How to automatically count people in a subway car using a video camera?

Question

Video processing

At the entrance to the subway car (not in the car) there is a video camera, it is necessary to count the number of passengers, taking into account how many got out and entered the car.

Answer 1

The gift does not need such perversions. The car knows perfectly well how many people are in it - it has "scales" on each cart. We subtract the container of the car from the readings of the scales, divide by 75 - 80 and get the number of people.

Answer 2

is it in php?

Answer 3

Your algorithm can be based on the following principles:
1) Motion detection against a stationary background, segmentation of moving objects, their tracking, and finally counting the number of trajectories that cross the entrance / exit. In your case, this approach will most likely not work, as there will be problems with identifying the background and with segmenting individual people - there are too many people in the metro - everything will merge.
2) Detection based on the detection of motion flows (or an equivalent correlation method) - identify areas of a characteristic size above the entrance / exit moving in a given direction and count them. This method also most likely will not work due to the fact that there are too many people in the metro and often they go close to each other.
3) Detect people based on their top view using HAAR, HOG or LBP cascade (see OpenCV). Then tracking (for example, correlation), and at the end, counting the number of trajectories that cross the entrance / exit. Helmet / Cascades will need to be trained (I have not seen those ready for this angle). Cons - people are too different (hats, hairstyles, rotation relative to the camera), cascades work well with similar objects (faces for example).
4) Refuse video analysis and look towards hardware sensors (although I am not an expert in them, I can’t advise anything).

Answer 4

Посчитать число всех вошедших и вычесть число всех вышедших? :)
Или вы спрашиваете про технологию подсчета людей с помощью камеры?
Как это сделать с помощью камеры я не знаю, но знаю, что есть готовые и работающие технологии подсчета пассажиров на общественном транспорте с помощью планки из ИК-светодиодов и ИК-приемников закрепленной над каждым входом. Планка распознает шаблон голова-плечи. И очень хорошо работает на взрослых, иногда ошибается на маленьких детях, так как они низкие.