How anti-distortion images should look like

Good anti-distortion picture

The good one: Two horizonal lines, one very close to one of the long edges, the other one 1/3 from the top. Note that tilting and rotating the camera is allowed, as well as changing the distance.

Bad calibration picture

A bad one: The horizonal lines are in the proper position (at the bottom, at least), but they are not running from one edge to the other. I need lines covering the full width.

Bad calibration picture

Another bad one: All horizonal lines are too far away from the long edges. Put one line insanely mind-bogglingly staggeringly close to the edge.

Now go back to the upload page.