Segmented LED Lighting for Rolling Shutter Cameras
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Solution Overview
Problem
Digital cameras using rolling shutters face inefficiencies in illumination due to the need for continuous lighting across the entire image area, which is energy-intensive and not synchronized with the rolling shutter's sequential exposure of sensor portions, leading to wasteful energy use.
Innovation Solution
Implementing a lighting system with multiple LEDs arranged in arrays that are controlled in synchronization with the rolling shutter's operation, activating only the LEDs corresponding to the portions of the image sensor being exposed, thereby illuminating only the necessary areas during exposure and conserving energy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If continuous illumination is used across the entire image area, then all sensor portions are adequately lit during the full capture period, but energy consumption increases significantly
Solution Approach 1:
The lighting system is divided into multiple independently controllable LED groups corresponding to different sensor portions. Each LED group can be activated or deactivated based on which sensor portion is currently being exposed, allowing illumination to be segmented in space and time rather than continuously illuminating the entire area.
Solution Approach 2:
The illumination system operates periodically by activating specific LED groups in synchronization with the rolling shutter's sequential exposure of sensor portions. Each LED group is turned on during its corresponding exposure window and turned off during other periods, creating a periodic illumination pattern that matches the rolling shutter operation cycle.
2Duration of action of stationary object
If all LEDs are activated for the full capture period, then illumination is provided throughout the entire image capture process, but time efficiency decreases due to unnecessary illumination
Solution Approach 1:
The system pre-synchronizes the activation timing of each LED group with the corresponding sensor portion exposure timing. Each LED group is activated at the precise moment its corresponding sensor portion begins exposure and deactivated when exposure ends, eliminating any illumination that would occur outside the necessary time window.
Solution Approach 2:
The illumination follows a periodic pattern where each LED group is activated only during its specific exposure window within the full capture period. This periodic activation ensures that illumination duration is maximized for each sensor portion while minimizing total illumination time across the entire capture process.
3Illumination intensity
If strobе type flashes are used, then illumination is provided during exposure, but the flash duration is insufficient for the extended capture time required by rolling shutters
Solution Approach 1:
Instead of using a single strobе flash for the entire capture period, the system segments illumination into multiple LED groups that are activated sequentially. Each LED group provides illumination for its corresponding sensor portion exposure window, collectively providing continuous illumination throughout the full capture period while maintaining the brief, intense illumination characteristic of strobe lighting for each segment.
Solution Approach 2:
The system uses periodic activation of multiple LED groups to achieve both strobе-like illumination intensity and extended duration. Each LED group is activated in a periodic manner synchronized with the rolling shutter, creating a sequence of illumination pulses that collectively cover the entire capture period, effectively combining the benefits of strobe lighting with extended duration.
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
This approach reduces energy consumption by ensuring that only the areas being captured are illuminated, improving the efficiency of the lighting system and extending battery life in camera devices.
Implementation Method 1
a plurality of light emitting elements which can be controlled to emit light
Data Source
AI summary
Illumination methods and apparatus are described. In some embodiments a lighting device includes one or more lighting modules. At least some but not necessarily all lighting modules include a light source, e.g., LED or bulb, a collimating lens positioned in front of said light source for generating a beam of light from light output by said light source and a beam flattening lens for flattening the beam of light in at least a first direction as it passes through the first beam flattening lens. In some but not necessarily all embodiments lighting modules are controlled based on which portion of a scene is being captured at a point in time thereby avoiding the need to illuminate the entire scene for the full duration of an image capture period. The lighting device may be used in combination with a rolling shutter and a sensor used to capture one or more images.