We present a new approach for automatically adjusting the brightness of under-exposed digital images and video sequence.Our approach employs "divide-and-conquer" scheme with gradient domain operation.The under-exposed image is first segmented into different regions according to the brightness.We then compute the brightness enhancement function for each region.Finally a constrained energy function on gradient domain is solved for preserving continuity among different regions.The algorithm is further extended to video.Several key frames are selected from the input video.We adjust them using the image brightness adjustment algorithm.Afterwards

through optical flow

we find the relationship of the regions between the key frames and intermediate frames

and use such relation to adjust the brightness of intermediate frames.Our approach works effectively for dealing with spatially non-uniformly exposed image and temporally non-uniformly under-exposed video.Meanwhile

detail information

such as strong structures as well as textures

is faithfully preserved

as demonstrated by experimental results.