Top hat top hat is a hard, black silk hat, with fur now often used. The acceptable colors of hats are much as they have traditionally been, with "white" hats (which are actually grey), a daytime racing color, worn at the less formal occasions demanding a top hat, such as Royal Ascot, or with a morning suit. In the U.S. top hats are worn widely in coaching, a driven horse discipline as well as for formal riding to hounds. The collapsible silk opera hat, or "crush hat", is still worn on occasions, and black in color if worn with evening wear as
Top-hat transform controlled by the choice of the structuring element formula_7. The bigger the latter, the larger the elements extracted. Both top-hat transforms are images that contain only non-negative values at all pixels. One of its most important uses in image segmentation is to adjust nonuniform lighting conditions on an image and provide a better threshold value for separating objects. Assume we are only interested in small blobs on the image and we want to remove the larger bright objects. In this case, the white top-hat transform can remove larger bright objects and retain small blobs by selecting the size of the