Andor Technology iXon Ultra 897 User Manual page 40

ELECTRON MULTIPLYING CCDS
Vertical and Horizontal Binning
Binning is a process that allows charge from two or more pixels to be combined on
the EMCCD-chip prior to readout (see Readout Sequence of a EMCCD above.)
Summing charge on the EMCCD, and doing a single readout gives better noise
performance than reading out several pixels and then summing them in the computer
memory. This is because each act of reading out contributes to noise.
There are two main variants of the binning process: vertical binning and horizontal
binning (described below). In addition there are several binning patterns that tailor
the main binning variants to typical application usage.
Vertical Binning
In Vertical Binning, charge from two or more rows of the EMCCD-chip is moved
down into the shift register before the charge is read out. The number of rows
shifted depends on the binning pattern you have selected. Thus, for each column of
the EMCCD-chip, charge from two or more vertical elements is 'summed' into the
corresponding element of the shift register. The charge from each of the pixels in
the shift register is then shifted horizontally to the output node of the amplifier and
read out.
The following example illustrates readout of data from adjacent tracks, each track
comprising two binned rows of the EMCCD-chip.
Section 3 . 1
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