Try to follow this:

https://www.researchgate.net/post/How_can_I_fill_data_gaps_in_Landsat_SLC_off_data_using_ERDAS_931

Hi rajat , you can use Destriping tool in ERDAS imaging for gap filling...

or

i have attached the model. Kindly see the attachment (.rar file).

you can gap fill the image successfully in ENVI software using the model "landsat_destripe" (another file in the attachment). I downloaded this ENVI code file from http://www.exelisvis.com/UserCommunity/CodeLibrary.aspx

You have to copy this file to "C:\Program files (x86)\ITT\IDL\Products\save_add" folder. Then while you open ENVI, go to Menu --> Basic Tools --> Preprocessing --> General Purpose Utilities --> Landsat 7 ETM+ Destripe

Using that tool you can destripe Landsat 7 ETM+ bands individually.

Give the same band when asked for "mask band".

You will get the destriped image. (Always give full scene ie., before subsetting)

Cheers.........!!!!!!!!!!!!

I didnot the path you mentioned C:\Program files (x86)\ITT\IDL\Products\save_add" folder. I am using envi 5.1. please tell where to copy this file. 

 Whats the stitched data?

How can we apply th gap fill tool in batch?

The landsat_gapfill is a Windows-only extension for ENVI 5.x (all versions). To install the plugin, place the landsat_gapfill.sav in the Extensions folder of the ENVI 5.x installation (C:\Program Files\Exelis\ENVI51\extensions) or your personal extensions folder under your home directory (e.g. C:\Users\jsmith\.idl\envi\extensions5_1). When you start ENVI, you will see the plugin under tool box in Extensions->landsat_gapfill

Cheers.........!!!!!!!!!!!!

does we need to specify any environmental path of the variables?

you can follow the steps from the video using the link below:

https://www.youtube.com/watch?v=qMIUcmKI3o4