A method for tone-mapping an input image to generate a tone-mapped output image, the method comprising: determining a tone-curve based on a model of image contrast distortion between the input image and a tone-mapped image; and tone-mapping the input image according to the determined tone-curve; and wherein determining the tone-curve comprises calculating values of the tone-curve for reducing image contrast distortion within the model of image contrast distortion; characterized in that: determining the tone-curve comprises: defining a plurality of luminance level segments corresponding to portions of luminance levels of the input image; determining, for each given luminance level segment, a piece-wise linear slope representing a portion of the tone-curve for the given luminance level segment, the linear slope for each luminance level segment being determined based on reducing: ε ′ s k = ∑ k N p l k 1 − s k 2 wherein p ( l k) is the probability of any region of the input image having a luminance level falling with the given ( k -th) luminance level segment, s k is the piece-wise linear slope of the given ( k -th) luminance level and (1 - s k) 2 is the differential value of the piece-wise linear slope for the given ( k -th) luminance level segment. determining a tone-curve based on a model of image contrast distortion between the input image and a tone-mapped image; and tone-mapping the input image according to the determined tone-curve; and wherein determining the tone-curve comprises calculating values of the tone-curve for reducing image contrast distortion within the model of image contrast distortion; characterized in that: determining the tone-curve comprises: defining a plurality of luminance level segments corresponding to portions of luminance levels of the input image; determining, for each given luminance level segment, a piece-wise linear slope representing a portion of the tone-curve for the given luminance level segment, the linear slope for each luminance level segment being determined based on reducing: ε ′ s k = ∑ k N p l k 1 − s k 2 wherein p ( l k) is the probability of any region of the input image having a luminance level falling with the given ( k -th) luminance level segment, s k is the piece-wise linear slope of the given ( k -th) luminance level and (1 - s k) 2 is the differential value of the piece-wise linear slope for the given ( k -th) luminance level segment. determining the tone-curve comprises: defining a plurality of luminance level segments corresponding to portions of luminance levels of the input image; determining, for each given luminance level segment, a piece-wise linear slope representing a portion of the tone-curve for the given luminance level segment, the linear slope for each luminance level segment being determined based on reducing: ε ′ s k = ∑ k N p l k 1 − s k 2 defining a plurality of luminance level segments corresponding to portions of luminance levels of the input image; determining, for each given luminance level segment, a piece-wise linear slope representing a portion of the tone-curve for the given luminance level segment, the linear slope for each luminance level segment being determined based on reducing: ε ′ s k = ∑ k N p l k 1 − s k 2 wherein p ( l k) is the probability of any region of the input image having a luminance level falling with the given ( k -th) luminance level segment, s k is the piece-wise linear slope of the given ( k -th) luminance level and (1 - s k) 2 is the differential value of the piece-wise linear slope for the given ( k -th) luminance level segment.