Calculating body height of people

Hi everyone,
I want to calculate height of human body inside video, but the camera angle is from above (commonly angle used by cctv). This case for tourism visitor area, so i can’t set camera position straight with human body because it will not covering all people.

Any model or technique are match with this case?
i have been looking for solution but the model just work if the camera angle straight with human body, not from above angle

thanks…

Can I use a fixed object to locate the height and calculate the ratio between the character and the reference object to obtain the character’s height? :tongue:The method is rather stupid because I just started to learn how to use it.