Optimizations for Rendering Realistic Lens Flares in Polynomial Optics

Lens flare is a common optical phenomenon exhibited by lens systems, like those used for professional photography or film. As light travels from the front of a lens system towards the sensor at the back, it can either refract through or reflect off of the surfaces of the lenses. A lens flare is the result of (typically) unwanted reflections and scattering caused by imperfections in the lenses. This reflected or scattered light then travels to the sensor following unexpected paths. While considered by some to be degrading artifacts, lens flares have grown to become an essential ingredient for realistic imagery and are often used as artistic effects. As such, adding lens flares to realistic image rendering has become a desired feature. However, while it is possible to render realistic lens flares using ray tracing, current techniques are often too slow to use in real-time. On the other hand, approximations can be made to vastly improve the frame rate of rendering, but this comes at the cost of visual fidelity. We present several methods of approximation in an effort to render a more realistic lens flare in real-time