Abstract: A method and apparatus for electronically mapping an updatable microfiche includes a microprocessor-based analyzer programmed to control and evaluate optical scanning of the imaging frame areas arranged in generally parallel rows and columns. Optical photosensors are used to detect the presence of a frame mark within an expected region of an imaged area. An electronic data mask retrievably stored in a mask table memory array is used to screen the output data from the sensors. The mask table is derived from relative sensor position data collected during a scanning operation on a calibrated microfiche. A look-up table memory array is used to store the results of an evaluation scan by storing which frames are imaged and which are available for imaging.