Motion tracking

In Android 9, camera devices can advertise motion tracking capability. Cameras that support this feature don't produce motion tracking data itself, but instead are used by ARCore or an image-stabilization algorithm along with other sensors for scene analysis. To support this feature, devices must support CONTROL_CAPTURE_INTENT_MOTION_TRACKING. If this intent is part of the capture request, the camera must limit the exposure time to a maximum of 20 milliseconds to reduce motion blur.

Examples and source

A reference motion tracking implementation on the HAL side is available as part of the Camera HAL.

Implementation

To enable motion tracking on a camera device, make sure:

• The ANDROID_REQUEST_AVAILABLE_CAPABILITIES_MOTION_TRACKING capability is enabled.
• The ANDROID_CONTROL_CAPTURE_INTENT_MOTION_TRACKING intent is supported and when included in a capture request limits the camera exposure time to a maximum of 20 milliseconds.

• Lens calibration data from the following list is accurately reported in the static information and dynamic metadata fields:

  • ANDROID_LENS_POSE_ROTATION
  • ANDROID_LENS_POSE_TRANSLATION
  • ANDROID_LENS_INTRINSIC_CALIBRATION
  • ANDROID_LENS_RADIAL_DISTORTION
  • ANDROID_LENS_POSE_REFERENCE

Validation

Camera devices supporting the motion tracking feature must pass the camera CTS tests.