Ground glass opacities in the lung are non-solid nebular-like shadows in the parenchyma tissue of the lung, which may be precursors of a lung cancer. According to the present invention, ground glass opacities may automatically be determined on the basis of a texture analysis of the parenchyma. Advantageously, according to the present invention, a robust and reliable determination of ground glass opacities may be provided, even if vessels, lung walls, airspace or bronchi walls are present within the local neighborhood of the ground glass opacity.