The metadata of Landsat TM and ETM+ contains the DN values. How we can convert these DN to reflectance for these satellite in ERDAS imagine? Is the conversion satellite specific or feature specific?
In ERDAS imagine, very nice tool is given and its satellite specific. You can give require inputs from the metadata file and convent very easily DN to Refelection. For your ready reference, please have a look attached figure
In ERDAS imagine, very nice tool is given and its satellite specific. You can give require inputs from the metadata file and convent very easily DN to Refelection. For your ready reference, please have a look attached figure
When you buy yourself a student version of ENVI you will notice thet it has two pre-processing calibration routines included to exacly perform what you ask. The routines convert DN to reflectance for LANDSAT MSS and TM. Piece of cake to do this with ENVI.
Writing these routines yourself would cost you a lot of time and hence money. When you are still a student buy the stand-alone student version of ENVI for Windows or ENVI for Linux. They are pretty cheap and have the same functionality as the ENVI source codes which you can compile in IDL. Of course these ENVI verisons are "as is"!
Mind that calibration does not include atmospheric correction, That's another tackle in the game.
Good luck,
Roy
PS.:
Reference: http://rsi-envi.software.informer.com/
I noticed at the site above, that there are even free ENVI versions which you can download. So the cost is nil.
There is a good help page for the open-source GRASS Gis Software package describing the fundamentals and also containing proper references to the subject.