Abstract: A method comprising: activating a strobed or pulsed illumination source to produce illuminating light; polarising the illuminating light in a first polarisation axis; illuminating at least part of a tall plant crop with the polarised illuminating light to produce reflected illuminating light; polarising the reflected illuminating light in a second polarisation axis transverse to the first polarisation axis produce cross-polarised reflected illuminating light; capturing an image of at least part of the tall plant crop using the cross-polarised reflected illuminating light; and analysing the captured image to determine a condition of the tall plant crop. Also a vehicle mounted image capture system, a vehicle mounted spraying system and a plant health management system.