Image Processing Apparatus for Secure Display via Temporal Masking
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Solution Overview
Problem
Existing image display technologies, such as those using shutter glasses or data hiding patterns, fail to adequately prevent accidental viewing of secret images, as misalignment or blinking can reveal the secret image, and division patterns can be visually annoying.
Innovation Solution
An image processing apparatus that outputs a first secret image and a second reverse image alternately, with a third public image having high spatial-frequency components, controlled by an optical shutter to ensure the secret image is difficult to perceive without proper viewing conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If shutter glasses are used to display secret images, then the secret image can be viewed only by authorized users, but the secret image can still be perceived accidentally through blinking or misalignment
Solution Approach 1:
The image display is segmented into multiple frames (secret image frames and public image frames) that are displayed alternately. The secret image is divided into multiple blocks, and different scrambling patterns are applied to different blocks across different frames, making accidental perception difficult even if some frames are viewed
Solution Approach 2:
The display alternates periodically between secret image frames and public image frames. This periodic switching ensures that even if a viewer blinks or experiences misalignment, they cannot perceive the complete secret image, as the required multiple scattered frames are displayed at different time intervals
2Reliability
If division patterns are used to protect secret images, then security is improved, but the public image becomes visually annoying
Solution Approach 1:
The public image parameters are optimized to have appropriate luminance and spatial frequency characteristics that are visually comfortable. The scrambling patterns applied to public image blocks are designed to create a natural-looking public image rather than obvious division patterns, eliminating visual annoyance while maintaining security
3Object-affected harmful factors
If high spatial-frequency public images are used for masking, then accidental viewing is prevented, but the complexity of image processing increases
Solution Approach 1:
Different processing techniques are applied to different regions of the image. High spatial-frequency masking is applied specifically to blocks that contain secret image information, while other blocks use simpler scrambling patterns. This localized approach prevents accidental viewing while minimizing overall processing complexity
Data Source
AI summary
An image processing apparatus sequentially provides a display device with a plurality of image output including a first image, a second image set to become at least a part of an image that is not correlated with the first image when luminance values of pixels of the first image are added to it, and a third image set to become an image, which is obtained by adding luminance values of pixels of all pluralities of images, higher spatial-frequency components than those of the first image. The image processing apparatus has an optical shutter control unit for controlling an optical shutter provided between the display device and a viewer to make the shutter be in a light transmission state while a part of or all the first image is displayed, and in a light interception state while other images are displayed.