Teledyne ProEM Series, Системное руководство

Страница: 99 / 162

Chapter 6 Advanced Topics 99
Figure 6-11: Typical LightField Sensor Expander: Kinetics Readout Mode
6.4.1 Kinetics Readout
Kinetics readout allows a burst of subframes to be captured with microsecond
resolution. This is accomplished by shifting each subframe exposure under the mask
before reading it out. Since there is no overhead of readout time between each
exposure, faster time resolution is achieved. At the end of a series exposure-shift cycles,
the entire frame is typically read out at a slower readout speed, which does not affect
the time resolution. The use of Multiplication Gain {EM Gain} in ProEM further improves
the SNR when the signal is below the read noise.
In Kinetics mode, a portion of the CCD image is optically masked in order to minimize
the cross-talk between subframes. Typically, in imaging applications, this is
accomplished by placing a knife edge or an optical mask in the collimated beam path.
Whereas, in spectroscopy, this is best achieved by limiting the height of the entrance slit
of the spectrograph. In most of the applications, the ability to mask as few rows as
possible sets the ultimate limit on the temporal resolution.
See
Figure 6-12 for two examples that comare using an optical test target image:
NOTE:
The illuminated area is the furthest from the serial register.
• The left image shows an illuminated area of 60 rows with a Window Size of 60
rows high.
• The right image shows an illuminated area of 12 rows with a Window Size of 12
rows high.
• A reduced number of rows in the right image illustrate a way to achieve better
time resolution between subframes.
• The timing diagram represents the exposure-readout sequence. Time
resolution between subframes is given by [t
exp
+ t
s
].
441
1-
0
12
6
_
0
0
5
6