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Currently, the switches of the lights and other electronic devices in the classroom are mainly relied on manual control, as
a result, many lights are on while no one or only few people in the classroom. It is important to change the current
situation and control the electronic devices intelligently according to the number and the distribution of the students in
the classroom, so as to reduce the considerable waste of electronic resources. This paper studies the problem of people
counting in classroom based on video surveillance. As the camera in the classroom can not get the full shape contour
information of bodies and the clear features information of faces, most of the classical algorithms such as the pedestrian
detection method based on HOG (histograms of oriented gradient) feature and the face detection method based on
machine learning are unable to obtain a satisfied result. A new kind of dual background updating model based on sparse
and low-rank matrix decomposition is proposed in this paper, according to the fact that most of the students in the
classroom are almost in stationary state and there are body movement occasionally. Firstly, combining the frame
difference with the sparse and low-rank matrix decomposition to predict the moving areas, and updating the background
model with different parameters according to the positional relationship between the pixels of current video frame and
the predicted motion regions. Secondly, the regions of moving objects are determined based on the updated background
using the background subtraction method. Finally, some operations including binarization, median filtering and
morphology processing, connected component detection, etc. are performed on the regions acquired by the background
subtraction, in order to induce the effects of the noise and obtain the number of people in the classroom. The experiment
results show the validity of the algorithm of people counting.
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