# Spy movie cliche: Cleaning up fuzzy pictures **URL:** \ **Category:** Factual Questions\ **Created:** [September 26, 2001, 1:27pm UTC](https://boards.straightdope.com/t/spy-movie-cliche-cleaning-up-fuzzy-pictures/83903 "2001-09-26T13:27:23Z")\ **Posts on this page:** 7\ **Page:** 2
**Author:** ![pulykamell](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pulykamell/32/3166_2.png) [@pulykamell](https://boards.straightdope.com/u/pulykamell)\ **Post date:** [September 27, 2001, 3:44pm UTC](https://boards.straightdope.com/t/spy-movie-cliche-cleaning-up-fuzzy-pictures/83903/21 "2001-09-27T15:44:53Z")
[Here](http://www.cs.uwa.edu.au/~pk/Forensic/ForensicDetails.html) is what I found that demonstrates forensic imaging. The amount of detail that can be recovered is fairly significant, but from this particular example, it’s not even close to what you get in the movies. **Chas** , now is this a typical example of image enhancement, or is technology significantly beyond this? ---
**Author:** ![Arjuna34](https://avatars.discourse-cdn.com/v4/letter/a/eb8c5e/32.png) [@Arjuna34](https://boards.straightdope.com/u/Arjuna34)\ **Post date:** [September 27, 2001, 3:55pm UTC](https://boards.straightdope.com/t/spy-movie-cliche-cleaning-up-fuzzy-pictures/83903/22 "2001-09-27T15:55:06Z")
> [@](#): > > \*Originally posted by pulykamell \* > \*\*Why didn’t they use deconvolution technology when they realized the Hubble telescope was focused on the wrong point? > … > Presumably, they knew all the data regarding the blurring, or else they would not be able to create the optical fix for it as they did. \*\* As **Chas.E** points out, they did. It wasn’t a great solution, though, because of the nature of the problem. Instead of focusing the image on the collector, the light was scattered around, with a good bit of it missing the collector altogether. Thus, the entire image wasn’t captured, and therefore it couldn’t be completely recovered. Here’s one paper about it: [Iterative/Recursive Image Deconvolution. Method and Application to HST Images](http://cadcwww.dao.nrc.ca/ADASS/adass_proc/adass3/papers/fulltonl/fulltonl.html). Arjuna34 ---
**Author:** ![Chas.E](https://avatars.discourse-cdn.com/v4/letter/c/e99b99/32.png) [@Chas.E](https://boards.straightdope.com/u/Chas.E)\ **Post date:** [September 27, 2001, 4:00pm UTC](https://boards.straightdope.com/t/spy-movie-cliche-cleaning-up-fuzzy-pictures/83903/23 "2001-09-27T16:00:11Z")
> [@](#): > > \*Originally posted by pulykamell \* > \*\ ***Chas** , now is this a typical example of image enhancement, or is technology significantly beyond this? \*\* I’ve seen much better work, but alas, I’ve been unable to find a good web cite. Geez, you’d think people would be promoting their best work via the web. ---
**Author:** ![Futile\_Gesture](https://avatars.discourse-cdn.com/v4/letter/f/f05b48/32.png) [@Futile\_Gesture](https://boards.straightdope.com/u/Futile_Gesture)\ **Post date:** [September 27, 2001, 5:06pm UTC](https://boards.straightdope.com/t/spy-movie-cliche-cleaning-up-fuzzy-pictures/83903/24 "2001-09-27T17:06:43Z")
> [@](#): > > \*Originally posted by Chas.E \* > I think you Futile Gesture ought to take a course in basic Forensic Imaging. It is quite possible to reconstruct information beyond what in a photograph (up to a point). But this is almost impossible to explain unless you are good with calculus. I have seen many examples of forensic photography where blurred data is sharpened up to the level of clear visibility. I’m willing to admit you know more about Forensic Imaging Chas, but I can’t see how you can possibly derive more information from a blurred photograph without a certain degree of guesswork. A photo is just information. Once you have reached the basic constituent part of the information then surely there is no more? To simplify; In a B/W photo the blob is a shade of grey, ranging from black to white. You cannot breakdown the blob into further smaller shaded blobs because the bounderies of these smaller blobs aren’t defined. They just aren’t there. All you’re going to get is an arbitary number of identical smaller blobs that amount to exactly the same thing you had to begin with. Now, you can apply any amount of effects, filters, calculus and jiggery poker you want to on the photo, and come up with a best guess of what may lie within the blob. The guess may even be spot on. But it’s always going to be a **guess** because all the photograph can tell you for certain is that it’s a solid blob. Isn’t it a universal truth; you can’t make something out of nothing? This addition detail has to have come from somewhere. It’s come from the process you’ve applied, not the photograph which is merely a starting point. The only other route for investigation I can see is an analysis of the chemistry of the photo emulsion. It may tell you more about what kind of lit detail could produce what kind of blob, but there would still be a large degree of guesswork and selection within multiple possibilities. ---
**Author:** ![Chas.E](https://avatars.discourse-cdn.com/v4/letter/c/e99b99/32.png) [@Chas.E](https://boards.straightdope.com/u/Chas.E)\ **Post date:** [September 27, 2001, 5:17pm UTC](https://boards.straightdope.com/t/spy-movie-cliche-cleaning-up-fuzzy-pictures/83903/25 "2001-09-27T17:17:31Z")
> [@](#): > > \*Originally posted by Futile Gesture \* > **Isn’t it a universal truth; you can’t make something out of nothing? This addition detail has to have come from somewhere. It’s come from the process you’ve applied, not the photograph which is merely a starting point.** That’s the whole trick. There IS information there, it just isn’t in visible form. ---
**Author:** ![Arjuna34](https://avatars.discourse-cdn.com/v4/letter/a/eb8c5e/32.png) [@Arjuna34](https://boards.straightdope.com/u/Arjuna34)\ **Post date:** [September 27, 2001, 5:34pm UTC](https://boards.straightdope.com/t/spy-movie-cliche-cleaning-up-fuzzy-pictures/83903/26 "2001-09-27T17:34:06Z")
> [@](#): > > \*Originally posted by Futile Gesture \* > \*\* > A photo is just information. Once you have reached the basic constituent part of the information then surely there is no more? To simplify; In a B/W photo the blob is a shade of grey, ranging from black to white. You cannot breakdown the blob into further smaller shaded blobs because the bounderies of these smaller blobs aren’t defined. They just aren’t there. All you’re going to get is an arbitary number of identical smaller blobs that amount to exactly the same thing you had to begin with. > … > Isn’t it a universal truth; you can’t make something out of nothing? This addition detail has to have come from somewhere. It’s come from the process you’ve applied, not the photograph which is merely a starting point. > \*\* But information _is_ on the film, it’s just invisible to the naked eye. There is information in those “featureless” blobs, even though it may not appear that way. None of these de-blurring techniques add information, just rearrange it so it’s visible to us humans. Think of a camera, out of focus, with the out-of-focus image hitting the film. Now, theoretically, if you knew the precise way it’s out of focus, you could construct a lens that would go in front of the film to refocus the light. This “lens” can be a physical lens, or a digital one done mathematically after the fact, _assuming the film captured the unfocused blobs accurately enough_, and assuming you have some idea of the original image and lens, and misfocus. The blurring function shape can be estimated with some knowledge of the blurring. Blur from an out-of-focus lens tends to create a smooth circularly symmetric lowpass filter, since most lenses are thin and circular. Blur from atmospheric turbulance tends to be gaussian. Blur from camera movement (or object movement) tends to have a sinc-shaped transfer function. Once you know the shape, you can often reduce the exact function to just estimating a few parameters. For a misfocused camera of known, if you know which camera and lens were used, the problem is merely estimating a single number, since the only variable would be the linear distance from the lens to the film. Arjuna34 ---
**Author:** ![Popup](https://avatars.discourse-cdn.com/v4/letter/p/94ad74/32.png) [@Popup](https://boards.straightdope.com/u/Popup)\ **Post date:** [September 28, 2001, 7:08am UTC](https://boards.straightdope.com/t/spy-movie-cliche-cleaning-up-fuzzy-pictures/83903/27 "2001-09-28T07:08:02Z")
I considered starting a new thread for this, but I think it would fit nicelly in here. I just read an article that claimed that **Retinex** is the best thing since sliced bread. It’s a one-size-fits-all algorithm for enhancing images, purportedly influenced by the way the human eye-brain complex handles images. (retinex - retina, get it?) NASA have invested quite a lot into making this a fully automatic procedure to treat satelite images, but claim that it works equally well for consumer pictures. The samples at their [website](http://dragon.larc.nasa.gov/viplab/retinex/background/background.html) are impressive. I can’t wait to find a plugin for GIMP or Photoshop. But before I get to excited I thought I’d put it to the test of SDMB: Does anyone have any info on it? Is it as good as they say? Are there any plugins available? [Previous page](https://boards.straightdope.com/t/spy-movie-cliche-cleaning-up-fuzzy-pictures/83903.md?page=1)