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Messages - stihl

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General / Re: 8000 EUR computer build recommended hardware
« on: February 15, 2015, 09:37:37 PM »
Some curiousities I've noticed with your build that I have some questions about.

Why two Xeon's from 2012 with socket 2011? Did you buy these new for this particular build or did you have them laying around?

Because it's socket 2011 you're stuck with DDR3. And even the relatively slow 1600Mhz ontop of that. And why go for a dual Xeon but only choose 64gb? I think you're much much better off with a faster i7-5xxx and overclock it as far as you can. I've noticed that Photoscan loves the Ghz'..

And what about those four(!) GPU's...Sounds like an extreme and ineffecient way to speed up processing time since GPU's are only used for the generating depth maps as far as I know.

To put things in perspective; how many images and how many MP were the images you used?; What the quality and parameters of the processing was?

General / Re: Multicam Rig for Drone Aerial Photography
« on: February 03, 2015, 05:09:54 PM »
There's a product on the market that does this already called the X-camB..

The immense downside to this product however is that it uses two cheap 200 dollar cannon camera's (and they sell the product for 30k.....) which gives you a nasty blurry photo.

Best is to copy their product but use proper camera's.

General / Re: GCP error low - high errors on DEM
« on: February 02, 2015, 11:15:57 AM »

General / Re: Agisoft and Amazon AWS - C4 instance Slower than my pc?
« on: January 27, 2015, 06:53:25 PM »

Is there a reason you went for the E5-2666 v3 Xeon? I also use one Xeon in one of my workstations but that's because it has 128GB of RAM and non-xeon cpu's can't handle that much. But since you're 'only' using 64 gigs...

« on: January 27, 2015, 01:56:38 PM »
It will certainly improve accuracy. Just make sure to set the Camera accuracy to 3cm in the Reference settings dialog.

Best results will obviously using precise camera positions in combination with precise (RTK) ground control points.

General / Re: Big Data Project
« on: January 22, 2015, 04:57:02 PM »
Images were 6000x4000 resolution, JPG.

Computer that was used was a

Intel Xeon E5-2630 v2
Win7 X64
nVidia GTX780

Total estimated time from start to finish for the processing is about 2-3 weeks.

General / Re: Architectural Example
« on: January 21, 2015, 01:40:32 AM »
Interesting results. Thanks for sharing!!

Did you optimize the model on the markers?

First disable all the camera positions by selecting them all and right click > uncheck.

Then go to the reference control pane and set the marker accuracy to 0.001m (1mm) and then optimize the model with the optimization tool with all the markers checked.

General / Re: Measuring in a model that was built using geotagged images?
« on: January 10, 2015, 03:46:05 PM »
Is it an aerial photogrammetry project or closed range photogrammetry?

If it's the first, you'll need ground control points (GCP's) to reference the relative model to giving it an absolute position. The aerial GPS is insufficient to scale or reference the model accurately. You'll need measured in GPS points on the project location that you can find in the photo's.

General / Re: Registration of scan data with UAV
« on: January 07, 2015, 12:52:46 PM »
That's the problem with using un-georeferenced aerial photo's...

It's a hell locating all the GCP's in Photoscan manually. Hence you need the image positions.

General / Re: Registration of scan data with UAV
« on: January 06, 2015, 10:44:06 PM »
I'd always go for rectangular or circular shaped targets. Black/white checkered pattern.

For your flying height anything between 10 and 30cm diameter is good enough.

General / Re: Distorted Ortho
« on: January 05, 2015, 05:02:51 PM »

Yes the advantage of using image positions (GPS) is that it will decrease the processing time for alignment if you align the photos with Pair preselection set to  'Reference' (v1.10)

In theory your 3D model will also then be geo referenced in an absolute sence but without the use of ground control points the mean absolute deviation of the model will be several meters but it's relative accuracy (the model scales) might also be better than aligning without image positions.

General / Re: Distorted Ortho
« on: December 29, 2014, 04:36:13 AM »
That's a good solution to an odd problem. Not sure why it would range so much, seems broken.

What you can do is make a mesh of only the ground points by using the automatic ground filtering option to make the ground points as one selection. Then make a mesh of only those points. This will increase object/building lean but it should also eleminate artifacts.

General / Re: Distorted Ortho
« on: December 27, 2014, 07:41:31 AM »
Improper geometry of the roofline and the staircase is due to noise and/or inadequate height data (point data) of those locations in your dense point cloud.

Increasing the overlap and/or lowering the GSD of the images (ie flying at a lower altitude) will increase the amount of points that can be generated during alignment process and dense cloud generation. Thus creating a more complete pointcloud which will improve the geometry. Unless extensive use of oblique imagery is used, camera position data isn't that important. I assume you used nadir only images.

General / Re: meaning of vertical resolution and vertical accurancy
« on: December 24, 2014, 09:08:40 PM »
With vertical resolution I think he meant the GSD ie Ground sampling distance. A GSD of .1m is a GSD of 10cm which translates to one pixel in the photo equals to 10 centimeter in real life.

A horizontal accuracy of 5 m means that anything on the XY plane is accurate within 5 meters of reality and this is the same for the vertical accuracy of 3m which only accounts for the Z-axis.

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