The present disclosures relates generally to digital watermarking and data hiding. One claim recites a smartphone comprising: a camera to capture video of a display that is rendering video, in which the video comprises a first watermark signal embedded in a first portion of the data, a second watermark signal embedded in a second portion of the data, and a third watermark signal embedded in a third portion of the data, in which at least two of the first watermark signal, second watermark signal and third watermark signal are inversely related to one another; electronic memory for buffering data representing captured video; one or more electronic processors programmed for: applying a first perspective distortion to the data representing the captured video to yield first perspective distorted video; and analyzing the first perspective distorted video to detect digital watermarking, in which a second perspective distortion is applied to the data representing the captured video to yield second perspective distorted video when the analyzing does not detect digital watermarking, and then performing analyzing the second perspective distorted video to detect digital watermarking. Of course, other claims are provided too.