отношение суммы длин периметров волокон к длине сгиба

материал помещают на угол ( край твердого предмета), так что был согнут, после чего смотрят сбоку под увеличением и измеряют длину периметра ( окружности) всех выступающих волокон, расположенных по линии сгиба.

" length is defined as the total length of the boundaries of all of the protruding fibers "

Отношение полученной суммы длин периметров всех волокон к длине линии сгиба и есть fuzz on edge

Это количественная характеристика и выражается в "мм / мм" - см. в источнике "...greater than about 1.5 mm/mm"

есть такое описание метода

The Fuzz on Edge methodology measures the amount of fibers that protrude from the surface of a fibrous material. The measurement is performed using image analysis to detect and then measure the total perimeter of protruding surface fibers observed when the material in question is wrapped over an “edge” to allow the fibers to be viewed from the side using transmitted light. An image analysis algorithm was developed to detect and measure the perimeter length (mm) of the fibers per edge length (mm) of material, where the perimeter length is defined as the total length of the boundaries of all of the protruding fibers (i.e. Perimeter/Edge Length or PR/EL for short). For example, an edge along the majority of the length of a fibrous material (e.g. facial tissue) can be measured by acquiring and analyzing multiple, adjacent fields-of-view to arrive at a single PR/EL value. Typically, several such material specimens are analyzed for a sample to arrive at a mean PR/EL value.

http://www.google.com/patents/US8834678