THORLABS DCU223x Operation Manual And Sdk page 67

The digital scaling functions result in a higher possible frame rate. The maximum frame rate is increased
approximately proportionally to the scaling factor. When using the scaling functions with USB 2.0 and GigE
cameras, you can set higher pixel clock frequencies. To achieve the maximum frame rate, select first the scaling
factor and then the maximum pixel clock frequency.
For improved image quality without undersampling artifacts, the digital scaling feature permanently uses an anti-
aliasing filter.
On color sensors the scaler works in consideration the color information.
Reducing the horizontal resolution does not result in a higher frame rate.
The available step widths for the position and size of image AOIs depend on the sensor. The values defining the
position and size of an AOI have to be integer multiples of the allowed step widths. For detailed information on
the AOI grid see the DCC1240x / DCC3240x
Multi AOI
When the Multi AOI function is enabled, no changes can be made to the image size settings (e.g. binning,
subsampling, scaling).
If sensor hotpixel correction and Multi AOI are enabled, the sensor displays a four pixel wide black line between
the AOIs.
Line scan mode
Fast line scan mode: The exposure time is fixed to the readout time of one sensor line. Exposure time cannot
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be changed in this line scan mode.
Fast line scan mode: The time stamp is generated for the complete image.
Fast line scan mode: There is a time gap between two frames with the line scan information. This corresponds to
the duration of 15 lines at a frame rate set to maximum.
In the fast line scan mode color images are not possible as
neighboring lines for color calculating. Therefore, only monochrome models support the line scan mode.
Log mode
The Log mode shows visible effect only for short exposure times (< 5 ms)
In global shutter mode the Log mode can help to increase the shutter efficiency for extremely short exposure
time (< 100 µ s).
To find the right operating point of the Log mode use the following procedure:
1. Set the Log mode gain to the minimum value.
2. Find the operating point via the Log mode value. The higher the value, the more bright image areas are
damped and more details become visible.
3. Set the image as bright as possible via the Log mode gain. A typical value is 2 or 3 for monochrome sensors
and 0 or 1 for NIR sensors.
The line view
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The master gain is disabled in Log mode.
Anti blooming
Activation: With exposure times over 10 ms and no use of gain or gain boost it can occur that bright image areas
do not reach saturation and so no white level which is caused by the sensor. A visible, firm pattern is formed in
bright image areas. For color sensors with enabled white balancing bright image areas gets purple. In this case,
disable the anti blooming mode (see
The anti blooming mode should not be enabled for short exposure times (< 5 ms). Depending on the shutter
mode a "Black Sun" effect or overexposure occurs.
Micro lenses
The sensor has non-removable micro lenses on each pixel. These micro lenses focus the incoming light for the
subjacent smaller photodiode. This lens has a directive efficiency.
To the corners of the active image area the micro lenses are slightly shifted to the photodiode. So the
unavoidable non-vertical light incidence of C mount lenses is compensated. The shift is constant from the center
to the corner and has a maximum of 12 degrees. When using a telecentric lens or parallel light incidence the
shift must be considered as little shading effects may occur.
© 2013 Thorlabs GmbH
in the uc480 Viewer is very helpful for this.
Shutter: Log mode
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Bayer color sensors
) or increase the master gain from 1x to 1.5x.
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3 Operation
needs at least two
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