Lack of automaticity and ineffective elimination of seam line exist in the present remote sensing image mosaic. Aimed

at solving these problems, this paper has improved the existing mosaic technology by using valid area. The valid area is obtained

using the automatic tracing method, based on which mosaic of multi remote sensing images is carried out. First, at the geometric

splicing stage, primitive rectangle image participation is replaced by the valid area to carry out splicing. Second, the seam

line is determined using the valid area of the two images, and is eliminated using the whole tone adjustment and the overlapping

area weighting. Finally, in the multi-image mosaic process, the valid area of the resultant image is obtained by collage of the

valid area of two original images. Through the mosaic experiment on two groups of multi remote sensing images, it is concluded

that this technical flow can implement completely the automatic image dodging, and the overall tone is consistent without obvious

seam line in the resultant images.