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Author Topic: Fusion of precision geotagged images with other images  (Read 3398 times)

dowallin

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Fusion of precision geotagged images with other images
« on: January 08, 2018, 11:44:24 PM »
Greetings.
I'm considering the purchase of an RTK GPS system like Vmap:
http://www.microaerialprojects.com/

This system requires the use of a camera with a hotshoe (ex. Sony A6000) to link individual images with the precision GPS coordinates of the Vmap. Nice but, I use several different cameras that lack a hotshoe (near-IR modified Canon S100s and Parrot Sequoia).

So, I'm wondering if there might be a way in Photoscan to fuse imagery from the Vmap-linked RGB camera with, say, a Canon S100 camera (or another camera with either no geotags or geotags with low accuracy) to create a multiband image that uses the high-accuracy geotags from the V-map linked camera. The goal here is to avoid the time consuming process of setting up ground control points and then finding these geotags in the imagery.

David
 

Jack_in_CO

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Re: Fusion of precision geotagged images with other images
« Reply #1 on: January 17, 2018, 12:56:35 AM »
Quote
The goal here is to avoid the time consuming process of setting up ground control points and then finding these geotags in the imagery.

Not sure you will get precision results with mixing camera types without some sort of ground control. If you have RTK level location data on some camera positions, then using targets, even though not directly georeferenced within the imagery might be the solution.

Simple work flow....
Lay out ground targets or control sticks with coded markers
obtain images with one camera with GPS on the image locations
obtain images with second camera
process as separate chunks
use the detect markers features with the two chunks
use the align chunks features via markers

Might work....

Walter Volkmann

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Re: Fusion of precision geotagged images with other images
« Reply #2 on: January 23, 2018, 01:20:01 AM »
Hi David,

We are doing the same as you are, only that we are using an RGB (GoPro) camera for the non-geotagged images. We have had no problems in getting both the geo-tagged Sony a6000 and the GoPro cameras aligned in the same alignment batch and judging by the sub-pixel alignment accuracy of the GoPro images, don't seem to suffer any degradation in overall accuracy. We still have to evaluate the resulting point cloud by means of validation points.

However, if in a separate alignment we use only the GoPro images (now geotagged with the positions as estimated in the first alignment), we strangely get large discrepancies between alignment output and geotagged camera positions. This does not make sense to me at all.  Until we have an explanation for this unexpected discrepancy we will have to always include the geotagged imagery (as baggage) in the approach. Nevertheless, the process does seem to give us the ability to align secondary (non event marking) cameras in combination with V-Map geo-tagged images - thus obviating the need for ground control.

We'll keep on working towards a more efficient solution.

Walter