Interacting with Image Signatures in Colour Space

A common requirement when working with images is to modify their colour distribution, for example to correct for changes in lighting or to achieve a certain visual effect. We present a novel interface for the modification of colour in images and video sequences through direct visualisation and manipulation of an image signature: a coarse representation of the image in three dimensional colour space. Additionally, we show how the signature of one image can be closely matched to the signature of another using an optimisation technique which minimises the Earth Mover's Distance between the two signatures. Our results are applied to single images for colour matching as well as video sequences, where we interactively correct non-uniform lighting in a video sequence.