Messages

61

Bug Reports / Re: Large coordinates truncated in PLY

« on: March 15, 2013, 03:55:08 AM »

Hello Alexey,

Yes, I see that if I save the PLY in ascii format the precision is kept and displays fine in several viewers if the coordinates are offset at import time by 0,4390000.0

I saved the same file again in binary and it does not display properly even with an offset at import time.

So declaring float is not the issue and either the coordinates are not being stored at double precision in the binary PLY or different viewing softwares that allow offset at viewing time are not reading the binary PLY file properly.

Here are links to both files I created.

https://www.dropbox.com/s/vv21m6wxq1pnio2/FMHP_RU_sparse_ascii.ply

https://www.dropbox.com/s/dhqtb1vhtrgbv8r/FMHP_RU_sparse_binary.ply

Tom

62

Bug Reports / Large coordinates truncated in PLY

« on: March 13, 2013, 02:41:46 AM »

Many projected coordinate systems have coordinates that exceed 1,000,000

PLY files are exported with the coordinates as property float which means that the coordinates are truncated.

Perhaps with most data sets that goes unnoticed, but a building placed in UTM coordinates that exceed 500,000,4,000,000 it is pretty obvious.

If any coordinate exceeds 1,000,000 it should be stored as property double.

Tom

63

General / Re: Modeling a bomb/mines field

« on: November 22, 2012, 08:28:48 PM »

It may be possible to do what you want with photos, but it is a function of the quality and consistency of your images and camera, as well as the quality and completeness of the geometry of the images. At present, using only PhotoScan would be tricky and difficult to assess and quantify the results.

Tom

64

General / Re: Problem with big camera calibration

« on: November 22, 2012, 12:49:44 AM »

First, if you have not already, go to Tools, Camera Calibration, select all the images and enter 10000 for both fx and fy - that is 120 mm / 0.012 mm
Enter 3840 in cx and 6912 in cy - those values are 7680 / 2 and 13824 / 2

Select Fixed for Calibration mode - make sure you hit Apply

Now go to the Ground Control panel and import the file you have with N, X, Y, Z, O, P, K

Make sure your image names include the file extension or the name won't match.

Under settings in the Ground Control panel set your camera accuracy to 0 if you like, at least for starters.

I would go ahead and do an alignment and use High and preselection of Ground Control.

After alignment, use Gradual Selection and delete selected points, then optimize - repeat until bundle_adjust is around or less than 0.3 or so.

Perhaps loosen the Camera accuracy and see what errors you have - it is a good check on your previous solution. The results will never agree exactly with any other AT result, but the errors should be about the same- again a good check.

If you have a ground control file, import it and have PhotoScan create markers for you. Go visit where the markers are projected to and perhaps even pin them for another check.

If you do mark the control in PhotoScan, uncheck the cameras as control and use only the ground control. Check the errors against what you had before. By then, you will have a pretty good feel for what is going on with PhotoScan

Tom

65

Feature Requests / Re: iPad Model Viewer

« on: November 15, 2012, 12:32:51 AM »

Decimate the model to 2,000,000 faces. Save it as .ply. Use MeshLab for ios to view.

66

General / Re: Agisoft PhotoScan 0.9.0 pre-release

« on: July 19, 2012, 05:54:22 PM »

Hello Alexey,

So in a normal 3 band RGB image that is displayed in color, only shows one channel under "Set Master Channel"

However, I have some images that only have 3 bands, 8 bits per channel, really a RGB image, but the file info shows a property -

Photometric interpretation YCbCr

and therefore has 3 channels, under "Set Master Channel" and will only display and use the master channel.

And the sparse point cloud from align photos as well as the resulting geometry only shows the master channel.

I think there needs to be a way to choose the display band combination and not be limited to a single band.

Tom

67

General / Re: Agisoft PhotoScan 0.9.0 pre-release

« on: July 18, 2012, 09:31:44 PM »

I have a couple of questions about how images formats are handled in 0.9.0

I have some 4 band digital aerial images in tif that now open in 0.9.0 without artifacts, but don’t show as color. Is there a way to change band combinations?

I also have some scanned color aerial tif images that now open in 0.9.0 as black and white also.

Curious.

Tom

68

General / Re: What Vertical Accuracy Should I get?

« on: May 26, 2012, 11:39:11 PM »

There is no reason you cannot meet or exceed lidar accuracies with photogrammetry - yes even with a lesser camera than a Nikon D3. When I say photogrammetry, I mean any photogrammetry based software and that includes PhotoScan, but there are rules that must be followed with regards to overlap of the images and more importantly, the base to height, or the geometry of the camera to subject. The focal length of the lens is the key to forming good geometry. You did not mention the lens used, but the best geometry is created using a lens in the range of 24 mm to 35 mm - expressed in full size 35 mm sensor equivalent terms. The only other source of error is the combination of lens and camera sensor distortions and their stability. A very high quality camera calibration can be derived if you have enough good photos (not blurry) with consistent settings, proper geometry, adequate overlap, and enough redundancy - overlapping strips or cross strips - so that lens parameters can be modeled correctly. I don't know if your set of photos meet all the requirements for PhotoScan to solve for a high quality calibration, but it is certainly possible with proper photos.

The differences you are seeing in your analysis of the DEM may be misleading. What are the errors shown in the Ground Control panel in PhotoScan?

Tom

69

General / Re: camera with no exif-data

« on: May 25, 2012, 09:56:15 PM »

You will get results without exif, but you can use exiftool http://www.sno.phy.queensu.ca/~phil/exiftool/ to add at least a focal length