Metal detection system
View Patent ↗A system includes a metal detector configured to provide an input signal responsive to being proximate an object; and a processing device configured to: receive the input signal from the metal detector; determine a plurality of features from the input signal; provide the plurality of features as input to a trained machine learning model (MLM); receive output from the trained MLM; and responsive to detection, based on the output, that the object comprises metal, cause output of a notification.
1 . A system comprising:
a pulsed induction (PI) metal detector configured to output a voltage signal responsive to being proximate to an object, wherein the PI metal detector comprises a power supply, a coil, and a waveform generating component; and
a processing device configured to:
receive the voltage signal outputted from the PI metal detector, wherein the voltage signal comprises a square wave including an on period and an off period;
determine, based on the voltage signal and position information associated with the PI metal detector, a plurality of features;
provide the plurality of features as input to a trained machine learning model (MLM);
receive output from the trained MLM, wherein the output comprises a confidence value associated with a class of a metal, and wherein the confidence value comprises a percentage;
determine whether the confidence value in the output satisfies a threshold criterion; and
responsive to determining that the confidence value satisfies the threshold criterion, cause output of a notification indicating a detection of the class of the metal in the object,
wherein determining the plurality of features further comprises:
selecting data points in the voltage signal satisfying a criterion;
identifying a first feature of the plurality of features by using a linear regression on the voltage signal;
identifying a second feature of the plurality of features by comparing predefined data points associated with the voltage signal;
identifying a third feature of the plurality of features by using a Fast Fourier transform (FFT) on the voltage signal;
using a proximity to the object of the position information as a fourth feature of the plurality of features;
using signal intensity information of the voltage signal as a fifth feature of the plurality of features; and
using a heat map representing detection confidence of the voltage signal as a sixth feature of the plurality of features.
2 . The system of claim 1 , wherein the voltage signal comprises a voltage measured over a time period.
3 . The system of claim 1 , wherein the trained MLM comprises a binary classification model.
4 . The system of claim 1 , wherein the trained MLM comprises a multi-class classification model.
5 . The system of claim 1 , wherein the trained MLM comprises a recurrent neural network with at least one hidden layer.
6 . The system of claim 1 , wherein the trained MLM is trained using data input comprising historical features of a type common with a type of the plurality of features associated with the voltage signal.
7 . The system of claim 1 , wherein the processing device is further configured to:
preprocess the voltage signal to detect a second plurality of features; and
select the plurality of features from the second plurality of features.
8 . The system of claim 1 , wherein the voltage signal is associated with a voltage measured across the coil.
9 . The system of claim 1 , wherein the output of the notification comprises providing an alert to a user device or making a physical marking proximate to the object.
10 . A method comprising:
receiving a voltage signal outputted from a PI metal detector responsive to the PI metal detector being proximate to an object, wherein the PI metal detector comprises a power supply, a coil, and a waveform generating component, wherein the voltage signal comprises a square wave including an on period and an off period;
determining, based on the voltage signal and position information associated with the PI metal detector, a plurality of features;
providing the plurality of features as input to a trained machine learning model (MLM);
receiving output from the trained MLM, wherein the output comprises a confidence value associated with a class of a metal, and wherein the confidence value comprises a percentage;
determining whether the confidence value in the output satisfies a threshold criterion; and
responsive to determining that the confidence value satisfies the threshold criterion, causing output of a notification indicating a detection of the class of the metal in the object,
wherein determining the plurality of features further comprises:
selecting data points in the voltage signal satisfying a criterion;
identifying a first feature of the plurality of features by using a linear regression on the voltage signal;
identifying a second feature of the plurality of features by comparing predefined data points associated with the voltage signal;
identifying a third feature of the plurality of features by using a Fast Fourier transform (FFT) on the voltage signal;
using a proximity to the object of the position information as a fourth feature of the plurality of features;
using signal intensity information of the voltage signal as a fifth feature of the plurality of features; and
using a heat map representing detection confidence of the voltage signal as a sixth feature of the plurality of features.
11 . The method of claim 10 , wherein the voltage signal comprises a voltage measured over a time period.
12 . The method of claim 10 , wherein the trained MLM comprises a recurrent neural network with at least one hidden layer.
13 . A non-transitory computer-readable medium storing instructions thereon, wherein the instructions, when executed by a processing device, cause the processing device to:
receive a voltage signal outputted from a pulsed induction (PI) metal detector responsive to the PI metal detector being proximate to an object, wherein the PI metal detector comprises a power supply, a coil, and a waveform generating component, wherein the voltage signal comprises a square wave including an on period and an off period;
determine, based on the voltage signal and position information associated with the PI metal detector, a plurality of features;
provide the plurality of features as input to a trained machine learning model (MLM);
receive output from the trained MLM, wherein the output comprises a confidence value associated with a class of a metal, and wherein the confidence value comprises a percentage;
determine whether the confidence value in the output satisfies a threshold criterion; and
responsive to determining that the confidence value satisfies the threshold criterion, cause output of a notification indicating a detection of the class of the metal in the object,
wherein determining the plurality of features further comprises:
selecting data points in the voltage signal satisfying a criterion;
identifying a first feature of the plurality of features by using a linear regression on the voltage signal;
identifying a second feature of the plurality of features by comparing predefined data points associated with the voltage signal;
identifying a third feature of the plurality of features by using a Fast Fourier transform (FFT) on the voltage signal;
using a proximity to the object of the position information as a fourth feature of the plurality of features;
using signal intensity information of the voltage signal as a fifth feature of the plurality of features; and
using a heat map representing detection confidence of the voltage signal as a sixth feature of the plurality of features.
14 . The non-transitory computer-readable medium of claim 13 , wherein the voltage signal comprises a voltage measured over a time period.
15 . The non-transitory computer-readable medium of claim 13 , wherein the trained MLM comprises a binary classification model.
16 . The non-transitory computer-readable medium of claim 13 , wherein the trained MLM comprises a multi-class classification model.
17 . The non-transitory computer-readable medium of claim 13 , wherein the trained MLM comprises a recurrent neural network with at least one hidden layer.
18 . The non-transitory computer-readable medium of claim 13 , wherein the trained MLM is trained using data input comprising historical features of a type common with a type of the plurality of features associated with the voltage signal.
19 . The non-transitory computer-readable medium of claim 13 , wherein the processing device is further configured to:
preprocess the voltage signal to detect a second plurality of features; and
select the plurality of features from the second plurality of features.
20 . The non-transitory computer-readable medium of claim 13 , wherein the output of the notification comprises providing an alert to a user device or making a physical marking proximate to the object.