Physiological detection system and operating method thereof

1. A physiological detection system, arranged in an electronic device, and configured to detect a change of skin microcirculation, the physiological detection system comprising:

a light source configured to be arranged facing a skin area of a user to irradiate the skin area;

a photosensitive array including a plurality of photosensitive pixels arranged in an array and configured to be arranged facing the skin area of the user, wherein each of the plurality of photosensitive pixels is configured to output a plurality of brightness signals as a photoplethysmography (PPG) signal by continuously detecting light from the skin area; and

a processing unit connecting to the photosensitive array to receive the PPG signals and configured to

convert the PPG signals of the plurality of photosensitive pixels into a plurality of frequency domain data to generate a 3D energy distribution of the frequency domain data associated with a heartbeat frequency,

calculate a variance of the 3D energy distribution as a variation value and calculate an average value of the 3D energy distribution of the frequency domain data,

identify different microcirculation states according to a change of the variation value and a change of the average value, and

notify the user of the identified microcirculation states through the electronic device using images or sound.

2. The physiological detection system as claimed in claim 1 , wherein light of the light source has a wavelength from 300 nm to 940 nm.

3. The physiological detection system as claimed in claim 1 , wherein the processing unit is further configured to identify the different microcirculation states according to the heartbeat frequency.

4. The physiological detection system as claimed in claim 1 , wherein the processing unit is further configured to calculate the heartbeat frequency according to a plurality of sums of brightness of a plurality of image frames outputted by the photosensitive array, and each of the plurality of sums of brightness is calculated by adding the brightness signals of a corresponding photosensitive pixel of the plurality of image frames.

5. The physiological detection system as claimed in claim 1 , wherein the processing unit is further configured to calculate a plurality of estimated heartbeat frequencies according to the plurality of frequency domain data, and the heartbeat frequency is one of the plurality of estimated heartbeat frequencies that has the highest statistic.

6. The physiological detection system as claimed in claim 1 , wherein the processing unit is configured to determine that the microcirculation state is in a warm up completion state when the average value is smaller than a warm up average threshold.

7. The physiological detection system as claimed in claim 6 , wherein the processing unit is configured to determine that the microcirculation state is in an in-exercise state when the average value is smaller than an in-exercise average threshold.

8. The physiological detection system as claimed in claim 1 , wherein the processing unit is configured to determine that the microcirculation state is in a warm up completion state when the average value is smaller than a warm up average threshold and when the variation value is larger than a warm up variation threshold.

9. The physiological detection system as claimed in claim 8 , wherein the processing unit is configured to determine that the microcirculation state is in an in-exercise state when the average value is smaller than an in-exercise average threshold and the variation value is larger than an in-exercise variation threshold.

10. The physiological detection system as claimed in claim 9 , wherein the processing unit is configured to determine that the microcirculation state is in a post-exercise cooling state when the average value increases to exceed a cooling average threshold and the variation value decreases to be below a cooling variation threshold.

11. An operating method of a physiological detection system for detecting a change of skin microcirculation via a plurality of photosensitive pixels arranged in an array, the physiological detection system being arranged in an electronic device and comprising a light source, the light source and the array being arranged to face a skin area of a user, the operating method comprising:

irradiating the skin area by the light source;

continuously detecting light from the skin area by each of the plurality of photosensitive pixels to output a brightness variation signal;

converting the brightness variation signals of the plurality of photosensitive pixels into a plurality of frequency domain data to generate a 3D energy distribution of the frequency domain data associated with a heartbeat frequency;

calculating a variance of the 3D energy distribution as a variation value and calculating an average value of the 3D energy distribution of the frequency domain data;

identifying a microcirculation state according to a change of the variation value and a change of the average value; and

notifying the user of the identified microcirculation state through the electronic device using images or sound.

12. The operating method as claimed in claim 11 , further comprising: comparing the average value with at least one average threshold.

13. The operating method as claimed in claim 11 , further comprising:

calculating the heartbeat frequency according to a plurality of sums of brightness of a plurality of image frames outputted by the array, and each of the plurality of sums of brightness is calculated by adding the brightness variation signals of a corresponding photosensitive pixel of the plurality of image frames.

14. The operating method as claimed in claim 11 , further comprising:

calculating a plurality of estimated heartbeat frequencies according to the plurality of frequency domain data, and the heartbeat frequency is one of the plurality of estimated heartbeat frequencies that has the highest statistic.

15. A physiological detection system, arranged in an electronic device, and configured to detect a change of skin microcirculation, the physiological detection system comprising:

a photosensitive array having a plurality of photosensitive pixels arranged in an array and configured to be arranged facing a skin area of a user to detect a microcirculatory data array of the skin area; and

a processing unit connecting to the photosensitive array to receive the microcirculatory data array, and configured to

convert the microcirculatory data array into a plurality of frequency domain data and generate a 3D energy distribution of the frequency domain data associated with a heartbeat frequency,

detect different microcirculation states according to a change of a variation value of the 3D energy distribution over time and according to a change of an average value of the 3D energy distribution of the frequency domain data, wherein the variation value is a variance of the 3D energy distribution, and

notify the user of the detected microcirculation states through the electronic device using images or sound.

16. The physiological detection system as claimed in claim 15 , wherein the processing unit is further configured to detect the different microcirculation states according to the heartbeat frequency.

17. The physiological detection system as claimed in claim 15 , wherein the processing unit is further configured to calculate the heartbeat frequency according to a plurality of sums of brightness of a plurality of image frames outputted by the photosensitive array, and each of the plurality of sums of brightness is calculated by adding microcirculatory data of a corresponding photosensitive pixel of the plurality of image frames.

18. The physiological detection system as claimed in claim 15 , wherein the processing unit is further configured to calculate a plurality of estimated heartbeat frequencies according to the plurality of frequency domain data, and the heartbeat frequency is one of the plurality of estimated heartbeat frequencies that has the highest statistic.