This article presents an overview of current automatic sign recognition research. A review of recent studies, as well as on our own research, has identified several problem areas that hamper successful sign recognition by a computer. Some of these problems are shared with automatic speech recognition, whereas others seem to be unique to automatic sign recognition. These latter difficulties include context dependency, determination of the basic units of modeling, the ability to distinguish between signs and gestures, movement epenthesis, and repetition within signs. As a possible solution to these problems, bottom-up processing should perhaps be supplemented with top-down processing.@en