US 12,241,658 B2
Heliostat calibration
Willem Jacobus Smit, Stellenbosch (ZA)
Assigned to Stellenbosch University, Stellenbosch (ZA)
Appl. No. 18/028,888
Filed by Stellenbosch University, Stellenbosch (ZA)
PCT Filed Oct. 1, 2021, PCT No. PCT/IB2021/059037
§ 371(c)(1), (2) Date Mar. 28, 2023,
PCT Pub. No. WO2022/070153, PCT Pub. Date Apr. 7, 2022.
Claims priority of application No. 2020/06085 (ZA), filed on Oct. 1, 2020.
Prior Publication US 2023/0341151 A1, Oct. 26, 2023
Int. Cl. F24S 50/20 (2018.01); F24S 23/70 (2018.01); F24S 23/77 (2018.01); G06T 7/13 (2017.01); G06T 7/60 (2017.01); G06T 7/73 (2017.01)
CPC F24S 50/20 (2018.05) [G06T 7/13 (2017.01); G06T 7/60 (2013.01); G06T 7/73 (2017.01); F24S 23/77 (2018.05); F24S 2050/25 (2018.05); G06T 2207/10024 (2013.01); G06T 2207/10032 (2013.01)] 18 Claims
OG exemplary drawing
 
1. A method of calibrating a heliostat, comprising:
positioning and orienting an imaging device so that a calibration target reflected by the heliostat is visible at the imaging device, the imaging device having a known position and the calibration target including multiple features arranged thereon;
by means of the imaging device, taking an image of the heliostat that includes the reflected calibration target visible on the heliostat;
identifying the multiple features of the calibration target in the image;
using the multiple features to determine a centroid of reflection within the image by determining segments defined by the multiple features and determining a weighted average of areas of the segments shown within the image;
mapping the centroid of reflection within the image to a corresponding centroid position on the calibration target;
determining a vector t that extends between the centroid position on the calibration target and a known center position of the heliostat;
determining a vector s that extends between the known position of the imaging device and the known center position of the heliostat;
determining a normal vector n of the heliostat as the vector that bisects the t-vector and the s-vector; and
calibrating the heliostat by updating parameters of a tracking model using the determined
n-vector.