By using the Closing transformation (“erosion of the image dilatation”) firstly dilate (widening) is applied to the image, and then erode (narrowing). The filter deletes dark details at the image, that means, smooths and deletes noises and helps to close inner openings of the area and eliminate fillings alongside the border of the area. By that the image can be both black and white and halftone.
The Closing filter removes dark details in the image, almost not changing the bright details, that means, smoothes and deletes the unwanted noises. It helps to close the inner openings of the area and delete the gulfs at the border of the area.
Size (size) parameter determines the environs of the filter influence around each point. Iteration (iteration) parameter determines the amount of iterations.