With the recent advancement of voice-recognition technology and search function, software such as Google Now, Siri and Cortana play its role from searching information to creating a task. However, most of the software are proprietary to their manufacturer such as Siri is available for iOS devices only.
University of Michigan has developed an open source digital assistant named Sirius. It features personal voice assistant that includes voice and image recognition. This software can be downloaded in any mobile platform for free.
Download Sirius Here