The effects of source resolution on resolution enhancement through shifted superimposition projection

Abstract

Resolution in a projected display is traditionally defined by the number of pixels in the projector's spatial light modulator (SLM). In recent years, different techniques that increase the resolution on the screen above the number of SLM pixels have gained popularity. In one such technique, called pixel‐shifting or shifted‐superimposition, the display physically shifts every nth frame on the projected screen, and the overlapping pixel grids forms a finer subpixel grid with a higher pixel count. There is still an open question how much this method increases the resolution and how to quantify it. The resolution on the screen also depends upon the resolution of the input image fed to the projector. In this work, we experimentally investigate how the projector performs with resolution enhancement through pixel‐shifting and how this method relates to the source resolution. We also investigate some known methods of resolution measurement and evaluate how these methods perform for the shifted‐superimposition case. We find that the resolution enhancement through shifted‐superimposition enhances the resolution to about 40% over native resolution, and we also find two different measurement methods (grille contrast and least resolvable line pair method) that is relevant for effectively measuring resolution within such systems.