Image Sensor ADC Bit Precision Segmentation
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Solution Overview
Problem
Conventional image sensors face inefficiencies in analog-to-digital conversion due to the need for uniform bit precision across all color filters, which can lead to increased processing time and reduced frame rates, especially when handling diverse color channels.
Innovation Solution
The image sensor employs a color filter array with different bit precision settings for various color filters, using shared floating diffusion nodes to combine signals from pixels of the same color and separate ADCs for each color filter set, allowing for efficient conversion and reduced data output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If uniform bit precision is used for all color filters in analog-to-digital conversion, then measurement precision is maintained across all color channels, but conversion time increases and frame rate decreases
Solution Approach 1:
The patent applies different bit precision levels to different color filter groups: first color filters (e.g., green) use higher bit precision (e.g., 10-bit) while second and third color filters (e.g., red and blue) use lower bit precision (e.g., 8-bit). This local differentiation optimizes the balance between measurement precision and conversion speed, as green pixels typically require higher precision while red and blue can tolerate lower precision with acceptable image quality.
Solution Approach 2:
The patent segments the color filter array into distinct groups (first color filters, second color filters, third color filters) with different ADC conversion settings. By dividing the pixel array into regions corresponding to different color filter types and applying different conversion parameters to each segment, the system achieves optimized performance for each color channel independently.
2Measurement precision
If higher bit precision is used for all color filters, then measurement precision is improved, but processing time increases
Solution Approach 1:
The patent implements local quality by assigning different bit precision levels to different color filter groups based on their specific requirements. First color filters use higher bit precision for applications requiring greater measurement accuracy, while second and third color filters use lower bit precision to reduce conversion time, thereby optimizing the trade-off between precision and speed for each color channel.
Solution Approach 2:
The patent changes the conversion parameter (bit precision) based on the color filter type and application requirements. By dynamically adjusting the number of conversion bits for different color channels, the system adapts the conversion process to achieve optimal performance, using higher precision where needed and lower precision where acceptable, thus reducing overall conversion time while maintaining necessary accuracy.
3Productivity
If separate ADCs are used for each color filter, then conversion efficiency is improved, but device complexity increases
Solution Approach 1:
The patent segments the ADC resources to match the segmented color filter array. Different groups of color filters are assigned to different ADCs with optimized conversion parameters. This segmentation allows each ADC to be tuned for its specific color channel requirements, improving conversion efficiency while maintaining manageable system complexity through structured organization.
Solution Approach 2:
The patent implements a multi-functional ADC architecture where ADCs can serve multiple color filter groups with different conversion parameters. The system achieves universality by allowing ADCs to handle different bit precision requirements for different color channels, thereby improving overall conversion efficiency without requiring a separate dedicated ADC for every single color filter, thus balancing complexity and 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 reduces the time required for analog-to-digital conversions, enhances frame rates, and improves the overall efficiency of image processing by optimizing the conversion process based on the specific bit precision needs of each color channel.
Implementation Method 1
each of which corresponds to a color filter of the color filter array and is configured to receive light passing through the corresponding color filter to generate an electrical signal
Data Source
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AI summary
An image sensor (10), an imaging apparatus (100), an electronic device (1000), an image processing system (10000), and a signal processing method. The image sensor comprises a filter array (11), a pixel array (12), and a plurality of analog-to-digital conversion circuits (14). The analog-to-digital conversion circuits (14) respectively convert a signal corresponding to a first color filter (A) into a digital pixel signal by a first bit precision and second bit precision less than the first bit precision, and convert signals corresponding to a second color filter (B) and a third color filter (C) into digital pixel signals.