Basler raL2048-48gm User Manual download pdf (Page 148)

Acquisition Control AW00118302000

138 Basler racer GigE

Factor 2, the exposure time, is the most restrictive factor. In this case, the exposure time setting is

limiting the maximum allowed line rate to 5117 lines per second. If you wanted to operate the

camera at a higher line rate, you would need to lower the exposure time.

Because the exposure time is the most restrictive factor, you could also remove the limit from the

Exposure Overhead parameter to increase the line rate. In this case C

= 3.4 µs would apply, and

according to the formula for Factor 2 a maximum allowed line rate of 5170 lines per second would

result.

For more information about removing the limit from the Exposure Overhead parameter and the

resulting side effects, see Section 8.5.1.

8.5.1 Removing the Parameter Limits for the

ExposureOverhead Parameter

By removing the parameter limits for the ExposureOverhead parameter you can improve the line

acquisition with respect to either of the following two goals:

 You can extend the exposure time: When operating a camera at a maximum allowed line rate,

the interval between two consecutive line start triggers will consist of the exposure time and

the time needed to prepare the sensor for the next acquisition.

In this situation, the time available for exposure will sometimes, despite bright illumination, be

too short for obtaining a sufficiently bright image. To brighten of the image at a given high line

rate, you can remove the parameter limits for the ExposureOverhead parameter. As a

consequence, the exposure time can to some degree be extended at the expense of the

sensor’s "preparation time" that will be shortened accordingly. Note that the image quality will

somewhat decrease.

 You can increase the maximum allowed line rate: If you remove the parameter limits for the

ExposureOverhead parameter, if you do not extend the exposure time accordingly, and if the

exposure time is the determining factor for the maximum allowed line rate (Factor 2), you will

be able to increase the maximum allowed line rate to some extent (see above). Note that the

image quality will somewhat decrease.

If you chose to extend the exposure time you can use the timed and trigger width exposure modes

(see Section 8.2.4.2 on page 88, Section 8.3.1 on page 123 and Section 8.3.3.3 on page 130 for

information about the timed exposure mode and Section 8.2.4.2 on page 88 and fSection 8.3.3.3

on page 130 or information about the trigger width exposure mode):

 When the camera is set for the timed exposure mode, the upper limit of the ExposureTime

parameters increases according to the decrease of the "preparation time".

 When the camera is set for the trigger width exposure mode, you can extend the ExLSTrig

signal period according to the decrease of the exposure overhead time. To maintain the line

rate, increase the Exposure Overlap Time Max Abs parameter value by the amount of time that

was gained for exposure time.

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Basler raL2048-48gm User Manual Page 148