Anderson, B. L. & Burr, D. C. (2018).

 Visual Perception: To Curve or Not to Curve, Current Biology, 4 (28), R150-R152.

A popular new illusion shows that the apparent curvature of sinusoidal contours depends on contrast and background luminance. We suggest that the illusion is driven by segmentation mechanisms of human vision, which isolate the contours into smaller segments, some which approximate straight lines, others curves.