When you place two projectors side by side, the human eye will notice the edge, the mismatched colors, and the split or overlap of the images. Simply put, when you have two projectors lined up next to each other creating one solid image, you will never be able to create a seamless edge without edge blending projectors.
In both cases, a number of projectors are needed which are firstly overlapped and then visually joined together using an edge blending technique. Typically, this is done to increase the size of a projected image to make a very wide image, or by combining a number of lower resolution devices together to increase the total resolution of a display. Edge blending is a technique used to describe the process of visually combining several projected images to make a single seamless image.
