Topics

1

General / How to treat Weights in alignment and optimization

« on: July 06, 2017, 01:24:46 AM »

Greetings - I would like a final model output using UTM coordinates.  The camera exif coordinates are in geographic.  My workflow is that I load the images and do an alignment  on low accuracy with the autonomous coordinates (Lat and Long).  I then export a camera xml file and then do a conversion to my UTM coordinates and then import them back into the project.  I then seed my accurate target coordinates, uncheck the photo coordinates and run the alignment in medium or high accuracy depending on how many photos there are. Then I do an optimization with only target marker coordinates checked and a rolling shutter correction.  This generally seems to work very well.  Ground checks confirmed this.

The weight for the camera coordinates is 10 metres and the weight for the target coordinates is 0.005 metres.  After the adjustment, the camera coordinates seem to be generally within a few metres as I would suspect and the accuracy of the target coordinates is very good as suspected.

I am wondering how the adjustment treats these weighted coordinates? Is the above workflow appropriate?  Or should I leave the camera location coordinates checked on with the 10m weighting?

I used to run the projects with only the target coordinates checked on, however, I found that often many of the cameras would not align unless I did the process outlined above.  I just did a nest of projects and I am having difficulty in getting the good adjustment/alignment accuracy that I normally have.  Not sure what to do? - deadlines for the data are now.

2

General / Large data set Alignment Tips

« on: October 08, 2015, 11:23:57 PM »

I have about a 1000 aerial photos taken with a UAV at about 50m AGL in a near nadir view.  The photos do not have geo-referencing.  I am having trouble with alignment.  There are some large areas (100 photos or so) that do not align.  As this is a large dataset, I don't want to have to run the project trying various settings as it will take a long time on my computer.   Can you recommend what alignment settings would be best to have the best chance of initial alignment.

Which settings would you recommend:

Accuracy:  high, medium or low  ( I set medium)
Pair Selection:  generic, pair selection or reference  (I set generic)
Key Point limit:  default  (40000 I think)
Tie point limit:  default (1000 I think)

And are there any other tricks to help obtain an alignment?  For example can you manually set tie points to help alignment? etc.

3

General / Point Cloud from Cropped Model

« on: September 26, 2015, 08:11:19 PM »

Hello to all - I cropped my model in Photoscan and exported a LAS point cloud.  When I view the cloud in Cloud Compare it has points for the whole original model.  How do I create a point cloud of just the cropped model?

4

General / Clone of eBee type aerial wing platform

« on: June 13, 2015, 09:52:56 PM »

I am hoping someone can provide a link to an aerial wing similar or equivalent to an eBee type aircraft that will perform in fairly high wind conditions.  I am hoping there is a supplier that has put together a clone of the eBee/Trimble UX5 type aircraft in a kit form or almost ready to fly setup.  Any recommendations would be appreciated.  I will want to be able to use an automated flight system like the PixHawk or equivalent.  I will of course process using Agisoft.  Thank you in advance.

5

General / NVidia Quadro 4000

« on: May 23, 2015, 02:36:59 AM »

We have a HPZ400 workstation that has 16gb RAM and I believe has an NVidia GeForce GTX 760 card in it.  I asked our IT department for an upgrade to at least 64gb of RAM for processing imagery in Agisoft.  They have another workstation that is a HPZ420 that they are going to build and swap out for the old one.  I mentioned to IT that a new SSD  that was recently installed in the old workstation and would be very helpful to have in the new workstation and that the NVidia GeForce GTX 760 card or better from the old machine is also critical for the processing.

IT replied that they will put in a good SSD and a Nvidia Quadro 4000 video card.  Can someone please let me know if the Quadro 4000 is better that the GeForce GTX 760 card?

6

General / Camera Calibration Method & Parameters

« on: June 29, 2013, 05:43:57 PM »

Greetings,  I found the following comment regarding camera calibration that questions the accuracy and limited paramaters used in the Browns model:

"I should also say that Agisoft has fewer parameters in its lens model than does ADAMTech. For many applications this is fine, but for high-accuracy geomatics work it's crucial, in my opinion, to have all lens parameters activated and long floating point representations of the parameters (many programs appear to truncate the values)."

Is this true that the Browns model does not accurately model all of the needed lens distortion parameters if the appropriate floating point representations are used? 

7

General / Texture Quality

« on: April 18, 2013, 05:25:30 PM »

Greetings,  I created 3D model in Agisoft from good quality aerial imagery.  I exported an orthophoto and it looks great (about 9mb file size).  The model is not a huge area.  I usually create 2 million triangle surface and then decimate the mesh to about 300, 000 faces and then export a 3DPDF.  I always find the 3DPDF's texture is very soft and poor quality.  I had a colleague take the orthophoto and drape it over the DEM and create a 3DPDF - he used Feature manipulation Tools (FME).  The texture on his 3DPDF is as good as the orthophoto, but is is about 50mb.  Not sure why it should be so large of a file size?

Are there quality settings that I may be missing for exporting textured 3DPDF?  I would appreciate any advice on how I can improve my output texture on the 3DPDF models.

Thank you,
Jim

8

General / Camera Coordinate Export

« on: April 12, 2013, 07:55:43 PM »

I have a project with ground control.  I would like to export the derived camera coordinates.  I tried exporting a camera calibration, but it did not seem to contain the camera positions.  I tried exporting a point cloud and it does not seem to contain the camera positions.  Can someone please tell how to obtain the derived camera positions.  Thanks you, Jim

9

General / GPS Control Of Aerial Camera Locations

« on: April 04, 2013, 06:40:06 AM »

Greetings, I am hoping someone can enlighten me on what the effect will be on the geo-referencing result of a model created by Agisoft where the camera positions are determined to an accuracy of about 0.3m accuracy via kinematic GPS positioning method?  If no additional ground control is added, will the resulting model use the input positions of the camera locations to geo-reference the model?  Will Agisoft do a least square best fit to all of these input camera coordinates?  Has anyone done any model accuracy testing when using just input coordinates of camera locations?  I will appreciate anyone sharing their comments/experience with this.  Thank you, Jim. 

10

General / Seeded Photo Coordinates Alignment Processing Effect

« on: April 01, 2012, 10:18:17 AM »

Just wondering if you seed the photos EXIF with coordinates, whether this will speed up the alignment process?  I guess it will not have an effect on the geometry process?

Also, if you do seed coordinates for the photos, will the final alignment be best fit to all the seeded original coordinates?

Thank you,
Jim

11

General / OrthoPhoto Needed

« on: August 12, 2011, 05:57:54 AM »

Hello to all

I have the standard version of Phototscan.  I occassionaly need an orthophoto produced from a model that I create from low level aerial images.

I currently have the need to create one orthophoto.  I have eight visible control points in the model and accurate coordinates. 

Will anybody on the list create an orthophoto from my model for a service fee?  It would be greatly appreciated.

contact:   jim@vrmapper.com

Thank you
Jim

12

General / Video Frames

« on: October 03, 2010, 10:39:06 AM »

Greetings,

I have processed point clouds from video frames using Photosynth and other point cloud generators.  I like to use video frames as I am capturing images from a pole.  This allows me to capture in video mode and then simply extract the frames at one or two second rates.  The HD image size is also very good for point cloud generation.  My cameras have continuous shoot, but the button needs to be held down which presents a bit of a problem.

The video frames do not seem to process in Photoscan.  I believe the image properties are the same as when taking still images.  I use an EXIF tool to set the focal length - I would think that is all that would be needed.

Is there any way to process thes evideo frame extracts in Photoscan?

Thank you

13

General / Angle of incidence to outdoor scene surface

« on: August 30, 2010, 12:56:25 PM »

What guidelines/limits would you recommend for capturing photos to model an outdoor scene regarding the angle of incidence to the scene surface?  It appears that perpendicular to the surface is prefered.

14

General / Lens Limits

« on: August 30, 2010, 12:47:43 PM »

I am using a Canon T2i with a 9mm Samyang lens.  I am having difficulty creating a 3D model with this lens.  Photoscan seems to align a set of photo's, but the resulting 3D model does not represent the true scene at all.

Q1) Are there any limits on the types of lenses that can be used with Photoscan?

Q2) Can Photoscan generate 3D models with the 9mm lens?  Would adding the lens calibration parameters assist the 3D model generation (I have calibration parameters from stitching full 360 panorama's)?