Camera Flash LED White Balance and Exposure Control
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Solution Overview
Problem
Existing camera systems using LED flashes face challenges in achieving optimal image quality due to varying ambient light conditions, limited control over spectral content, increased power consumption, and difficulties in calculating exposure and white balance settings without known object distance and reflectance.
Innovation Solution
A method and apparatus that calculate ambient light levels and estimate flash light reflection to determine color compensation gains, exposure time, and gain settings for improved image quality, using sensors and pre-stored values to optimize flash usage, including the option to use a predetermined reflectance value when feedback is insufficient.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the flash is turned on for a long time to allow AE and AWB control to adjust to optimum settings, then image quality is improved, but power consumption increases and LED lifetime is shortened
Solution Approach 1:
The system performs preliminary calculations of ambient light level and reflected flash light before the actual image capture. Based on these pre-calculated values, the optimal exposure time and white balance gains are determined in advance, allowing the flash to be activated only for the necessary duration to achieve proper exposure without excessive power consumption or LED heating.
2Manufacturing precision
If the flash is turned on for a long time to allow AE and AWB control to adjust to optimum settings, then image quality is improved, but the lifetime of LED flash is shortened
Solution Approach 1:
The system performs preliminary calculations of ambient light level and reflected flash light before the actual image capture. Based on these pre-calculated values, the optimal exposure time and white balance gains are determined in advance, allowing the flash to be activated only for the necessary duration to achieve proper exposure without excessive power consumption or LED heating.
3Manufacturing precision
If the flash is turned on for a long time to allow AE and AWB control to adjust to optimum settings, then image quality is improved, but the delay between shutter-key press and actual image capturing is prolonged
Solution Approach 1:
The system performs preliminary calculations of ambient light level and reflected flash light before the actual image capture. Based on these pre-calculated values, the optimal exposure time and white balance gains are determined in advance, allowing the flash to be activated only for the necessary duration to achieve proper exposure without excessive power consumption or LED heating.
4Adaptability or versatility
If color filters are mounted on the lens to control spectral content, then image characteristics are affected, but continuous control of spectral content is not provided and filters must be physically interchanged
Solution Approach 1:
Instead of using physical filters that must be manually interchanged, the system dynamically adjusts the spectral content by varying the drive current of the LED flash. This allows continuous control of the flash output spectrum through electrical parameter changes, eliminating the need for mechanical filter switching while maintaining adaptability to different lighting conditions.
5Use of energy by moving object
If exposure and white balance settings are guessed before the flash is fired to minimize power consumption and capture delays, then power consumption and delay are reduced, but accurate settings cannot be calculated without known object distance and reflectance
Solution Approach 1:
The system uses feedback from the camera's existing sensors to measure ambient light levels and estimate reflected flash light. These measured values are fed back into the calculation system to determine accurate exposure and white balance settings, eliminating the need for guesswork while minimizing power consumption and capture delays.
6Illumination intensity
If a very bright light is pointed to the user's eyes during flash operation, then the flash provides sufficient illumination, but user comfort is reduced
Solution Approach 1:
The system dynamically adjusts the flash drive current based on calculated exposure requirements and ambient conditions. By optimizing the current level to match the actual lighting needs, the system provides sufficient illumination for proper image capture while preventing excessive brightness that would cause user discomfort or eye damage.
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 enhances image quality by optimizing exposure and white balance settings, reducing power consumption, and extending LED flash lifespan, while minimizing capture delays and user discomfort from bright lights.
Implementation Method 1
the amount of reflected flash light from the object back to the camera depends mostly on flash efficiency, object reflectance and especially on a distance from the object to the flash
Implementation Method 2
using flash (e.g., comprising LEDs) for improving quality of images provided by the camera
Data Source
AI summary
The specification and drawings present a new method, apparatus and software product for using a flash light with, e.g., light-emitting diodes (LEDs) or other light sources of a camera of an electronic device for improving quality of images provided by the camera. The flash related parameters comprising a white balance setting and/or exposure settings can be determined using, e.g., an ambient light level and an estimate of the flash light reflected from said object.