An automated document processing system, particularly for mobile image capture and processing of financial documents to enhance images captured on a mobile device with camera capabilities for data extraction. The systems comprise a mobile device that includes a capture device configured to capture color images of documents, and that has a processor for performing certain operations, such as color reduction, and a transmitter for sending an image from the mobile device to a server. The server is configured to optimize and enhance the image, and to apply an improved binarization algorithm using a window within a relevant document field and/or a threshold for the document field. Orientation correction may also be performed at the server by reading the MICR line on a check and comparing a MICR confidence to a threshold. A check image may also be size corrected using features of the MICR line and expected document dimensions.