1. A method of user interaction in augmented reality comprising the steps of: capturing a video image of a scene; for each pixel in at least a sub-region of the captured video, classifying the pixel as either a skin or non-skin pixel responsive to whether the colour of the pixel exceeds a predetermined threshold purity of red; generating a mask based upon the classification of the pixels of the captured video; generating an augmentation image layer to superpose on the captured video image; and limiting a mode of combination of the captured video and the augmentation image layer, responsive to the mask.