thesis Essay

2257 Words Sep 5th, 2014 10 Pages
D6T thermal sensor and People Counting Algorithm

In this thesis work, a new indoor people counting algorithm is created by using Omron D-6T thermal sensor and Raspberry Pi. The sensor periodically generate thermal map of heat emitted in its field of view which is a one dimension array and pass the array to Raspberry for further processing. The people counting algorithm is created in Raspberry Pi by processing thermal map generated by D6T. After processing the number of people indoor is obtained. This chapter presents the hardware structure used including D6T thermal sensor and Raspberry Pi, moreover the people counting algorithm is discussed in detail.

D6T thermal sensor

D6T is a new product which is designed by Omron and
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A super loop is implemented in the algorithm to obtain the heat map array periodically. Also in each loop, after the heat map array is obtained, a new array called difference map is produced by calculating the difference between current heat map and previous heat map (heat map of previous loop). Our algorithm is mainly focus on processing the difference map.

Figure 5. Heat map of D6T thermal sensor

Figure 5 shows the heat map which in program is array heatmap[16]. The number in the left side is the detected temperature in Celsius while the number in the right side is the index number.

Figure 6 presents the difference map which in program is array difference[16]. The difference[16] is calculated after the heat map is obtained and it is the difference between current heatmap[16] and previous heatmap[16] (heat map of previous loop). As we can see from the figure 6 that the value of each element in difference[16] is either 0 or -0.1. This is because nobody is moving in the detecting area so the difference[16] does not vary much. Usually the value of each element varies between -0.1 – 0.1. We have the same situation if somebody keeps stationary in the detecting area. On the contrast, once someone starts to moving in the detecting area, the difference[16] would have a significant change in corresponding element. Usually the value is bigger than 0.3

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