Of quantity and quality

Abstract

A quarter century ago students of comparative literature and musicology seized upon the computer to advance the quantitative aspect of their studies. At the most rudimentary level this means investigating such properties as sentence length, the frequency and distribution of articles and prepositions, etc: the side of literature that has no apparent bearing on style, authorship or literary merit but which, it was suspected, might reveal hidden truths-if only the tabulation could be accomplished without pain or confusion. Far more sophisticated analyses of texts have evolved. It would be out of place to discuss them here but the interested reader is referred to the journal Computers and the Humanities (CHum), now in its twenty-first year of publication. Until recently scholars of the visual arts have been spared the rigors of statistics, for it has not, as a rule, been feasible to capture the necessary numbers of numbers. A short story of perhaps ten pages may consist of 50 000 or fewer characters (i.e. key strokes); and, once these have been transcribed to machine-readable bytes, all counting and calculation can be automated. Even major literary monuments do not tax the storage and processing capacity of readily available computer systems. In contrast, the digital representation of one picture requires from 500 000 to more than six million bytes, depending upon the precision of spatial and tonal discrimination or resolution. The sheer quantity of data has precluded the capture, storage, transmission and analysis of images. The bad or good news is that advancing technology has removed the obstacles or, if the reader prefers, breached the humanist’s defenses. A device called a stunner can capture an image in digital representation. The digital optical disk (not quite the same as the videodisc) has the capacity to store a library of images economically. Optical fibers, having more bandwidth than even a television channel, can transmit an image to any distance in reasonable time. Much analytical image processing is within the reach of today’s miniand supermicro computers, while a new class of machine called The Connection Machine (TM) is ideally suited to more esoteric image processing without the costs associated with very large systems. Finally, modern bit-mapped screens are able to display an image at nearly photographic resolution. Some can do so in color. A digitized image is, of course, nothing but a series of numbers. In this series one or three numbers correspond to each componentpititrre element orpixel of the image, three being needed for color. The entire image consists of a rectangular array of tiny pixels, usually between 250 and 1000 in each dimension. This is more than adequate for viewing and all foreseeable statistical analysis. The minimal representation of a pixel is a single bit indicating white or black. The maximal color resolution, to date, requires three 16-bit numbers per pixel, able to specify up to 65 356 intensity levels for each of three primary colors. Obviously this is far too many but most computers are happiest doing arithmetic with 16-bit numbers. Three-dimensional images of sculpture and other solids cannot be digitized directly