You can have a look at the BandMath application. It performs pixel based image operation and you can use it to create a mask, for example, the expression :
im1b1 > 150 ? 0 : 1 can be used to create a binary raster masking all pixels that have their first band value superior to 150.
Thanks Cedric. I have a satellite image and I want to mask out the no value areas surround it that are black in colour.
How would I use band math to give a value of 0 to the no value areas and a value of 1 to those areas with information?
If the no data value is written into the meta data of your image, you can use the ManageNoData in buildmask mode, to produce a mask based on no data value.