Non-contact vital sign sensing system and sensing method using the same
A non-contact vital sign sensing system including a vital sign sensing module and at least one body movement interference cancellation module is provided. The vital sign sensing module and the at least one body movement interference cancellation module are under a self-injection locking (SIL) mode. The vital sign sensing module senses an isotropic vital sign of a body. A mutual injection locking (MIL) mode is achieved between the vital sign sensing module and the at least one body movement interference cancellation module to sense the anisotropic body movement signal and to cancel the body movement interference.
1. A non-contact vital sign sensing system, comprising:
a vital sign sensing module for sensing a vital sign of an object, comprising:
a first antenna for transmitting a first transmission wireless signal to the object and receiving a first reflected wireless signal reflected from the object;
a first voltage control oscillator (VCO) directly connected to the first antenna for outputting the first transmission wireless signal to the first antenna and receiving the first reflected wireless signal via the first antenna, and accordingly the vital sign sensing module is under a self-injection locking (SIL) mode;
a frequency demodulation unit coupled to the first VCO for demodulating a frequency variation of the first VCO; and
a signal processing unit coupled to the frequency demodulation unit and the first VCO for obtaining the vital sign of the object based on the frequency variation of the first VCO and for determining a first oscillation frequency of the first VCO; and
at least one body movement interference cancellation module wirelessly coupled to the vital sign sensing module, for canceling a body movement signal of the object, wherein each body movement interference cancellation module comprises:
a second antenna for transmitting a second transmission wireless signal to the object and receiving a second reflected wireless signal reflected by the object; and
a second VCO directly connected to the second antenna for outputting the second transmission wireless signal to the second antenna and for receiving the second reflected wireless signal via the second antenna, and accordingly the at least one body movement interference cancellation module is under the SIL mode;
wherein,
the first antenna transmits the first transmission wireless signal to the second antenna of the at least one body movement interference cancellation module, and the first transmission wireless signal is received by the second VCO via the second antenna;
the second antenna transmits the second transmission wireless signal to the first antenna of the vital sign sensing module, and the second transmission wireless signal is received by the first VCO via the first antenna; and
accordingly a mutual injection locking (MIL) mode is achieved between the vital sign sensing module and the at least one body movement interference cancellation module.
2. The non-contact vital sign sensing system according to claim 1 , wherein,
the first transmission wireless signal and the first reflected wireless signal have different frequencies; and
the second transmission wireless signal and the second reflected wireless signal have different frequencies.
3. The non-contact vital sign sensing system according to claim 1 , wherein,
the body movement interference cancellation module further comprises a frequency control unit coupled to the second VCO for determining a second oscillation frequency of the second VCO; and
the first oscillation frequency of the first VCO is the same with the second oscillation frequency of the second VCO.
4. The non-contact vital sign sensing system according to claim 1 , wherein,
the vital sign of the object is isotropic to the vital sign sensing module and the at least one body movement interference cancellation module.
5. The non-contact vital sign sensing system according to claim 4 , wherein,
the body movement signal of the object is anisotropic to the vital sign sensing module and the at least one body movement interference cancellation module.
6. The non-contact vital sign sensing system according to claim 5 , wherein,
during sensing, the vital sign sensing module and the at least one body movement interference cancellation module are located at opposite sides of the object.
7. The non-contact vital sign sensing system according to claim 5 , wherein,
during sensing, the vital sign sensing module and the at least one body movement interference cancellation module are located at the same side of the object.
8. The non-contact vital sign sensing system according to claim 1 , further comprising a plurality of body movement interference cancellation modules for transmitting a plurality of second transmission wireless signals to the object from a plurality of directions for canceling a multi-dimensional body movement signal of the object.
9. A non-contact vital sign sensing method, comprising:
a vital sign sensing module transmitting a first transmission wireless signal to an object and receiving a first reflected wireless signal reflected by the object and accordingly a first VCO is under a self-injection locking (SIL) mode;
a body movement interference cancellation module for canceling a body movement signal of the object, transmitting a second transmission wireless signal to the object and receiving a second reflected wireless signal reflected by the object and accordingly a second VCO is under the SIL mode; and
receiving the second transmission wireless signal by the vital sign sensing module, and receiving the first transmission wireless signal by the body movement interference cancellation module and accordingly a mutual injection locking (MIL) is achieved between the first VCO and the second VCO.
10. The non-contact vital sign sensing method according to claim 9 , further comprising:
transmitting the first transmission wireless signal to the object via a first antenna;
outputting the first transmission wireless signal to the first antenna by the first VCO, wherein the first VCO receives the first reflected wireless signal via the first antenna, and accordingly the first VCO is under the self-injection locking (SIL) mode;
demodulating a frequency variation of the first VCO;
obtaining a vital sign of the object from the frequency variation of the first VCO and determining a first oscillation frequency of the first VCO;
transmitting the second transmission wireless signal to the object via a second antenna; and
outputting the second transmission wireless signal to the second antenna by the second VCO, wherein the second VCO receives the second reflected wireless signal via the second antenna, and accordingly the second VCO is under the SIL mode;
wherein,
the first antenna transmits the first transmission wireless signal to the second antenna, and the first transmission wireless signal is received by the second VCO via the second antenna;
the second antenna transmits the second transmission wireless signal to the first antenna, and the second transmission wireless signal is received by the first VCO via the first antenna;
the first transmission wireless signal and the first reflected wireless signal have different frequencies; and
the second transmission wireless signal and the second reflected wireless signal have different frequencies.
11. The non-contact vital sign sensing method according to claim 10 , further comprising:
determining a second oscillation frequency of the second VCO;
wherein, the first oscillation frequency of the first VCO is the same with the second oscillation frequency of the second VCO.
12. The non-contact vital sign sensing method according to claim 10 , wherein, the vital sign of the object is an isotropic signal.
13. The non-contact vital sign sensing method according to claim 12 , wherein, the body movement signal of the object is an anisotropic signal.
14. The non-contact vital sign sensing method according to claim 13 , wherein, during sensing, the first transmission wireless signal and the second transmission wireless signal are transmitted to opposite sides of the object.
15. The non-contact vital sign sensing method according to claim 13 , wherein, during sensing, the first transmission wireless signal and the second transmission wireless signal are transmitted to the same side of the object.
16. The non-contact vital sign sensing method according to claim 9 , further comprising:
transmitting a plurality of second transmission wireless signals to the object from a plurality of directions for canceling a multi-dimensional body movement signal of the object.