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Next time when you visit your doctor for routine checkup and he asks you to get in front of camera to measure your pulse rate then don’t get surprised. Researchers at MIT have invented a new technique, where pulse rate can be measured analyzing movements of you head.

Heart is one of the most important organ in human body. It beats (pumps blood in and out from heart to various body parts) in a very uniform way. In order to keep up hearts functionality, it should keep up the beat rate, always. The little increase or decrease in beat rate may cause problems.


What is Heart Beat Rate ?

Heart beat rate (Pulse Rate) is determined by the number of heartbeats occurs per unit of time, typically expressed as beats per minute (BPM). It can vary according to the requirement of oxygen. For the instance, when we do exercise we need more oxygen, on the contrary during the sleep we need a minimum of it.

The measurement of heart rate helps medical professionals to aid in the diagnosis and tracking of heart conditions in patients. It is also used by individuals, such as athletes, who are interested in monitoring their heart rate to gain maximum efficiency during their training.

Heart rate is measured by analyzing the pulse rate of the body. This pulse rate can be measured at any point on the body where an artery’s pulsation is transmitted to the surface like  wrist, neck etc.


Drawbacks of Electrocardiograph [ECG]:

Even though there are various methods available to measure the pulse rate. However these methods are not exact , so that we can not use these methods in diagnosis of major cardiovascular diseases. A more precise method of determining pulse rate  involves the use of an electrocardiogram or ECG.

Even though if we use the ECG for Heart rate measurement ,some times its is not feasible to check pulse rate in newborns or in the elders, whose has sensitive skin, which could be damaged by frequent attachment and removal of ECG leads.


New Technique [Name yet to be disclosed]:

Now there is a new way to measure Heart rate without damaging body skin. Researchers at MIT’s Computer Science and Artificial Intelligence Laboratory have developed a new algorithm that can accurately measure the heart rates of people depicted in ordinary digital video by analyzing imperceptibly small head movements.


Even though with naked eyes human head looks steady, seems shaking when observes under zooming at 10x and visualize with the assistance of ultra slow motion technology, it keeps shaking due to the rush of blood in head along with the heart contractions.


How Algorithm works:

Guha Balakrishnan, a graduate student in MIT’s Department of Electrical Engineering and Computer Science, and his two advisers — John Guttag, the Dugald C. Jackson Professor of Electrical Engineering and Computer Science and director of MIT’s Data-Driven Medicine Group depicted working of algorithm as below

The algorithm works by combining several techniques common in the field of computer vision.

  • It uses standard face recognition to distinguish the subject’s head from the rest of the image. Then it randomly selects 500 to 1,000 distinct points, clustered around the subjects’ mouths and noses, whose movement it tracks from frame to frame.
  • Next, it filters out any frame-to-frame movements whose temporal frequency falls outside the range of a normal heartbeat — roughly 0.5 to 5 hertz, or 30 to 300 cycles per minute( This is standard calculated by MIT researchers). That eliminates movements that repeat at a lower frequency, such as those caused by regular breathing and gradual changes in posture.
  • Finally, using a technique called principal component analysis (PCA), the algorithm decomposes the resulting signal into several constituent signals, which represent aspects of the remaining movements that don’t appear to be correlated with each other. Of those signals, it selects the one that appears to be the most regular and that falls within the typical frequency band of the human pulse.

For demonstration watch the video:

Credits: This article is written and edited by Majeed Jamkhani