Stilb (unit) Stilb (unit) The stilb (sb) is the CGS unit of luminance for objects that are not self-luminous. It is equal to one candela per square centimeter or 10 nits (candelas per square meter). The name was coined by the French physicist André Blondel around 1920. It comes from the Greek word "stilbein" meaning "to glitter". It was in common use in Europe up to World War I. In North America self-explanatory terms such as candle per square inch and candle per square meter were more common. The unit has since largely been replaced by the SI unit: candela per square
Compactness measure of a shape Compactness measure of a shape The compactness measure of a shape is a numerical quantity representing the degree to which a shape is compact. The meaning of "compact" here is not related to the topological notion of compact space. Various compactness measures are used. However, these measures have the following in common: A common compactness measure is the isoperimetric quotient, the ratio of the area of the shape to the area of a circle (the most compact shape) having the same perimeter. Compactness measures can be defined for three-dimensional shapes as well, typically as functions of volume and surface area.