Comparison of sharpening techniques for Lunar Images

sheeny (Al) · #1 11-12-2006, 10:02 PM

Just playing around with different sharpening techniques for lunar images. I thought it would be interesting to compare Unsharp Masking, Wavelets, and High Pass Filtering.

I must admit to not thinking too much about masking when applying an unsharp mask in the past. Playing aorund with the high pass technique has helped me to realise the value of a mask to help to avoid burning out the brighter edges of lunar craters with the USM. We go to a lot of trouble to get the exposure right and and make good use of the histogram but often even a little bit of USM saturates the bright points. A mask allows them to be dropped back inside the dynamic range of the histogram.

The images are as follows:
First:
Unsharpened

Second:
Registax Wavelets, Gaussian Linear, 10.6, 4.4, 1.0, 1.0, 4.4, 11.2

Third:
PS Unsharp Mask, whole frame, 0 threshold, 1 pixel radius, 200%

Fourth:
PS High Pass Filter Mask, 10 pixel radius, burned out rims masked only

Fifth:
PS High Pass Filter Mask applied twice, 10 pixel radius, burned out rims masked only

Al.

[1ponders] (Paul) · #2 11-12-2006, 10:16 PM

Third one does it for me Al

joe_smith · #3 12-12-2006, 04:27 AM

Second one. Its brighter and more sharper on my LCD moniter

iceman (Mike) · #4 12-12-2006, 06:11 AM

2nd for me too.. can you post a "raw" so we can have a play too?

sheeny (Al) · #5 12-12-2006, 07:38 AM

Sometimes I like the wavelets and other times USM. I guess somethings work better on some images... Maybe better results can be achieved with High Pass

...I only learned the technique last night so maybe more fiddling and experimentation required.

Mike I'll post a TIFF to the members upload area tonight if you like. I'll probably have to find the instructions on how to do that

.

Al.

iceman (Mike) · #6 12-12-2006, 07:41 AM

No worries Al, follow the instructions here: IIS FTP Service

PM me for the password.

Robert_T · #7 12-12-2006, 01:22 PM

Hey Al, which one's which? I like the second from the top down the left margin - apprears to have the best overall balance to my eyes.

cheers,

stephenmcnelley · #8 12-12-2006, 01:28 PM

2nd, the details jump out at you, the 3rd is a bit smoother though.

ving (David) · #9 12-12-2006, 04:42 PM

i'm with stephen... if kyou want a stck of detail the secondone is best but the 3rd looks more natural.

nice comaprision

sheeny (Al) · #10 12-12-2006, 05:09 PM

Quote:

Originally Posted by Robert_T

Hey Al, which one's which? I like the second from the top down the left margin - apprears to have the best overall balance to my eyes.

cheers,

Robert,

The list 1 st to 5th in the original post is the order they are in from top left to bottom right (across the page first...)

Al.

Robert_T · #11 12-12-2006, 05:48 PM

Quote:

Originally Posted by sheeny

Robert,

The list 1 st to 5th in the original post is the order they are in from top left to bottom right (across the page first...)

Al.

Thanks Al, must be my formatting or something as I don't see a bottom right, just three across and three down the left margin. I get the idea though

sheeny (Al) · #12 12-12-2006, 08:52 PM

For those who are interested to have a play with the same image I started from it's now been uploaded to the IIS upload area:

http://www.iceinspace.com.au/uploads/0010Moon1.zip

Enjoy,

Al.

EDIT: PS It's about 521M zipped!

iceman (Mike) · #13 13-12-2006, 07:24 AM

I think you mean 520kb, not mb, Al.. you may have scared some people off

I've just downloaded it, will have a play.

iceman (Mike) · #14 13-12-2006, 07:43 AM

Ok here's my attemps:

1. Registax soft wavelets, followed by levels, high-pass filter and smart-sharpen in Photoshop.

2. LR deconvolution in AstraImage, followed by levels, high-pass filter and smart-sharpen in Photoshop.

3. Raw image, followed by levels, high-pass filter and smart-sharpen in Photoshop.

In the end they all came out fairly similar.. I guess that says something for my taste in lunar images more than anything else.

sheeny (Al) · #15 13-12-2006, 03:43 PM

Quote:

Originally Posted by iceman

I think you mean 520kb, not mb, Al.. you may have scared some people off

I've just downloaded it, will have a play.

Whooooopppssss!!!!!

They're only 2 letters apart in the alphabet and practically next door on the keyboard!!!

Al.

spearo (Frank) · #16 17-12-2006, 07:46 AM

Hi
I like the 2nd of Mike's and the third and fourth of Al's
I especially like the use of the word "comparison" in the title as it drew my attention to it right away as well as for future reference
thanks
frank