I flew a structure with a Phantom 4 RTK and have accurate xyz positions for all my images. I’ve turned up the weight of the prior pose in the alignment settings to 100 and most of the images align great with only slight shifts away from their RTK coordinates. However, I keep getting groups of images that are pulled far off their prior pose, which is creating a big misalignment. In the screenshot, the red arrows point to the same feature which has been duplicated by the images with the large orange error lines, which I’m trying to fix. The images without the long lines look great.
I can see why this is happening in this case, because there are alot of similar looking patterns in these images. In other components though, the entire model is scaled or rotated. I know the prior pose is correct and accurate to 4cm yet the misalignment is often 100m+.
Is there any way to force the images to be within x distance of their prior pose or to prevent them from aligning to something that isn’t near this RTK positon?
Hello,
if you are sure the gps coordinates of the “missaligned” images is correct then this is only a case of bad overlaps and wrong shooting. What you could do is edit the alignment settings as such:
And also after the alignment will be done, add multiple control points along the middle line of the (bridge?) I think it is, where these images and the pointcloud seems to fall apart. I would go for like 10 control points distributed all over the line near the disconnected area and then align again.
Ok thanks, I’ll try this. I had added 4 common tie points along the bridge as well as 5 accurate ground control points. This didn’t help it align, it just caused the entire component to flip on it’s side.
I’m seeing this problem in other areas too. For instance, the screenshot below is a standard grid pattern flight with 90% overlap between each image. In this case, I’m seeing a correct alignment in general, but the whole component is rotated and skewed. I’ve had other components that are more or less correct but all the images are being stretched so that the scale is wrong. Adding ground control only makes the component rotate and flip.
I know my control and camera positions are good because I have some components that look great and you can see everything in the correct place.
Please check in Map view whether the GCPs and Photos have correct coordinates according to the world.
Also, please show us how are the GCPs distributed across the captured scene.
What are the errors in GCPs in the 1Ds window on the left?
The coordinates could be switched or not fitting the coordinate system which is set in the scene.
If no hints in the above specified, then make sure to group all of the cameras and run the alignment again.