  Capturing images with incorrect exposure settings fails to deliver a
satisfactory visual experience. Only when the exposure is properly set, can the
color and details of the images be appropriately preserved. Previous exposure
correction methods based on convolutions often produce exposure deviation in
images as a consequence of the restricted receptive field of convolutional
kernels. This issue arises because convolutions are not capable of capturing
long-range dependencies in images accurately. To overcome this challenge, we
can apply the Transformer to address the exposure correction problem,
leveraging its capability in modeling long-range dependencies to capture global
representation. However, solely relying on the window-based Transformer leads
to visually disturbing blocking artifacts due to the application of
self-attention in small patches. In this paper, we propose a CNN Injected
Transformer (CIT) to harness the individual strengths of CNN and Transformer
simultaneously. Specifically, we construct the CIT by utilizing a window-based
Transformer to exploit the long-range interactions among different regions in
the entire image. Within each CIT block, we incorporate a channel attention
block (CAB) and a half-instance normalization block (HINB) to assist the
window-based self-attention to acquire the global statistics and refine local
features. In addition to the hybrid architecture design for exposure
correction, we apply a set of carefully formulated loss functions to improve
the spatial coherence and rectify potential color deviations. Extensive
experiments demonstrate that our image exposure correction method outperforms
state-of-the-art approaches in terms of both quantitative and qualitative
metrics.

Computer Vision and Pattern Recognition