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In hospitals, monitoring systems are essential for better care of patients or for medical observation and research. Most hospitals now use television systems and low-light monitoring systems, which have high requirements for light, while medical monitoring systems based on infrared imaging technology do not have this problem.

Hardware Implementation

As shown in Figures 1 and 2, the entire infrared monitoring system is divided into two parts: one part is placed in the patient's ward to obtain patient information, called the front end; the other part is placed in the monitoring room, responsible for providing patient information to the monitoring personnel, called the back end; the two can be wired, wireless or infrared video transmission according to the situation.

Figure 1 Front end of infrared monitoring system

Figure 2 Back end of infrared monitoring system

The front-end focusing module controls the optical focusing of the lens to ensure clear imaging quality. The infrared detector is the core of the entire system, responsible for converting the collected infrared signal into a video electrical signal. The support module provides appropriate bias voltage to ensure the normal operation of the infrared detector. The function of the correction module is to provide a uniform infrared intensity reference point for the infrared detector, which is an essential module to ensure correct imaging. Electronic zoom is a supplement to optical zoom, which can perform more detailed focus control within a relatively small range. Due to the inconsistent characteristics of the various detection elements of the infrared detector, the bias voltage provided by the support module cannot meet the normal operation requirements of all detection elements, causing a small number of detection elements to fail to work properly, which will affect the quality of the image. This problem is solved by the bad element processing module.

The infrared signal generated by the human body is focused by the infrared lens and converges on the detection plane of the infrared detector. Under the coordinated action of the support module, the correction module and the electronic zoom module, the infrared detector in normal working state converts the received infrared signal into an initial video electrical signal, and outputs this signal to the subsequent processing module in a specific format. After bad element processing and nonlinear correction, the target video signal is formed. The target video signal is then sent to the back end of the system after encoding processing.

The back end receives the video code sent by the front end, first decodes it, and then sends it to the subsequent module for further processing. The decoded video signal is electronically amplified (or not amplified) as needed, and then directly sent to the display and control module to achieve real-time monitoring; at the same time, it is sent to the storage module for encoding and storage for future needs. The analysis module analyzes the video signal sent. If the patient is found to have an uncomfortable reaction, the alarm module is triggered to remind the medical staff to take measures.

Software Implementation

The software flow of the infrared monitoring system is shown in Figure 3. After the system is powered on, it first performs a self-test. If an error is found in the self-test, the error is reported on the monitor at the back end, and a fault code is provided to assist in analysis and judgment. If the self-test is normal, the infrared detector is started, electronic correction and electronic focusing are performed, and a working instruction is issued to the infrared detector after it is ready. The infrared detector begins to receive infrared signals and process them. According to the settings of the monitoring personnel, the processed image can be stored on the one hand and displayed on the other hand to achieve real-time monitoring, or only real-time monitoring is performed. If necessary, the processed image is also sent to the computer for automatic analysis. If the patient is found to have discomfort symptoms, an alarm is issued.

Figure 3 Software Flowchart of Infrared Monitoring System

Comparison with Traditional Monitoring Systems

Traditional medical monitoring systems are generally television systems, and in a few cases, they are low-light systems, or both. In the daytime with sufficient light, the television medical monitoring system can well realize the monitoring function. However, in rainy weather and other conditions, the imaging quality of the television system will be affected to a certain extent. At night, unless the lights are turned on, the TV system will not work at all, and turning on the lights will inevitably affect the patient's rest, so the TV monitoring system has great limitations.

For the low-light medical monitoring system, it can only work within a certain brightness range. During the day, due to the overly strong signal input and poor visibility, it is impossible to observe the patient's condition normally, and the system may even be burned due to the strong light. In the case of too dark light or even no light source at all, the low-light system is also unable to monitor the patient. Even with the addition of an automatic gain control system, the above problems can only be alleviated to a certain extent, and this approach requires a corresponding price in cost, volume and weight.

Infrared medical monitoring solves all the above problems. Since the infrared monitoring system receives infrared signals emitted by the patient's body, the system is not affected by the strength, weakness, presence or absence of visible light, and can work normally around the clock. Especially when monitoring at night, no additional processing is required, and it will not have a negative impact on the patient's rest. Moreover, the change in infrared signal intensity caused by the change in the patient's body temperature is not very drastic, and it is only a very narrow range for the infrared system, which will not affect the normal operation of the infrared system at all. On the contrary, this change can also be clearly reflected on the monitor, thus reminding medical staff that they need to take care of the patient. However, neither the TV system nor the low-light system can reflect this change. Therefore, the infrared system not only makes up for the shortcomings of the TV system and the low-light system, but also realizes a more powerful monitoring function.

Conclusion

The infrared monitoring system has stable and clear imaging quality, and can observe details such as eyebrow movements, which can fully meet the needs of observation. By analyzing the image with software, when the patient is uncomfortable, an alarm can be issued, and appropriate supporting measures can be taken, and even unattended monitoring can be realized. Since the infrared monitoring system adopts a passive working mode, the infrared required for its work is naturally emitted by the human body, so it is a pollution-free, environmentally friendly monitoring system, especially suitable for medical treatment.