1. An image processor, comprising: a memory operable to store an image from a series of real time images of a location captured by an imaging device over time, the stored image at least partially including a target that is subject to movement from one point in the time to another point in the time; a detector operable to detect the target and a movement component thereof by detecting features of the captured images at different points in the time; and an image generator operable to generate an object image representing a predetermined object so that a color of a predetermined portion of the object image varies according to the detected movement component of the target, the image generator being further operable to generate a combined image from the object image and the stored image and to output in real time a signal representing the combined image, to permit the combined image to be displayed to the location imaged by the imaging device.