US 12,405,284 B2
Systems for differential measurement of a fluid level in a sample receptacle
Rolf Silbert, Del Mar, CA (US)
Assigned to GEN-PROBE INCORPORATED, San Diego, CA (US)
Appl. No. 17/996,923
Filed by GEN-PROBE INCORPORATED, San Diego, CA (US)
PCT Filed Apr. 22, 2021, PCT No. PCT/US2021/028719
§ 371(c)(1), (2) Date Oct. 21, 2022,
PCT Pub. No. WO2021/216929, PCT Pub. Date Oct. 28, 2021.
Claims priority of provisional application 63/015,129, filed on Apr. 24, 2020.
Prior Publication US 2023/0176085 A1, Jun. 8, 2023
Int. Cl. G01N 35/10 (2006.01); G01N 35/02 (2006.01)
CPC G01N 35/1009 (2013.01) [G01N 35/02 (2013.01); G01N 2035/1025 (2013.01)] 35 Claims
OG exemplary drawing
 
1. An automated system for detecting a level of a fluid contained in sample receptacle, the sample receptacle having a closed bottom and a receptacle wall extending from the closed bottom to a rim defining an open top of the sample receptacle, the system comprising:
a sensor for periodically measuring a distance between the sensor and (i) one or more surfaces of the sample receptacle and (ii) a surface of a fluid contained within the sample receptacle, respectively, including measuring a distance between the sensor and the rim of the sample receptacle, wherein at least one of the sensor and sample receptacle is controllably movable relative to the other to enable the sensor to obtain a sequence of discrete surface distance measurements of distances between the sensor and (i) the one or more surfaces of the sample receptacle and (ii) the surface of the fluid contained within the sample receptacle; and
a controller operatively coupled to the sensor and configured to receive and process an output signal from the sensor comprising a digital representation of the sequence of discrete surface distance measurements to thereby determine a level of the fluid contained within the sample receptacle relative to the rim of the sample receptacle, wherein the controller is configured to determine which measurements in the sequence of discrete surface distance measurements correspond to each of a first portion of the rim, the top surface of the fluid, and a second portion of the rim opposite the first portion of the rim using an edge finding technique, wherein the edge finding technique comprises:
(a) analyzing a rate of change of the distances in the sequence of discrete surface distance measurements, identifying edges of the rim as measurements that correspond to peaks of the rate of change, and identifying the measurements between the peaks as either rim measurements or fluid measurements; or (b) identifying the measurements where the rate of change of the distances in the sequence of discrete surface distance measurements are within a threshold window.