Hat box collapsible version for evenings, known as a gibus. They might also include storage space for items such as a hat brush. Designs became quite large during the Victorian era. A letter to "The Times" in 1844 warned travellers that Blackwall Railway's porters had charged a 1d to carry a hat box onto the train and a further 6d for transporting it to the London terminus, with the traveller himself paying only 4d for the journey. He recommended that travellers with luggage should go by steamboat. While traditionally hat boxes are circular or square in shape, some versions may follow the
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