Canon provides explanation of Dual Pixel AutoFocus System

Canon on Wetpixel

Canon introduced their Dual Pixel AutoFocus (DPAF) system on the EOS 70D SLR. It was then also incorporated into many of the company’s pro level SLR cameras, including 7D Mark II and 5D Mark IV. It is also on the Cinema EOS line, including the C100, C300 and C300 Mark II.

DPAF is an on sensor phase detection system, so is used when shooting either in Live View or video modes.

Canon posted an article explaining how DPAF worked. In addition, they have recently posted a video on YouTube explaining the technology.