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Electronic Shutter Types#

The shutter type determines the way in which image data is captured and processed. Depending on the design of the imaging sensor, your camera model has more than one shutter type.

If your camera model has more than one shutter type, see the Sensor Shutter Mode topic for information about how to change shutter types.

Advantages and Disadvantages#

Sensor Shutter Type Advantage Disadvantage
Global shutter Well suited for capturing fast-moving objects Higher ambient noise
Rolling shutter Lower ambient noise Image distortion can occur if very fast-moving objects are captured.
Global Reset Release shutter Lower ambient noise
Well suited for capturing fast-moving objects
Flash lighting must be used.

Available Shutter Types#

Global Shutter#

During image acquisition, all of the sensor's pixels start exposing at the same time and also stop exposing at the same time. Immediately after the end of exposure, pixel data readout begins and proceeds row by row until all pixel data has been read. This is particularly useful if you want to capture fast moving objects or if the camera is moving rapidly while capturing images.

The sensor readout time is the sum of all row readout times. Therefore, the sensor readout time is influenced by the image ROI height. You can determine the readout time by checking the value of the camera's SensorReadoutTime parameter.

On some camera models, the Sensor Readout Mode feature is available. This feature allows you to reduce the sensor readout time.

Global Shutter

Rolling Shutter#

During image acquisition, the camera exposes the pixel rows one after the other, with a temporal offset (tRow) from one row to the next. With this method, the ambient noise is typically significantly lower than with the global shutter method.

When frame start is triggered, the camera resets the first row and begins exposing it. For most cameras, this row is the first row of the image ROI.

A short time later (= 1 x tRow), the camera resets the second row and begins exposing that row. After another short time (= 1 x tRow), the camera resets the third row and begins exposing that row.

This continues until a last row of pixels is reached. For most cameras, this row is the last row of the image ROI.

The length of tRow varies by camera model.

Rolling Shutter

The pixel values for each row are read out at the end of the exposure time of each row. The exposure time is the same for all rows. Because the readout time for each row is also tRow, the temporal shift for the end of readout is identical to the temporal shift for the start of exposure.

The sensor readout time is the sum of all row readout times: tRow x image ROI height.

Therefore, the sensor readout time also depends on the image ROI height. To determine the readout time, check the value of the camera's SensorReadoutTime parameter.

Other Factors Influencing the Frame Period#

Besides the exposure time and the sensor readout time, there are other factors influencing the frame period, e.g., the time needed to prepare the sensor for the next acquisition.

These other factors vary by camera model and configuration. Therefore, Basler recommends calculating the frame period. To do so, check the value of the camera's ResultingFrameRate parameter value and take its reciprocal:

1 / resulting frame rate

This takes all influencing factors into account.

Possible Image Distortion (Rolling Shutter Effect)#

On rolling shutter cameras, if the object or the camera is moving very fast during image capture, image distortion may occur. This is also known as the rolling shutter effect.

This is due to the temporal shift between the start of exposure of the individual rows.

To prevent the rolling shutter effect, Basler recommends the use of flash lighting. Most cameras can supply a Flash Window output signal to facilitate the use of flash lighting.

Exposure Active Signal#

On rolling shutter cameras, if your camera provides an Exposure Active output signal, the Exposure Active signal goes high when the exposure time for line one begins and goes low when the exposure time for the last line ends. This means that the signal width is greater than the exposure time.

Global Reset Release Shutter#

The Global Reset Release (GRR) shutter is a variant of the rolling shutter. It combines the advantages of the global and rolling shutter.

On GRR shutter cameras, all of the pixels in the sensor start exposing at the same time. However, at the end of exposure, there is a temporal offset (tRow) from one row to the next.

The tRow values are the same as on rolling shutter cameras and vary by camera model.

Global Reset Release Shutter

With the GRR shutter type, you must use flash lighting. Otherwise, the brightness in the acquired images will vary significantly from top to bottom due to the differences in the exposure times of the individual rows. Also, when you are capturing images of fast moving objects, images can be distorted due to the temporal shift caused by the different exposure end times of the individual rows.

Most cameras can supply a Flash Window output signal to facilitate the use of flash lighting.

Other Factors Influencing the Frame Period#

→ See above.

Specifics#

Show all camera models

Camera Model Temporal Offset tRow [µs]
a2A1920-51gcBAS -
a2A1920-51gcPRO -
a2A1920-51gmBAS -
a2A1920-51gmPRO -
a2A1920-160ucBAS -
a2A1920-160ucPRO -
a2A1920-160umBAS -
a2A1920-160umPRO -
a2A2590-22gcBAS 7a
a2A2590-22gcPRO 7a
a2A2590-22gmBAS 7a
a2A2590-22gmPRO 7a
a2A2590-60ucBAS 7a
a2A2590-60ucPRO 7a
a2A2590-60umBAS 7a
a2A2590-60umPRO 7a
a2A3840-13gcBAS 9a
a2A3840-13gcPRO 9a
a2A3840-13gmBAS 9a
a2A3840-13gmPRO 9a
a2A3840-45ucBAS 9a
a2A3840-45ucPRO 9a
a2A3840-45umBAS 9a
a2A3840-45umPRO 9a
a2A4504-5gcBAS -
a2A4504-5gcPRO -
a2A4504-5gmBAS -
a2A4504-5gmPRO -
a2A4504-18ucBAS -
a2A4504-18ucPRO -
a2A4504-18umBAS -
a2A4504-18umPRO -
a2A5320-7gcBAS -
a2A5320-7gcPRO -
a2A5320-7gmBAS -
a2A5320-7gmPRO -
a2A5320-23ucBAS -
a2A5320-23ucPRO -
a2A5320-23umBAS -
a2A5320-23umPRO -
a2A5328-4gcBAS -
a2A5328-4gcPRO -
a2A5328-4gmBAS -
a2A5328-4gmPRO -
a2A5328-15ucBAS -
a2A5328-15ucPRO -
a2A5328-15umBAS -
a2A5328-15umPRO -
acA640-90gc -
acA640-90gm -
acA640-90uc -
acA640-90um -
acA640-120gc -
acA640-120gm -
acA640-120uc -
acA640-120um -
acA640-121gm -
acA640-300gc -
acA640-300gm -
acA640-750uc -
acA640-750um -
acA720-290gc -
acA720-290gm -
acA720-520uc -
acA720-520um -
acA780-75gc -
acA780-75gm -
acA800-200gc -
acA800-200gm -
acA800-510uc -
acA800-510um -
acA1280-60gc 14
acA1280-60gm 14
acA1300-22gc -
acA1300-22gm -
acA1300-30gc -
acA1300-30gm -
acA1300-30uc -
acA1300-30um -
acA1300-60gc 14
acA1300-60gm 14
acA1300-60gmNIR 14
acA1300-75gc -
acA1300-75gm -
acA1300-200uc -
acA1300-200um -
acA1440-73gc -
acA1440-73gm -
acA1440-220uc -
acA1440-220um -
acA1600-20gc -
acA1600-20gm -
acA1600-20uc -
acA1600-20um -
acA1600-60gc 8-bit pixel formats: 13
12-bit and 12-bit packed pixel formats: 17
acA1600-60gm 8-bit pixel formats: 13
12-bit and 12-bit packed pixel formats: 17
acA1920-25gc 35
acA1920-25gm 35
acA1920-25uc 35
acA1920-25um 35
acA1920-40gc -
acA1920-40gm -
acA1920-40uc -
acA1920-40ucMED -
acA1920-40um -
acA1920-40umMED -
acA1920-48gc -
acA1920-48gm -
acA1920-50gc -
acA1920-50gm -
acA1920-150uc -
acA1920-150um -
acA1920-155uc -
acA1920-155ucMED -
acA1920-155um -
acA1920-155umMED -
acA2000-50gc -
acA2000-50gm -
acA2000-50gmNIR -
acA2000-165uc -
acA2000-165um -
acA2000-165umNIR -
acA2040-25gc -
acA2040-25gm -
acA2040-25gmNIR -
acA2040-35gc -
acA2040-35gm -
acA2040-55uc -
acA2040-55um -
acA2040-90uc -
acA2040-90um -
acA2040-90umNIR -
acA2040-120uc -
acA2040-120um -
acA2440-20gc -
acA2440-20gm -
acA2440-35uc -
acA2440-35ucMED -
acA2440-35um -
acA2440-35umMED -
acA2440-75uc -
acA2440-75ucMED -
acA2440-75um -
acA2440-75umMED -
acA2500-14gc 35
acA2500-14gm 35
acA2500-14uc 35
acA2500-14um 35
acA2500-20gc -
acA2500-20gcMED -
acA2500-20gm -
acA2500-20gmMED -
acA2500-60uc -
acA2500-60um -
acA3088-16gc 25
acA3088-16gm 25
acA3088-57uc 8
acA3088-57ucMED 8
acA3088-57um 8
acA3088-57umMED 8
acA3800-10gc 8-bit pixel formats: 31.6
12-bit packed pixel formats: 36.4
12-bit pixel formats: 39.6
acA3800-10gm 8-bit pixel formats: 31.6
12-bit packed pixel formats: 36.4
12-bit pixel formats: 39.6
acA3800-14uc 8-bit pixel formats: 24.725
12-bit packed pixel formats: 28.475
12-bit pixel formats: 30.975
acA3800-14um 8-bit pixel formats: 24.725
12-bit packed pixel formats: 28.475
12-bit pixel formats: 30.975
acA4024-8gc 35a
acA4024-8gm 35a
acA4024-29uc 8-bit pixel formats: 10a
12-bit and 12-bit packed pixel formats: 12a
acA4024-29um 8-bit pixel formats: 10a
12-bit and 12-bit packed pixel formats: 12a
acA4096-11gc -
acA4096-11gm -
acA4096-30uc -
acA4096-30ucMED -
acA4096-30um -
acA4096-30umMED -
acA4096-40uc -
acA4096-40ucMED -
acA4096-40um -
acA4096-40umMED -
acA4112-8gc -
acA4112-8gm -
acA4112-20uc -
acA4112-20ucMED -
acA4112-20um -
acA4112-20umMED -
acA4112-30uc -
acA4112-30ucMED -
acA4112-30um -
acA4112-30umMED -
acA4600-7gc 8-bit pixel formats: 39.4
12-bit packed pixel formats: 43.4
12-bit pixel formats: 47.4
acA4600-10uc 8-bit pixel formats: 30.75
12-bit packed pixel formats: 33.875
12-bit pixel formats: 37
acA5472-5gc 8-bit pixel formats: 52a
12-bit and 12-bit packed pixel formats: 55a
acA5472-5gm 8-bit pixel formats: 52a
12-bit and 12-bit packed pixel formats: 55a
acA5472-17uc 8-bit pixel formats: 13a
12-bit and 12-bit packed pixel formats: 16a
acA5472-17ucMED 8-bit pixel formats: 13a
12-bit and 12-bit packed pixel formats: 16a
acA5472-17um 8-bit pixel formats: 13a
12-bit and 12-bit packed pixel formats: 16a
acA5472-17umMED 8-bit pixel formats: 13a
12-bit and 12-bit packed pixel formats: 16a
boA4096-93cc -
boA4096-93cm -
boA4112-68cc -
boA4112-68cm -
boA4500-45cc -
boA4500-45cm -
boA6500-36cc -
boA6500-36cm -
boA8100-16cc -
boA8100-16cm -
daA1280-54lc -
daA1280-54lm -
daA1280-54uc -
daA1280-54um -
daA1600-60lc -
daA1600-60lm -
daA1600-60uc -
daA1600-60um -
daA1920-15um -
daA1920-30uc -
daA1920-30um -
daA1920-160uc -
daA1920-160um -
daA2500-14lc -
daA2500-14lm -
daA2500-14uc -
daA2500-14um -
daA3840-45uc -
daA3840-45um -
puA1280-54uc -
puA1280-54um -
puA1600-60uc -
puA1600-60um -
puA1920-30uc -
puA1920-30um -
puA2500-14uc -
puA2500-14um -

  1. The first row exposed is always the first row of the sensor, regardless of the image ROI settings. This may result in an image ROI exposure start delay. Also, the last row exposed is always the last row of the sensor, regardless of the image ROI settings.