Filming a moving source - Averaged energy

This is a variant of the video , showing the wave energy averaged over a time window instead of the wave height. The simulation illustrates what happens when one films a moving source of light, with a simple camera consisting of a single lens. While the source is moving upwards, the image created on the film that would be put in the image plane near the right-hand border moves downwards. This is how single lenses work - one way of producing an image that is right side up is to use a second lens. This will be illustrated in a forthcoming video. Due to spherical aberrations, the image is not as well focused when the source of light is away from the horizontal symmetry axis of the system. Note also the delay between the position of the source and of its image. This is because the wave speed is much slower in this simulation than for real light. The color hue shows the wave energy, averaged over a time window. More precisely, it shows an average from the beginning of the simulation to the current time, but with weights decaying exponentially with the elapsed time. The display on the right shows the time-averaged energy through a vertical slice, located close to the right boundary. Render time: 1 hour 15 minutes Compression: crf 23 Color scheme: Inferno by Nathaniel J. Smith and Stefan van der Walt Music: “Porches and Universes“ by Puddle Of Infinity See also for more explanations (in French) on a few previous simulations of wave equations. The simulation solves the wave equation by discretization. The algorithm is adapted from the paper C code: Many thanks to Marco Mancini and Julian Kauth for helping me to accelerate my code! #wave_equation #interferenceoflight #lens