Spatial registration of multidate or multisensor images is required for many applications in remote

sensing, such as change detection, the construction of image mosaics, DEM generation from stereo

pairs, and orthorectifi cation. Registration is the process which makes the pixels in two images pre-

cisely coincide to the same points on the ground. Although the images are then in



relative



registra-

tion, the



absolute



ground coordinates of the pixels may be unknown. Registration is easier to

achieve with imagery that has been previously corrected for sensor and orbit distortions. Once reg-

istered, the images can be combined, or



fused



, in a way that improves information extraction.

Examples of fusion include extraction of DEMs from stereo image pairs and compositing of images

with different spatial and spectral resolutions.-Spatial registration of multidate or multisensor images is required for many applications in remote

sensing, such as change detection, the construction of image mosaics, DEM generation from stereo

pairs, and orthorectifi cation. Registration is the process which makes the pixels in two images pre-

cisely coincide to the same points on the ground.　Although the images are then in



relative



registra-

tion,　the



absolute



　ground　coordinates　of　the　pixels　may　be　unknown.　Registration　is　easier　to

achieve with imagery that has been previously corrected for sensor and orbit distortions. Once reg-

istered,　the　images　can　be　combined,　or



fused



,　in　a　way　that　improves　information　extraction.

Examples of fusion include extraction of DEMs from stereo image pairs and compositing of images

with different spatial and spectral resolutions.