Image Alignment Algorithm for Multi-projector Display System Based on Structured Light

In order to solve the problem of image alignment in a multi-projector display system, an image alignment algorithm based on the structured light projection technique was proposed. The algorithm uses intersection points of phase-equal lines to establish the mapping relation between projector images and camera images. For an arbitrary pixel point on projector images, it has a horizontal phase value and a vertical phase value. In horizontal phase unwrapping diagram of camera images, a series of discrete coordinate points with a phase value equal to the horizontal phase value of this pixel point is found, and these discrete points are fit to a horizontal phase-equal line. In the same way, a vertical phase-equal line of the pixel point can be obtained. And the intersection point of the horizontal and vertical phase-equal lines is the pixel point on camera images corresponding to the projector pixel. The analytic expressions of display wall and the internal parameters of a camera are not necessary for the proposed algorithm, so the algorithm is suitable for curved display walls with arbitrary smooth surface. The comparison experiments between aligned images and original images show that the peak signal to noise ratio reaches 27.904 and the structure similarity is 0.972 4 to demonstrate that the proposed algorithm can improve image alignment accuracy effectively.