Flash Current Ratio Control for Consistent Image Quality
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Portable electronic devices with LED flashes face challenges in maintaining consistent image quality due to varying ambient lighting and battery charge levels, which affect the current available for flash outputs, impacting automatic exposure and white-balance settings.
Innovation Solution
A method is implemented to identify the available current for the main flash output, set a corresponding current value for a preflash output, and use it to determine and set automatic exposure and white-balance values for capturing digital images, ensuring consistent ratios and improved image quality across different battery charge states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the main flash output uses full current, then the flash provides sufficient light for image capture, but the preflash-to-main flash current ratio becomes inconsistent when battery charge level varies
Solution Approach 1:
The patent applies dynamics by making the preflash current adaptive rather than fixed. The preflash current dynamically adjusts based on the detected battery charge level to maintain a consistent ratio with the main flash current. This is achieved through: (1) detecting the battery charge level, (2) determining the main flash current based on this level, and (3) setting the preflash current as a predetermined ratio of the main flash current. This dynamic adjustment ensures reliable automatic exposure and white-balance measurements across varying battery conditions while maintaining image quality consistency.
Solution Approach 2:
The patent applies parameter changes by modifying the preflash current parameter based on battery charge level. Instead of using a fixed preflash current, the system changes this parameter dynamically according to the detected battery state. The main flash current is determined based on battery charge level, and the preflash current is set as a predetermined ratio (e.g., 1/10th) of this adjusted main flash current. This parameter adjustment ensures that the preflash-to-main flash current ratio remains consistent regardless of battery charge variations, resolving the contradiction between reliability and adaptability.
2Use of energy by moving object
If the preflash current is reduced to conserve battery, then battery life is extended, but the automatic exposure and white-balance measurements become inaccurate
Solution Approach 1:
The patent applies parameter changes by adjusting both the main flash current and preflash current based on battery charge level while maintaining their ratio. The system detects battery charge level and determines the main flash current accordingly, then sets the preflash current as a predetermined ratio of this adjusted main flash current. This ensures that even when battery energy is limited, both flash currents are reduced proportionally, maintaining measurement accuracy for automatic exposure and white-balance while adapting to available battery energy.
Solution Approach 2:
The patent applies feedback by detecting the battery charge level and using this information to adjust the flash current settings. The system continuously monitors battery state and adjusts the main flash current and preflash current accordingly. This feedback mechanism ensures that the preflash-to-main flash current ratio remains consistent regardless of battery charge variations, maintaining measurement accuracy while adapting to available energy resources.
3Measurement precision
If the preflash current is increased to improve measurement accuracy, then automatic exposure and white-balance settings become more accurate, but the battery is depleted faster
Solution Approach 1:
The patent applies parameter changes by making both preflash and main flash currents adaptive to battery charge level. Instead of using fixed high currents that would deplete the battery quickly, the system detects battery charge level and adjusts both currents proportionally. The preflash current is set as a predetermined ratio of the battery-adjusted main flash current, ensuring measurement accuracy is maintained while battery energy consumption is optimized for the available charge level.
4Volume of moving object
If the flash component is made compact for portability, then the device is easier to carry, but the flash output intensity and image quality are compromised
Solution Approach 1:
The patent applies parameter changes by optimizing the flash current parameters based on battery charge level rather than relying solely on increased hardware power. The system detects battery charge level and adjusts the main flash current and preflash current accordingly, extracting maximum performance from the compact LED flash component. This software-based parameter optimization compensates for the limitations of compact flash hardware, maintaining adequate illumination intensity and image quality while preserving portability.
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 ensures more accurate and consistent automatic exposure and white-balance settings, resulting in better image quality even when the battery is low, by maintaining a constant ratio of preflash to main flash current values, independent of battery charge level.
Implementation Method 1
Flash devices such as LED flashes used in portable electronic devices provide additional light in a compact size
Implementation Method 2
receiving light at an image sensor, and based on the light received at the image sensor, setting automatic exposure and automatic white-balance values
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A method of controlling a portable electronic device including a digital camera for setting automatic exposure and automatic white-balance values for capturing a digital image. The method includes identifying an available current for a main flash output of the digital camera for capturing the digital image, in response to determining that the available current for the main flash output is less than a full current value, identifying a corresponding current value for a preflash output based on the available current for the main flash output and setting the current value for the preflash output to the corresponding current value, actuating the preflash output utilizing the corresponding current value and receiving light at an image sensor, and based on the light received at the image sensor, setting automatic exposure and automatic white-balance values for use in capturing the digital image.