Checkerboard marker targets function like traditional checkerboards, but have the added benefit of unique identification of squares. This allows stereo calibration from partial views (just the central identification markers need to be visible), allowing the user to capture calibration images from the sensor periphery. This is beneficially especially for distortion parameter estimation. See our Knowledge Base for details.
Note that checkerboard detection with markers is available in our calibration software Calibrator. Only the finder dots need to be visible in every image for detection. There is also a partial implementation in OpenCV's cv::findChessboardCornersSB (only version 4.3 and later). Markers targets can also be successfully detected by most normal chessboard detection algorithms with the entire board visible.
All of our calibration targets are made from aluminium/LDPE composite sheets which offers excellent flatness and stiffness, while being lightweight. Additionally, the composite material offers good thermal stability and corrosion resistance.
The patterns are transferred to the composite material using a specialised precision direct UV (Ultra-Violet) printing process resulting in a durable matte finish. Through extensive testing, we have found this process to be ideal for machine vision applications, where both accuracy, good optical performance and physical robustness are of utmost importance.
To mount or position these targets on tripod, frames or fixtures, see Accessories.
The following sizes are available:
800 x 600 x 6
31.496 x 23.622 x 0.236
600 x 400 x 6
23.622 x 15.748 x 0.236
400 x 300 x 6
15.748 x 11.811 x 0.236
300 x 200 x 6
11.811 x 7.874 x 0.236
For checkerboard unique patterns, we offer the following pattern specifications: