Jay said:
Yeah, the DS9 episode was upscaled. TNG is being remastered from the original film elements like TOS though.
The problem lies in the effects shots. While they did use models for the ships, the composite shots with all the effects in place were done at standard def. They'd have to recomposite all the original film and re-render the CGI bits to recreate them in HD. I could see that being fairly time-consuming.
If all of the original effects shots exist, and are well catagorized, it should be fairly easy to scan everything in a computer and recomposite everything. To be quite honest, TNG wasn't an FX showcase. A lot of the establishing shots of the Enterprise flying by are practically the same in every episode. You've got the warp drive stars wizzing by in the windows (should be easier than snot to recreate and recomposite). Same for the main bridge screen. Phaser blasts are easy to recreate, and hell, most people can make them on their home computer. The transporter effect would more than likely have to be recreated and will take a bit more time.
Of course, there are more complicated effects shots for,the Q episodes, and the hologram episodes, and I suppose any space battle episodes.
In the end, it shouldn't be too difficult. It will just take a lot of time.