Dramatic change of the grayscale in aerial images

such as high-brightness region and large areas of shadow

leads to a grayscale distortion phenomenon in dodging images. This study improves the method of background image generation in the Mask dodging algorithm and enhances the quality of background image by using an expansion and engulfment algorithm. The dodging experiment on an aerial image

which includes high-brightness rooftop

high-brightness water

and large areas of shadow

shows that the improved algorithm obtains better result than other current Mask dodging algorithms. The approach eliminates the grayscale distortion problem among the high-brightness and shadow regions effectively and enhances the texture details among the dark regions apparently.