UPDATE FROM MABULA
I have had a very rough 2 months unfortunately health wise. I was struck 3x in a row with bacterial infections. The second infection occurred  after a routine hospital checkup and I became very sick. I had to rest and take a lot of antibiotics. Once I was recovering and restarting work 1 month ago, I again became sick. The infection was not yet gone, so even more antibiotics and rest was needed. Needless to say, it took a lot of my energy and I needed a lot of rest.
Finally, the infection is really gone and my energy is coming back step-by-step now and I have started work again. I am terribly sorry to have kept you waiting for support. I will address all outstanding questions and e-mails step-by step and will be on the forum daily from today.
APP 2.0.0-beta47 will come soon as well, a lot of work was already completed before I became very ill, so the release is also nearly ready for you. Beta47 will be much faster actually. Many workflows will be more than 2x faster, mosaics can even be 10x faster than before because registration really received a major boost... all compared to beta46. Â Before I release it, I will make sure that everything is working properly and then I will release it.
I'm integrating Vespera 2 scope tiff files - in this case 7 - and I believe Median mode is the one to use (feel free to contradict). I note that in the console file it seems to say I'm using Average Mode.
Am I misunderstanding - any ideas?
Ta
Hi @domhenry,
Thank you very much for you post with your question and for sharing all the related information.
I can see that you are integrating only 7 frames, then yes, median is advised over average integration.
But... I can also see that you are using Drizzle integration instead of resampling/interpolation. This is the main issue here.
Drizzle always requires average integration for drizzle to work as intended. Drizzle simply can not function well with median integration. Technically: for drizzle to work properly we require flux conservation, average integration will ensure that. Median not. So we have built in a fail-safe in the integration engine. If you set median integration and also Drizzle integration, APP will automatically do the correct integration mode of average for Drizzle.
Drizzle requires on the other hand many images (50+) for it to be really usefull, so I would adivse you to disable drizzle integration, enable average, and then use median. That should work much better, the result should look better.
Please let me know if all is clear and/or if you have any other question about this.
In 2.0.0-beta41, we have included an updated drizzle engine as well. I have made a note as well to test drizzle with median integration in the new engine to see how it would look like, and I will try to put this information as well in our soon to be released manual.
Mabula
Hi @mabula-adminÂ
Not quite with you on the Drizzle setting. I have "regular integration / no Drizzle...... or am I still missing something....?
Thanks
Dom
Hi @domhenry, thanks, yes I looked too quickly. I will do some testing here and will get back to you.
Mabula
Hi Dom @domhenry,
I forgot the possibility of a mosaic registration. Are you runnign a mosaic? Then also in that case, average is always forced over median, because that is really needed then to get better results.
Is it a mosaic or not?
Median is only advised for non-mosaics with little amount of images that simply overlap mostly.
Mabula
I think I might have stumbled on the answer. I had MBB enabled  - I turned it off and the integration used Median Mode.....
Is that the expected operation?
The problem is that if I dont use MBB then I get some quite strong edge effects.... The data I'm looking at uses images from several sessions and the images are not framed identically.
Dom
Hi Dom @domhenry,
Ah, yes, that is expected behaviour as well. Please accept my apologies for not mentioning this earlier.
I have checked our code and issue list. In 2.0.0-beta26, we have fixed this problem for Multi-Band-Blending. If you use MBB on less then 10 images with median integration, you will get artefacts in the borders of the field of View. In light frame integration, median technically means the the pixel stacks are integrated with a weighted median. This is a big issue for the MBB algorithm with a little amount of frames, that simply does not work together. MBB works only well with weighted Average/Mean integration.
So median is always turned off in the following cases for good reasons:
- drizzle/bayer drizzle
- multi-band blending
- mosaics
Can LNC + MBB solve the issue not with average integration? Could you show a screenshot of how it looks?
Feel free to upload the data here, so I can test and see myself what is happening? Maybe i can find a way to solve it?
https://upload.astropixelprocessor.com/
username: uploadData
password: uploadTestData
Please make a folder with your name and issue like: DomHenry-Median-MBB-issue
and upload the data there and let me know once done 😉
Thanks,
Mabula
@mabula-adminÂ
Ok data is uploaded. It's Sagittarius Star Cloud. I included the created FITs files, one with MBB off and Median - the other with MBB on and MBB on and therefore Average. Towards the bottom of the images you will see the round IC1284 - in the MBB Off Median IC1284 has a flat side..... its all good with MBB On Average.
The data is from 9 sessions from different days - well different years too! They have different FOV too. They are from Vespera 2 - it produces scope stacked TIFFs - which can then be stacked together. I often do this type of processing - even using data from other people around the world and different Vaonis scopes. The TIFFs make this approach quite easy.
Dom
Hi Dom @domhenry,
Thank you very much for sharing this. We have received the upload in good order 😉
I will soon look at it and will get back to you.
Mabula
