Range of HC-SR04 for soft bodies (people)

I am looking to measure the distance to a person and was considering ultrasonic sensors. The HC-SR04 is listed as having a 4m range, however, I am under the impression that soft bodies (such as people) do not have as much range as a hard body due to absorption of the waves. I googled around and was unable to find anything about these sensors in particular for person detection.

Does anyone know about what distance I can expect from the HC-SR04 when aimed at a person?

I guess you missed all the threads relating to sensing people with the HC-SR04. It is even worse if they have clothing on.

Paul

Paul_KD7HB:
I guess you missed all the threads relating to sensing people with the HC-SR04. It is even worse if they have clothing on.

Paul

While there are plenty on the subject of person detection, I have yet to find any that give figures on range while detecting people. If you know of any threads giving such info, I'd love to see them!

It depends on what they’re wearing and how they are oriented,and what is around them

It’s very much a case of “suck it and see”

TheMemberFormerlyKnownAsAWOL:
It depends on what they're wearing and how they are oriented,and what is around them

It's very much a case of "suck it and see"

Yeah I kind of figured, luckily they're cheap enough that I can buy it and not have to worry about it.

If they wear suits of armour you'll be good, thick woolly jumper, then maybe not. Top concert halls tune their acoustic elements to match the number of people attending as people usually act as strong absorbers of sound.
However car reversing sensors detect people pretty reliably, so its probably a matter of dialing up the sensitivity and dealing with false-positives.

MarkT:
If they wear suits of armour you'll be good, thick woolly jumper, then maybe not. Top concert halls tune their acoustic elements to match the number of people attending as people usually act as strong absorbers of sound.
However car reversing sensors detect people pretty reliably, so its probably a matter of dialing up the sensitivity and dealing with false-positives.

Oddly enough, mostly bare skin (it's for near a pool).