Which filter is best to remove the verticle line artifact?

which filter is best to remove the verticle line artifact?

All I see is dark grey. Where is the artifact you want to remove?

Also, how did it get there?

there are verticle lines that come from different value.eg.left 5 pixel equal 0.2 while right 10pixel equal 0.6 then there is a vertical line there which i want to remove so can make it smooth