Looking for a USM filter with 8 pixel radius.

peterhuh · 16th August 2014, 17:45

Hi!

I have this film in high definition but extremely soft focus. According to my pixel counting, the soft focus had a glow radius of about 8 pixels.

I was thinking of using a vanilla unsharp masking filter like those found in Photoshop and GIMP to "subtract" out the soft glow with USM's halo.

It works quite well in GIMP, but I had problem locating an equivalent filter for AVISynth. Most sharping filter uses 3x3 kernels which unsharps film grain rather than removing the soft glow.

I was wondering if anyone knows a USM filter with an option to adjust the radius. I never had a need to use a sharpener until now. Thanks in advance.

colours · 16th August 2014, 21:08

There're a couple of USM filters (and other sharpeners) linked on the wiki.

raffriff42 · 17th August 2014, 04:56

I know of two good ways;
- with VariableBlur by Tritical:

Code:

# http://avisynth.nl/index.php/Variableblur
# http://forum.doom9.org/showthread.php?t=88645
# (libfftwf3-3.dll needs to be in the search path)
LoadPlugin(pathBase + "variableblur07\variableblur.dll") 

#@function Unsharp(float "varY", float "varC", float "strength"[0-1], int "border"=4,
##\               bool "integrate"=false, int "Y"=3, int "U"=2,int "V"=2,
##\               int "gfunc"=-1, int "gfuncc"=-1, int "pcr"=0, int "pcrc"=0, int "nthreads")
##
Unsharp(varY=Sqrt(8.0), varC=Sqrt(4.0), strength=0.7)

- and with NonlinUSM by Didée:

Code:

## posted at:
# http://forum.doom9.org/showthread.php?p=1555234#post1555234

#@function NonlinUSM(clip o, float "z", float "pow", float "str", 
##\                 float "rad", float "ldmp")
## @ z    - default 6     (3 = subtle; 16 = massive)  
## @ pow  - default 1.6   (1.0 = oversharp; 4.0 = mild)  
## @ str  - default 0.7   (3 = strong; 18 = massive) 
## @ rad  - default 9     (0.6 = sharpen; 18 = soft) 
## @ ldmp - default 0.001 (block overlap? 0.01 = a little smoother?)
##
NonlinUSM(z=6, pow=1.0, str=0.7, rad=8.0)

NonlinUSM is much more versatile; recommended.
EDIT - for example:

Code:

NonlinUSM(pow=4)                          ## enhance: for low bitrate sources
NonlinUSM(z=3, pow=4.0, str=1, rad=6)     ## enhance less 

NonlinUSM(z=6, str=1.5, rad=0.6).Sharpen(0.3)  ## sharpen: for hi-q sources
NonlinUSM(z=3, str=2.5, rad=0.6)          ## sharpen: less noise
NonlinUSM(z=6, pow=1.0, str=0.7, rad=6.0) ## unsharp 

NonlinUSM(pow=1.0, rad=2, str=0.7)        ## smoothen: for noisy sources
NonlinUSM(pow=1.0, rad=18, str=0.5)       ## smear: soft glow

NonlinUSM(z=16, pow=4.0, str=18, rad=6)   ## B+W psycho 
NonlinUSM(z=16, pow=4.0, str=3, rad=6)    ## sepia/artistic 
NonlinUSM(z=6, pow=4.0, str=1, rad=36)    ## local contrast 
NonlinUSM(z=6, pow=1.0, str=1, rad=36)    ## local contrast 
NonlinUSM(z=16, pow=2.0, str=2, rad=36)   ## solarized

peterhuh · 17th August 2014, 16:02

NonlinUSM seems to do the trick!

Thanks!

zerowalker · 17th August 2014, 22:13

Mind showing Before/After, out of interest?

16th August 2014, 17:45	#1 \| Link
peterhuh Registered User Join Date: Jul 2003 Location: Singapore Posts: 26	Looking for a USM filter with 8 pixel radius. Hi! I have this film in high definition but extremely soft focus. According to my pixel counting, the soft focus had a glow radius of about 8 pixels. I was thinking of using a vanilla unsharp masking filter like those found in Photoshop and GIMP to "subtract" out the soft glow with USM's halo. It works quite well in GIMP, but I had problem locating an equivalent filter for AVISynth. Most sharping filter uses 3x3 kernels which unsharps film grain rather than removing the soft glow. I was wondering if anyone knows a USM filter with an option to adjust the radius. I never had a need to use a sharpener until now. Thanks in advance. __________________ Oh! Signature! My very own Signature! What should I put?! What can I write?! I must write something! Something that everyone can see! And it will appear at the bottom of my every post! Then everybody will be able to read my signature! Nobody will not read my signature! Somebody will tell others to read my signature! Which will be at the bottom of my every post! And i ca...<cropped>

17th August 2014, 16:02	#4 \| Link
peterhuh Registered User Join Date: Jul 2003 Location: Singapore Posts: 26	NonlinUSM seems to do the trick! Thanks! __________________ Oh! Signature! My very own Signature! What should I put?! What can I write?! I must write something! Something that everyone can see! And it will appear at the bottom of my every post! Then everybody will be able to read my signature! Nobody will not read my signature! Somebody will tell others to read my signature! Which will be at the bottom of my every post! And i ca...<cropped>

16th August 2014, 21:08	#2 \| Link
colours Registered User Join Date: Mar 2014 Posts: 308	There're a couple of USM filters (and other sharpeners) linked on the wiki.

17th August 2014, 22:13	#5 \| Link
zerowalker Registered User Join Date: Jul 2011 Posts: 1,121	Mind showing Before/After, out of interest?