I wouldn't expect that to be possible, unless you had set the background value for the mosaic to be 323.256042, which seems unlikely. I recommend that you contact Exelis VIS tech support directly, so they can get copies of your images, and try to track down what is going wrong. You can contact tech support at support@exelisvis.com or (303) 413-3920, or through your local ENVI distributor. - Peg

Hey Peg, Another thread - another issue. Just to clarifiy the problem mentioned in this topic. The 322 value only occured when "color balancing" was applied. Just mosaicking slc-on with slc-off data resulted in an 255 maximum value picture. Do you know the gap-filling addon for ENVI? -> http://www.exelisvis.com/...x?tabid=1540&id=1277 i just realized, that the "Global" function does exactly the same as mosaicking with color balancing. Both the "local" and "global" function results in values around 322. (i guess the point is, that no cloud detection is done when selecting the gap fill image) Regards, kchien

I just ran a mosiac with color balancing on an SLC-on and SLC-off image. Since both input images are stored as byte data type, the result is also byte and so cannot have a value larger than 255. The only way I can see you receiving a value larger than 255 is if one of the input datasets are not byte but something like integer or floating point data.