The main forms of heat dissipation of the human body are radiation, convection, and evaporation. The overall heat radiation and convection can be calculated by the environmental temperature and the radiation temperature, while heat evaporation can be calculated by the environmental humidity and the finger surface humidity.
A revised heat transmission method is applied in this product to determine the blood flow velocity. A heat transfer bar with thermistors on both ends contacts the skin of the finger with one end, so the temperature change of the bar can be measured. Meanwhile, an infrared radiation temperature sensor is used to take the temperature of the finger surface. These values are combined to calculate the blood flow velocity.
The photoelectric method is adopted to determine the parameters of oxygen saturation and haemoglobin concentration. The surface of the finger is exposed to infrared light of a specific wave length in an assigned sequence and the light intensity penetrating the finger is detected. Based on the change of light intensity, the required parameters are calculated. Considering that the heat dissipating capacity cannot represent the local metabolic heat, the latter is then corrected by core temperature, dressing impedance and blood flow volume. The blood glucose value of the metabolic heat integration method can be calculated by local metabolic rate, blood flow volume, haemoglobin concentration, oxygen saturation and corrected value of blood glucose. The blood glucose value of the infrared method is calculated from photoelectric signals and the haemoglobin concentration. By combining the blood glucose values of the two methods, the blood glucose concentration in the human body is obtained.
This product integrates various of sensors for signal collection, a processing circuit for signal conversion and amplification, a microprocessor to calculate the values of the parameters (blood glucose concentration, oxygen saturation, haemoglobin concentration, blood flow volume, pulse, ambient temperature and humidity, and shell temperature and humidity), and finally displays the results.
人體的散熱形式主要有三種:輻射、對流和蒸發。由環境溫度和輻射溫度計算輻射熱總量和對流量,用環境濕度和手指濕度計算蒸發量。
對於血流速度的測量,本產品使用改進的熱傳遞法進行檢測,將傳熱棒的兩端貼上熱敏電阻,其中壹端與手指皮膚接觸,測量傳熱棒的溫度變化情況,同時與紅外輻射溫度傳感器測得的手指皮膚表面溫度壹起計算得到血流量參數。
對於血氧飽和度和血紅蛋白濃度兩個參數的測量,可以使用光電法測量,將特定波長的紅外光按照壹定時序照射到手指皮膚表面,然後檢測透過手指的光強,根據檢測得到的光強變化來計算所需的參數信息。因為散熱量並不能代表局部代謝熱量,用核心溫度、穿衣阻抗和血流量校正局部代謝熱;利用局部代謝率、血流量、血紅蛋白濃度、血氧飽和度和血糖校正量計算出代謝熱整合法的血糖值;用光電信號並借用血紅蛋白濃度值得到紅外方法的血糖值。最後融合代謝熱方法的血糖和紅外方法的血糖,獲得人體的血糖濃度。
本產品是通過各種傳感器采集信號並輸入,經過信號處理電路轉化並放大,再由信號微處理器計算出血糖濃度、血氧飽和度、血紅蛋白濃度、血液流量、脈搏、環境溫濕度、體表溫濕度9個參數的值,最後顯示結果。