Security Device Depth Map Segmentation for 3D Optical Effects
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current security devices for documents such as banknotes and passports are vulnerable to counterfeiting due to their inability to effectively replicate optically variable effects, which can be easily copied using available reproduction techniques.
Innovation Solution
A method of manufacturing a security device involving a depth map of a macroimage segmented into regions with distinct color or tone ranges, each with a microimage element array of constant pitch and orientation, combined with a sampling element array to generate a three-dimensional representation through the moiré effect, providing a unique and challenging appearance to replicate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional security devices are used, then they can be easily reproduced using available reproduction techniques, but they fail to provide effective optically variable effects
Solution Approach 1:
The patent transitions from two-dimensional flat security features to three-dimensional relief structures that cast real shadows. The macroimage contains depth information encoded through varying relief heights, which interact with light to produce optically variable effects that cannot be replicated by conventional two-dimensional reproduction techniques.
Solution Approach 2:
The patent changes the physical parameter of the security device by introducing variable relief depth (z-height) across the macroimage. Different regions have different relief heights that correspond to depth map values, creating optically variable effects based on light interaction with the three-dimensional surface geometry.
2Reliability
If a three-dimensional effect is introduced to enhance security, then the visual impact and complexity increase, but the manufacturing process becomes more complex
Solution Approach 1:
The patent segments the macroimage into multiple regions based on depth map threshold values. Each region is assigned a specific relief height, creating discrete depth levels that are easier to manufacture than continuous variations. This segmentation approach simplifies the manufacturing process while maintaining the three-dimensional optical effects.
Solution Approach 2:
The patent performs preliminary processing of the macroimage by generating a depth map and segmenting it into regions before creating the final relief structure. This pre-processing step organizes the complexity into manageable segments, making the subsequent manufacturing process more straightforward and controllable.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The resulting security device exhibits a highly distinctive three-dimensional effect that is difficult to counterfeit, offering a high security level by creating a multi-colored or multi-tonal appearance that enhances the visual impact and complexity, making it resistant to reproduction.
Implementation Method 1
the sampling element array cooperates with each of the microimage element arrays to generate magnified versions of the microimage elements in each region due to the moiré effect
Data Source
AI summary
A method of manufacturing a security device includes: a) providing a depth map of a macroimage depicting a three-dimensional object, the depth map representing the depth of each part of the three-dimensional object relative to a reference plane by different colours and/or different tones of one colour; b) segmenting the depth map into a plurality of regions based on the colours and/or tones of the depth map; c) for each region, creating a respective microimage element array; and d) providing a sampling element array of a predetermined pitch and orientation. The pitch and/or orientation of each respective microimage element array is different, and is configured such that the magnified versions of the microimage elements generated in any one of the regions have a different apparent depth relative to those generated in the other region(s), so as to form a three-dimensional representation of the macroimage.