METHODS FOR MANUFACTURING A SAFETY DEVICE

Abstract

The invention relates to a method for manufacturing a security device comprising the steps of: a) providing a depth map of a macro-image representing a three-dimensional object, the depth map representing the depth of each part of the three-dimensional object relative to a reference plane by means of different colors and / or different tones of the same color; b) segmenting the depth map into a plurality of regions based on the colors and / or tones of the depth map, each region comprising the part or parts of the depth map having a color or tone value in a respective predetermined range;(c) for each region, creation of a grouping of respective micro-image elements, the micro-image elements forming the grouping of micro-image elements being arranged on a regular one- or two-dimensional grid with a constant step and orientation in the region, at the periphery of the micro-image element a network corresponding substantially to that of the region, the resulting plurality of networks of micro-image elements being arranged relative to each other in the positions of the respective regions in the depth map to form a first image layer;and d) provide a sampling element array of a predetermined step and orientation, the sampling element array overlapping the plurality of micro-image element arrays, wherein the steps of the sampling element array and the micro-image element arrays and their relative locations are such that the sampling element array cooperates with each of the image element arrays to generate enlarged versions of the image elements in each region due to the moiré effect. The height and / or orientation of each respective micro-image element array is different and is configured so that the enlarged versions of the micro-image elements generated in any one of the regions have a different apparent depth compared to those generated in the other region(s), so as to form a three-dimensional representation of the macro-image.