Readout Of The Array; Interline Ccd Readout; Figure 9. Interline Ccd Readout - Princeton Instruments PI-MAX 3 System Manual

Chapter 5
Corrections tab. Then, acquire the image, save the raw image data to disk, and, via
the Image (or Spectra) Math function (accessed from the Process menu), subtract
the background file data from the raw image data. The subsequent data can then be
saved to a separate file.

Readout of the Array

At the end of the exposure, the charge from the pixels is shifted to the shift register, amplified,
and digitized. Depending on the experiment design, binning may also occur as part of the
readout operation..
For the PI-MAX3:1024x1024 camera, dual port readout mode is selected whenever full
image readout is selected or when the region of interest (ROI) is defined to be
horizontally symmetrical and centered. Single port readout is activated when the ROI is
not horizontally symmetrical and centered. The same rules apply whether or not binning
is utilized. Readout in single port mode may be slower than dual port mode readout. The
port used for single port mode is dictated by the CCD design.
For the PI-MAX:1024x256, signal is read out of a single port.

Interline CCD Readout

In this section, a simple 6  3 pixel
interline CCD is used to demonstrate
how charge is shifted and digitized
using a single port. As described
below, two different types of readout,
overlapped and non-overlapped can
occur. In overlapped operation, each
exposure begins while the readout of
the previous one is still in progress. In
non-overlapped operation (selected
automatically if the exposure is
shorter than the readout time) each
readout goes to completion before the
next exposure begins.
Non-Overlapped Operation Exposure and Readout
Figure 10 illustrates exposure and readout when operating in the non-overlapped mode.
Non-overlapped operation occurs automatically any time the exposure is shorter than the
readout time. Figure 10 contains four parts, each depicting a later stage in the exposure-
readout cycle.
Part 1 of the figure shows the array early in the exposure. The imaging cells contain charge
proportional to the amount of light integrated on each of them. The storage cells are empty
because no charge has been transferred to them. The arrows between adjacent imaging and
storage cells indicate the direction the charge will be shifted when the transfer occurs.
Part 2 of Figure 10 shows the situation early in the readout cycle. The charge in the imaging
cells has been transferred to the adjacent storage cells and up-shifting to the readout register
has started. Note that a second exposure does not begin while the readout is in progress.
Part 3 of Figure 10 shows the transfer to the output node. The lowermost cell in each
column is shown empty. Each row of charges is moved in turn into the readout register,
General Operation Factors

Figure 9. Interline CCD Readout

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