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Chapter 7
MicroMAX DIF Camera
(Double Image Feature)
Supported by WinView/WinSpec Version 2.5 when the communication protocol is
TAXI (PCI), this feature is not supported when the protocol is USB 2.0.
Introduction
This chapter describes operation of the MicroMAX DIF system. Both the Controller and
a MicroMAX Interline camera must have factory modifications installed for DIF
operation. In addition to the internal changes, a camera modified for DIF operation would
ordinarily include a mechanical shutter. Execution of the DIF functions is done via the
WinView/32 software (v2.2 or higher), which, when controlling a DIF system, provides
three timing modes unique to DIF systems.
Basically, a DIF system is one that has been factory
modified to allow images to be taken
in pairs with very short exposure times (as small as 1 µs). This capability makes it ideal
for use in experiments where the goal is to obtain two fast successive images for the
purpose of characterizing a time-differentiated laser-strobed process. LIF and velocity
measurements are specific measurements that can be easily performed using the DIF
system.
The ability of the interline chip to quickly transfer an im
age under the masked columns
and hold it there makes this method of acquiring images possible. As soon as the first
image is acquired, it is shifted under the masked area and held. The second exposure
begins and is continuously held in the photodiode region until the mechanical shutter
closes. Light entering the camera while waiting for the shutter to close is small compared
to that captured during the strobed event and has little effect on the acquired data.
In addition to the Free Run mode, which allows single image acquisitions, three DIF
tim
ing modes, IEC (Internal Exposure Control), EEC (External Exposure Control) and
ESABI (Electronic Shutter Active Between Images) are provided. Each works basically
as follows.
IEC: Allows two successive fast im
ages of equal duration to be acquired, with the second
image acquisition taking place immediately after the first. Acquisition is initiated by
applying a single externally derived trigger to the controller's Ext. Sync connector.
EEC
rived trigger to the controller'
s Ext. Sync
connector, the same as in IEC operation.
: Allows two successive fast images of differing duration to be acquired, with the
second image acquisition taking place immediately after the first. Acquisition is
initiated by applying a single externally de
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