Fig. 3: Resolution testing of the BVMLs.

a Schematic of the experimental setup used to perform different order radial differential processing. b The standard 1951 USAF resolution test chart as the input object. c, d Imaging results of the test target 6-2 marked by the red box in (b) through the first- and second-order BVMLs. e, f Imaging results of the test target 5-4 marked by the blue box in (b) through the third- and fourth-order BVMLs. Each lower panel of (c–f): the normalized intensity distribution along the corresponding vertical dashed line.