Particle counting apparatus, systems and methods

Patent metadata

Field	Value
Publication number	US-12050169-B2
Application number	US-202017430191-A
Country	US
Kind code	B2
Filing date	Mar 20, 2020
Priority date	Mar 22, 2019
Publication date	Jul 30, 2024
Grant date	Jul 30, 2024

Abstract

In one embodiment a first light plane is generated across the passageway by a first LED emitter array. A corresponding photodiode receiver array detects particles passing through a first number of light channels comprising the first light plane. In a second embodiment a second light plane is generated across the passageway at 90 degrees from the first light plane and longitudinally offset from the first light plane by a second LED emitter array. A corresponding photodiode receiver array detects particles passing through a second number of light channels comprising the second light plane. The second light plane is capable of identifying particles in a third dimension that may go undetected when passing through the first light plane. The raw output signals generated by respective photodiodes is normalized, analyzed and characterized to differentiate between particles passing through light planes as individual particles or groups of overlapping particles to be separately counted.

First claim

The invention claimed is:

1. A method of counting particles passing through a passageway, the method comprising:
(A) generating a first number of light channels at a defined spacing across the passageway transverse to a longitudinal axis of the passageway, the first number of light channels collectively defining a first light plane, each of the first number of light channels generated by a corresponding one of a first number of LED emitters disposed on a first side of the passageway, each of the first number of LED emitters having a known spacing and each producing a light intensity;
(B) with a first number of photodiodes disposed on a second side of the passageway and with each one of the first number of photodiodes disposed opposite to one of the first number of LED emitters, generating raw output signal values proportional to the light intensity of each of the first number of light channels;
(C) as the particles pass through the first light plane, recording the raw output signal values generated across each of the first number of light channels in parallel relation over a series of sequential data scans, the raw output signal values being stored in data cells within a first data set;
(D) normalizing the raw output signal values in each of the data cells of the first data set such that each data cell of the first data set has a Normalized Output Signal (NOS) value;
(E) analyzing the NOS values of each of the data cells of the first data set to identify data cells joined as a cluster by at least one NOS value within a predefined range of NOS values, each of the identified clusters of joined data cells of the first data set defining a separate first plane Event corresponding to at least one particle passing through the first light plane;
(F) identifying each said separate first plane Event with a unique first plane identifier;
(G) summing the NOS values of each said identified first plane Event;
(H) determining a group speed of each said identified first plane Event;
(I) determining for each said identified first plane Event, an Event Volume by multiplying the NOS value sum from step (G) by said group speed from step (H) for each said identified first plane Event;
(J) determining a particle count of each said identified first plane Event by characterizing the Event Volume.

2. The method of claim 1 , further comprising:
(K) generating a second number of light channels at a defined spacing across the passageway transverse to a longitudinal axis of the passageway, the second number of light channels collectively defining a second light plane, each of the second number of light channels generated by a corresponding one of a second number of LED emitters disposed on a third side of the passageway oriented 90 degrees from the first side of the passageway, each of the second number of LED emitters having a known spacing and each producing a light intensity, the second light plane offset from the first light plane along the longitudinal axis of the passageway by a known distance;
(L) with a second number of photodiodes disposed on a fourth side of the passageway and with each one of the second number of photodiodes disposed opposite to one of the second number of LED emitters, generating raw output signal values proportional to the light intensity of each of the second number of light channels;
(M) as the particles pass through the second light plane, recording the raw output signal values generated across each of the second number of light channels in parallel relation over a series of sequential data scans, the raw output signal values being stored in data cells within a second data set;
(N) normalizing the raw output signal values in each of the data cells of the second data set such that each data cell of the second data set has a Normalized Output Signal (NOS) value;
(O) analyzing the NOS values of each of the data cells of the second data set to identify data cells joined as a cluster by at least one NOS value within a predefined range of NOS values, each of the identified clusters of joined data cells of the second data set defining a separate second plane Event corresponding to at least one particle passing through the second light plane;
(P) identifying each said separate second plane Event with a unique second plane identifier;
(Q) summing the NOS values of each said identified second plane Event;
(R) determining a group speed of each said identified second plane Event;
(S) determining for each said identified second plane Event and Event Volume by multiplying each said identified second plane Event's NOS value sum from step (Q) by each said identified second plane Event's group speed from step (R);
(T) determining a particle count of each said identified second plane Event by characterizing the Event Volume of each identified second plane Event;
(U) associating each said identified first plane Event with a corresponding one of said identified second plane Event;
(V) determining which of said associated first plane and second plane identified Events has a greater particle count;
(W) calculating a running particle count over a period of operation by adding the greater particle count from step (V) to a particle count of an immediately preceding one of said associated first plane and second plane identified Events.

3. The method of claim 2 , wherein step (N) of normalizing the raw output signal values in each data cell of the second data set includes:
converting the raw output signal values in each data cell of the second data set to an NOS value between 0 and 1, whereby an NOS value of 0 corresponds to the light intensity being at a maximum for a corresponding one of the second number of light channels and which is indicative of that one light channel being unblocked by any of the particles passing through that one light channel, and whereby an NOS value of 1 corresponds to the light intensity at a minimum for a corresponding one of the second number of light channels and which is indicative of that one light channel being entirely blocked by the particles passing through that one light channel.

4. The method of claim 2 , wherein the step of determining the group speed of said identified second plane Event includes:
determining a change in time between said identified first plane Event and said identified second plane Event associated with said first plane Event and dividing the change in time by the known distance of the offset of the second light plane from the first light plane.

5. The method of claim 2 , wherein the known distance of the offset of the second light plane from the first light plane is between 0.05 to 1 inches (0.13 to 2.5 cm).

6. The method of claim 2 , wherein the step of determining a particle count under step (T) characterizing the Event Volume includes:
determining if the Event Volume of the identified second plane Event volume satisfies criteria for a defined particle count.

7. The method of claim 6 , wherein the defined particle count is one of: (i) a five particle count, (ii) a four particle count, (iii) a three particle count, (iv) a two particle count and a (v) a one particle count.

8. The method of claim 2 , further comprising:
analyzing the NOS values of each of the data cells of the second data set to identify troughs within the joined clusters of NOS data cells defining said separate second plane Event;
subdividing each said separate second plane Event having troughs within the joined clusters of NOS data cells into additional separate second plane Events.

9. The method of claim 2 , wherein the passage is a distribution tube on an air seeder and the particles are one of (i) seeds; (ii) fertilizer; or (iii) seeds and fertilizer.

10. The method of claim 2 , w

Assignees

• Prec Planting Llc

Inventors

• Plattner Chad E
• Steiner Philip

Classifications

• G01N2015/1027

  Determining speed or velocity of a particle · CPC title

• G01N2015/1493

  Particle size · CPC title

• G01N2015/1486

  Counting the particles · CPC title

• G01N2015/0046

  in gas, e.g. smoke · CPC title

• G01N15/1434

  Optical arrangements · CPC title