Non-invasive physiological signal detection device

Abstract

This invention provides a non-invasive physiological signal detection device, comprising multiple light sources and multiple photodetectors to form multiple optical channels. The light sources and adjacent photodetectors form shallow reflection sampling with a short source-detection distance, ensuring that the measurement optical path mainly focuses on the epidermis and upper dermis. The output time-series physiological waveform corresponds to the blood volume changes in this layer. A driving and acquisition unit drives the light sources and acquires the reflected light signals. A signal processing unit evaluates the signal quality of the reflected light signals from each channel and selects at least one channel to output the time-series physiological waveform. This invention, through a multi-channel quality evaluation mechanism, improves signal stability and usability under different skin types, vascular distributions, and wearing conditions, and helps reduce the required light source driving energy and improve measurement efficiency.

Claims

1. A non-invasive physiological signal detection device, disposed on and attached to the skin of a subject, the non-invasive physiological signal detection device comprising: Multiple light sources are configured to emit light toward the skin of the test subject; A plurality of photodetectors are configured to receive light reflected and / or scattered back from the subject's skin and output a corresponding reflected light signal, wherein each photodetector and at least one light source are arranged adjacent to each other; a driving and capturing unit is electrically connected to the plurality of light sources and the plurality of photodetectors and is configured to drive the emitted light of the plurality of light sources and capture the reflected light signal; a signal processing unit is electrically connected to the driving and capturing unit and is configured to perform a signal quality assessment on the reflected light signal corresponding to the plurality of optical channels formed by each light source and each photodetector, and select the reflected light signal of at least one optical channel according to the signal quality assessment result, so as to output a time-series physiological waveform through at least one reflected light signal; And therein, a shallow reflection sampling is formed between the light source and at least one photodetector and the skin of the subject, so that the time series physiological waveform corresponds to a change in blood volume in the epidermis and the upper dermis.

2. The non-invasive physiological signal detection device as claimed in claim 1, wherein the signal processing unit further integrates the reflected light signals corresponding to a plurality of the optical channels to output the time-series physiological waveform.

3. The non-invasive physiological signal detection device as claimed in claim 2, wherein the signal processing unit integrates the reflected light signals corresponding to each optical channel in a weighted manner, and the weighting method determines the corresponding weighting coefficients based on the signal quality evaluation results of each optical channel, wherein the signal quality evaluation results include at least one of the following indicators: indicator (1): signal-to-noise ratio of each optical channel; indicator (2): the ratio of spectral energy of the heartbeat-related frequency band to the spectral energy of the non-heartbeat frequency band; indicator (3): peak intelligibility and / or waveform consistency of the waveform formed by the reflected light signals corresponding to each optical channel; and indicator (4): signal stability calculated from the periodicity characteristics of each reflected light signal; and the weighting coefficients are positively correlated with indicators (1) to (4).

4. The non-invasive physiological signal detection device as described in claim 3, wherein the signal processing unit establishes a quality matrix Q(i,j) for each optical channel, the element values ​​of the quality matrix Q(i,j) corresponding to the signal quality evaluation result of the optical channel formed by the i-th light source and the j-th photodetector, and the weighting coefficient is determined based on the Q(i,j) value of each optical channel.

5. The non-invasive physiological signal detection device as claimed in claim 1, wherein the signal quality assessment further includes generating a quality matrix Q(i,j) for each optical channel based on signal-to-noise ratio analysis and / or spectral analysis to characterize the signal quality assessment result of each optical channel.

6. The non-invasive physiological signal detection device as claimed in claim 5, wherein selecting at least one of the optical channels comprises: Choose the optical channel with the largest Q(i,j) value, or choose the optical channel with a Q(i,j) value greater than a threshold value.

7. The non-invasive physiological signal detection device as claimed in claim 1, wherein the source-detection distance between each of the light sources and the adjacent photodetector is between 0.3 and 2.0 mm.

8. The non-invasive physiological signal detection device as claimed in claim 1, wherein the change in blood volume between the epidermis and the upper dermis is caused by the change in blood volume of the microvessels in the capillary layer of the upper dermis.

9. The non-invasive physiological signal detection device as claimed in claim 1, wherein at least one of the plurality of light sources emits wavelengths between 500 and 2000 nm.

10. The non-invasive physiological signal detection device as claimed in claim 1, wherein the plurality of light sources include at least two different emission wavelengths, and the signal processing unit is configured to select at least one optical channel based on the signal quality assessment results corresponding to the different emission wavelengths to output the time-series physiological waveform.

11. The non-invasive physiological signal detection device as claimed in claim 1, wherein the driving and capturing unit further activates each of the light sources sequentially in a time-division driving manner, and simultaneously captures the reflected light signal of each of the photodetectors when each of the light sources is activated.

12. The non-invasive physiological signal detection device as claimed in claim 1, wherein the sensing area of ​​each photodetector is between 0.5 and 2 mm².

13. The non-invasive physiological signal detection device as claimed in claim 1, wherein the plurality of light sources and the plurality of photodetectors are arranged in a matrix, ring, or arc shape.

14. The non-invasive physiological signal detection device as claimed in claim 1, wherein the signal processing unit is configured to remove the DC component and / or de-trend the reflected light signal to eliminate low-frequency variations caused by skin scattering, contact pressure, or temperature drift.

15. The non-invasive physiological signal detection device as claimed in claim 1, wherein the signal processing unit is further configured to establish a personal optical feature vector, the personal optical feature vector including the reflection intensity distribution at different source distances, the AC / DC ratio at different wavelengths, and / or the signal-to-noise ratio or spectral index of each optical channel, and the signal processing unit is configured to use the personal optical feature vector for subsequent signal correction and / or as input to a physiological parameter model.

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