US 11,694,323 B2
Image-based sensor for measuring rotational position of a rotating shaft
Michael Rutberg, Arlington, MA (US)
Assigned to CAMX Power LLC, Lexington, MA (US)
Filed by CAMX Power LLC, Lexington, MA (US)
Filed on Feb. 23, 2021, as Appl. No. 17/183,068.
Claims priority of provisional application 63/014,236, filed on Apr. 23, 2020.
Prior Publication US 2022/0076403 A1, Mar. 10, 2022
Int. Cl. G06T 7/00 (2017.01); G06T 7/70 (2017.01); G06T 1/00 (2006.01); G06T 7/40 (2017.01); H04N 23/56 (2023.01)
CPC G06T 7/0004 (2013.01) [G06T 1/0007 (2013.01); G06T 7/40 (2013.01); G06T 7/70 (2017.01); H04N 23/56 (2023.01); G06T 2207/30164 (2013.01)] 18 Claims
OG exemplary drawing
 
1. A non-contact sensor comprising:
an image sensor configured to capture image data of a portion of a circumferential surface of a rotatable shaft;
an illuminating device configured to obliquely illuminate the circumferential surface of the rotatable shaft, wherein the image sensor is configured to capture image data from a portion of the illuminated circumferential surface of the rotatable shaft, wherein the image sensor comprises a pixel array comprising a predefined number of pixel lines and columns, whereby each pixel in a pixel line is read out before a pixel in a subsequent pixel line, and the pixel lines of the image sensor are nominally aligned with a direction of rotation of the rotatable shaft such that an imaging frame rate is faster compared to other orientations of the image sensor; and
an electronic control unit communicatively coupled to the image sensor, the electronic control unit configured to:
receive image data from the image sensor and store the image data in a memory component of the electronic control unit, the image data comprising a plurality of image frames,
determine a transformation in image space between one or more surface features that appear in a first frame of the image data and the same one or more surface features that appear in a second frame of the image data,
determine a rotational position of the rotatable shaft at a time of capture of the second frame of the image data based on the transformation and a quantitatively characterized relationship between image space and object space, and
store the rotational position of the rotatable shaft at the time of capture of the second frame of the image data in the memory component of the electronic control unit.