He showed how he did this. He said he took an image with the camera, and edited the tv to be perfectly white and used that as the target: "After some fruitless

He showed how he did this. He said he took an image with the camera, and edited the tv to be perfectly white and used that as the target: "After some fruitless attempts at simple image statistics, I realized it's possible to edit a camera picture by hand and use that as a ground truth."