Ambient Light Sensor for Camera Exposure Control
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Solution Overview
Problem
Existing camera modules in wireless devices face challenges in setting optimal exposure settings due to size constraints, which limit the use of conventional SLR and DSLR exposure metering techniques, leading to inefficiencies in automatic exposure schemes.
Innovation Solution
An apparatus and method utilizing an ambient light sensor to set an initial exposure setting, which is responsive to ambient lighting conditions, allowing the camera module to converge to a final exposure setting by adjusting parameters like integration time, gain, or shutter speed, while also controlling backlight intensity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional SLR and DSLR exposure metering techniques are used, then exposure measurement precision is improved, but device size increases beyond acceptable constraints
Solution Approach 1:
The patent applies multi-functionality by using the ambient light sensor to serve dual purposes: controlling display backlighting and providing initial exposure settings for the camera module. This eliminates the need for dedicated exposure metering hardware in the camera module, thereby maintaining compact size while achieving functional requirements through a shared sensing component.
Solution Approach 2:
The patent introduces an intermediary approach by using the ambient light sensor's readings as a proxy for exposure measurement. Instead of directly measuring light through the lens (which would require additional hardware), the system uses the ambient light sensor as an intermediary to estimate and set initial exposure parameters, achieving adequate measurement precision without conventional TTL metering equipment.
2Device complexity
If automatic exposure schemes are implemented without initial exposure setting, then device complexity is reduced, but convergence time to final exposure increases
Solution Approach 1:
The patent applies preliminary action by setting an initial exposure value based on ambient light sensor readings before the automatic exposure algorithm begins its convergence process. This pre-initialization step provides a closer starting point to the final optimal exposure, reducing the number of iterations required and thereby decreasing the time loss without adding significant complexity to the control system.
3Measurement precision
If multiple sensors are used for backlight control and exposure setting, then measurement precision is improved, but device size and cost increase
Solution Approach 1:
The patent applies multi-functionality by making the ambient light sensor serve dual purposes: controlling display backlighting and providing initial exposure settings for the camera module. This eliminates the need for dedicated exposure metering hardware in the camera module, thereby maintaining compact size while achieving functional requirements through a shared sensing component.
Solution Approach 2:
The patent merges the functions of backlight control and camera exposure setting into a single sensing operation. By combining these two functions that were previously performed by separate sensors, the system reduces component count and device size while still meeting the functional requirements for both display visibility and image capture exposure.
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 quicker convergence to a final exposure setting, reducing the number of poorly exposed frames and improving user experience by using a single sensor for both backlight control and exposure setting, thus minimizing device size and cost.
Implementation Method 1
an ambient light sensor is provided in the device. The ambient light sensor is adapted to sense ambient light conditions and to provide an indication of a level of the ambient light conditions
Data Source
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AI summary
An apparatus, and an associated method, for a device containing a camera module. An ambient light sensor senses ambient light conditions and provides an indication of the sensed conditions to an exposure setter. The exposure setter utilizes the indication of the ambient light conditions in the selection of the initial exposure. Convergence procedures are utilized to converge the exposure settings to a final exposure setting.