Wavelets

[bsn...@gmail.com]

Good afternoon Eduard and Alex.

While watching ezCol slowly collecting drift scan data on a Raspberry Pi and my repaired and old 3-D corner reflector I was looking though the archives and found a posting from Apr 19, 2026 wherein Eduard asked:

“I know planetary imagers use techniques like wavelet sharpening and drizzle to go a bit beyond the resolution that the seeing and their equipment can offer in real-time, however I don't know much about the details behind these image processing techniques and how far one can stretch this. Has anyone here tried any of these techniques from optical astronomy on radio astronomy data?”

I have no idea whether wavelets have been used in any kind of astronomy but I’d be surprised if they haven’t been.

In a former life when I used satellite “imagery” to study glaciers and ice sheets, mostly in the Arctic, I used wavelet transforms. If you are interested how such things change over time then the oldest images and the newest images are the ones you want. But...often the oldest image(s) are panchromatic, black-and-white with a pixel/spatial resolution of 100 or 300 meters IF you are lucky. More modern images consisting of multiple frequencies (colors) have spatial resolutions of 30m or 5m or even less.

Would it not be nice IF you could so how make the old images have the same or similar spatial resolution as the new images?

And you can using wavelet transforms in a process called image fusion. Wonderful “magic” but with all such magic be careful you are not “seeing” something in the old image that is not REALLY there.

Been 10 years since I played with this stuff...a winter project?….

Thanks to you both…..bill sneed….

[Alex P]

Hello Bill, 

With regards to large areas of emission as H1 clouds, I have no idea if more sophisticated processing is applicable.

And, you're working with a One Pixel Spectrograph.

I put this comparison together for your perusal : ..  both drifts at Dec +30 degrees through RA 18-24 Hrs

my 1.2 m vs a 12. m Dish

Cheers,

Alex

[bsn...@gmail.com]

Thanks Alex,

I think your demonstration may answer Eduard's question ....if I understood it...

That said, people are finding other uses in radio astronomy for wavelets than image analysis.

I stumbled upon the following but have only read the abstract....looks interesting.....

"Wavelets and Multiresolution Analysis in Radio Interferometry
Matyas Molnar and Bojan Nikolic
Astrophysics Group, Cavendish Laboratory, University of Cambridge
20th October 2022"

Again, thanks Alex...you folks here are a constant source education and entertainment......bill.....