Livestock heart rate measurement with bolus sensor
Various examples describe a livestock monitoring system and method. A sensor signal may comprise a rotational component describing a rotation of the sensor within an animal and a linear component describing a linear movement of the sensor within the animal. The rotational component may be used to identify an animal respiration signal. The animal respiration signal and the linear component may be used to generate a respiration-corrected linear component. An animal heart signal may be detected from the respiration-corrected linear component.
1. A livestock monitoring method comprising:
accessing a motion sensor signal generated by an animal bolus sensor located within the reticulum or rumen of a non-human mammal, the motion sensor signal comprising a rotational component describing a rotational motion of the sensor within an animal and a linear component describing a linear movement of the sensor within the animal;
identifying an animal respiration signal with the rotational component of the motion sensor signal;
generating a respiration-corrected linear component through use of the linear component of the motion sensor signal and the animal respiration signal; and
detecting an animal heart signal from the respiration-corrected linear component.
2. The method of claim 1 , wherein the rotational component of the motion sensor signal comprises a rotational magnitude component describing a magnitude of the rotation of the sensor within the animal; and wherein the linear component of the motion sensor signal comprises a linear magnitude component describing a magnitude of the linear movement of the sensor within the animal; the method further comprising:
detecting at least one acceleration peak of the rotational magnitude component; and
correlating the at least one acceleration peak of the rotational magnitude component to at least one correlated acceleration peak of the linear magnitude component, the generating of the respiration-corrected linear component comprising removing the at least one correlated acceleration peak of the linear magnitude component of the motion sensor signal to generate a respiration-corrected linear magnitude.
3. The method of claim 2 , further comprising, before detecting the at least one acceleration peak of the rotational magnitude component, applying a first bandpass filter to the rotational magnitude component of the motion sensor signal, the first bandpass filter having a passband corresponding to an expected respiration rate of the animal.
4. The method of claim 2 , wherein the generating of the respiration-corrected linear component further comprises applying a second bandpass filter to the respiration-corrected linear magnitude component to generate a filtered respiration-corrected linear magnitude component, the second bandpass filter having a passband corresponding to a first expected heart rate range for the animal.
5. The method of claim 4 , further comprising:
determining that the filtered respiration-corrected linear magnitude component does not indicate the animal heart rate; and
applying a third bandpass filter to the respiration-corrected linear magnitude component to generate a second filtered linear magnitude component, the third bandpass filter having a passband different than the passband of the second bandpass filter, wherein the detecting of the animal heart signal uses the second filtered linear magnitude component.
6. The method of claim 1 , further comprising:
determine a down direction through use of the rotational component;
identifying at least one acceleration peak of the rotational component directed towards the down direction; and
correlating the at least one acceleration peak of rotational component directed towards the down direction to at least one correlated acceleration peak of the linear component, wherein the generating of the respiration-corrected linear component comprises removing the at least one correlated acceleration peak from the linear component.
7. The method of claim 1 , further comprising:
sending, by a collection device, an interrogation signal to an animal bolus comprising the animal bolus sensor; and
receiving the animal motion sensor signal by the collection device and from the animal bolus.
8. The method of claim 1 , further comprising:
determining that an animal heart rate indicated by the animal heart signal is outside of an animal heart rate range; and
sending a heart rate alert to a user computing device.
9. A livestock monitoring system comprising:
at least one hardware processor programmed to perform operations comprising:
accessing an animal motion sensor signal generated by an animal bolus sensor located within the reticulum or rumen of a non-human mammal, wherein the animal motion sensor signal comprises a rotational component describing a rotational motion of the sensor within an animal and a linear component describing a linear movement of the sensor within the animal;
identifying an animal respiration signal with the rotational component of the motion sensor signal;
generating a respiration-corrected linear component through use of the linear component of the motion sensor signal and the animal respiration signal; and
detecting an animal heart signal from the respiration-corrected linear component.
10. The system of claim 9 , wherein the rotational component of the motion sensor signal comprises a rotational magnitude component describing a magnitude of the rotation of the sensor within the animal; wherein the linear component of the motion sensor signal comprises a linear magnitude component describing a magnitude of the linear movement of the sensor within the animal; the operations further comprising:
detecting at least one acceleration peak of the rotational magnitude component; and
correlating the at least one acceleration peak of the rotational magnitude component to at least one correlated acceleration peak of the linear magnitude component, wherein the generating of the respiration-corrected linear component comprises removing the at least one correlated acceleration peak of the linear magnitude component of the motion sensor signal to generate a respiration-corrected linear magnitude.
11. The system of claim 10 , the operations further comprising, before detecting the at least one acceleration peak of the rotational magnitude component, applying a first bandpass filter to the rotational magnitude component of the motion sensor signal, the first bandpass filter having a passband corresponding to an expected respiration rate of the animal.
12. The system of claim 10 , the generating of the respiration-corrected linear component further comprising applying a second bandpass filter to the respiration-corrected linear magnitude component to generate a filtered respiration-corrected linear magnitude component, the second bandpass filter having a passband corresponding to a first expected heart rate range for the animal.
13. The system of claim 12 , the operations further comprising:
determining that the filtered respiration-corrected linear magnitude component does not indicate the animal heart rate; and
applying a third bandpass filter to the respiration-corrected linear magnitude component to generate a second filtered linear magnitude component, the third bandpass filter having a passband different than the passband of the second bandpass filter, the detecting of the animal heart signal through use of the second filtered linear magnitude component.
14. The system of claim 9 , the operations further comprising:
determining a down direction through use of the rotational component;
identifying at least one acceleration peak of the rotational component directed towards the down direction; and
correlating the at least one acceleration peak of rotational component directed towards the down direction to at least one correlated acceleration peak of the linear component, wherein the generating of the respiration-corrected linear component comprises removing the at least one correlated acceleration peak from the linear component.
15. The system of claim 9 , the operations further comprising:
sending, by a collection device, an interrogation signal to an animal bolus comprising the animal bolus sensor; and
receiving the animal motion sensor signal by the collection device and from the animal bolus.
16. The system of claim 9 , the operations further comprising:
determining that an animal heart rate indicated by the animal heart signal is outside of an animal heart rate range; and
sending a heart rate alert to a user computing device.
17. A non-transitory machine-readable medium comprising instructions thereon that, when executed by at least one hardware processor, causes the at least one hardware processor to perform operations comprising:
accessing an animal motion sensor signal generated by an animal bolus sensor located within the reticulum or rumen of a non-human mammal, wherein the animal motion sensor signal comprises a rotational component describing a rotation of the sensor within an animal and a linear component describing a linear movement of the sensor within the animal;
identifying an animal respiration signal with the rotational component of the motion sensor signal;
generating a respiration-corrected linear component through use of the linear component of the motion sensor signal and the animal respiration signal; and
detecting an animal heart signal from the respiration-corrected linear component.
18. The medium of claim 17 , wherein the rotational component of the motion sensor signal comprises a rotational magnitude component describing a magnitude of the rotation of the sensor within the animal; wherein the linear component of the motion sensor signal comprises a linear magnitude component describing a magnitude of the linear movement of the sensor within the animal; the operations further comprising:
detecting at least one acceleration peak of the rotational magnitude component; and
correlating the at least one acceleration peak of the rotational magnitude component to at least one correlated peak of the linear magnitude component, the generating of the respiration-corrected linear component comprising removing the at least one correlated peak of the linear magnitude component of the motion sensor signal to generate a respiration-corrected linear magnitude.
19. The medium of claim 18 , wherein the generating of the respiration-corrected linear component further comprises applying a second bandpass filter to the respiration-corrected linear magnitude component to generate a filtered respiration-corrected linear magnitude component, the second bandpass filter having a passband corresponding to a first expected heart rate range for the animal.
20. The medium of claim 17 , the operations further comprising:
determining a down direction through use of the rotational component;
identifying at least one peak of the rotational component directed towards the down direction; and
correlating the at least one peak of rotational component directed towards the down direction to at least one correlated peak of the linear component, the generating of the respiration-corrected linear component comprising removing the at least one correlated peak from the linear component.