Microcirculation detection system and method
A microcirculation detection system including a heating device, a photosensitive array and a processing unit is provided. The heating device is used to heat a skin area. The photosensitive array is used to detect outgoing light from the skin area, and output a plurality of brightness variation signals respectively at different time points within a heating period. The processing unit is used to calculate a change of an array energy distribution varied within the heating period according to the plurality of brightness variation signals to accordingly identify a microcirculation state.
1. A microcirculation detection system, comprising:
a light source configured to irradiate light to illuminate a skin area;
a heating device configured to heat the skin area within a heating period;
a photosensitive array configured to detect outgoing light from the skin area and output a plurality of PPG signals;
a processing unit configured to
convert the plurality of PPG signals to an array energy distribution,
identify a first arc-like pattern in the array energy distribution at a first time point and a second arc-like pattern in the array energy distribution at a second time point, and
identify whether a frequency variation of an oscillation frequency, of oscillating between the first arc-like pattern and second arc-like pattern has a peak respectively within a first time interval and a second time interval of the heating period to detect a biphasic blood flow response to heat; and
a display, wherein the processing unit is further configured to control the display to show the first and second arc-like patterns, and the frequency variation within the heating period.
2. The microcirculation detection system as claimed in claim 1 , wherein
the first time interval is between 2 and 5 minutes of the heating period; and
the second time interval is between 10 and 15 minutes of the heating period.
3. The microcirculation detection system as claimed in claim 1 , wherein a wavelength of the light is between 500 nm and 550 nm.
4. The microcirculation detection system as claimed in claim 1 , wherein the heating device comprises:
a heating chamber configured to accommodate the skin area; and
an infrared heat lamp or an electric heating tube disposed inside the heating chamber and configured to heat the skin area.
5. The microcirculation detection system as claimed in claim 1 , wherein
the photosensitive array comprises a plurality of pixel areas arranged in a matrix and respectively configured to output a brightness variation signal as one of the plurality of PPG signals, and
each of the plurality of pixel areas includes at least one sensing pixel.
6. The microcirculation detection system as claimed in claim 5 , wherein the array energy distribution is an energy value distribution, corresponding to a two dimensional space of the plurality of pixel areas, of spectrum energies at a predetermined frequency of the plurality of PPG signals.
7. The microcirculation detection system as claimed in claim 1 , further comprising a temperature sensor configured to detect a temperature of heated skin.
8. The microcirculation detection system as claimed in claim 4 , further comprising a temperature sensor configured to detect a temperature of the heating chamber.
9. The microcirculation detection system as claimed in claim 1 , further comprising a temperature sensor configured to detect a temperature of unheated skin.
10. The microcirculation detection system as claimed in claim 1 , wherein the first arc-like pattern and the second arc-like pattern are out of phase from each other.
11. The microcirculation detection system as claimed in claim 1 , further comprising a memory configured to store the first arc-like pattern and the second arc-like pattern, wherein the processing unit is further configured to compare similarity or correlation of every identified arc-like pattern within the heating period with the stored first arc-like pattern and the stored second arc-like pattern.
12. The microcirculation detection system as claimed in claim 1 , wherein the light source is configured to irradiate the light after the heating device is powered on.
13. The microcirculation detection system as claimed in claim 1 , wherein the photosensitive array is configured to output the PPG signals after the heating device starts to heat the skin area.
14. The microcirculation detection system as claimed in claim 4 , wherein the light source and the photosensitive array are arranged inside the heating chamber.
15. The microcirculation detection system as claimed in claim 1 , wherein the processing unit is further configured to record the frequency variation after an arc-like pattern is identified at first.