Abstract: The invention concerns a method and device for binarization of pixel data in which a number of black-and-white binary images each having binarization characteristics of different degrees of sensitivity is formed from a set of grey scale value binary data. A dimension S is calculated for each of these binary images, according to the equation ##EQU1## where FS designates the number of black binary pixels and U designates the number of black-and-white transitions. A selection of the binary image for which the dimension S is at its maximum is optimally carried out.

Abstract: A roller tool having material-deforming rollers the axis of rotation of which extends lengthwise of and forms an angle with the longitudinal axis of a tube to be secured, is inserted into that portion of the tube which is located within the confines of a passage of the support. The roller tool is then rotated in contact of its rollers with the inner circumferential surface of the tube, so as to form at one axial location of the tube a corresponding outward face deformation of the tube in the passage. During this time, axial displacement of the roller tool relative to the tube is prevented until the outward deformation has reached a desired dimension in direction radially outward of the tube. When this dimension is reached, the rotation of the roller tool is continued but the roller tool is now also permitted to advance axially of the tube so as to form a second outward deformation in the latter axially adjacent the first one. An apparatus for carrying out the method is also disclosed.