Method for creating a mosaic image using masks

A method for creating a mosaic of a large surface of interest such as the earth from a plurality of small, overlapping photographic images, said method comprising the steps of:

• providing a first tile from a first orthorectified photograph of the surface of interest, the first photograph having been taken with a camera at a first distance and at a first time, the first tile divided into discrete sections and associated with an absolute coordinate location and orientation relative to the surface of interest;
• providing a first mask for the first tile in which any known moving foreground objects are assigned low priority grayscale values and all other areas in the first tile are assigned a high priority grayscale value, the first mask being divided into discrete sections corresponding to the sections of the first tile;
• providing a second tile from a second orthorectified photograph of the surface of interest at least partly overlapping the first tile, the second photograph having been taken with a camera at a second distance and at a second time, the second time being different from the first time, the second tile divided into discrete sections and associated with an absolute coordinate location and orientation relative to the surface of interest;
• creating a second mask for the second tile in which any known moving foreground objects are assigned low priority grayscale values and all other areas in the second tile are assigned a high priority grayscale value, the second mask being divided into discrete sections corresponding to the sections of the second tile;
• comparing coincident sections in the first and second tiles and
• replacing the coincident section in the first tile with the coincident section from the second tile if the grayscale value of the corresponding section in the second mask has a higher priority than the grayscale value of the corresponding section in the first mask.