Real-time Exposure Control for Imager Pixels
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing imaging devices face challenges in efficiently controlling exposure to light during image capture, particularly in applications like swallowable pills, where using previous illumination may not be sufficient, leading to energy waste by keeping light sources on longer than needed.
Innovation Solution
Implementing real-time monitoring of light incident on imager pixels using comparators and a voltage reference generator to adjust gain and exposure time dynamically, ensuring only selected pixels are monitored for exposure control, thereby conserving energy and maintaining image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If light source is kept on longer than exposure period to ensure sufficient illumination, then image quality is improved, but energy consumption increases
Solution Approach 1:
The system performs preliminary monitoring of pixel signals during the exposure period to assess present illumination levels before finalizing the exposure control decision. This allows the system to determine in advance whether additional illumination is needed, avoiding energy waste from unnecessary extended lighting.
Solution Approach 2:
The system continuously monitors pixel signals during exposure and uses this feedback to dynamically adjust the exposure control. By comparing real-time pixel signal levels to reference values, the system can determine whether the light source should be extended or terminated, optimizing both image quality and energy consumption.
2Measurement precision
If all pixels are monitored for exposure control, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The system segments the pixel array into a first plurality of pixels for exposure control monitoring and a second plurality of pixels for image capture. This segmentation allows the system to monitor only a subset of pixels for exposure control purposes, reducing the complexity of the monitoring circuitry while still achieving sufficient measurement precision for effective exposure control.
Solution Approach 2:
Instead of monitoring all pixels in the array, the system uses a partial action approach by monitoring only a first plurality of pixels. This partial monitoring provides sufficient exposure control information without the excessive complexity of full-array monitoring, achieving the right balance between precision and 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 allows for automatic light control during exposure using present illumination, reducing energy waste and ensuring optimal image capture by adjusting parameters in real-time without resetting pixels, thus enhancing the efficiency and power conservation of the imaging process.
Implementation Method 1
Each pixel cell includes a photosensor, for example, a photogate, photoconductor or a photodiode overlying a substrate for accumulating photo-generated charge
Data Source
AI summary
An imager and a method for real-time, non-destructive monitoring of light incident on imager pixels during their exposure to light. Real-time or present pixel signals, which are indicative of present illumination on the pixels, are compared to a reference signal during the exposure. Adjustments, if necessary, are made to programmable parameters such as gain and/or exposure time to automatically control the imager's exposure to the light. In a preferred exemplary embodiment, only a selected number of pixels are monitored for exposure control as opposed to monitoring the entire pixel array.