Messages

1

General / Re: orthophoto from single aerial image and DSM

« on: May 30, 2018, 04:30:52 PM »

Hello Alexey,

thank you. Is there a way that Photoscan can compute camera calibration plus yaw, pitch, roll or omega, phi, kappa from the control points?

2

General / orthophoto from single aerial image and DSM

« on: May 30, 2018, 04:12:12 PM »

Is it possible in Photoscan to create an orthophoto from a single aerial image, a DSM and some ground control points? Theoretically, it should work (camera position and orientation computable from ground control points, then projecting the image over the DSM) - but how?

Example:
- load image
- import markers with georeferenced XYZ coordinates
- set coordiante system
- try to import DSM --> error: "empty frame path"

3

General / orthophoto from single aerial image and DSM

« on: May 30, 2018, 03:58:50 PM »

Is it possible in Photoscan to create an orthophoto from as single aerial image, a DSM and some ground control points? Theoretically, it should work (camera position and orientation computable from ground control points, then projecting the image over the DSM) - but how?

4

General / Re: Will a GPS camera improve the accuracy of DTMs?

« on: February 01, 2014, 09:41:08 PM »

Hi Jack-in_CO,

do you have a link to that document?

5

General / Re: Correcting for tree tops

« on: February 01, 2014, 09:38:49 PM »

Chances are high that you will be disappointed. Forest canopy will usually make it impossible to reconstruct DEM below the trees. If you have a sparse plant cover, it may work. I have successfully used Photoscan to reconstruct canopy as well as ground elevations for sparse desert vegetation (and in the end created a plant height map). Plant cover in that case was below 50%, and I used pole photography (camera 6 m above surface, plants were up to 1 m tall) to acquire the images. I found that having the camera point somewhat obliquely (approx. 30°) helped because that way I got much more photo coverage of the actual ground surface than if I had used vertical images. High image overlap and good ground surface texture will be helpful. In Photoscan, I used high or ultra quality reconstruction settings and mild depth filtering.

It would be great if you could report how it went in your case.

6

General / Re: Pairing cameras to provide scale and minimise accumulation of error

« on: January 19, 2014, 04:08:56 PM »

Hi,

this has been suggested before (http://www.agisoft.ru/forum/index.php?topic=916.msg4358#msg4358) and I still think it could be useful. Perhaps if the topic keeps popping up the feature will one day become reality.

7

General / Re: Calculation of motion blur, ground resolution and image overlap

« on: January 14, 2014, 02:49:01 PM »

I have now added calculation of rotation blur:

http://blog23d.wordpress.com/2014/01/14/rotation-is-the-enemy/

8

General / Re: Trouble with aligning photos

« on: January 11, 2014, 04:05:49 PM »

A little more information (camera setup etc.) would be helpful to find the reason for this problem. Did you use multiple snchronous cameras or a single camera (in the latter case, the problem could be due to movement of the subject between images).

9

General / Calculation of motion blur, ground resolution and image overlap

« on: January 10, 2014, 03:04:08 PM »

Hi all,

this open source tool may be of interest to some of you:

http://blog23d.wordpress.com/2014/01/10/uavphoto-a-simple-calculation-tool-for-aerial-photography/

UAVphoto is a simple tool that allows to calculate parameters like ground pixel size, motion blur and sequential image overlap from flight parameters (velocity and altitude) and camera parameters (focal length, shutter time, image interval etc.).

10

Feature Requests / Re: Invert selection

« on: July 28, 2013, 05:06:39 PM »

+1

11

Feature Requests / Re: Report and estimations.

« on: July 06, 2013, 11:32:11 PM »

+1

12

General / Re: Geometry type requirement for 2D orthomosaic

« on: July 01, 2013, 10:27:01 AM »

As in so many cases, the answer is it depends. In many cases, creating an orthophoto based on a height field model with "point cloud" selected as geometry type will provide good results, but depending on topography and camera positions you sometimes get better results with higher quality height field models. I suggest doing some comparative tests with what would for you be typical topographies and image acquisition geometries.

13

General / Re: Gradual selection???

« on: June 29, 2013, 03:53:39 PM »

+1!

Would be great if the Agisoft team could clarify this!

I also only have a relatively vague idea of what the numbers might mean, and being able to interpret them correctly would definitely help.

Also, it would be great if these parameters could be (optionally) added to the exported file when exporting dense point clouds.

14

Feature Requests / Re: anomalous diffraction approximation

« on: June 29, 2013, 02:19:51 PM »

+1

15

Feature Requests / Re: Add ortho options for median, standard deviation, intensity (or calculator)

« on: June 29, 2013, 02:19:30 PM »

+1