1. A computer-implemented process for training a computer using a set of training images each of which depicts a person's face to generate a sketch of a person's face from an image of that person's face, comprising using a computer to perform the following process actions: drawing a training sketch of the face of each person depicted in a training image, each of said training sketches comprising a plurality of lines that represent and correspond in location to facial features of the person depicted in the associated training image; defining an average face shape which represents the average shape and location of a prescribed set of facial features depicted in the training images; defining a geometric transform function for each training image which when applied to its associated training image warps the image so that said prescribed set of facial features correspond in shape and location to the average face shape; warping each training image and its corresponding sketch using the geometric transform function associated with the training image to create transformed versions thereof; training an active shape model using the training images to automatically identify the shape and location of said prescribed set of facial features in an arbitrary image depicting a person's face; and defining a sketch model comprising a set of lines representative of the lines found in the transformed training sketches.