An apparatus comprising an array of polarized light filter cells, each cell has a first polarized filter having a first polarization direction and a second polarized filter having a second polarization direction, the second polarization direction different from the first polarization direction; an optical system to direct light onto the array of polarized light filters; and a first and second light sensors to produce data from light received through the first and second polarized filters respectively. Additionally, a method of directing light onto an array of polarized light filter cells, each cell having a first polarized filter having a first polarization direction and a second polarized filter having a second polarization direction different from the first polarization direction; producing data from light received through the first and second polarized filters by respective first and second light sensors; and deriving polarization pattern based on the data.