Methods and devices for measuring object motion using camera images

A device for measuring the motion of an object using camera images, the device comprising:

• memory configured to store an image sequence of a scene including a target object and a reference object captured as representations in the image sequence;
• and
• a processor configured to:
• measure a global optical flow field of the scene from the image sequence of the scene;
• determine motion, relative to the scene, of a camera used to capture the image sequence by measuring an apparent, sub-pixel motion of the reference object with respect to an imaging plane of the camera by measuring the apparent, sub-pixel motion of the reference object within a frequency range of motion on a same order of magnitude as a frequency range of motion of the target object;
• and
• calculate a corrected motion of the target object, corrected for the camera motion, based on the optical flow field of the scene and on the apparent, sub-pixel motion of the reference object with respect to the imaging plane of the camera.

A method of measuring motion of an object using camera images, the method comprising:

• measuring a global optical flow field of a scene including a target object captured as representations in an image sequence of the scene;
• determining motion, relative to the scene, of a camera used to capture the image sequence by obtaining a motion measurement from an external sensor, the motion measurement being sub-pixel with respect to a pixel array of the camera, wherein determining motion of the camera includes obtaining the sub-pixel motion measurement from the external sensor within a frequency range of motion on a same order of magnitude as a frequency range of motion of the target object;
• and
• calculating a corrected motion of the target object, corrected for the camera motion, based on the optical flow field of the scene and the sub-pixel motion measurement from the external sensor.