NHK STRL has developed a "Before/After VR," a 360° video player that enables viewers to compare, for example, the state after recovering from a disaster and the state immediately after the disaster. A video depicting this is shown below.
As explained in the video (scenes of areas affected by floods in West Japan in July 2018), it shows a comparison between the 360° images taken immediately after the disaster and the images taken a few months later at the same location.
The system works by mapping two sequences of 360° images shot from a specific location, such as a disaster area at two different time periods, to each hemisphere in a virtual space (Fig. 1). When the viewer operates the controller, the border of the two hemispheres move horizontally (Fig. 2). The viewer can switch between the images to compare the two different time periods that they wish to see in the 360° image.
With this technology, a viewer can notice small differences and simultaneously observe the situation at the time of the disaster and the state of reconstruction, which will be useful in raising people’s awareness of disaster prevention.
With a higher resolution and specification of the VR images, the viewers might feel as though they are actually experiencing before/after scenes of an incident by going back and forth in time. This enables people to witness firsthand a significant incident and share actual experiences with people.