English pewter English pewter While the term pewter covers a range of tin-based alloys, the term English pewter has come to represent a strictly-controlled alloy, specified by BSEN611-1 and British Standard 5140, consisting mainly of tin (ideally 92%), with the balance made up of antimony and copper. Significantly, it is free of lead and nickel. Although the exact percentages vary between manufacturers, a typical standard for present-day pewter is approximately 91% tin, 7.5% antimony and 1.5% copper. By the 15th century, the Worshipful Company of Pewterers controlled pewter constituents in England. This company originally had two grades of pewter, but in the
Structuring element are two main characteristics that are directly related to structuring elements: Structuring elements are particular cases of binary images, usually being small and simple. In mathematical morphology, binary images are subsets of a Euclidean space "R" or the integer grid "Z", for some dimension "d". Here are some examples of widely used structuring elements (denoted by "B"): In the discrete case, a structuring element can also be represented as a set of pixels on a grid, assuming the values 1 (if the pixel belongs to the structuring element) or 0 (otherwise). When used by a hit-or-miss transform, usually the structuring