It happens in hotel rooms as well as in Airbnb apartments: In South Korea alone, 6,800 cases of illegally hidden cameras were reported last year. Mind you, these are only those situations in which the unauthorized recording device was discovered. The number of unreported cases should therefore be significantly higher again. This is extremely uncomfortable for the people concerned. However, it has not been that easy to tackle the problem so far. For example, a research team sent human test persons in specially furnished hotel rooms to look for hidden cameras. However, these were only successful in 46 percent of the cases. More than half of the cameras remained undetected despite targeted search work. A rather unsatisfactory result. In the future, however, the values could be significantly better. The researchers have developed a simple smartphone app that discovered 88 percent of the hidden cameras in a similar test.
Camera lenses reflect infrared light particularly strongly
The big advantage: the app works on the vast majority of Android smartphones. The cell phones only need to have a so-called time-of-flight sensor. This is actually used to use infrared light to check how far away objects or people are. This in turn ensures that the built-in smartphone camera produces better images. The researchers now took advantage of the fact that camera lenses reflect infrared light particularly strongly. In a first step, the app is used to scan the room and check for particularly violent reflections. However, these can not only be caused by camera lenses, but also, for example, by plastic bags. That’s why software is then used to look at the shape of the suspicious object. Round objects are particularly suspicious. To be on the safe side, artificial intelligence is also used at the end.
A three-step process identifies suspicious objects
This was trained with photos from 10,000 spy cameras and should finally decide whether the object is a prohibited camera. This three-stage process is intended to ensure that as many hidden recording devices as possible can be found without causing too many false positives. In the tests carried out so far, the app was able to meet these expectations. It was also designed in such a way that it can also detect extremely small cameras – up to a diameter of just two millimeters. The researchers involved in the project now have to decide how they want to advance the topic further. For example, consideration is being given to publishing the source code of the app called LAPD. A crowdfunding project would also be conceivable to distribute the app as widely as possible and thus help to discover more illegal cameras.
Via: The Register