“…The methods in the first group [19,23,24,26,29,30,31,32,33,34,35,36,37,38] suffer from the problem of not accurately processing over-and under-exposed regions, but provide more compact systems. Methods in the second group use a group of bracketed overand under-exposed images as input to directly learn to generate HDR output [39,39,40,41,42,43,44,45,46], as similarly utilized in photographic HDR generation. Methods belonging to these two groups differ mainly according to their network components, such as non-local blocks [42] and attention mechanisms [40].…”