Hi Peter,
Welcome to IIS!!!!!
I've used DSS and had no problems ( to the extent of your pictures )
Strange to see the horizontal banding.......
I'm also still kinda new to all of this ....(so no answers from me, just eager to see an answer myself....
)
I certainly dont wont to put you on the wrong track ( and please anybody set me straight), but from memory it might have to do with the sensor heating up and/or some anomalies with the sensor.
Here is a quick google search I did. seems helpful to some degree....
Hope it helps
Bartman