Modulated LED Visual Privacy System for Rolling Shutter Cameras
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Solution Overview
Problem
Current visual privacy systems are limited in effectively protecting against unauthorized camera use without special modifications, as they require coordination with camera owners and are costly or impractical for large areas or moving objects, especially in environments with ambient light that cannot be controlled.
Innovation Solution
A unilateral visual privacy system using modulated LED lights that interact with rolling shutter cameras to obscure images through banding or watermarking, allowing for area-wide protection without requiring camera modifications, and can switch to a barcode mode for detection in adverse conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If camera-blinding light sources are used to enforce visual privacy, then privacy protection is achieved, but the system becomes costly and impractical for large areas or moving objects
Solution Approach 1:
The LED light fixtures serve dual purposes: providing ambient illumination for the space and simultaneously functioning as privacy protection devices through modulation. This eliminates the need for separate camera-blinding hardware, reducing system cost and complexity while maintaining privacy protection effectiveness across large areas.
Solution Approach 2:
The existing ambient lighting infrastructure is leveraged to provide privacy protection without requiring additional dedicated hardware. The modulation of standard LED fixtures enables them to self-serve the dual function of illumination and privacy enforcement, making the system economically viable for large-scale deployment.
2Reliability
If camera-blinding light sources are placed in close proximity to protected objects, then privacy protection is achieved, but the system becomes impractical for moving objects or situations where premeditated placement is difficult
Solution Approach 1:
By making ambient lighting fixtures privacy-protective through modulation, the system removes the requirement for specialized hardware placement near protected objects. This enables privacy protection to follow moving objects or be deployed in environments where premeditated placement is difficult, significantly improving deployment flexibility.
Solution Approach 2:
The system shifts from spatial proximity-based protection (requiring hardware near protected objects) to temporal modulation-based protection (using time-varying light patterns). This dimensional shift from space to time enables privacy protection without close proximity placement, accommodating moving objects and flexible deployment scenarios.
3Reliability
If LED lights are modulated at high frequency to obscure images, then privacy protection is achieved, but the lights may cause perceivable flicker degrading ambient light quality
Solution Approach 1:
The system carefully selects modulation frequencies that fall within the rolling shutter camera's exposure characteristics to produce obscuring banding effects, while simultaneously remaining above the human flicker fusion threshold to prevent perceivable flicker. This parameter optimization maintains both privacy protection effectiveness and ambient light quality.
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 system provides effective protection against unauthorized photography in large areas with minimal cost and complexity, allowing authorized cameras to function while obscuring images taken by unauthorized cameras, and can adapt to varying ambient light conditions.
Implementation Method 1
A modulator communicates with the light fixtures to synchronously modulate the light of the light fixtures between on and off values at a frequency above the flicker fusion rate to impose a banding in images taken by rolling frame shutter cameras
Data Source
AI summary
A visual privacy system unilaterally blocks rolling shutter cameras by providing a periodically interrupted ambient light source imposing bright and dark bands on the image yet at a frequency imperceptible to human observers in the environment. Communication of the modulation pattern to authorized cameras allows unaffected imaging in these regions by authorized individuals. The system also contemplates operation in a barcoding mode with a light modulation providing embedded barcodes that can be extracted from images taken in the region to indicate that the images were improperly acquired and to block the images in certain applications.