24. A system comprising: a mobile device network configured to transmit digital images; a server environment configured to provide electronic search service over a computer network; and means for connecting the mobile device network with the server environment, the means for connecting comprising means for applying optical character recognition to extract words from the digital images and means for providing the extracted words and the digital images to the server environment for electronic search service of the digital images via the computer network; wherein the means for applying comprises means for selecting between at least two dictionary based language models according to received indications of document type, and means for post-processing the extracted words in accordance with the selected dictionary based language model; and wherein an indication of document type comprises a user specified category selected from a group including business cards and credit card receipts.
31. The system of claim 24 , wherein the means for applying comprises means for obtaining a gray level at a higher resolution pixel by iteratively taking a weighted combination of gray levels of neighboring pixels at a lower resolution.