When will people learn....To my knowledge, as it stands it is currently impossible to upscale the TNG masters as they are to HD. They currently exist only on video - VHS and have 720×576 pixels of resolution. For FULL HD you need 1920x1080 pixels, and you cant magically make 1704 pixels out of thin air to make up for the loss. It's like taking a postage stamp and enlarging it in a photocopier to billboard size print. Its going to look fuzzy, blurred and have no more detail than the original postage stamp had.
Now, the live action footage was filmed on..film, so it has a digital equivalent of around 4000 pixels - more than enough for HD, but the FX only exist at video resolution, the aforementioned 720×576.
This is why they didn't release TNG on Blu Ray right after TOS, because it is technically impossible without major work being done to it.