Optical system and method to identify plastic

Patent metadata

Field	Value
Publication number	US-2023314314-A1
Application number	US-202117924329-A
Country	US
Kind code	A1
Filing date	May 11, 2021
Priority date	May 11, 2020
Publication date	Oct 5, 2023
Grant date	—

Abstract

A system for the identification of sample types and method of using same. The system and method including an optical mechanism, and a detector. The system accepts a sample, directs input light from the optical mechanism onto that sample, producing output light that is received by the detector. The detector produces a sample-derived spectrum for classification. The present disclosure provides for a classification method to classify spectrum into one of many sample types, preferably plastic types.

First claim

1 . A system for the identification and classification of plastic type, comprising:
an optical mechanism configured to produce input light having mid-infrared wavelengths, and said input light is capable of impinging a plastic sample and whereby output light is created upon impinging the plastic sample; a space between said optical mechanism and the plastic sample; a detector to receive said output light, producing a spectrum; and a processor configured to classify a first property of said spectrum using a classification model; wherein said input light travels through said space.

2 . The system of claim 1 wherein said classification model maps at least a portion of said spectrum into one category of a plurality of categories and wherein said one category of said plurality of categories is a type of plastic.

3 . The system of claim 2 wherein said plurality of categories represent different types of plastic.

4 . The system of claim 1 wherein said optical mechanism is a quantum cascade laser.

5 . The system of claim 1 wherein said output light is created after said input light transmits a single time through the plastic sample without reflection.

6 . The system of claim 1 further comprising a mirror; and wherein said output light transmits a first time through the plastic sample, reflects off said mirror and transmits a second time through the plastic sample.

7 . The system of claim 1 further comprising a housing, an interface, and a power source; said housing provides protection from environmental; and wherein said optical mechanism, said space, said detector, said processor, and said power source are contained within said housing.

8 . The system of claim 1 further comprising a light modifier configured to modify the output light.

9 . The system of claim 1 wherein said classification model is further configured to normalize and transform said spectrum.

10 . The system of claim 9 wherein said classification model is supplied with a training set and a test set, and said classification model is further configured to apply an analyzer routine on at least said test set.

11 . A method to classify a type of plastic, the method comprising the steps of:
(a) selecting a system having an optical mechanism, a sample holder, a space between said sample holder and said optical mechanism, and a detector, said optical mechanism producing input light suitable for impinging a sample, said input light consisting of mid-infrared wavelengths; (b) placing a plastic sample onto said sample holder; (c) directing said input light across said space and onto said plastic sample, producing output light; (d) capturing said output light by said detector, producing a spectrum; and (e) analyzing said spectrum with a classification model to classify at least one property of said spectrum, producing a classification result.

12 . The method of claim 11 wherein said classification model classifies said at least one property of said spectrum into one category of a plurality of categories; and wherein said one category of said plurality of categories is a type of plastic.

13 . The method of claim 12 further comprising the steps of:
(f) applying a normalization routine to said spectrum, producing a normalized spectrum; and
(g) applying a transformation routine to said normalized spectrum, producing a transformed spectrum;
wherein said spectrum in step (e) is said transformed spectrum.

14 . The method of claim 12 further comprising the steps of:
(f) applying a normalization routine to said spectrum, producing a normalized spectrum;
(g) applying a transformation routine to said normalized spectrum, producing a transformed spectrum; and
(h) applying a smoothing routine to said transformed spectrum, producing a smoothed spectrum;
wherein said spectrum in step (e) is said smoothed spectrum.

15 . The method of claim 14 further comprising the steps of:
(i) repeating steps (b) though (h); thereby producing a plurality of smoothed spectrum;
(j) forming a test set from said plurality of smoothed spectrum; and
(k) applying an analyzer routine to said test set to produce, in part, said classification result.

16 . The method of claim 11 wherein said output light is created after said input light transmits a single time through said plastic sample without reflection in step (c).

17 . The method of claim 11 wherein said system further comprising a mirror; and wherein in step (c), said output light transmits a first time through said plastic sample, reflects off said mirror and transmits a second time through said plastic sample.

18 . The method of claim 11 wherein said system further comprising a mirror; and wherein in step (c), said output light transmits a first time through said plastic sample and reflects off said mirror at an angle other than 180 degrees from said plastic sample.

19 . The method of claim 11 wherein said system further comprises a housing, an interface, and a power source; said housing provides protection from environmental factors; and wherein said optical mechanism, said space, said detector, said processor, and said power source are contained within said housing.

20 . The method of claim 19 further comprising the step of (1) moving said system by a user.

Assignees

• Woods Hole Oceanographic Inst

Inventors

• Michel Anna

Classifications

• G01N21/3563 Primary

  for analysing solids; Preparation of samples therefor · CPC title

• G01N33/442 Primary

  Resins; Plastics · CPC title

• G02B27/0006

  with means to keep optical surfaces clean, e.g. by preventing or removing dirt, stains, contamination, condensation (G02B1/18 takes precedence; cleaning in general B08B) · CPC title

• G01N2201/0636

  Reflectors · CPC title

• Y02W30/62

  Plastics recycling; Rubber recycling · CPC title