Variable Opacity Optical Filter for Camera Exposure Control
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Solution Overview
Problem
Conventional camera systems face challenges in maintaining consistent exposure and reducing motion artifacts under changing lighting conditions, particularly with rolling shutter effects and temporal aliasing.
Innovation Solution
A camera system incorporating a variable opacity optical filter that can operate in temporal filtering, global shuttering, and neutral density modes, controlled by a processor to adjust opacity levels dynamically and correct for color shifting and white point shifts in image data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a variable opacity optical filter is used to maintain consistent exposure under changing lighting conditions, then exposure consistency is improved, but device complexity increases
Solution Approach 1:
The patent implements a variable opacity optical filter that can dynamically adjust its transmissivity during the exposure period. The filter transitions from a static component to a dynamic one, allowing real-time modulation of light intensity to maintain consistent exposure under varying lighting conditions. This is achieved through controlled changes in the filter's opacity level during the exposure period.
Solution Approach 2:
The patent changes the optical parameter (opacity/transmissivity) of the filter dynamically during exposure. By modulating the filter's opacity level as a variable parameter rather than keeping it fixed, the system can adapt to changing lighting conditions. The processor controls the filter to achieve desired exposure levels by adjusting this key parameter in real-time.
2Reliability
If temporal filtering mode is used to reduce motion artifacts, then image quality is improved, but loss of light transmission occurs
Solution Approach 1:
The patent employs periodic modulation of the optical filter's opacity during the exposure period to achieve temporal filtering. The filter undergoes cyclic changes in transmissivity, creating a periodic action that helps reduce motion artifacts and temporal aliasing. This periodic variation in light transmission allows the sensor to capture multiple temporal samples, improving image quality while managing the trade-off with light loss.
3Reliability
If global shutter mode is used to capture entire frame simultaneously, then motion artifact reduction is improved, but exposure control flexibility is reduced
Solution Approach 1:
The patent makes the optical filter dynamic, allowing it to change opacity levels during the exposure period even in global shutter mode. This dynamic capability provides exposure control flexibility while maintaining the global shutter's ability to capture the entire frame simultaneously. The filter can be adjusted to different opacity levels at different times during the exposure, enabling adaptive exposure control.
Solution Approach 2:
The patent utilizes parameter changes in the filter's opacity to achieve both global shutter functionality and exposure flexibility. By varying the opacity parameter during exposure, the system maintains the simultaneous frame capture benefit while gaining the ability to control exposure levels dynamically, thus resolving the contradiction between motion artifact reduction and exposure control flexibility.
4Reliability
If optical filter is used to control exposure, then exposure control is improved, but color shifting in image data occurs
Solution Approach 1:
The patent incorporates feedback mechanisms to detect and correct color shifting caused by the optical filter. The system monitors the image data for color accuracy and uses this feedback to adjust the filter's opacity or apply computational corrections. This closed-loop approach allows the system to maintain exposure control benefits while compensating for the harmful color shifting effect.
Solution Approach 2:
The patent converts the color shifting effect, initially a harmful factor, into a controllable parameter. By deliberately modulating the filter's opacity in specific patterns during exposure, the system can actually use the filter-induced color changes to achieve temporal filtering and motion artifact reduction. The harmful color shift is transformed into a useful signal that, when properly managed, contributes to improved image quality through subsequent processing.
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
The system effectively maintains consistent exposure and reduces motion artifacts, such as rolling shutter effects and temporal aliasing, while allowing for creative flexibility in shooting conditions by dynamically controlling the optical filter's opacity and applying image data modifications.
Implementation Method 1
The light can pass through a variable opacity optical filter situated in the optical path prior to arriving at the image sensor
Implementation Method 2
The image sensor can convert light entering the camera housing into digital image data
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
In one embodiment, a camera includes an image sensor within a camera housing that converts light entering the camera housing through an optical filter into digital image data. The optical filter can have a variable opacity. A processor in communication with the image sensor identifies operation settings for the optical filter and adjusts an opacity level of the optical filter over an exposure period in accordance with the operation settings for the optical filter. In addition, the processor modifies values of the digital image data based at least on the operation settings for the optical filter.