  Image composition is an important operation in image processing, but the
inconsistency between foreground and background significantly degrades the
quality of composite image. Image harmonization, which aims to make the
foreground compatible with the background, is a promising yet challenging task.
However, the lack of high-quality public dataset for image harmonization, which
significantly hinders the development of image harmonization techniques.
Therefore, we contribute an image harmonization dataset iHarmony4 by generating
synthesized composite images based on existing COCO (resp., Adobe5k, day2night)
dataset, leading to our HCOCO (resp., HAdobe5k, Hday2night) sub-dataset. To
enrich the diversity of our dataset, we also generate synthesized composite
images based on our collected Flick images, leading to our HFlickr sub-dataset.
The image harmonization dataset iHarmony4 is released at
https://github.com/bcmi/Image_Harmonization_Datasets.
