Imaging Device Area-Specific Exposure Control
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Solution Overview
Problem
Existing imaging devices face challenges in acquiring high-quality, high dynamic range images without impairing frame rate, particularly when capturing moving images, due to time lags and deviations in exposure conditions between preliminary and actual imaging.
Innovation Solution
The imaging device employs a pixel unit with multiple rows and columns of photoelectric converters, using a pixel control unit to manage first and second exposure periods, and an exposure time decision processing unit to adjust the second exposure period based on signals from each area, allowing for synchronized and optimized exposure times across different areas within a frame.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If preliminary shooting is performed to create an exposure map and control exposure time based on it, then dynamic range is improved, but frame rate deteriorates due to time lag between decision and actual imaging
Solution Approach 1:
The patent performs preliminary exposure time decision for all areas within the same frame period, using the first signal output from pixels to determine second exposure times before actual imaging begins. This eliminates the time lag between exposure decision and imaging that occurs in conventional sequential methods, thereby maintaining high frame rate while achieving optimized dynamic range through area-specific exposure control.
2Illumination intensity
If exposure time is controlled based on preliminary imaging, then dynamic range is improved, but image quality deteriorates due to deviation between preliminary and actual imaging conditions
Solution Approach 1:
The patent uses the first signal output from pixels during the current frame as feedback to determine the second exposure time for the same frame's imaging. This real-time feedback mechanism ensures that exposure decisions are based on actual current imaging conditions rather than outdated preliminary imaging data, eliminating deviation between exposure conditions and actual imaging conditions, thereby maintaining high image quality while achieving optimized dynamic range.
3Manufacturing precision
If exposure time decision is performed for all areas before imaging, then image quality is improved, but frame rate deteriorates due to processing time
Solution Approach 1:
The patent performs exposure time decision processing continuously within the same frame period in which the imaging occurs, using the first signal output from pixels to determine second exposure times without interrupting or delaying the imaging process. This continuous processing approach eliminates idle time between exposure decision and imaging, thereby maintaining high frame rate while achieving optimized image quality through area-specific exposure control.
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 the acquisition of high-quality, high dynamic range images without reducing frame rate, by ensuring accurate and synchronized exposure times across the imaging area, thereby improving image quality and maintaining frame rate performance.
Implementation Method 1
a plurality of pixels each including a photoelectric converter... a first signal based on a charge generated in the photoelectric converter during a first exposure period
Data Source
AI summary
An imaging device includes a pixel unit including pixels arranged in rows and columns, a pixel control unit that outputs, from each pixels, a first signal based on a charge generated during a first exposure period and a second signal based on a charge generated during a second exposure period, and an exposure time determination processing unit that determines a length of the second exposure period based on the first signal. The pixel unit includes areas each including at least one pixel, the exposure time determination processing unit determines the length of the second exposure period in each areas based on the first signal in each areas, and the pixel control unit starts the second exposure period in the pixels in a first area after outputting the first signal from the pixels in the first area and before outputting the first signal from the pixels in a second area.