When using data from different sensors there are sometimes slight issues with co-registration. If you know one image is well registered (the reference image) it is possible to register the other (the floating image) to it. Within RSGISLib there are two options for automatically generating tie points between two images for this task, which are a simplified versions of the algorithm proposed in:
Bunting, P.J., Labrosse, F. & Lucas, R.M., 2010. A multi-resolution area-based technique for automatic multi-modal image registration. Image and Vision Computing, 28(8), pp.1203–1219. http://dx.doi.org/10.1016/j.imavis.2009.12.005
The following XML script utilises the basic algorithm in RSGISLib which assumes all tie points are independent of each other. The search (search) can be reduced if the images are already closely registered to reduce run time. If data are very different (e.g., optical and SAR) the correlation threshold (threshold) may need to be reduced. The tie points generated are added to a GDAL file, and gdalwarp is used to warp the image, in this case using the thin plate splines transform.
To run the script use:
rsgisexe -x warpImage.xml
More details on the parameters are available in the RSGISLib documentation (pdf).