Binned Readout (Hardware Binning); Table 3. Readout Rates For Kodak 1024 × 1024 Array At 5 Mhz - Princeton Instruments PI-MAX System Manual

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The readout time is approximately given by:
where
The readout rate in frames per second for the PI-MAX2:1003 Kodak 1024 × 1024
interline array running at 5 MHz is shown in Table 3.
A subsection of the CCD can be read out at full resolution, sometimes increasing the
readout rate while retaining the highest resolution in the region of interest (ROI).

Binned Readout (Hardware Binning)

Introduction
Binning is the process of adding the charge from adjacent pixels together to form a single
pixel (sometimes called a super-pixel), and it can be accomplished in either hardware or
software. Rectangular groups of pixels of any size may be binned together, subject to
some hardware and software limitations.
Hardware binning reduces readout time and the burden on computer memory by
summing charge before the preamplifier reads out the signal. For signal levels that are
readout noise limited this method improves S/N ratio linearly with the number of pixels
grouped together. For signals large enough to render the camera photon shot noise
limited, the S/N ratio improvement is roughly proportional to the square-root of the
number of pixels binned. In the WinX application, hardware binning is set up on the
Acquisition|Experiment Setup...|ROI Setup tab card by entering a value in the
Group fields: for example, a "2" in each of the Group fields will set up 2 x 2 hardware
binning.
Limitations of hardware binning include:


PI-MAX/PI-MAX2 System Manual
t
R
N is the smaller dimension of the CCD
x
N is the larger dimension of the CCD.
y
t is the time needed to shift one pixel out of the shift register
sr
t is the time needed to digitize a pixel
v
t is the time needed to shift one line into the shift register
i
Region of Interest Size
Binning 1024 × 1024
1 × 1
2 x 2
4 × 4
Table 3. Readout Rates for Kodak 1024 × 1024 Array at 5 MHz
Lowered resolution because charge from adjacent pixels is summed into a super
pixel.
Increased possibility to blooming. Because shift register pixels typically hold only
twice as much charge as image pixels, the binning of large sections may result in
saturation and spilling of charge back into the image area
= [N · N · (t + t )] + (N
x y sr v
400 × 400
4 10
8 17
15 27
Version 5.F
· t )
x i
200 × 200
17
27
37
(2)