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Vegetation areas - blurry images

Hi, I have over 1,000 images with nothing but forest.
I used 80% and 85 % overlap, with 7 to 8 cm / pixel.
I already checked the tutorial on vegetation areas.

All the results are good (initial processing, point cloud densification), but when I get to the mosaic, there is a lot of distortion / blurriness in some parts.

This blurriness appears in areas where the original images are good, with high overlap. If I process the same area in a smaller project, the results are perfect, but if I process everything (all 1,000 images) the results are worse.

Do you have any idea on what the problem may be? I really need to process everything in one project, for colour balancing and overall georeferencing.

Does anyone know why this happens, and what processing options I can use to avoid it?

Thanks!

Hi Alexandre, 

If you see differences in the matching of different regions of the project in Section 2D Keypoint Matches from the Quality Report. The problem may come from step 1 of processing.

In addition, if you think that the artifacts you see in the orthomosaic are correlated to uncalibrated images in the regions with lower matching, you could try to do the following:

  1. Make a backup of your project, so that you can make changes on another saved copy.

  2. Change the size of the Keypoints Image scale to 1/2 (maybe also try 1/4).
    In Process > Processing Options > 1. Initial Processing > General > Keypoints Image Scale, select Custom and set Image Scale to 1/2 (Half image size) or 1/4 (Quarter image size). Then, you need to run step 1. Initial Processing again.

  3. Verify in the Quality Report if this gives a better matching in lower regions. If this is still a problematic area, you could try to add Manual Tie Points (MTPs) and Reoptimize, which should help create matches in this area. Instructions on how to add MTPs:https://support.pix4d.com/hc/en-us/articles/202560349

  4. Then, you can process step 2 and 3 again.

In any case, we would suggest to add Manual Tie Points (MTPs) to your project and Reoptimize, as in 3).

Best regards,