AN APPARATUS FOR GENERATING AND DISPLAYING AN IMAGE OF AN OBJECT COMPRISING A RADIATION SOURCE AND A SERIES OF AT LEAST TWO LINEAR (3A, 3B, 3C) DETECTORS CAPABLE OF RESOLVING INCIDENT SOURCE RADIATION (1) SPECTROSCOPICALLY SPACED THEREFROM TO DEFINE A SCANNING ZONE THEREBETWEEN MEANS TO CAUSE AN OBJECT TO MOVE (7) RELATIVE TO AND THROUGH THE SCANNING ZONE IN USE,- AN IMAGE GENERATION APPARATUS TO GENERATE AT LEAST A FIRST IMAGE FROM THE OUTPUT OF A FIRST LINEAR DETECTOR, A SECOND IMAGE FROM THE OUTPUT OF SECOND LINEAR DETECTOR, AND A THIRD IMAGE, SUCH THAT EACH SUCH IMAGE INCLUDES A REPRESENTATION OF SPECTROSCOPICALLY RESOLVED INCIDENT RADIATION AN IMAGE DISPLAY ADAPTED SUCCESSIVELY TO DISPLAY AT LEAST THE FIRST, SECOND AND THIRD SUCH IMAGES AND THUS DISPLAY THE MONOCULAR MOVEMENT PARALLAX BETWEEN THE IMAGES.