1. A computerized method for cell-based pattern recognition, comprising: using a computer coupled to a database containing a plurality of images of biological tissue sections, calling up one or more first images of said plurality of digital images for analysis; with said first images: executing a feature extraction algorithm, said feature extraction algorithm configured to detect cells within said first images and analyze one or more cell features thereof; and performing an interactive classifier learning algorithm, said interactive classifier learning algorithm creating an application-specific classifier based on interactive user annotations of said cell features of the first images; and with one or more second images of said plurality of digital images: executing the feature extraction algorithm to detect cells within the second images and analyze one or more cell features thereof; and executing an automated classification algorithm, said automated classification algorithm being configured to characterize the cells and cell features of the second images using the application-specific classifier; the method further comprising: in a calibration step, adjusting the application-specific classifier for variations in cell features from images of distinct biological specimens.