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USB Camera Calibration#

Authors: Holoscan Team (NVIDIA)
Supported platforms: aarch64
Language: Python
Last modified: May 13, 2025
Latest version: 1.0
Minimum Holoscan SDK version: 2.1.0
Tested Holoscan SDK versions: 2.2.0
Contribution metric: Level 1 - Highly Reliable

Overview#

This application performs monitor registration using a USB camera. It detects April tags placed at the four corners of a monitor to establish the monitor's position and orientation in 3D space.

Hardware Requirements#

  • Logitech 4k Pro Webcam or compatible USB camera
  • Monitor with April tags at all four corners
  • Proper lighting conditions (well-lit environment without backlight)

Setup Instructions#

  1. Ensure the USB camera is properly connected
  2. Place the calibration image with April tags on the monitor
  3. Position the camera so it can see all four corners of the monitor
  4. Verify camera visibility using the v4l2_camera app

Running the Application#

./run build usb_cam_calibration
LD_PRELOAD=/usr/lib/aarch64-linux-gnu/nvidia/libnvjpeg.so ./run launch usb_cam_calibration

Output#

The application generates a calibration file usb-cali.npy in the build directory, which contains the monitor's corner coordinates.

Notes#

  • The camera must have a clear view of all four April tags
  • Avoid backlighting or glare on the monitor
  • If using a different camera model, update the camera settings in the Python app or YAML configuration file