Sesame Street’s Count von Count loves to count things. However, depending on what needs to be counted, there are a variety of different techniques. Is it people, objects, steps, or?
Counting people
Turnstiles are commonly seen at events, fairgrounds, stadiums, arenas, amusement parks, or anywhere pedestrian counting and/or pedestrian crowd control is required. The simplest and most straightforward technique to count the attendees uses gears, a ratchet and springs, a mechanical counter, to provide the incremental count. In contrast, electronic counters, possibly using Hall effect sensors, can both display the count at the point of entry and transmit the number to a central monitoring location for more thorough analysis. Even then, mechanical counters can be used as a backup to electronic devices where a redundant or fail-safe counter is desired.
For counting people in corporate offices, commercial real estate, and industrial locations, other techniques include optical, Wi-Fi, and infrared people counters.
Optical people counters use closed-circuit television (CCTV) and stereo vision, but these are primarily employed for security purposes — not simply counting. Alternatively, with the pervasive use of smartphones, each device having a unique Media Access Control (MAC) address, a probe request in a specific area can provide a rough count of the number of people. Perhaps the least invasive and most accurate count can be obtained with time-of-flight (ToF) technology using infrared emitters. Using an innovative and proprietary people counting algorithm, one company has claimed 98% accuracy with this counting approach.
Counting objects
In several locations in a manufacturing plant, object counting provides the basic and essential measurements for monitoring and controlling production as well as measuring yield. Often the counting is performed by proximity sensors, typically, photoelectric diffuse sensors. With two sensors, the facility’s management can obtain the total count and good count. However, with today’s computing capability and techniques provided by different suppliers, the same two production counting sensors can provide a production monitor that automatically tracks counts, rates, cycle times, production times, overall equipment efficiency (OEE), total effective equipment performance (TEEP), and more.
Counting steps
Today, perhaps the most common counting application is the steps a person takes on a daily basis or during a specific activity — a pedometer. In addition to smart phones that can routinely perform this counting, fitness trackers also provide the counting capability. Within these two devices, techniques can also vary greatly. With a built-in accelerometer and sometimes the built-in gyroscope as well, algorithms can count the user’s steps and provide other metrics, such as distance traveled, calories expended and more. For step counting, the accelerometer detects the motion and speed of the user’s steps, and the gyroscope monitors the user’s orientation and rotation. With the combination of accelerometer and gyroscope data, counting algorithms can distinguish steps from other movements.
Counting flocks of birds
In some cases, going back to basics is essential. For example, accurately and consistently estimating the numbers of birds in flocks in real time relies on the experience of the observer and a technique to break the flock into smaller sections. Physically counting the birds in the small group and then multiplying by the number of sections provides the best approximation.
References
Image source: Richard Termine, https://planetsesamestreet.com/count-von-count-dracula-sesame-street/
How people counter sensors work: A tech comparison
How production counters can help you improve your OEE and productivity
