Optical Spatial Frequency Filtering of Image Sensors ?

Started Nov 20, 2012 | Discussions thread
gollywop Veteran Member • Posts: 8,245
Re: GH2 + LGV 7-14mm Image Deconvolution Experiments, Phase II

Detail Man wrote:

gollywop wrote:

Here, DM, are 6 versions: 3 from ACR with differing parameters and 3 using the Glenn Mitchell web script with differing level opacities. The ACR versions are named ACR x(0.5)y, where x is the amount, and y is the detail. All have radius 0.5. A detail of 100 is pure deconvolution, a detail of 0 is whatever the heck that means (nobody has given me a good answer to that question). The Glenn Mitchell versions are simply the percent opacity of the 100% effect.

I've had time only to do the "center" version.

Edit: after posting, I notice that the captions did not come through. I have found this bug in the new editor to have occurred in several of my posts.

These images are, in order:

ACR 150(0.5)0
ACR 60(0.5)50

Glenn Mitchell at 65%
Glenn Mitchell at 50%
Glenn Mitchell at 35%

Hi gollywop !

Am not sure what your reference to Glenn Mitchell refers to. Can you explain what was done ?

Did some searching on the internet, and found this:


Is that the method which you are referring to having used on those particular images ? Please advise.

My understanding is that it is not necessarily possible to improve an image's SNR using such techiques - though such techniques are a method for implementing particular tone-curve transfer-functions. Perhaps I am wrong about. Am interested as what your understanding may be.

Well, DM, I'm not sure what to say about Glenn Mitchell's sharpening techniques. They are available as PS actions and as scripts. They are excellent, and very involved. The problem is that they are a dying breed because Glenn has not continued to upgrade them for the latest PS versions. I believe they are still available for CS4 and CS5, but not CS6.

The only reason I was able to use his script on your image is because the WebSharpening script is the only one that continues to work with CS6. All the actions continue to work with CS6 but not the scripts. Unfortunately, the scripts are better. The actions use USM but the scripts use SmartSharpening, which is essentially deconvolution.

Glenn's techniques (separate for inkjet of various dpi and for web of various overall pixel sizes) make use of quite clever surface and edge masks along with blending options that prevent any highlight blowing from the edge boosts and level blends that prevent color shifts. Once applied their effects can be regulated by using the opacity sider on the group level.

Glenn has written a book on sharpening that is really quite a good and informative read. You can purchase a download version at


and you can find the scripts at


The site you went to, thelightsrightstudio.com is Glenn's photo studio. The resource site is at


You can get to the full set of tools from the home page; click on the Tools tab near the top.

I'm heartbroken that Glenn is not able to keep these wonderful tools up to date. I continue to use the actions for inkjet sharpening, but prefer the script for web sharpening. I suspect in another PS iteration or two none of them will work.

Meanwhile, I consider the Ronnie Gaubert technique as my backup for web sharpening. It appears to work amazingly (surprisingly) well and is very simple to apply. I couldn't try it on your image, since I would need a version of at least 1560 pixels for the first pass before reducing it to 936 (or whatever).

Glenn also has actions/scripts for capture sharpening, but they have been supplanted by the ACR sharpening facility. I use the ACR facility for my capture sharpening but rarely use it for output sharpening, which I do in PS.

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