In general, multispectral fusion can refer to combining two or more different types of image data from a scene to produce a single image of the scene. Certain weapon sights, for example, utilize multispectral fusion to fuse together visible image data and thermal image data from a scene to produce a composite image that includes both a visible component and a thermal component. The scene could be anything, such as battlefield, a forest, a shooting range, etc.
Image accuracy in some such systems can suffer from a phenomenon known as parallax, which can occur, for example, when radiation from a particular element (e.g., a target) in a scene enters two or more input apertures of a weapon sight from different angles. In some instances, this can result in an offset between the visible and thermal components, for example, in the resulting composite image. This offset can vary depending on the distance between the target and each input aperture and can have a meaningful impact on accuracy and usefulness of the composite image, particularly in applications such as weapon sights or the like.