counting people inside a lift

Hello, I am planning to count the number of people inside a lift. Please give me some information on how to approach this.

Thank you.

[John D'Errico]

Trivial. Count the number of ears, add the number of noses, and divide by 3.

[amir]

Can you please explain more. How Can I count the number of ears and noises?Would you link me to a website/paper. thanks

[Star Strider]

That’s a jest.

What instrumentation do you have available to you with respect to monitoring the lift? For example, if it can measure weight, and if one person gets on (or off) at a time, then weight will change step-wise, as people enter or leave the lift. The number of weight-change steps would equal the number of people. (You don’t have to know the individual weights of the passengers.)

[amir]

I don't get what you mean by other instruments. The only thing I have is a logitech camera with automatic lightening adjustments.