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University using ceiling scanners to count students and staff in attendance

7 December 2021

You may have seen scanners hanging from the ceiling at the entrance to or in a teaching room in one of our buildings. This is a Classroom Scanner, a scanner that counts how many people are in the room. As we as a university did not inform you in good time about the purpose of the scanners and what they do (and do not) measure, we will now provide more information about the ins and outs of the classroom scanners.

Classroom Scanners and privacy

Read the pdf for more information about the images that the Classroom Scanners create.

Explanation of Classroom Scanner images

The University guarantees the privacy of its students and staff through the privacy settings on the Classroom Scanners. At present, the scanners are set to privacy level 3, the highest level. On the right you can see what a scanner can ‘see’ at this level. In ‘Explanation of Classroom Scanner images’ you can see the differences between this and the other privacy levels.

Counting the number of people present

The University started using these scanners in 2020. In August 2020 these were hung up at building entrances to count students, staff and visitors as they enter the building. This enabled the University to monitor how many people were present in the buildings and take action if necessary. This summer the scanners were also hung in the teaching rooms. 

No personal characteristics visible

The scanners do not store any camera images or record any specific characteristics of people. The only thing that is stored is numerical data on the number of people entering or leaving a room. The University emphasises that it does not collect any other data. The technology, its use and the data-processing agreement have been reviewed by the Data Protection Officer.

Occupancy and use of teaching rooms

This valuable information allows the University to take action if there are more than 75 people in a room, the maximum according to the current coronavirus measures. And, outside of the pandemic, it provides relevant information for our timetable makers: if a room for 300 students is only used by 60 people, a smaller room can be booked next time.  What also happens is that lecture theatres are booked but not used: we call this ‘no show’.  This is a shame and a waste of resources. By using the scanners to flag this up in good time, such a room can be released quickly, for example to provide extra study spaces. Finally, the data on occupancy provide relevant information for University plans for renovation or new buildings.

Questions?

We understand that you have questions about the Classroom Scanners, especially about privacy and data storage. We’ve answered the FAQ below. If you have any other questions, please contact the University Services Department.

The University has to comply with the GDR when processing personal data (only data that can be linked directly or indirectly to an individual). This is no different when using the Classroom Scanners. Images from the scanners are processed within 0.2 seconds so that individuals are only registered as silhouettes/‘circles’ and are unrecognisable. Although silhouettes are not personal data because they cannot be traced back to an individual, personal data is still involved in this process. In the fraction between the registration of an image and its conversion into a silhouette on the scanner itself, there is a moment in which personal data is processed (see also the answers to questions 2 and 3). Therefore, prior to implementation, on the advice of the independent Data Protection Officer, the University drew up a data-processing agreement with the supplier of the classroom scanners. The images, which are used to calculate how many people are present, do not leave the scanner and are deleted immediately after these 0.2 seconds.

A Classroom Scanner scans the environment for movement, taking a picture of an object (such as a person) for 0.2 seconds (200 milliseconds) and immediately converting this into a silhouette/‘circle’. These images, which are used to calculate how many people are present, do not leave the scanner and are deleted immediately after these 0.2 seconds.

Classroom Scanners recognise people as moving objects, but do not register or store specific characteristics of these people. The scanner ‘measures’ people’s height in order to be able to determine their walking route. This information is needed to accurately count people, particularly if several people walk under the scanner at the same time. We emphasise that people’s height is never stored or collected.

Classroom Scanners only collect numerical information about the number of people entering or leaving a room and the time of measurement. No other information is collected.

The University can use the classroom scanners to monitor the occupancy and use of classrooms at any time of the year and day, and take action if necessary. For instance, it can take action if there are more than 75 people in a room, the maximum according to the current coronavirus measures. And, outside of the pandemic, this provides relevant information for our timetable makers: if a room for 300 students is only used by 60 people, a smaller room can be booked next time. What also happens is that lecture theatres are booked but not used: we call this ‘no show’. This is a shame and a waste of resources. By using the scanners to flag this up in good time, such a room can be released quickly, for example to provide extra study spaces. Finally, the data on occupancy provide relevant information for University plans for renovation or new buildings.

The University has taken steps to minimise the risk of this happening. In the event of someone gaining unauthorised access to the scanners, they will only have access to the numerical information about the number of people entering or leaving a room and the time of measurement. We emphasise that when logged in to the scanners, you can neither see people nor make them visible.

In recent years the University has carried out accuracy tests to count the number of people in a room or building. It tested infrared scanners and methods of converting wifi signals or CO2 values into the number of people present. The outcome of these tests was not accurate enough. The current scanners proved to be the most accurate.

The University intends to continue using the classroom scanners. We want to offer additional privacy and security guarantees by having frequent audits carried out.

Other universities also use this type of scanner. Other universities again use wifi tracking to report about how busy the buildings are.

Classroom scanners have been installed in all the teaching buildings and rooms.

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