Andor Technology iXon Ultra 897 User Manual page 83

• Exposure Time in seconds - i.e. the time during which the EMCCD
collects light prior to readout. The system will default to a minimum
Exposure Time should you attempt to enter too low a value.
•
Delay in seconds - i.e. the time you require between scans. The system will
default to a minimum delay should you attempt to enter too low a value: in
Video Mode the system will actually acquire data at a faster rate than it can be
displayed on the monitor.
As with Setup Image, the Video Mode Dialog box allows you set and control
various Binning Patterns, and define Sub Images of the CCD. These Dialog boxes
can only be accessed if the Use Settings From Standard Setup radio button in
disabled.
By default, taking an Acquisition supplies you with a count from each pixel on the
CCD, in effect allowing you to take a picture of the light pattern falling on the pixel
matrix of the CCD. This default is referred to as a Full Resolution Image. The
image may be viewed in grayscale or false color, or it may be displayed as 2D or 3D
traces.
However, for the purpose of initial focusing and alignment of the camera, or to
increase the readout speed, you may use the software to select a Sub Image of the
chip. When the iXon is running in Sub Image mode only data from the selected
pixels will be readout. Data from the remaining pixels will be discarded.
To read out data from a selected area, or Sub Image, of the CCD use the radio
buttons to select the resolution, which you require. The software offers a choice of
three defined sub images: 256 x 256, 128 x 128, and 64 x 64 pixels. There is also
an option for you to define a Custom Sub Image. This function allows you to set
the Sub Image to any size and location on the CCD chip. To define a Custom
Sub Image use the co-ordinate entry Dialog boxes to select the size and location of
your sub image.
As well as selecting a Sub Image of the CCD, you can also use a system of pixel
charge aggregation, known as Binning, to create superpixels. Superpixels consist
of two or more individual pixels that are binned and read out as one large pixel: the
CCD, or your selected sub-area, becomes a matrix of superpixels.
SETTING THE AQUISITION
Page 83
Sub Image
Superpixels
Section 4 . 5