US 11,774,360 B2
Method for determining relative degrees of reflectance of a measurement surface
Gregor Bern, Freiburg (DE); Peter Schöttl, Freiburg (DE); Anna Heimsath, Freiburg (DE); and Peter Nitz, Freiburg (DE)
Assigned to Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e. V., Munich (DE)
Appl. No. 17/282,422
Filed by Fraunhofer-Gesellschaft zur Fordergung Der Angewandten Forschung e.V., Munich (DE)
PCT Filed Sep. 30, 2019, PCT No. PCT/EP2019/076475
§ 371(c)(1), (2) Date Apr. 2, 2021,
PCT Pub. No. WO2020/070076, PCT Pub. Date Apr. 9, 2020.
Claims priority of application No. 102018124368.5 (DE), filed on Oct. 2, 2018.
Prior Publication US 2021/0381970 A1, Dec. 9, 2021
Int. Cl. G01N 21/55 (2014.01); F24S 50/20 (2018.01); F24S 23/70 (2018.01)
CPC G01N 21/55 (2013.01) [F24S 50/20 (2018.05); F24S 23/70 (2018.05); G01N 2201/06113 (2013.01)] 18 Claims
OG exemplary drawing
 
1. A method for determining relative reflectance values of a measurement surface (6), the method comprising the steps of:
A. applying measurement radiation to the measurement surface (6) such that a measurement spot (7a, 7b) arises on the measurement surface (6),
B. moving the measurement spot in accordance with a first path movement over the measurement surface (6) along at least one first straight measurement spot path (8a),
C. recording a first image set of a plurality of spatially resolved images of the measurement surface (6) during the first path movement in accordance with step B, and
D. determining relative reflectance values for a plurality of localities on the measurement surface (6),
wherein, method step B further comprises additionally moving the measurement spot (7a, 7b) in a second path movement over the measurement surface (6) at least along a second straight measurement spot path (8b) which is not parallel to the first measurement spot path (8a), such that a first measurement path region of the measurement surface (6), over which the measurement spot (7a, 7b) sweeps during the first path movement, at least overlaps with a second measurement path region of the measurement surface (6), over which the measurement spot (7a, 7b) sweeps during the second path movement,
method step C further comprises recording a second image set of a plurality of spatially resolved images of the measurement surface (6) during the second path movement, and
method step D further comprises carrying out an evaluation at points of intersection, the localities of which on the measurement surface (6) are defined by straight evaluation lines (10a, 10b), wherein a first group of the straight evaluation lines are at least one of specified or determined within the first measurement path region and at least a second group of the straight evaluation lines are at least one of specified or determined within the second measurement path region, and at least the first group has at least two of the evaluation lines that are spaced apart from one another, the evaluation lines of the first group are parallel to the first measurement spot path and the evaluation line or the evaluation lines of the second group is parallel to the second measurement spot path, and each of the evaluation lines of the first group has a point of intersection with at least one of the evaluation lines of the second group,
for each image set, determining a maximum grayscale value at least for each said point of intersection, and
determining relative reflectance values of the measurement surface (6) at least at a subset of the points of intersection based on these maximum grayscale values.