Banding Noise on Canon PowerShot - What Causes This?

[anonymous]

I hope someone here can can help me with one small request. I have been using a Canon PowerShot G6 digital camera for some time now. I am working on a diploma project, its about analyzing image sharpness. One of my problems is "banding noise". I have spent hours searching the internet for some closer information about this problem but found nothing useful.

I have read also this site's tutorials about image noise and this seemed like the place to ask :-)

I would be very grateful if someone could clarify where banding noise actually comes from, not just what it is.

[McQ]

In short, banding noise = read-out noise. I am no expert on CCD and CMOS sensors, but here's a brief take on this:

Unlike other types of image noise, this is primarily induced by the way the pixels are read as opposed to from thermal noise or statistical variation in the number of photons reaching each site. It results from the pattern/way at which the pixels are read (multiple simultaneous read-outs), combined with performing this read-out at a high speed.

Many newer cameras have problems with banding noise primarily because the pixel information is read in parallel (by several read-out channels) in order to increase how fast they can access the pixel values--and therefore how high of a frame rate the camera can achieve.

While I know this is not your camera, the Canon 20D, for example, has a 4-channel read-out system which allowed it to up the frame rate, but at the expense of increased banding noise in the shadows.