TouchView is a human computer interface that allows you to explore images by only using your fingers.
https://www.youtube.com/watch?v=_IW_YldafOo
The app requests the server to annotate the image and the server sends back annotation data. The rendering engine then provides audio-visual feedback on the annotations as the user drags, pinches, and zooms the image. This provides more spatial context to the automatically generated alt-tags for the visually impaired.
MIT