Camera Flash Color Balance via Ambient Light Matching
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Solution Overview
Problem
Digital cameras face challenges in achieving proper color balance under mixed light conditions due to the fixed color temperature of camera flash modules, which often does not match natural ambient light, leading to unsightly color casts and increased processing time for estimating ambient light characteristics using a single multi-purpose image sensor.
Innovation Solution
A method and camera unit configuration that monitor ambient light characteristics to adjust the camera flash's color temperature and intensity in real-time or discrete intervals, allowing the flash to match the ambient light, and select an appropriate color balancing algorithm before capturing an image, thereby reducing shutter lag and improving image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed color temperature flash module is used, then the device complexity is reduced, but the color balance quality deteriorates under mixed light conditions
Solution Approach 1:
The flash module is segmented into multiple LED chips with different color temperatures (e.g., warm white and cool white LEDs). Each LED chip emits light at a specific color temperature, and by controlling the intensity ratio of these segmented light sources, the overall flash color temperature can be adjusted to match various ambient lighting conditions, thereby improving color balance quality without significantly increasing device complexity.
Solution Approach 2:
The invention changes the color temperature parameter of the flash light by adjusting the drive current ratios of multiple LED chips with different color temperatures. By dynamically modifying the intensity contribution of each LED chip, the system can adapt the flash output color temperature to match ambient light conditions (e.g., matching incandescent, fluorescent, or natural light), thus improving color balance quality while maintaining a relatively simple flash module structure.
2Manufacturing precision
If the flash color temperature is adjusted to match ambient light, then the color balance quality is improved, but the device complexity increases
Solution Approach 1:
The flash module is designed with multi-functionality by incorporating LED chips that can operate in different color temperature modes. The same flash module can serve multiple purposes: providing illumination at various color temperatures to match different ambient lighting conditions (incandescent, fluorescent, natural light), and the control system can selectively activate appropriate LED chips based on detected ambient light characteristics, thereby achieving adaptability without proportionally increasing device complexity.
Solution Approach 2:
The flash module implements dynamic color temperature adjustment by enabling real-time control of LED chip intensity ratios based on ambient light detection. The system can dynamically switch between different color temperature configurations (e.g., predominantly warm white for incandescent lighting, mixed ratios for fluorescent lighting) to match the ambient environment, providing adaptive color balance improvement while maintaining reasonable device complexity through software-controlled dynamic adjustment.
3Device complexity
If a single multi-purpose image sensor is used to estimate ambient light characteristics, then the device complexity is reduced, but the measurement precision deteriorates
Solution Approach 1:
The system performs preliminary action by capturing a pre-flash image at a reduced exposure level before the main flash discharge. This preliminary exposure allows the image sensor to estimate ambient light characteristics (color temperature and intensity) in advance. By conducting this measurement before the main flash, the system can pre-calculate the appropriate flash color temperature adjustment, thereby improving measurement precision without requiring additional dedicated sensors or increasing device complexity.
Solution Approach 2:
The invention applies partial action by using a reduced-strength pre-flash exposure instead of a full-strength flash. This partial exposure is sufficient for the image sensor to estimate ambient light characteristics without overexposing the scene or requiring the full flash power. The pre-flash uses only enough light to enable accurate ambient light measurement, and the remaining flash power is then optimized for the actual imaging task, improving measurement precision while avoiding excessive energy consumption or device complexity.
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 enables better color balancing and reduced shutter lag by dynamically adjusting the flash to match ambient light conditions, resulting in higher quality images with minimized residual color casts and reduced processing time.
Implementation Method 1
a first converter layer including a quantum dot layer and a first wavelength selective filter arranged in sequence along a direction of light propagation from the first LED
Implementation Method 2
an image sensor formed out of an array of photosensitive pixels to capture images of a scene... each pixel in the array is photosensitive to a certain range of light
Data Source
AI summary
A camera unit and method of control are described. The camera unit has a camera flash sub-unit configurable to emit flash light having an adjustable characteristic. A camera sensor sub-unit generates raw color data when exposed to light for processing into a digital image. The camera unit also includes a camera controller for coordinating operation of the camera flash sub-unit and the camera sensor sub-unit. The camera controller monitors one or more ambient light characteristics in a vicinity of the camera unit. Prior to receiving a command instructing the camera unit to generate the digital image, the camera controller repeatedly configures the camera flash sub-unit based on the monitored ambient light characteristics to adjust the characteristics of the emitted flash light. Once the camera controller receives the command, the camera sensor sub-unit is instructed to expose an image sensor using the pre-adjusted camera flash light to increase illumination.