Fast Readout Mode Artifacts Correction; Exposure Alignment: Overview; Synchronous Exposure Alignment; Reset Exposure Alignment - Teledyne m640 User Manual

Fast Readout Mode Artifacts Correction

With all Nano OnSemi sensor models: A simple software host based "Flat Line" correction available
with Sapera LT , can be used to eliminate this Fast Readout Mode artifact. Users can test this with
the Sapera CamExpert tool. Refer to the manual (Sapera Getting Started - Cameras) for
instructions in calibrating and using the software based Flat Line correction.
With specifically the Nano XL models: Enable the camera based Flat Line features as described in
the Flat Field Correction
Alternatively for maximum acquisition quality, disable Fast Readout Mode to eliminate
acquisition DN variances, at a small reduction of the maximum frame rate. Also remember that
high gain settings will increase overall sensor noise therefore additional gain should be used only
as necessary.

Exposure Alignment: Overview

Exposure Control modes define the method and timing of controlling the sensor integration period.
The integration period is the amount of time the sensor is exposed to incoming light before the
video frame data is transmitted to the controlling computer.
Exposure control is defined as the start of exposure and exposure duration.
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The feature Exposure Mode selects the controlling method for the exposure.
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The start of exposure is initiated by an internal timer signal, an external input trigger signal
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(Trigger Mode=ON), or a software function call.
• The exposure duration can be programmable (Exposure Mode = Timed, free run or external
trigger) or controlled by the external input trigger pulse width (Exposure Mode = TriggerWidth).
Note that different Nano models will support different combinations of exposure controls.
See also Trigger Overlap: Feature

Synchronous Exposure Alignment

Exposure is synchronous to the internal timing of the sensor. The readout is concurrent to the
exposure for the fastest possible frame rate.
When a valid trigger is received and the Exposure Time is shorter than the readout period, the
Exposure Start event is latched in the previous frame's readout. That is; the Exposure Start Event
is delayed and is initiated when the actual exposure starts such that the exposure ends and
readout begins as soon as the previous readout has completed.
• For Sony sensor models the exposure is synchronous to the line timing of the sensor. The frame
exposure start is subject to 1 horizontal line jitter.
The programmable exposure duration is in 1µs steps.
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Exposure duration is from a camera sensor specific minimum (in µs) up to 16 sec.
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Any trigger received before the start of frame readout is ignored and generates an invalid frame
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trigger event.

Reset Exposure Alignment

Sensor timing is reset to initiate exposure when a valid trigger is received. Readout is sequential to
exposure, reducing the maximum achievable frame rates. That is, a trigger received during
exposure or readout is ignored since data would be lost by performing a reset.
72 • Operational Reference
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Nano Series GigE Vision Camera