CIDRE is a retrospective illumination correction method for optical microscopy. It is designed to correct collections of images by building a model of the illumination distortion directly from the image data. Larger image collections provide more robust corrections. Details of the method are described in:

K. Smith, Y. Li, F. Ficcinini, G. Csucs, A. Bevilacqua, and P. Horvath
CIDRE: An Illumination Correction Method for Optical Microscopy, Nature Methods, Early Online Access 16 March 2015, doi:10.1038/NMETH.3323