@OSUblake Thank you for the swift and accurate reply.
I implemented your code snippet to the above example, and you are right, it works perfectly.
The key to work with TiltShiftFilter(), and perhaps other similar filters, is to always have background texture to blend with.
For those of you who stumbled upon the same issue, see the link below ...
https://codepen.io/kenarai/pen/wvwEMXz
Thank you!