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Messages - cbnewham

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91
General / Problems with dense cloud using two different cameras
« on: April 07, 2016, 12:47:36 PM »
While I have created models successfully with two cameras before, I've run into real problems with a recent situation in photographing a piece of sculpture.

I have two cameras: Canon 1dsIII and a Panasonic GM1. Both have made a couple of hundred images each for the same scene. I began the imaging with the Canon and swapped to the GM1 half way through (battery running out of power). There is plenty of overlap between images themselves and between the image sets from each camera.

The sparse cloud is generated successfully and the camera positions all look to be correct for both cameras.

However, when I generate the dense cloud, the images from the GM1 seem to be missing for great swathes of the sculpture - the point cloud has large gaps in it with sharp edges, yet these areas are covered very well by the images, and the gaps also have points in them in the sparse cloud.

If I create the sparse and then the dense cloud by using just one or the other camera's images then the result is fine (although, obviously, incomplete because not all areas were imaged with one camera).

Looking at the camera params after the initial sparse cloud is created, I notice that photoscan has not updated the camera distortion parameters for the GM1. They are updated if I exclude the Canon images.

Any ideas?

92
General / Dense point cloud updates slowly
« on: March 22, 2016, 02:53:03 PM »
I've just upgraded (Standard Edition) from 1.1.6 to 1.2.4 and I notice the dense point cloud can be seen to "generate" every time it's moved. It used to just display instantly.

Why is this?


93
General / Re: Curved ceiling Orthophoto
« on: March 21, 2016, 05:47:14 PM »
I would just put it in Blender and set an ortho camera at the "focal point" of the curve and then scan the camera across the model, rendering with very small strips. Then combine the strips together using something like ImageMagic. I've done this many times with curved ceilings.

94
General / Re: Is masking useful?
« on: February 10, 2014, 07:49:50 PM »
Interesting.

I wasn't sure if mask were used for the dense cloud because there isn't an option to switch them on or off like there is with the sparse cloud.

I had suspected that the masks were used for texturing as I've noticed cleaner results when I have masked.

95
General / Is masking useful?
« on: February 10, 2014, 05:15:44 PM »
I ask because, at first glance it looks like a good thing - you don't have to process anything in the pictures except the subject.

However, on many examples over the past few months I've found that masking produces inferior results. It seems to be fairly obvious why: when the image has extensive masking it means that points are only being used in a small area of the image, and therefore the position of the cameras will not be as accurate. e.g.: if the pictures are masked so that only a small central section is available, then the angles between extreme points in each picture will be less and thus the camera positioning error will be greater along the line connecting the camera and the subject.

So, it seems reasonable to not mask for creating the initial point cloud. However, masking does not appear to be used for the dense cloud (why is that?) and I wonder whether it is useful at the texturing phase?

Thoughts anyone?

96
General / Re: programs to edit 3d model
« on: February 04, 2014, 07:00:53 PM »
I think the learning curve for Blender being steep is a bit of a myth these days - certainly since the UI was changed several years ago. I had no knowledge of 3D editors and picked up the basics very quickly. There are also plenty of tutorials and lots of documentation available.

Indeed, from what I've seen Meshlab seems to have very little documentation and very few users...

97
General / Re: programs to edit 3d model
« on: February 04, 2014, 01:48:58 PM »
You could use Blender. Export in any of several formats (eg: Wavefront).

98
General / Re: Poor model details from good dense cloud
« on: January 28, 2014, 12:25:42 PM »
Thanks Alexey.

Do you have any plans to provide a UI control for the parameters so we can tweak them? Maybe even a manual way to specify thin parts of the cloud that need different params to the rest?

99
General / Re: Poor model details from good dense cloud
« on: January 27, 2014, 06:32:12 PM »
Ok, thanks for the feedback so far. Although I am curious as to why that would impact on generating the model incorrectly from the dense cloud (as that's already bee created at that point).


100
General / Re: Poor model details from good dense cloud
« on: January 24, 2014, 07:19:19 PM »
I've shared a dropbox folder with you via your

info@agisoft.ru

address.

It contains the model. (or will do - at 156 Mb and I'm on a slow link it will take a while to synch)



101
General / Re: Poor model details from good dense cloud
« on: January 24, 2014, 06:38:53 PM »
Alexey,

I took the Project as created in 1795, reinstalled 1812 and loaded it.

The model looks fine (as generated in 1795).

I then regenerated the model from the dense point cloud with 700,000 polys.

The model no longer looks fine - again missing parts and with bad edges.

So therefore the model generated by 1812 using the same point cloud as 1795 is no good.



102
General / Re: Poor model details from good dense cloud
« on: January 24, 2014, 06:06:53 PM »
I've now confirmed this.

Build 1795 produces the correct model (values for the various phases as given previously, although I made the mesh 700,000 and didn't decimate to 500,000).




103
General / Re: Poor model details from good dense cloud
« on: January 24, 2014, 01:52:20 PM »
Hi Alexey,

Yes, this is with the dense cloud.

Once the generation with the older PS release is finished and I can see what has happened, I'll send you the project. What is the best way to do this? It's pretty big.

104
General / Re: Poor model details from good dense cloud
« on: January 24, 2014, 12:03:27 PM »
It is as I said - lots more triangles but a degenerate surface.

This was with 5 million triangles. The surface is just not being generated correctly from the dense cloud. My next test will be with the earlier release, and I suspect it will produce a much nicer result judging from my results on the 8th of Jan.

105
General / Re: Poor model details from good dense cloud
« on: January 24, 2014, 10:49:08 AM »
I set the triangle count at one point to several million and still ended up with everything the same, except with far more triangles in the broken pieces.

I will try this again to double check, but in the older example that came out fine, I can tell you that my mesh will have had no more than 1 million before decimation.

I am still suspicious about build 1812...  :-)


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