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Sorry for another question:
In the workflow tutorial you suggest to enable MBB and a setting of 5%. In one of Sara's videos she uses 9%. Can you explain to me the difference and when to best use which setting?
Thanks a lot and sorry for the many questions 🙂
Best Frank
Hi Frank,
No problem at all 😉
MBB or Multi-Band Blending is a tool to blend images into each other. It will reduce stack artefacts at the borders of regular integrations and will remove seams in mosaics.
In most cases a value of 5-15% is okay. For regular integrations, usually 5% is nice. For mosaics it really depends on the amount of overlap between the mosaic panels. If the amount of overlap is about 10%, setting MBB at 10% will work very nicely.
So the MBB % is relative to the image dimension of each frame independently in the stack. Setting at at 10%, will mean that the outside 10% of each image will be blended.
If you experiment with the %, you should get a good feeling on how it will work on your data.
High percentages like 25%, are only needed if you have images that overlap for say 25%.
Low percentages like 1-2%, will still blend, but will be too little in most cases.
An example, 10 images of 5 photographers of the Rosette Nebula:
- First image is without MBB,
- second with MBB 5%,
- third MBB 15%.
In this case possibly the MBB % is best around 20-25%. You can clearly see that 15% is better than 5%, but that there is still room for improvement possibly.
Kind regards,
Mabula
p.s. made a sticky of this as well..
Awesome thanks for your answers!
You're most welcome Frank 😉
If your source images don't overlap much (ie: scope tracking the target well), is MBB useful?
How much extra processing time does it take?
Hi Toddy @toddy,
Thank you for your questions and welcome to the APP forum 😉
If your source images don't overlap much (ie: scope tracking the target well), is MBB useful?
ie: scope tracking the target well, so that would mean, the images overlap for almost 100% right? They nearly have the same field of view. Then yes MBB will still help by reducing stack artefacts at the borders of the integration. If the images have very little overlap onthe other hand, MBB becomes very important.
How much extra processing time does it take?
Yes, processing time is inpacted by using MBB, because a weight map needs to be created of the image and that needs to be used in integration for integration weights. The actual impact really depends on a lot of factors, but a fair estimate would be that MBB enabled increases integration time by 15% perhaps. It depends on the amount of images, the amount of CPU cores, the type of diskdrive used etc..
So it won't impact integration time by doubling it, but it will increase the integration time by
0.1-0.2 x integration time
without MBB roughly. It's simple to test off course, integrate 10 frames with and 10 frames without MBB. The actual MBB % shouldn't have impact on the processing time.
Kind regards,
Mabula
