Images un-calibrating after rematch and optimise

PIX4Dmapper PIX4Dmapper Questions/Troubleshooting
1

I am having an issue with images in my project becoming uncalibrated after re-matching and optimising. I have merged multiple projects without any issue. 

When adding the latest section, everything looks fine - all images are fully calibrated in the new merged project until I re-match and optimise - then the entire data set becomes uncalibrated… Any suggestions on how to overcome this would be greatly appreciated!

New Data Set

 

After Project Merge, but Before Rematch and Optimise

 

Plenty of Key Points / Automatic Tie Points

 

After Rematch and Optimise

 

No longer any automatic Tie Points

 

Any Ideas??

2

Hi Sam,

Could you try Reopzimizing the project instead of Rematch and Optimize? Do some of the images still get uncalibrated?

As mentioned in the How to merge projects article:

…
16. If more than one blocks are created, connect the blocks together by adding Manual Tie Points in the intersection / common area between the subprojects following: How to import and mark Manual Tie Points (MTPs).
17. On the Menu bar, click  Process > Reoptimize. (Even if only one block was generated directly after step 14, it is recommended to Reoptimize).

Best,

3

Thanks Blaž, 

Thats where I was going wrong… all working well now

4

Hi may I ask how did you fix it? Did you follow the only reoptimize or did you create MTP on intersection? Blocks means what can anyone describe for me?

5

Hi @ganerdene.qc,

What is a block - explanation?

Before calibrating the images, the software has to extract key features on each image and match them together, making connections/reconstruction of the dataset. Please have a look at the example below:
image

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image770×423 136 KB

However, sometimes it happens that despite the good overlap you seems to have, the software connected images in separate parts - blocks. But, couldn’t create one entire structure.
image

Once it happens you will be informed about it in the Quality Report; in Quality Check section as well as in 2D Keypoint Matches Figure were earlier mentioned blocks will be painted in colour.
image

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image583×597 28.8 KB

Usually, as a resolution to merge the blocks, we advise adding more MTPs at the intersection. Especially when the issue occurs after merging subprojects. However, that has to be checked in detail. I noticed you gave more information about your problem in the post: Survey on Large Area with 8000 images, so we will continue to assist you there.

Best