Are there any programs for calculating the distance to an object using a webcam or a smartphone / tablet?

Question

Programming

Conditions. The user sits in front of the camera. Distance from 0.5 to 5 meters. I would like to calculate the distance to the camera in real time (position changes are slow or discrete) and transfer it to another program. Searched but didn't find anything similar. Is such an algorithm possible? We take calibration pictures at a distance of 1 and 5 meters. Is it possible, knowing the interpupillary distance, to track its change in a series of images? Then, KMK, you can calculate the distance ...

Answer 1

I won’t say for ready-made programs, but the school geometry course suggests that it’s possible from the pupils if you don’t turn your head. Although I would recommend something a la a ball over your head. And count the diameter of the ball.

Answer 2

I am not a programmer. Although I remember the geometry :). About the ball is cool.

Answer 3

play.google.com/store/apps/details?id=kr.sira.measure&hl=en - the first thing I found. There are many such things.

Answer 4

I here http://habrahabr.ru/post/126290/ described an example of using FaceAPI. It has everything you need for a webcam.

Answer 5

I have a Rangefinder installed: Smart Measure - shows results that are similar to the truth.

Answer 6

Here I found:
www.youtube.com/watch?v=cQHSXXjhXes&feature=plcp
Such a program would be with the reference of calculations not by a paper mark, but by the size of the line connecting the centers of the pupils of the eyes.