1

My application needed to measure human height on a standing kiosk. I need to attach the sensor on kiosk ceiling type top. I used different kind of ultrasonic sensor for this purpose but nothing proving reliable results.

First, general ultrasonic sensor have deadband within which the sensor doesn't work and second human head and should varies and thus the reflecting pattern. Can anyone suggest the best method and sensor to use for this purpose? I didn't use laser till now because of eye safety reasons.

Prasan Dutt
  • 121
  • 3
  • Any error caused by hair and hairstyle? – Solar Mike Apr 05 '18 at 06:13
  • Yes, hair also causes error in reading. – Prasan Dutt Apr 05 '18 at 06:17
  • Best is not defined. Anyway a time of flight laser wont work any better than the ultrasonic. I would try to use somekind of 3D camera system. Some of those admittedly many also use infrared lasers, which arent visible, but works by triangulation. – joojaa Apr 05 '18 at 06:28
  • Thanks for your input. I am looking into these options for putting a 3D camera for height measurement seems very costly option. – Prasan Dutt Apr 05 '18 at 08:19
  • Do the people at the kiosk have instructions to stand with a proper posture? If not, slouching and leaning or perhaps some physical problem may cause errors of a few centimetres, which cannot be corrected by a simple sensor system. – ChP Apr 06 '18 at 10:42
  • Yes, operators at kiosk guide in taking measurement with optimum position and posture. – Prasan Dutt Apr 07 '18 at 05:00

1 Answers1

3

Hair is mostly transparent to ultrasonic, so this is still the reliable&convenient approach - any EM spectrum readouts (3D, video, laser) will be completely falsified by hair.

You just need a narrow cone ultrasonic sensor - one with readout area restricted to top of the head. It's not something to be found in robotics/industrial equipment supplies, but ones qualified for medical use should work. This is still not 100% reliable, but allows for quick, easy, contactless measurement.

The only 100% reliable but way less convenient method is mechanical - like a stadiometer. Electronic determination of the position of the slider should be vastly easier, e.g. using a linear encoder with Grey code encoded positioning.

enter image description here

SF.
  • 6,125
  • 25
  • 45