The technique involves taking the scattered light and passing it through a Spatial Light Modulator (SPL). This is may sound daunting, but an SPL is a common device found in overhead projectors for showing computer images. It works by modulating the phase and intensity of light. In wavefront shaping, the SPL takes the frosted glass or other light-scattering medium and uses the modulation to change it into a light-scattering lens with a known focal length. That is, instead of having one big fuzzy image, you get a lot of little focused fuzzy images. These little images interfere with one another to produce a “memory effect” that recreates the original image. This is then passed through a bandpass filter that removes unwanted optical wavelengths and enhances the image, which a lens can then focus.