Sunday, February 26, 2012

The Problem of Blur

We've all done it. It's too dark, or we're not steady enough or we've left our camera on some odd settings. Now we've got a blurry picture. Our first instinct is probably to erase it and take another try. That's probably not a bad idea. If that's not an option, however, what can be done?

Unfortunately, the current answer is -- not much.

Software Limitations

Current graphics programs, even the several hundred dollar ones, have limited options for sharpening blurred pictures. Common fixes are Sharpen Gaussian Blur and Sharpen Motion Blur. The first attempts to fix 'soft' images and the latter fixes *single direction* motion.

The problem is, of course, that blur motion is more often little curves, wiggles or at the very least - not a uniform speed.

A more sophisticated approach is being looked at here.

Image Limitations

The second problem, is that blur is destructive - meaning that information is overwritten or mangled. Bright objects leave trails that overwhelm other picture elements. Areas of similar brightness muddle together.

Having the picture taken in RAW mode helps, as all the information is saved. That means that there's no 'averaging' of colours or extra noise from lossy compression.

2D vs 3D

When you're fixing a image, you're working with a 2 dimensional representation of a 3 dimensional space. If you're only changing the brightness or saturation, this really doesn't matter. Blur, however, is a different sort of problem.

Objects that are closer blur differently than objects that are farther away. More or less depends on the type of movement.

To illustrate, next time you're in a vehicle try two different things. First, turn your head about 30 degrees. Closer objects have barely moved at all in your field of view, but things at a distance have. Next move your head a bit to the right (or left if you drive on that side of the road). The opposite has happened -- nearby objects have 'jumped' and next to no change at long distances.

Applying any type of uniform solution will not work - necessitating sections and/or masking to get the best result.


Shadowsdream said...

Well written explanation to the problem. My advice to resolve is: don't take blurry pictures (unless you want them or are okay with them) haha.

James said...

There's a few times where blur can be used to enhance the picture. More often than not it's accidental - and still difficult to do artificially Here

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