Abstract: When receiving input scan lines from a conventional scanner, a system of the present invention simultaneously provides a sequence of pixels for display and a second sequence of pixels for storage, for example on a hard disk. A pixel for display has an intensity resolution greater than a pixel of the input scan line. The intensities of scan line pixels in a 16 by 16 matrix are accumulated for incrementally revising the intensity of the pixel to display. An incremental intensity is identified by a table indexing technique. The second sequence is the result of performing a data compression method on two sets of transitions. Each set is derived from an input scan line by noting the run length between changes in intensity. Intensities in one embodiment have single bit resolution. A subset of transitions is identified by a table indexing technique. Disk writes are delayed until a buffer has exceeded a limit value.