This system gives the experimenter great flexibility to present spatio-temporal stimulation patterns to a subject. A video configuration file (VCF) editor allows the experimenter to determine the electrical stimulation parameters for each electrode. A Pattern Stimulation software program allows direct stimulation of chosen patterns of electrodes, scaled by the subject's VCF, through a Graphical User Interface. The subject then responds by drawing the outline of the phosphene he or she perceives on a touchscreen. The Pattern Stimulation program saves all of the trial parameters and the parameters of an ellipse fit to their drawing, as well as a raw data file containing the input to the touchscreen is saved. After the experiment, offline image analysis can be performed to obtain a detailed quantitative description of the subject's percepts. Image descriptors can assigned to the touchscreen data; these image descriptors can be used to make formalized comparisons between various experimental conditions. Various types of image descriptors can be used, including simple ellipse fitting, projections of the 2-D drawings onto one-dimensional axes, calculations of Hu moments, PCA, and ICA.