What to do with bad photos?

PIX4Dmapper PIX4Dmapper Questions/Troubleshooting
1

I have a large site over 1000 acres with 5500 photos.


Due to high winds, there were many photos where the camera flipped up and caught the horizon.  I assumed that Pix4D would throw out those photos but it seems they were included, as shown by the screenshot below.

  1. Are the “clouds” above from the bad photos?
  2. Does Pix4D ever throw out bad photos?
  3. What is the best way to deal with bad photos?  With 5000 photos, it would be very time consuming to review each one prior to processing.  I
  4.  Is there an automated way to check photos?

Some more screenshots below that show the photos:

Image below shows the clouds over areas that were not part of the flight.

Image below shows the camera thrown towards the horizon.

 

 

2

Pix4D can’t make a personal determination on what photos you like or don’t like…it is a pain but we all sort our bad photos out manually.  I wish there was a magic “easy button” but there isn’t.

I have sorted more than 5,000 pictures for a project and that is why collecting good data is so important or at least reviewing in the field to make sure processing will be successful. If you need an extra hand in processing or access to a Core i9 machine with 128GB of RAM then give me a shout as I can do processing at reasonable rates.

Adam.Jordan@nhiae.com 

3

Thanks Adam, I’ll keep you in mind for future projects.  I built a Ryzen X w 64GB RAM and that cut my processing time down from 10 days to 3 days.  Feature Request for Version 5  - Easy Button" 

Looking at my screenshots, does it seem the clouds in the 3D mesh is from the “bad” photos?  

4

Having more RAM, especially VRAM, can open up options in Pix4D…well at least I hit limits with very high MP pictures on 64GB RAM and 6GB VRAM of my old i7 machine.

Certainly the clouds are from the tilted pictures…the nadir pictures have no clouds and Pix4D doesn’t create its own data :) 

5

Follow up question:  I deleted the photos from the folder and now when I open the project, I get an error message that the images are not found.  I cannot bypass the error and it closes the project.

Do I have to start over with a new project?  I don’t want to lose the GCP work I’ve already done. 

 

6

Well in that case it would be best to put the pictures back in the folder and disable them in the rayCloud view or Image Editor in Pix4D.

7

I also think that the clouds and the areas outside the project area itself were created due to the tilted images. 

Even though these are manual tools, they helped me out more than once in such cases to remove the noise in the point cloud: 

  1. Carve feature: if you already have the densified point cloud, you can select unwanted areas in an image and it will directly cut through the point cloud to remove them. I would recommend to read these two articles: 
    https://support.pix4d.com/hc/en-us/articles/212262943 and https://support.pix4d.com/hc/en-us/articles/212262883
  2. Point cloud editing + clipping box: I would isolate the noise with the clipping box and then delete the points with the point cloud editing tool. This is rather fast once we get used to the tool. I’d recommend these articles: 
    https://support.pix4d.com/hc/en-us/articles/202560499 and https://support.pix4d.com/hc/en-us/articles/204048035

Also regarding how the Ground Control Points (GCPs) are placed on the project area, whenever possible, I would recommend to place them over the entire project area, this should give more consistent accuracy over the project, see here: https://support.pix4d.com/hc/en-us/articles/202557489