US 12,142,010 B2
Method for calibrating a vehicle cabin camera
Petronel Bigioi, San Jose, CA (US); and Piotr Stec, San Jose, CA (US)
Assigned to FotoNation Limited, (IE)
Filed by FotoNation Limited, Galway (IE)
Filed on Dec. 23, 2022, as Appl. No. 18/087,938.
Application 18/087,938 is a continuation of application No. 17/398,965, filed on Aug. 10, 2021, granted, now 11,538,192.
Prior Publication US 2023/0127692 A1, Apr. 27, 2023
Int. Cl. G06T 7/80 (2017.01); B60R 1/12 (2006.01); B60R 11/00 (2006.01); B60R 11/04 (2006.01); G06T 7/13 (2017.01)
CPC G06T 7/80 (2017.01) [B60R 1/12 (2013.01); B60R 11/04 (2013.01); G06T 7/13 (2017.01); B60R 2001/1253 (2013.01); B60R 2011/0033 (2013.01); G06T 2207/30268 (2013.01)] 16 Claims
OG exemplary drawing
 
1. A method for calibrating a vehicle cabin camera, said camera having: a pitch angle X around a vehicle transverse axis, a yaw angle Y around a vertical axis and a roll angle Z around a vehicle longitudinal axis; and a field of view capturing a plurality of vehicle cabin features which are symmetric about said vehicle longitudinal axis across a range of pitch, yaw and roll positions of said camera, said camera being incorporated within a vehicle rear view mirror,
the method comprising:
obtaining an acceleration measurement from an accelerometer incorporated within said camera or said vehicle rear view mirror;
obtaining an acceleration measurement from an accelerometer incorporated in said vehicle outside of said vehicle rear view mirror;
combining said acceleration measurements to determine a rotation Rx around said transverse axis;
selecting a set of points from within an image of the vehicle cabin acquired by said camera;
projecting each of said points onto a 3D unit circle in accordance with a camera projection model;
determining a rotation around the vertical axis and the vehicle longitudinal axis;
computing rotation values for the vertical axis and the vehicle longitudinal axis based on the determined rotation; and
transforming the selected set of points based on the rotation values.