Sunday, August 21, 2011

What's the professional approach to removing noise from a cell phone pic?

Question

I have a cell phone photo that's a bit grainy and slightly blurry. It's not the out-of-focus type of blur, but the blur brought on when edges run together due to lack of sharpness.

I have Adobe Photoshop CS5 and have used Filters > Noise > Reduce Noise. After playing with the options, I finally got a decent look. The options I used are Strength:5, Preserve Details:0, Reduce Color Noise:0, Sharpen Details:100.

Are there other more effective ways to remove grain noise and blur from a cell phone pic? What would the pros do provided they use CS5?

Answer

These days, I would think pros use tools like Adobe Lightroom as much as Photoshop. Lightroom 3.x specifically is particularly well suited to removing noise as it uses a newer, more advanced algorithm to do so. It may also be the case that the latest version of ACR (Adobe Camera RAW) for photoshop has the same noise reduction tools if you happen to be using RAW. Lightroom will work with JPEG images as well as RAW, however, so its advanced noise reduction should still be viable for a cell phone photo. Lightroom is quite a bit cheaper than Photoshop as well, currently listing at $299.

I would say a moderate amount of luminance noise reduction, 60-80, would be sufficient to clear up a cell phone pic to reasonable levels. I would still throw back in some sharpening, to offset the effects of noise reduction and the blur (which is probably diffraction softening, given that it was a cell phone photo...they tend to have excessively small sensors with extremely high MP count, which when paired with the incredibly small apertures for the tiny lens, usually results in a fair amount of diffraction softening.) As far as sharpening tools, Lightroom's is ok, but not superb. Photoshops Smart Sharpen filter is probably one of the better sharpening tools. There are also a variety of other manual sharpening techniques that you can find around the web that involve various layer duplications, inversions, filtrations, and blending modes to achieve. Some algorithms and procedures are better for some types of photography, while others are better for different types of photography (i.e. how you sharpen a landscape would be different from how you sharpen a portrait.)

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