Messages

16

Bug Reports / Re: Photoscan freezes when opening photos in tab

« on: August 08, 2017, 10:20:49 PM »

I actually just performed a clean install of Windows 10 build 1703 on my laptop, so I don't think it is related to the update. I had noticed the problem first after updating, but had to do a clean install today because of other issues affecting my system.

17

Bug Reports / Re: Photoscan freezes when opening photos in tab

« on: August 08, 2017, 09:44:18 PM »

Alexey,

I'm experiencing the same exact problem after updating my OS to Windows 10 build 1703. I've tried the newest driver for my GTX 960M (384.94), but that hasn't worked. I'll try downgrading to 382.33 like the previous user.

18

General / Re: Orientation of a wall for orthophoto

« on: June 26, 2017, 05:54:22 PM »

If you already have a coordinate reference system in place in your model (from a total station, for example), there is another method you can use, detailed in this thread: http://www.agisoft.com/forum/index.php?topic=6377.msg33969#msg33969.

This works perfectly for me to make orthomosaics of walls, archaeological profiles, etc.

19

Python and Java API / Re: "Split in chunks" not working?

« on: June 23, 2017, 12:26:10 AM »

Ok - I now see that I was being dumb. I complete missed the "custom menu" in the toolbar. However, it seems that this script will only split the sparse cloud. Is there a way to split a dense cloud? I already have a very large dense cloud that is too large to process the mesh. I'd rather not have to redo the dense cloud since it took almost a full day to process.

20

Python and Java API / "Split in chunks" not working?

« on: June 23, 2017, 12:00:35 AM »

I've tried to use the "split in chunks" script several times (http://wiki.agisoft.com/wiki/Split_in_chunks.py), but it doesn't seem to do anything. It only outputs "7777" in the console the first I try it, then nothing happens each subsequent time. I've tried with a couple different projects too. I'm not certain what I am doing wrong. I've used other scripts (e.g. PS130_coordinate_system_to_bounding_box.py) successfully before.

21

General / Re: GCPs with dumpy level?

« on: June 15, 2017, 07:46:17 PM »

Hi SAV,

Thanks for your helpful response. Yes, I'm an archaeologist. Normally I use a total station for this kind of work, but for this particular project, I don't have one.

I understand the basic process you are describing, except for the last step to acquire the coordinates for each marker. The only way I can figure this might work is if I place the markers in a grid and use the pythagorean theorem to triangulate their coordinates. If I place the markers randomly, I can't reason how I would calculate their coordinates from the two origin points since I would only know one distance (from point 0,0 to the marker). At most I could also measure from the north point, too, but this triangle would not be a right triangle, and it doesn't seem to help with the coordinates.

Sorry if I'm missing something obvious here - it's been many years since I did trigonometry! Can you clarify?

22

General / GCPs with dumpy level?

« on: June 14, 2017, 06:20:33 PM »

I've been trying to design a strategy to create a nice DEM and orthomosaic of a small area (about 40 x 23 meters), but I don't have access to a Total Station or high quality GPS to enter coordinates for GCPs. I'm considering trying to enter local coordinates using a dumpy level. This should give me relative elevation (z coordinates), at least accurate to the nearest cm. I'm not sure, though, how to get reasonably accurate x, y coordinates. I can triangulate distance measurements from known points to plot this on grid paper, but how can I convert this to reasonably accurate x and y coordinates. Is it possible to only enter z coordinates for GCPs and use a meter bar for scale elsewhere in the project? Any thoughts?

23

Bug Reports / Re: Error (Mac, AMD GPU) "Another GPU context is already active"

« on: May 16, 2017, 11:07:03 PM »

Same error occurring for me after the most recent update. Running on Windows 10.

24

General / Re: Orthophotos of Wall Facades and other vertical surfaces

« on: May 12, 2017, 04:09:46 PM »

Seboon,

Thanks for your suggestion. While I understand in theory what you are suggesting, I'm not sure how you can use the bounding box as a guide since you cannot create shapes on the bounding box. You can only create shapes on the model itself. Is this what you meant?

25

General / Re: DEM without GCPs and UAV?

« on: May 04, 2017, 05:35:40 PM »

Good to know, Thibaud. I could set up targets just for the purposes of alignment, but I wont have a Total Station to include coordinates for them. Are targets a necessity, from your experience, in a grassy situation? Would I need to have enough so that one was visible in each photo?

26

General / Re: DEM without GCPs and UAV?

« on: May 04, 2017, 05:24:07 PM »

Thank you, Jan, for your response. I found an academic article where they use a similar methodology for creating models without a Total Station or GCPs. They use a builder's square with levels on each arm to ensure a proper horizontal x,y plane. My only concern would be finding a builder's square large enough - I would figure that to properly scale a larger model you would want one at least 1 x 1 meter? There's also the question of how many. Would a single one be enough? Or would multiple scale bars be needed?

Second, I'm a bit concerned about the ground coverage, which is mainly a grassy lawn. Is there sufficient detail and variability for Photoscan to align multiple images of grass? I normally work in the Mediterranean where the terrain is fairly rocky and dry, so this isn't usually an issue. But for this project I'm dealing with grass - nice for digging, but not so good for photogrammetry. Anyone have success with modelling a grassy landscape from a low altitude?

27

General / DEM without GCPs and UAV?

« on: May 03, 2017, 07:58:41 PM »

I'm trying to work out a method to create a DEM to serve as a base map for an archaeological project in a relatively small area (a property surrounding a historic home). Normally, I use a Total Station to shoot in the coordinates for GCPs, but I likely won't have access to one for this project. These coordinates not only help to georeference the resulting orthomosaics and DEMs, but they provide the x,y plane. To get around this, I was wondering if I could do something relatively simple: get a bubble level with some measurements on it. I would attach a couple targets at known distances for scale, then use the bubble levels to ensure that it was level. The resulting scale bar could also serve as the x,y plane for creating orthomosaics.

The second issue is how to get the proper coverage and image overlap without the use of a drone. I'm guessing that a pole would do the trick, since taking photos from my standing height, even in a relatively small project area, would probably not work.

Would this work? Am I missing anything or making any unintentional mistakes?

28

General / Re: Orthophotos of Wall Facades and other vertical surfaces

« on: January 24, 2017, 10:44:42 PM »

Hey Chris,

Thank you! I've tried this out and I believe I now have it working. I just wanted to clarify a couple steps to make sure that I am doing this correctly.

First, my models are not georeferenced, but use a local coordinate system based upon targets shot in using a total station. This doesn't seem to matter.

After I create the first two markers by right clicking onto the mesh (near the left and right side of the wall to be projected in the orthomosaic), I've noticed that the only way to view their coordinates is to click on the "View Estimated" icon in the Reference panel. The "View Source" icon has no values assigned to the markers unless they are inputted manually. When I've attempted to change these values, as you suggested to put "KS-U" and "KS-X" at the same altitude (Z-value), it seems to have no effect upon the location of the markers. They remain in the same location where I clicked on the mesh. Rather, I suspect that it is adding incorrect information to the model's scale and reference system, so I've decided to simply skip this step.

However, by right-clicking within the Reference panel to create the third marker (KS-Y), I am then able to use the x, y, and z coordinates of KS-U from the "View Estimated" to move this marker around, and make it exactly one meter higher than KS-U.

When I create the orthomosaic, I use "KS-U" --> "KS-X" for the horizontal axis, and "KS-U" --> "KS-Y" for the vertical axis, leaving the vertical axis box checked.

Matt

29

General / Re: Orthophotos of Wall Facades and other vertical surfaces

« on: January 21, 2017, 12:23:05 AM »

Many thanks to everyone for the suggestions.

Chris - I've read the article, but I'm afraid that I do not quite follow the workflow. How do you create a point that is exactly one meter vertically higher than another in Photoscan? This seems to be the issue that I was having since I can only place markers manually using the mouse. Is there a way to create a marker in a location if I know the coordinates I want? It's also unclear to me where the "profile nails" should be placed - in the profile? On the ground? Does this method require a total station in prismless mode? (If so, this isn't a possibility)

Alexey - This method sounds very intriguing. Are there any Python scripts available that would allow me to do this? Ideally, I would define the horizontal axis using the GCPs and the vertical axis using manually placed markers on the wall surface.

30

General / Orthophotos of Wall Facades and other vertical surfaces

« on: January 16, 2017, 10:05:13 PM »

I use Photoscan in archaeology to document standing architecture and archaeological trenches. I have a question about the feasibility of using Photoscan to create orthophotos of wall facades or other vertical surfaces. Our GCPs are measured using a total station, and these allow us to create perfect "top down" orthophotos for archaeological plans, but is it possible to do the same for walls and the sides of trenches, allowing for the creation of archaeological section drawings? I know that it is possible to choose a planar projection using markers to define the horizontal and vertical axes for the orthophoto, but if these markers are manually placed onto the 3D model from Photoscan, how accurate is the resulting orthophoto? For instance, will the horizontal orientation of the orthophoto be parallel to the x and y axis from our GCPs, or will it follow the arbitrary horizontal plane between my two markers on the wall? I have the same question for the vertical axis - will it align along the z axis from the GCPs or the line between my markers? What if the wall in question was "slanted" and not perfectly vertical? I'd appreciate any input that anybody could provide.