Interleaved Line-scan Acquisition Principles
System Description
Main elements of an line-scan acquisition system configured for Interleaved Area-scan Acquisition
The system is composed of:
| ● | One asynchronous reset grabber-controlled exposure line-scan camera. |
| ● | One acquisition channel of a compatible frame grabber configured for Interleaved Line-scan acquisition. |
| ● | Two illumination devices, each being controlled by a specific strobe output of the frame grabber. |
Usually, the Line Trigger event is obtained by processing signals delivered by a motion encoder. As for any line-scan imaging systems, it can be processed by the rate converter or the rate divider.
Usually, the Trigger and the EndTrigger events are delivered by a presence detector.
WEB, PAGE and LONGPAGE line-scan acquisition modes are compatible with Interleaved Line Acquisition.
Operation
The Interleaved Acquisition feature allows to capture, in a single scanning operation, a composite image where the odd and even lines are captured with different exposure time, strobe duration, strobe delay and strobe output settings.
As shown on the following diagram, the Camera and Illumination Controller executes both programs alternatively: P1 then P2 then P1 … :
Acquisition sequence showing the alternating P1 and P2 cycles
Note: In this example, the line trigger interval is larger than the minimum allowed.
The toggling program sequence is reset at every start-of-scan to ensure that the first captured image line of a scanned object is always built using P1.
In WEB acquisition mode, a reset occurs only once at the beginning of the acquisition sequence.
In PAGE acquisition mode, a reset occurs at the beginning of every acquisition phase.
In LONGPAGE acquisition mode, a reset occurs at the beginning of the first acquisition phase of every acquisition sequence. No reset occurs at the beginning of the subsequent phases of the same sequence.