Master-Slave Illumination System for Uniform Lighting and Red-Eye Reduction
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Solution Overview
Problem
Integrated camera flashes often result in harsh foreground lighting and poor background lighting due to limited light intensity range, which decreases with distance, and can cause the 'red-eye' phenomenon due to the flash's proximity to the lens, making it difficult to achieve proper illumination in small devices like smartphones.
Innovation Solution
A method and system where an image capture device initiates a master-slave relationship with secondary light sources, allowing remote activation and adjustment of their intensity, timing, and position to ensure uniform illumination, reducing red-eye reflections by positioning the light sources off-center from the lens.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If an integrated flash is used for illumination, then the device structure remains compact, but the lighting uniformity deteriorates with harsh foreground lighting and poor background lighting
Solution Approach 1:
The illumination system is divided into multiple independent light sources (master flash and multiple slave flashes) positioned at different locations. Each flash unit can be controlled independently to provide distributed illumination across the scene, improving lighting uniformity while keeping the camera device compact.
Solution Approach 2:
The patent introduces spatial distribution of light sources by positioning slave flashes at different distances and angles from the camera lens. This multi-dimensional arrangement allows light to reach both foreground and background areas effectively, solving the lighting uniformity problem without increasing the camera's physical size.
2Device complexity
If the flash is positioned near the lens, then the device structure is simplified, but red-eye reflections occur due to direct light path
Solution Approach 1:
The slave flash units are positioned asymmetrically at specific angles (e.g., 45 degrees) relative to the camera lens axis. This asymmetric positioning alters the light path so that light does not reflect directly back into the lens from the subject's eyes, eliminating red-eye effects while maintaining simple device structure.
Solution Approach 2:
The slave flashes act as intermediary light sources that illuminate the scene from angles different from the camera lens. This intermediary positioning breaks the direct light-reflection-path between lens and subject eyes, preventing red-eye reflections without complicating the overall device structure.
3Illumination intensity
If multiple secondary light sources are added to improve illumination, then the lighting uniformity improves, but the device complexity increases
Solution Approach 1:
The master camera unit communicates with slave flash units through a master-slave communication system. The master unit sends control signals to synchronize and regulate the intensity of slave flashes, while slave units provide feedback on their operational status. This feedback mechanism enables coordinated illumination control without requiring complex manual configuration, managing system complexity through automated communication protocols.
Data Source
AI summary
A method for capturing an image with an image capture device, such as a camera or mobile electronic device. The method includes initiating a master-slave relationship between the image capture device and at least one secondary device. Once the master-slave relationship is initiated, remotely activating one of an at least one light source of the at least one secondary device. As the light source is activated, capturing a test image of a scene illuminated by the at least one light source by the image capture device. Then, analyzing the test image to determine if an illumination of the scene should be adjusted and if the illumination of the scene is to be adjusted, providing a control signal to the at least one secondary device including at least one of a position instruction, an intensity level, or timing data.