Imaging Element Exposure Control for High-Frame-Rate Flicker Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing imaging apparatuses face challenges in promptly responding to changes in exposure during both still and moving image capture, leading to potential flickering due to asynchronous control of aperture and electronic shutter/gain settings, especially with high-frame-rate moving images, where exposure calculation processes may not be completed in time.
Innovation Solution
An imaging element with a gain unit and control unit that sets the gain and accumulation time based on detected luminance values, allowing for exposure control within the imaging element to reduce the load on arithmetic processing units and minimize exposure changes caused by aperture control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If exposure calculation process is performed by CPU for high-frame-rate moving images, then exposure control accuracy is improved, but processing time increases causing delay in responding to aperture changes
Solution Approach 1:
The patent segments the exposure control function by separating luminance calculation (performed by CPU) from exposure determination (performed by imaging element). This division allows the CPU to focus only on calculating luminance values from image data, while the imaging element independently determines exposure settings, thereby reducing overall processing time and enabling high-frame-rate operation without sacrificing exposure control accuracy.
Solution Approach 2:
The imaging element is equipped with an exposure determination unit that autonomously determines exposure settings based on luminance values received from the CPU. This self-service capability eliminates the need for the CPU to perform complex exposure calculations, significantly reducing processing delay and enabling real-time response to aperture changes in high-frame-rate moving image capture.
2Device complexity
If aperture control is performed asynchronously with electronic shutter and gain settings, then device complexity is reduced, but image quality deteriorates due to flickering
Solution Approach 1:
The patent implements a feedback mechanism where the imaging element receives luminance values calculated by the CPU and uses them to determine appropriate exposure settings. This feedback loop ensures that exposure adjustments are made in response to actual image data, synchronizing aperture control with electronic shutter and gain settings to prevent flickering while maintaining manageable device complexity through the centralized luminance calculation approach.
Solution Approach 2:
The CPU calculates luminance values in advance from captured image data before the imaging element determines exposure settings. This preliminary action provides the imaging element with the necessary information to synchronize exposure control with aperture changes, ensuring image quality stability without requiring complex real-time coordination mechanisms.
3Measurement precision
If all exposure control processing is performed by CPU, then control precision is improved, but processing load increases causing incomplete exposure calculation within frame time
Solution Approach 1:
The patent segments the exposure control processing load by assigning luminance calculation to the CPU and exposure determination to the imaging element. This segmentation allows the CPU to focus on the computationally intensive luminance calculation using image data, while the imaging element handles the exposure determination, thereby maintaining high calculation precision while increasing overall processing speed to meet frame time requirements.
Solution Approach 2:
The patent introduces luminance values as an intermediary data structure between the CPU and imaging element. The CPU calculates these luminance values from raw image data, and the imaging element uses them to determine exposure settings. This intermediary approach maintains exposure calculation precision while reducing the processing load on the CPU, enabling complete exposure calculations within frame time for high-frame-rate operation.
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 solution enables reduced exposure control processing for arithmetic processing units, minimizing flickering by synchronizing exposure adjustments with aperture operations, even under high-frame-rate conditions, thereby maintaining proper exposure states.
Implementation Method 1
an imaging element with a photoelectric conversion unit that converts incident light into an electrical signal and outputs the electrical signal
Data Source
AI summary
An imaging element that outputs an image signal acquired by an imaging unit which has a plurality of pixel units is provided that includes a gain unit that sets gain with respect to an output signal of the imaging unit; a control unit that controls an accumulation time of the pixel units; and an arithmetic operation unit that receives a target luminance value and exposure control information, calculates the gain or the accumulation time by detecting a luminance value using an image signal read from the pixel units, and causes the gain unit or the control unit to perform exposure control of the imaging unit.