Remote measurement of cardiac pulse gives more comfortable than other techniques using electrodes. Digital Medical Devices are considered to be more helpful for collection of complete information about the individual physiological data. Medical mirror or otherwise known as Magical mirror is one that displays our heartbeat. It gives contact free measurement about our physiological information using basic image processing devices. Users have the experience of health monitoring by just looking into medical mirror. It recognizes our heartbeat without any external or internal sensor and displays it in real time. This invention helps people to access their own physiological data.
This can be used in our home, not just in doctor’s office and research labs. Currently many techniques are available for counting our heartbeat. But it all needs bundles of sensors and wires. For heartbeat measurement using Electrocardiograph (ECG) method, we have to attach a bundle of leads in our chest and have to use adhesive gel. It is very difficult to patients and it can cause irritation to the skin. Another type is pulse oximetry sensor. In this method sensors are attached to the finger tips or earlobes. This is also difficult for user. In case of medical mirror, it is capable to offer details like Electrocardiograph (ECG) method. It displays continuous respiratory rate or heartbeat rate, sleep studies, burn or trauma patient checking, monitoring long-term epilepsy, and for cases were uninterrupted measure of heartbeat is needed, medical mirror is inconvenient.
Working of Medical Mirror
When the heart beats measurement of cardiovascular pulse is done by analyzing changes in the light reflected off the users face. This is the main working principle behind the Medical mirror. And also we can easily measure information about the cardiac vascular system like cardiac output and autonomic function, heart rate, arterial blood oxygen saturation, Blood pressure. The main components in medical mirror systems are LCD display, camcorders/cameras, two-side mirror and a laptop. Two side mirrors is nothing but a panel of glass that can be seen through from one side and is a mirror on the other side. To make an interactive display we have to connect built-in web cam with LCD monitor. Through this camera users face can be recognized. This web camera can be embedded in a laptop to record video for analyzing. A two way mirror is fitted on the LCD screen surface. It resembles a reflective surface for the users in ordinary lighting condition. Due to this; mirror, LCD monitor and webcam are not visible to the user. LCD monitor is used for displaying data onto the reflective surface of the mirror. Laptop is connected to the LCD monitor and to the web cam for running software in real time mode. After analyzing the video that was given from the camera; laptop sends an output signal to the LCD monitor. Video of the face were recorded by the web cam in colour with pixel resolution of 640 x 480 at fifteen frames per second and saved on to the laptop. All images should be stored in AVI format. Approximate distance between the user and web cam will be 0.5m.
Whenever the heart beats, an invisible color change will occur in our blood vessels; that is, a pulse of blood will send through blood vessels when our heart beats. This blood containing vessels absorbs more light from the light hitting on our skin. These small fluctuations in reflected light from the users face are captured by the web cam in the monitor behind the two way mirror. System measures even small variation in brightness produced due to the flow of blood in the blood vessels.
First one is the automated face tracker which detects largest face from the video captured by webcam. Automatic face tracker is a technology to detect size and location of the users face. It detects only human face and ignores anything else such as human body, building etc. This region of interest (ROI) will be separated into three RGB (Red Green Blue) channel. At this phase; density of red, green and blue measurement will occur for each channel. From the recorded video, RGB colour sensor capture a blend of the reflected plethysmographic signal with the other source of change in light caused by the movement or changes in ambient lighting condition. This is the amplitude of the signal for all the pixels in the facial region at a time t. In Independent Components Analysis (ICA) the number of recoverable sources can’t be greater than the number of detected signals.
And then these Red Green Blue (RGB) signals are decomposed into three separate components using independent components analysis (ICA). From this component we can find out power spectrum of the compounds that contain strongest signal that contain large blood volume. At last heart beating rate is calculated as the frequency that corresponds to the area that containing highest power spectrum within 45-240 bpm operational frequency band. Further processing and data analysis of recorded video physiological recording are done by using MATLAB. When user looks into the mirror, a square box will be displayed around his/her face. On the top of this box, timer will be seen. Users will be asked to stay comparatively as per timer count down. After a short time, user’s heart beat will be displayed on the screen. Allow users to stay in front of the mirror, and then his/her heart rate will be updated simultaneously until the users look away.
After the invention of medical mirror there are some health reporter mirrors available in market. Magical mirror is the integrated version of the medical mirror. John Walmsley, a British designer is the author of this magical mirror, which can monitor health of the person when looking at it. This mirror is very interactive by using a touch screen in the mirror. Persuasive Mirror gives the information about the user’s diet and exercise creates a projection of how they will look in 6 months.
Advantages & Disadvantages
The main advantage of this method is very low cost compared with other methods. For each human, one can easily construct this technology and access and control their own physiological data daily. This method is also applicable in hospitals, when it would be difficult to attach sensor to a patient’s skin. Medical mirror allows visualization of both user’s physical appearance and physiological information. Disadvantage of medical mirror is that continuous heartbeat measurement like ECG technology is not possible. We have to wait a time period of 15 seconds to get heartbeat count.
This technology shows an advanced approach to users health monitoring depends upon the state of the art technology. The Medical Mirror turns effortlessly into the home environment for data collection process into the course of our daily life. For example, one can visualize collecting health data when using the mirror for brushing teeth, shaving, etc. This interface helps to provide a convenient means for people to track their daily health without any effort.
Note: Vital Radio- Smart Home Technology Monitoring Health Status....