Revision as of 11:52, 24 January 2011

What is it?

Pixel Binning refers to the method of combining blocks of photosites on the sensor into a bigger "virtual" photosite. This is an on-sensor-feature.

Articles describing "Binning" (also sometimes refered to as "Pixel Binning")

http://www.ccd.com/ccd103.html

http://www.imagingu.com/articles/binning.html

http://www.echenique.com/index.php/2009/05/16/phaseone-sensor-pixel-binning-and-the-future-of-digital-photography/

http://www.ptgrey.com/support/kb/index.asp?a=4&q=163

Pixel Binning in Elphel Cameras

Using Binning you can:

• lower the resolution of an image while using a bigger sensor area
• achieving higher FPS for the same resulting resolution
• decrease image noise (averaging) or increase light sensitivity (summing)

But be careful: Binning/Decimation effectively results in skipped pixels (both horizontally and vertically) meaning smooth lines will be subject to stepping/block artefacts!

Binning Modes

The "normal" Binning mode averages the charges from photosites in the same "bin" thus reducing noise in the image but not altering light sensitivity. [1]

There is an alternative mode that sums up the charges and therefore makes the binned pixel more light sensitive. [2]

In Elphel Camera (since 8.X Software) the different binning modes can be set at http://*cameraIP*/parsedit.php?embed=0.18&SENSOR_REGS32

The default value is "0x40" which means averaging binning mode.

If you set it to "0x60" you switch to summing binning mode and will get increased light sensitivity.

Using PHP you can access this register with:

echo elphel_get_P_value(ELPHEL_SENSOR_REGS+32);