Estimating relative nib position from images captured at different orientations
AssigneeSilverbrook Research Pty Ltd
InventorsPaul Lapstun, Kia Silverbrook, Tobin Allen King
Life of this patent
Estimating the term…
Abstract
A method of estimating a position of nib of a pen relative to an optical sensor removably mounted on the pen. The optical sensor captures at least two images of a coded surface when the nib contacts the coded surface. The images are captured with the nib at a same position on the coded surface and the pen at different orientations relative to the coded surface. From a perspective distortion of the coded surface in each image, an estimated rotation and viewing distance for each image are estimated, and from the estimated rotations and viewing distances, the position of the nib relative to the optical sensor is estimated.
Claims6
A method of estimating a position of nib of a pen relative to an optical sensor removably mounted on the pen, said method comprising the steps of:
- capturing, using the optical sensor, at least two images of a coded surface when the nib contacts the coded surface, the at least two images being captured with the nib at a same position on the coded surface and the pen at different orientations relative to the coded surface;
- determining, from a perspective distortion of the coded surface in each image, an estimated rotation and viewing distance for each image;
- and
- estimating, from the estimated rotations and viewing distances, the position of the nib relative to the optical sensor.
An electronic pen comprising:
- a body;
- a nib at one end of the body for contacting a coded surface;
- an optical sensor removably mounted on the body for capturing images of the coded surface;
- and
- a processor configured for estimating a position of nib relative to the optical sensor from at least two images of the coded surface, the at least two images being captured with the nib at a same position on the coded surface and the pen at different orientations relative to the coded surface:
- determining, from a perspective distortion of the coded surface in each image, an estimated rotation and viewing distance for each image;
- and
- estimating, from the estimated rotations and viewing distances, the position of the nib relative to the optical sensor.
Dependencies are inferred from the claim text.