| 摘要 |
In order to draw up maps from stereoscopic source images, for example photographs taken by satellite, a source image fraction is presented representing an area on which characteristic points have to be marked, on a visual display screen, with the aid of control means 12, 14 equipped with digital coders having resolution superior to that of the source image, the representation of a characteristic point to be indicated on the map is displaced, the point estimated by visual observation with integration over several adjacent pixels and from its environment, until the representation of the point is brought into coincidence with an indexing cursor, and, by manual point insertion, the coordinates of the estimated point are recorded. The digital coders are given a resolution which is superior to that of the source image and, by the said manual point insertion, the coordinates are recorded in the form of a number having significant figures identifying a pixel and at least one less significant figure corresponding to only a fraction of a pixel. <IMAGE> |
