Dual Imaging Cell Sensor for Wide Dynamic Range
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Solution Overview
Problem
Conventional imaging devices face challenges in achieving a wide dynamic range while maintaining concurrency and sensitivity, as existing methods either require longer exposure times or compromise on sensitivity and saturation electrons, leading to inferior imaging characteristics.
Innovation Solution
The proposed imaging device incorporates two imaging cells with different sensitivity and saturation characteristics, where one cell is optimized for high sensitivity and the other for high saturation, with distinct circuit configurations and operation frequencies to achieve concurrent high-sensitivity and low-noise imaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single imaging cell is used to image both bright and dark subjects, then the device structure is simple, but the dynamic range is insufficient and imaging quality deteriorates in extreme brightness conditions
Solution Approach 1:
The imaging device is divided into two separate imaging cells: a first imaging cell with high sensitivity for capturing dark subjects, and a second imaging cell with low sensitivity for capturing bright subjects. This segmentation allows each cell to be optimized for its specific function, achieving wide dynamic range without excessive complexity
Solution Approach 2:
Different imaging cells are assigned different sensitivity characteristics tailored to their specific roles. The first imaging cell has high sensitivity optimized for low-light conditions, while the second imaging cell has low sensitivity optimized for high-light conditions. This local quality differentiation enables each cell to perform optimally in its designated brightness range
2Measurement precision
If the exposure period is extended to capture dark subjects, then sensitivity to dark subjects improves, but the bright subjects become overexposed and lose detail
Solution Approach 1:
The imaging system segments the capture function into two parallel paths: the first imaging cell captures dark subjects with extended exposure for high sensitivity, while the second imaging cell simultaneously captures bright subjects with shorter exposure to preserve highlight details. Both images are then synthesized
Solution Approach 2:
The imaging device performs periodic switching between different exposure durations for the two imaging cells, allowing the first cell to accumulate light for longer periods while the second cell uses shorter periods, thereby capturing both dark and bright subjects at optimal exposure levels
3Adaptability or versatility
If multiple imaging cells with different sensitivities are used to achieve wide dynamic range, then the dynamic range improves, but the signal processing complexity and power consumption increase
Solution Approach 1:
The signal processing system is segmented into dedicated processing circuits for each imaging cell type. The first signal processing circuit handles data from the high-sensitivity first imaging cell, while the second signal processing circuit handles data from the low-sensitivity second imaging cell. This segmentation simplifies the overall processing architecture by assigning specialized processing to each cell type
Solution Approach 2:
The signal processing circuits are designed with multi-functional capabilities to handle different data types and processing requirements. The circuits can perform multiple functions including noise filtering, signal amplification, and image synthesis, reducing the need for separate dedicated circuits for each function
4Adaptability or versatility
If high sensitivity imaging is performed concurrently with low sensitivity imaging, then the dynamic range is widened, but the power consumption increases
Solution Approach 1:
The imaging system segments the concurrent imaging function into two independent but coordinated imaging cells, each optimized for specific brightness conditions. This segmentation allows the system to activate only the necessary imaging cell based on scene brightness, reducing overall power consumption while maintaining concurrent imaging capability
Solution Approach 2:
The imaging device dynamically adjusts the operation of the two imaging cells based on scene conditions. The control circuit determines which imaging cell should be active based on brightness levels, allowing the system to switch between high-sensitivity and low-sensitivity modes dynamically, thereby optimizing power consumption while maintaining imaging performance
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 imaging of subjects with large brightness differences without blown-out highlights or blocked-up shadows, optimizing output data and reducing signal processing load, thereby enhancing imaging performance and power efficiency.
Implementation Method 1
a first photoelectric converter that generates a first signal by photoelectric conversion
Data Source
AI summary
An imaging device includes: a first imaging cell including a first photoelectric converter that generates a first signal by photoelectric conversion, and a first signal processing circuit that is electrically connected to the first photoelectric converter and detects the first signal; and a second imaging cell including a second photoelectric converter that generates a second signal by photoelectric conversion, and a second signal processing circuit that is electrically connected to the second photoelectric converter and detects the second signal. Sensitivity of the first imaging cell is higher than sensitivity of the second imaging cell. The first signal processing circuit has a circuit configuration different from the second signal processing circuit. An operation frequency of the first signal processing circuit is different from an operation frequency of the second signal processing circuit.