The purpose of the calibration is to compensate for the internal camera and lens sys‐
tem distortion in order to locate parts with high accuracy. This is achieved by measuring
a well-defined calibration target in different poses and estimating the internal camera
parameters based on these measurements. User level Service is required.
A successful calibration procedure is crucial in order to obtain valid part localization
results.
Calibration target
NOTE
For best performance it is recommended to use one of the official targets, see PLOC2D
version accessories at www.sick.com/PLOC2D.
The calibration target should preferably cover the field of view at the intended working
distance.
For evaluation purpose, it is possible to download a printable PDF file of the selected
target by clicking in the user interface, Calibration page. The target image must be
printed at 100% scale and glued to a flat non-flexible surface.
NOTE
Depending on lens and intended working distance it could be difficult to cover the
entire field of view in every image if the calibration target is smaller than the field of
view. Minimizing the aperture allows placing the calibration target closer to the camera,
but results in darker images.
Pre-requisites
Make sure the following before starting the calibration procedure:
•
Suitable calibration target.
•
The aperture is set to a suitable value.
•
The camera is focused on the intended working distance.
Procedure
In the user interface, go to the Calibration page.
A good calibration requires a number of images that show the calibration target in
different poses that together cover the entire field of view. Ideally, each part of the field
of view should be covered with calibration target data at least three times at different
tilt angles. If possible, cover the entire field of view in every image.
The calibration procedure consists of the following steps:
•
Collect image data.
•
Start calibration.
•
Check results.
Collect image data
1. Click Auto adjust exposure in the Advanced section to update the image exposure
settings.
2. Select the correct calibration target in the Calibration target list.
3. Click Acquire or Continuous in the user interface to acquire calibration images.
4. For each image acquisition, place the calibration target in a new position and with
a new tilt angle in the camera's field of view. Tilt by lifting a different corner of the
calibration target for each image.
✓
A colored circle and a colored grid are displayed in the image window to indicate
7 OPERATION
40
O P E R A T I N G I N S T R U C T I O N S | PLOC2D 4.1 8020736/1K3Z/2023-06 | SICK
Subject to change without notice
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