An Algorithm for Transforming Color Images into Tactile Graphics
  This paper presents an algorithm that transforms color visual images, like photographs or paintings, into tactile graphics. In the algorithm, the edges of objects are detected and colors of the objects are estimated. Then, the edges and the colors are encoded into lines and textures in the output tactile image. Design of the method is substantiated by various qualities of haptic recognizing of images. Also, means of presentation of the tactile images in printouts are discussed. Example translated images are shown. 
Artur Rataj