Image Sensor Readout via Segmented Color and Panchromatic Pixels
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Solution Overview
Problem
Current image capture systems face challenges in achieving faster pixel response times without increasing power consumption or sensor size, leading to motion-related aberrations and reduced light sensitivity, especially in rolling shutter arrangements and varying light conditions.
Innovation Solution
The system employs a combination of color and panchromatic pixels with staggered timing and shared charge storage elements, allowing for concurrent exposure and read operations, which reduces image shear effects and enhances light sensitivity by optimizing the exposure times of both pixel types.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the readout rate is increased to reduce image shear distortion, then the distortion is reduced, but power consumption and device size increase
Solution Approach 1:
The pixel array is divided into multiple independent components (e.g., first component with color pixels, second component with panchromatic pixels). Each component has its own readout circuitry and can be read out independently and concurrently. This segmentation allows the total readout task to be distributed across multiple channels, effectively increasing the readout rate without requiring a single high-power readout channel, thus reducing overall power consumption.
Solution Approach 2:
Multiple components with different pixel types (color and panchromatic) are combined in a single sensor array, each with dedicated readout circuitry. The readout operations of multiple components are merged into concurrent operations, achieving high-speed readout through parallel processing rather than sequential processing, which reduces total power consumption compared to a single high-speed channel.
2Speed
If the readout rate is increased to reduce image shear distortion, then the distortion is reduced, but the device size increases
Solution Approach 1:
The sensor is segmented into multiple components, each with its own readout circuitry. This allows the readout function to be distributed across multiple smaller units rather than requiring one large centralized readout system. The compact arrangement of multiple small readout circuits achieves high readout rate while maintaining compact device size.
Solution Approach 2:
The patent transitions from a single-dimensional sequential readout approach to a multi-dimensional concurrent readout approach by organizing pixels into multiple components that can be read out in parallel. This dimensional change in the readout architecture enables high-speed readout without proportionally increasing device area.
3Use of energy by moving object
If the exposure time is extended to improve light sensitivity, then light sensitivity improves, but motion-related artifacts increase
Solution Approach 1:
The sensor array is segmented into multiple components that can operate with different exposure times. Color pixels and panchromatic pixels can have different integration periods, allowing optimization for their respective functions. This segmentation enables the system to achieve good light sensitivity through extended exposure where needed while maintaining reliability by having components with shorter exposure times that capture motion information.
Solution Approach 2:
The patent implements dynamic control of exposure times for different pixel types and components. The integration period can be adjusted independently for color and panchromatic pixels, allowing the system to adapt exposure duration based on lighting conditions and motion content. This dynamic adjustment enables optimization of both light sensitivity and motion artifact reduction.
4Device complexity
If the readout is performed sequentially row-by-row to simplify design, then device complexity is reduced, but the readout time increases causing image shear
Solution Approach 1:
The sensor is divided into multiple components, each capable of independent readout. This segmentation transforms a single long sequential readout operation into multiple shorter concurrent readout operations. Each component maintains a relatively simple design similar to traditional rolling shutter, but the concurrent operation of multiple components achieves fast total readout time, eliminating image shear without requiring complex global readout circuitry.
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 faster data access times, reduces motion-related artifacts, and improves light sensitivity, allowing for more accurate motion detection and compensation, while maintaining a balance in photographic speed between color and panchromatic pixels.
Implementation Method 1
The reset step can be accomplished by transferring residual charge from a photodiode to associated floating diffusion circuitry
Data Source
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AI summary
A method for obtaining image data from an image sensor array including the steps of: providing an image sensor array having a first component subset of panchromatic pixels for integrating charge and a second component subset of color pixels for integrating charge; reading pixel charge to produce pixel signals from the first component subset of the panchromatic pixels while exposing the second component subset of color pixels and digitizing and storing the first component subset signals; and reading pixel charge to produce pixel signals from the second component subset of color pixels that were exposed for at least a portion of time during the reading of pixel signals from the first component subset of the panchromatic pixels and digitizing and storing the second component subset signals.