114° E 118°45′ E 123°30′ E 128°15′ E137°45′ E142°30′ E147°15′ E 133° E 118°45′ E 123°30′ E 128°15′ E (a) 130° E 131° E 132° E 133° E 134° E 135° E 133° E 137°45′ E 142°30′ E 130° E 131° E 132° E 133° E 134° E 135° E (b) 0100 km FIGURE 1. (a) The true color composite of the GOCI level-1b product taken at 8:16 a.m. on 5 April 2011, where the study area is a rectangular region off northern Ulleungdo (540 # 322.5 km), denoted by a red box. (b) The GOCI level-2a Kd(490) product for the study area is used as the base image. Nine images are generated by applying a uniform yet noninteger amount of shift to this base image in the x and y directions, respectively. (Continued) SEPTEMBER 2021 IEEE GEOSCIENCE AND REMOTE SENSING MAGAZINE 143 38° N 39° N 40° N 23°45′ N 28°30′ N 33°15′ N 38° N 42°45′ N 23°45′ N 38° N 39° N 40° N 28°30′ N 33°15′ N 38° N 42°45′ N