Thanks Kesoju Sandya Rani, Kavita Mitkari for your response. I have already solved my problem.
Anyway It will be helpful for me Kavita Mitkari If you tell me about the DN TO Reflectance conversion procedure for Landsat 8 Image.
I have applied the formula which has given in the landsat 8 handbook for converting DN value to Reflectance value. In this case I have used Erdas Model. But the output image shows empty.
I can not fix this. Do yo have any idea where can i make mistake?
Attachments are a case for landsat. First you must convert from ND to radiances. After radiance to reflectance TOA .gmd files can be opened from ERDAS modelmaker