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Overlapping Image Acquisition#

With overlapping image acquisition, the exposure of a new image begins while the camera is still reading out the sensor data of the previous image.

This is useful if you want to increase the frame rate of your camera.

Prerequisites#

How It Works#

Non-Overlapping Image Acquisition#

Whenever the camera is able to complete the entire image acquisition process (exposure + readout) before the next image acquisition starts, images will not overlap.

On cameras configured for Global shutter mode, non-overlapping image acquisition looks like this (using Trigger Width exposure mode as an example):

Non-Overlapped Mode of Operation (Global Shutter Mode)

On cameras configured for Rolling shutter mode, non-overlapping image acquisition looks like this (using Timed exposure mode as an example):

Non-Overlapped Mode of Operation (Rolling Shutter Mode)

Overlapping Image Acquisition#

With overlapping image acquisition, the camera exposes a new image while still reading out the sensor data of the previous image.

This is useful if you want to increase the frame rate of your camera.

On cameras configured for Global shutter mode, overlapping image acquisition looks like this (using Trigger Width exposure mode as an example):

Overlapped Mode of Operation (Global Shutter Mode)

On cameras configured for Rolling shutter mode, overlapping image acquisition looks like this (using Timed exposure mode as an example):

Overlapped Mode of Operation (Rolling Shutter Mode)

Enabling Overlapping Image Acquisition#

Automatic#

On most camera models, there is no camera parameter that allows you to turn overlapping image acquisition on or off. Instead, the way that you operate the camera determines whether image acquisitions are overlapped.

Image acquisitions are overlapped if the following condition applies:

Frame Period ≤ Exposure Time + Sensor Readout Time

  • Frame Period: Period of time from the start of one image acquisition to the start of the next image acquisition.
  • Exposure Time:
  • Sensor Readout Time: Time it takes to read out the data of an image from the sensor. If available, you can use the Sensor Readout Time feature to get the value.

If the camera is configured for free run image acquisition, overlapping image acquisitions occur automatically.

If the camera is configured for triggered image acquisition, overlapping image acquisitions occur whenever you trigger the camera at a sufficiently high rate.

Manual#

On some camera models, you can manually enable or disable overlapping image acquisition. To do so, set the OverlapMode parameter to one of the following values:

  • On: Enables overlapping image acquisition. The camera automatically overlaps exposures and readouts.
  • Off: Disables overlapping image acquisition. The camera never overlaps exposures and readouts. This can improve image quality, especially when you are operating the camera at low frame rates.

Info

Basler recommends setting the OverlapMode parameter to Off whenever the acquisition mode is set to Continuous and you are acquiring less than 10 frames per second.

Avoiding Overtriggering#

Global Shutter Mode#

If you have configured the Global shutter mode and the Trigger Width exposure mode on the camera and you want to use overlapping image acquisition, the following guideline applies:

You must not stop the exposure of the current frame until readout of the previously acquired frame is complete.

If you violate this guideline, the camera drops the current frame and declares a Frame Start Overtrigger event.

Overtriggering with Overlapping Image Acquisition

You can avoid violating this guideline by monitoring the camera's Frame Trigger Wait signal and by specifying an appropriate value for the Exposure Overlap Time Max parameter.

Specifics#

Show all camera models

Camera Model Overlapping Image Acquisition Availability Enabling Overlapping Image Acquisition
a2A1920-51gcBAS Always (free run and triggered image acquisition) Automatic
a2A1920-51gcPRO Always (free run and triggered image acquisition) Automatic
a2A1920-51gmBAS Always (free run and triggered image acquisition) Automatic
a2A1920-51gmPRO Always (free run and triggered image acquisition) Automatic
a2A1920-160ucBAS Always (free run and triggered image acquisition) Automatic
a2A1920-160ucPRO Always (free run and triggered image acquisition) Automatic
a2A1920-160umBAS Always (free run and triggered image acquisition) Automatic
a2A1920-160umPRO Always (free run and triggered image acquisition) Automatic
a2A3840-13gcBAS Always (free run and triggered image acquisition) Automatic
a2A3840-13gmBAS Always (free run and triggered image acquisition) Automatic
a2A3840-45ucBAS Always (free run and triggered image acquisition) Automatic
a2A3840-45umBAS Always (free run and triggered image acquisition) Automatic
acA640-90gc Always (free run and triggered image acquisition) Automatic
acA640-90gm Always (free run and triggered image acquistion) Automatic
acA640-90uc Always (free run and triggered image acquisition) Automatic
acA640-90um Always (free run and triggered image acquisition) Automatic
acA640-120gc Always (free run and triggered image acquisition) Automatic
acA640-120gm Always (free run triggered image aquisition) Automatic
acA640-120uc Always (free run and triggered image acquisition) Automatic
acA640-120um Always (free run and triggered image acquisition) Automatic
acA640-121gm Always (free run and triggered image acquisition) Automatic
acA640-300gc Always (free run and triggered image acquisition) Automatic
acA640-300gm Always (free run and triggered image acquisition) Automatic
acA640-750uc Always (free run and triggered image acquisition) Automatic
acA640-750um Always (free run and triggered image acquisition) Automatic
acA720-290gc Always (free run and triggered image acquisition) Automatic
acA720-290gm Always (free run and triggered image acquisition) Automatic
acA720-520uc Always (free run and triggered image acquisition) Automatic
acA720-520um Always (free run and triggered image acquisition) Automatic
acA780-75gc Always (free run and triggered image acquisition) Automatic
acA780-75gm Always (free run and triggered image acquisition) Automatic
acA800-200gc Always (free run and triggered image acquisition) Automatic
acA800-200gm Always (free run and triggered image acquisition) Automatic
acA800-510uc Always (free run and triggered image acquisition) Automatic
acA800-510um Always (free run and triggered image acquisition) Automatic
acA1280-60gc Only when the camera is configured for free run image acquisition. Automatic
acA1280-60gm Only when the camera is configured for free run image acquisition. Automatic
acA1300-22gc Always (free run and triggered image acquisition) Automatic
acA1300-22gm Always (free run and triggered image acquisition) Automatic
acA1300-30gc Always (free run and triggered image acquisition) Automatic
acA1300-30gm Always (free run and triggered image acquisition) Automatic
acA1300-30uc Always (free run and triggered image acquisition) Automatic
acA1300-30um Always (free run and triggered image acquisition) Automatic
acA1300-60gc Only when the camera is configured for free run image acquisition. Automatic
acA1300-60gm Only when the camera is configured for free run image acquisition. Automatic
acA1300-60gmNIR Only when the camera is configured for free run image acquisition. Automatic
acA1300-75gc Always (free run and triggered image acquisition) Automatic
acA1300-75gm Always (free run and triggered image acquisition) Automatic
acA1300-200uc Always (free run and triggered image acquisition) Automatic
acA1300-200um Always (free run and triggered image acquisition) Automatic
acA1440-73gc Always (free run and triggered image acquisition) Automatic
acA1440-73gm Always (free run and triggered image acquisition) Automatic
acA1440-220uc Always (free run and triggered image acquisition) Automatic
acA1440-220um Always (free run and triggered image acquisition) Automatic
acA1600-20gc Always (free run and triggered image acquisition) Automatic
acA1600-20gm Always (free run and triggered image acquisition) Automatic
acA1600-20uc Always (free run and triggered image acquisition) Automatic
acA1600-20um Always (free run and triggered image acquisition) Automatic
acA1600-60gc Only when the camera is configured for free run image acquisition. Automatic
acA1600-60gm Only when the camera is configured for free run image acquisition. Automatic
acA1920-25gc Only when the shutter mode is set to Rolling, i.e., when Global Reset Release shutter mode is disabled. Automatic
acA1920-25gm Only when the shutter mode is set to Rolling, i.e., when Global Reset Release shutter mode is disabled. Automatic
acA1920-25uc Only when the shutter mode is set to Rolling, i.e., when Global Reset Release shutter mode is disabled. Automatic
acA1920-25um Only when the shutter mode is set to Rolling, i.e., when Global Reset Release shutter mode is disabled. Automatic
acA1920-40gc Always (free run and triggered image acquisition) Automatic
acA1920-40gm Always (free run and triggered image acquisition) Automatic
acA1920-40uc Always (free run and triggered image acquisition) Automatic
acA1920-40ucMED Only when the Standard camera operation mode is enabled. Automatic
acA1920-40um Always (free run and triggered image acquisition) Automatic
acA1920-40umMED Only when the Standard camera operation mode is enabled. Automatic
acA1920-48gc Always (free run and triggered image acquisition) Automatic
acA1920-48gm Always (free run and triggered image acquisition) Automatic
acA1920-50gc Always (free run and triggered image acquisition) Automatic
acA1920-50gm Always (free run and triggered image acquisition) Automatic
acA1920-150uc Always (free run and triggered image acquisition) Automatic
acA1920-150um Always (free run and triggered image acquisition) Automatic
acA1920-155uc Always (free run and triggered image acquisition) Automatic
acA1920-155ucMED Only when the Standard camera operation mode is enabled. Automatic
acA1920-155um Always (free run and triggered image acquisition) Automatic
acA1920-155umMED Only when the Standard camera operation mode is enabled. Automatic
acA2000-50gc Always (free run and triggered image acquisition) Automatic
acA2000-50gm Always (free run and triggered image acquisition) Automatic
acA2000-50gmNIR Always (free run and triggered image acquisition) Automatic
acA2000-165uc Always (free run and triggered image acquisition) Automatic
acA2000-165um Always (free run and triggered image acquisition) Automatic
acA2000-165umNIR Always (free run and triggered image acquisition) Automatic
acA2040-25gc Always (free run and triggered image acquisition) Automatic
acA2040-25gm Always (free run and triggered image acquisition) Automatic
acA2040-25gmNIR Always (free run and triggered image acquisition) Automatic
acA2040-35gc Always (free run and triggered image acquisition) Automatic
acA2040-35gm Always (free run and triggered image acquisition) Automatic
acA2040-55uc Always (free run and triggered image acquisition) Automatic
acA2040-55um Always (free run and triggered image acquisition) Automatic
acA2040-90uc Always (free run and triggered image acquisition) Automatic
acA2040-90um Always (free run and triggered image acquisition) Automatic
acA2040-90umNIR Always (free run and triggered image acquisition) Automatic
acA2040-120uc Always (free run and triggered image acquisition) Automatic
acA2040-120um Always (free run and triggered image acquisition) Automatic
acA2440-20gc Always (free run and triggered image acquisition) Automatic
acA2440-20gm Always (free run and triggered image acquisition) Automatic
acA2440-35uc Always (free run and triggered image acquisition) Automatic
acA2440-35ucMED Only when the Standard camera operation mode is enabled. Automatic
acA2440-35um Always (free run and triggered image acquisition) Automatic
acA2440-35umMED Only when the Standard camera operation mode is enabled. Automatic
acA2440-75uc Always (free run and triggered image acquisition) Automatic
acA2440-75ucMED Only when the Standard camera operation mode is enabled. Automatic
acA2440-75um Always (free run and triggered image acquisition) Automatic
acA2440-75umMED Only when the Standard camera operation mode is enabled. Automatic
acA2500-14gc Only when the shutter mode is set to Rolling, i.e., when Global Reset Release shutter mode is disabled. Automatic
acA2500-14gm Only when the shutter mode is set to Rolling, i.e., when Global Reset Release shutter mode is disabled. Automatic
acA2500-14uc Only when the shutter mode is set to Rolling, i.e., when Global Reset Release shutter mode is disabled. Automatic
acA2500-14um Only when the shutter mode is set to Rolling, i.e., when Global Reset Release shutter mode is disabled. Automatic
acA2500-20gc Always (free run and triggered image acquisition) Automatic
acA2500-20gcMED Always (free run and triggered image acquisition) Automatic
acA2500-20gm Always (free run and triggered image acquisition) Automatic
acA2500-20gmMED Always (free run and triggered image acquisition) Automatic
acA2500-60uc Always (free run and triggered image acquisition) Automatic
acA2500-60um Always (free run and triggered image acquisition) Automatic
acA3088-16gc Only when the shutter mode is set to Rolling, i.e., when Global Reset Release shutter mode is disabled. Automatic
acA3088-16gm Only when the shutter mode is set to Rolling, i.e., when Global Reset Release shutter mode is disabled. Automatic
acA3088-57uc Only when the shutter mode is set to Rolling, i.e., when Global Reset Release shutter mode is disabled. Automatic
acA3088-57um Only when the shutter mode is set to Rolling, i.e., when Global Reset Release shutter mode is disabled. Automatic
acA3800-10gc Only when the camera is configured for free run image acquisition and the shutter mode is set to Rolling. Automatic
acA3800-10gm Only when the camera is configured for free run image acquisition and the shutter mode is set to Rolling. Automatic
acA3800-14uc Only when the camera is configured for free run image acquisition and the shutter mode is set to Rolling. Automatic
acA3800-14um Only when the camera is configured for free run image acquisition and the shutter mode is set to Rolling. Automatic
acA4024-8gc Only when the camera is configured for free run image acquisition and the shutter mode is set to Rolling. Automatic
acA4024-8gm Only when the camera is configured for free run image acquisition and the shutter mode is set to Rolling. Automatic
acA4024-29uc Only when the camera is configured for free run image acquisition. Automatic
acA4024-29um Only when the camera is configured for free run image acquisition. Automatic
acA4096-11gc Always (free run and triggered image acquisition) Automatic
acA4096-11gm Always (free run and triggered image acquisition) Automatic
acA4096-30uc Always (free run and triggered image acquisition) Automatic
acA4096-30ucMED Always (free run and triggered image acquisition) Automatic
acA4096-30um Always (free run and triggered image acquisition) Automatic
acA4096-30umMED Always (free run and triggered image acquisition) Automatic
acA4096-40uc Always (free run and triggered image acquisition) Automatic
acA4096-40ucMED Always (free run and triggered image acquisition) Automatic
acA4096-40um Always (free run and triggered image acquisition) Automatic
acA4096-40umMED Always (free run and triggered image acquisition) Automatic
acA4112-8gc Always (free run and triggered image acquisition) Automatic
acA4112-8gm Always (free run and triggered image acquisition) Automatic
acA4112-20uc Always (free run and triggered image acquisition) Automatic
acA4112-20ucMED Always (free run and triggered image acquisition) Automatic
acA4112-20um Always (free run and triggered image acquisition) Automatic
acA4112-20umMED Always (free run and triggered image acquisition) Automatic
acA4112-30uc Always (free run and triggered image acquisition) Automatic
acA4112-30ucMED Always (free run and triggered image acquisition) Automatic
acA4112-30um Always (free run and triggered image acquisition) Automatic
acA4112-30umMED Always (free run and triggered image acquisition) Automatic
acA4600-7gc Only when the camera is configured for free run image acquisition and the shutter mode is set to Rolling. Automatic
acA4600-10uc Only when the camera is configured for free run image acquisition and the shutter mode is set to Rolling. Automatic
acA5472-5gc Only when the camera is configured for free run image acquisition and the shutter mode is set to Rolling. Automatic
acA5472-5gm Only when the camera is configured for free run image acquisition and the shutter mode is set to Rolling. Automatic
acA5472-17uc Only when the camera is configured for free run image acquisition and the shutter mode is set to Rolling. Automatic
acA5472-17um Only when the camera is configured for free run image acquisition and the shutter mode is set to Rolling. Automatic
boA4096-93cc Always (free run and triggered image acquisition) Automatic
boA4096-93cm Always (free run and triggered image acquisition) Automatic
boA4112-68cc Always (free run and triggered image acquisition) Automatic
boA4112-68cm Always (free run and triggered image acquisition) Automatic
daA1280-54lc Only when the camera is configured for free run image acquisition. Manual
daA1280-54lm Only when the camera is configured for free run image acquisition. Manual
daA1280-54uc Only when the camera is configured for free run image acquisition. Manual
daA1280-54um Only when the camera is configured for free run image acquisition. Manual
daA1600-60lc Only when the camera is configured for free run image acquisition. Manual
daA1600-60lm Only when the camera is configured for free run image acquisition. Manual
daA1600-60uc Only when the camera is configured for free run image acquisition. Manual
daA1600-60um Only when the camera is configured for free run image acquisition. Manual
daA1920-15um Only when the shutter mode is set to Rolling, i.e., when Global Reset Release shutter mode is disabled. Automatic
daA1920-30uc Only when the shutter mode is set to Rolling, i.e., when Global Reset Release shutter mode is disabled. Automatic
daA1920-30um Only when the shutter mode is set to Rolling, i.e., when Global Reset Release shutter mode is disabled. Automatic
daA2500-14lc Only when the shutter mode is set to Rolling, i.e., when Global Reset Release shutter mode is disabled. Automatic
daA2500-14lm Only when the shutter mode is set to Rolling, i.e., when Global Reset Release shutter mode is disabled. Automatic
daA2500-14uc Only when the shutter mode is set to Rolling, i.e., when Global Reset Release shutter mode is disabled. Automatic
daA2500-14um Only when the shutter mode is set to Rolling, i.e., when Global Reset Release shutter mode is disabled. Automatic
daA2500-60mc Always Automatic
puA1280-54uc Only when the camera is configured for free run image acquisition. Manual
puA1280-54um Only when the camera is configured for free run image acquisition. Manual
puA1600-60uc Only when the camera is configured for free run image acquisition. Manual
puA1600-60um Only when the camera is configured for free run image acquisition. Manual
puA1920-30uc Only when the shutter mode is set to Rolling, i.e., when Global Reset Release shutter mode is disabled. Automatic
puA1920-30um Only when the shutter mode is set to Rolling, i.e., when Global Reset Release shutter mode is disabled. Automatic
puA2500-14uc Only when the shutter mode is set to Rolling, i.e., when Global Reset Release shutter mode is disabled. Automatic
puA2500-14um Only when the shutter mode is set to Rolling, i.e., when Global Reset Release shutter mode is disabled. Automatic