Figure 22.

A taut piece of string in front of a face, photographed in the Google Pixel 5 camera app in ultrawide mode (0.5×). This app uses a version of Shih et al. (2019), which is content-aware: the face is detected, and the region around it projected with stereographic projection, while the rest of the image uses linear perspective. As a result, the face does not exhibit marginal distortion as it would in linear perspective, but the piece of string is not straight, nor are the lines on the wall near the face. (Photo by Elena Adams.).