR computer build recommended hardware

« on: February 16, 2015, 05:33:10 PM »

I didn't have time to read the whole thread, I just wanted to say that using the Anandtech benchmarks to compare systems is not really a good idea in my opinion. Their benchmark uses low resolution images and processes in minutes (which makes total sense, they don't have time to have benchmarks run for hours). Photoscan will be spending a lot of time on setting up and other things that would normally take only a small percentage of the time, and this might skew results.

Real life projects run for hours or even days, and might have different performance characteristics. Our own experience is that a fast single CPU outperforms a slower dual CPU system in most cases. So depending on your memory requirements you might be better off with a single CPU system (you would be limited to 128GB). Xeons with single CPU support are much cheaper, so you can purchase a faster one for much less money.

94

General / Re: Best camera for Photoscan?

« on: January 20, 2015, 11:17:56 AM »

well the title said Best Camera for Pscan... not Best cheapest Camera for Pscan... this is why I posted..

btw, are you sure of your statements ..? have you done any tests yet..? what about a Hasselblad H4D ?

best
f/

We have done hudnreds of  scans with both a Canon 5D MKIII and a Nikon D800. We haven't done any tests with a Leica or Hasselblad, but the scans from the Canon and Nikon are literally perfect. There is simply nothing to improve (when done right, there is zero noise and enough detail).  The D800 has a resolution advantage, but when your point clouds are over 1 billion points already, it doesn't really matter much anyway.

Regarding 'best camera', I would rather buy the latest model high end Canon / Nikon every 2 years for the next 15 years, than owning a single Leica / Hasselblad system. Overall this will give me superior quality.

95

General / Re: Best camera for Photoscan?

« on: January 17, 2015, 11:58:52 PM »

actually this Leica would be the best bet... best pixel quality.. chroma abb to a min...

http://en.leica-camera.com/Photography/Leica-S/About-the-S-System

Are you sure you do not want to recommend the Hubble Space telescope?

Recommending a camera system that costs well over 30.000$ (body and lenses) is not useful in any way. You will not see any difference in quality of the scans compared to a full frame Canon/Nikon camera (which costs a fraction).

96

General / Re: dense point clouds and depth filtering

« on: December 20, 2014, 09:54:25 PM »

At 'Medium' the image is used at half of the size, because the image is downscaled it becomes much sharper. It could be that because of this extra sharpness Photoscan does find useful points on Medium, while on Ultra (full sized image) it has trouble finding good points in the same area.

This is the only reason I can think of. (In the end, everything always comes down to image quality)

97

General / Re: Texture/Count

« on: December 16, 2014, 06:58:40 PM »

Are there plans to implemented PTEX in Photoscan? It would be an idea format for textures on 3D scans (maximized UV use).

http://ptex.us/
http://blog.digitaltutors.com/understanding-ptex-is-it-the-future-of-texturing/

98

General / Re: Dual cameras for better results in Photoscan

« on: December 15, 2014, 09:42:17 PM »

Capturing with two cameras at a known distance from each other has no benefit in Photoscan (apart from capturing twice as fast). This distance information is not used so you do not gain processing speed or accuracy.

In PhotoScan Pro version 1.1.0 it is possible to create scale-bars between pairs of camera centers and use this information for scaling and optimization purposes. However, the stereobase should not be negligibly small compared to the distance to object.

Hey, that is awesome!

Could you tell us what the actual effect is on processing speed and quality?

99

General / Re: Dual cameras for better results in Photoscan

« on: December 15, 2014, 04:12:18 PM »

There is a difference between subject matter:

If you are doing human scans then multiple cameras will be better (faster acquisition so less movement between photos).

If you do fully static objects then a single camera will give you exactly the same quality as using multiple cameras.

Capturing with two cameras at a known distance from each other has no benefit in Photoscan (apart from capturing twice as fast). This distance information is not used so you do not gain processing speed or accuracy.

100

General / Re: Troubles while scanning back of my house(For Freshman 3D Modeling Class)

« on: December 01, 2014, 12:45:00 PM »

If you are photographing only a single row of images than it's hard for Photoscan to do a correct alignment.

Try photographing multiple 'rows'. This way, the features Photoscan can use to align the images are always visible in multiple photos. So photograph one row with the tripod at the lowest setting, one row at medium setting and one row with the tripod at the highest setting. Try to keep the distance to the house the same.

Of course you will have to setup your camera for maximum quality

- low ISO like ISO 100
- aperture bigger than F8 for a deeper depth of field
- use a remote release cord or timer so you don't wobble the camera when pressing the shutter release.

Search the forum for more information on camera settings.

101

General / Re: digital calibration..?

« on: December 01, 2014, 12:31:09 PM »

It looks like your camera moved when taking the photo. Any kind of movement/blur will degrade quality of the scan.

Are you using a tripod?

102

General / Re: Crash - how much Ram is recommended? I have 20 gigs

« on: December 01, 2014, 12:26:48 PM »

What is the size of your Dense Point Cloud?

Photoscan will always build the mesh at maximum resolution, and then Decimate the mesh back to the setting you chose. That means if your point cloud is 60 million points, Photoscan might make (for example) a 100 million polygon mesh before Decimating it back to 4 million polygons.

The only solutions right now are:
-  re-build the Dense Cloud at a lower quality setting
- add even more RAM

A way to decimate the Dense Point Cloud would be very useful (especially if the reduction in points would be done in a smart way), but currently this is not available.

103

General / Re: how can i scan bottom of object???

« on: August 10, 2014, 10:37:02 AM »

Just turn it upside down and take more pictures 

104

General / Re: Problem aligning photos?

« on: August 08, 2014, 08:23:51 PM »

Grey dots are unused points: ie. a feature was detected in this photo, but Photoscan could not find a similar feature in other photos. Blue dots are valid points.

105

General / Re: Hardware/Processing optimization

« on: July 26, 2014, 11:54:47 PM »

Not all parts of the process are multi-threaded. If the CPU is not fully utilized it could be because it's running a calculation that just uses one thread/core.

As long as you are not running out of memory there aren't really any bottlenecks. Photoscan just needs a long time on large projects.