Color Imaging Pixel Addition for Aliasing and Sensitivity Balance
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Solution Overview
Problem
Conventional solid-state imaging devices face challenges in outputting image signals without frame rate changes, leading to aliasing issues and decreased sensitivity due to pixel decimation methods, especially with ultra-megapixel devices, which result in low vertical resolution and false signals.
Innovation Solution
A solid-state color imaging apparatus that uses a pixel adding technique with color filters arranged in specific patterns to achieve spatial resampling in both horizontal and vertical directions, allowing for the selection of an optimum number of output pixels and maintaining high sensitivity by utilizing all pixels effectively, thereby reducing aliasing and balancing image sampling densities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pixel decimation method is used to increase frame rate, then output speed is improved, but vertical resolution decreases and aliasing occurs
Solution Approach 1:
The patent merges adjacent pixels in the vertical direction by adding their signal values together. Specifically, pixels are grouped in sets (e.g., 2×2 or larger blocks) and their signals are summed to produce fewer output pixels. This merging approach reduces the total pixel count in the output stream, enabling higher frame rates while maintaining adequate vertical resolution through the combined signal information.
Solution Approach 2:
The patent creates a composite pixel structure by combining signals from multiple physical pixels. By adding signals from adjacent pixels (particularly in vertical groups), the system creates composite pixel values that retain more information than simple decimation. This composite approach suppresses aliasing while achieving the required pixel reduction for high frame rate operation.
2Productivity
If pixel decimation method is used to increase frame rate, then output speed is improved, but false signals increase due to aliasing
Solution Approach 1:
By merging adjacent pixels through signal addition before output, the patent effectively performs a form of spatial averaging. This combining process suppresses high-frequency aliasing components that would otherwise appear as false signals, while still achieving the pixel reduction necessary for high frame rate operation.
Solution Approach 2:
The patent converts the potentially harmful effect of having too many pixels (which causes aliasing when heavily decimated) into a benefit by deliberately adding pixel signals together. The excess pixel information, which could cause aliasing if simply discarded, is instead combined to suppress aliasing noise while maintaining frame rate performance.
3Productivity
If pixel decimation method is used to increase frame rate, then output speed is improved, but sensitivity decreases
Solution Approach 1:
The patent merges signals from multiple pixels through addition, which increases the total signal level and improves sensitivity. By combining signals from adjacent pixels (e.g., in 2×2 or larger blocks), the system achieves both pixel reduction for high frame rate and signal enhancement for improved sensitivity, unlike conventional decimation that simply discards pixels.
4Productivity
If pixels are added together to reduce output number, then frame rate increases, but pixel arrangement becomes irregular causing image defects
Solution Approach 1:
The patent segments the pixel array into regular blocks (e.g., 2×2 or larger systematic groups) and applies the addition operation within each block. This segmentation approach maintains a regular, systematic pattern in the output pixel arrangement, preventing the irregularity and image defects that would result from arbitrary pixel selection or addition patterns.
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
The solution enables high-speed image capture with low power consumption and high image quality by suppressing high-frequency aliasing noise and ensuring 100% pixel utilization, resulting in balanced horizontal and vertical resolutions.
Implementation Method 1
Solid-state imaging devices for converting incident light into an electric signal and outputting the signal as an image signal
Data Source
AI summary
A pixel area of a megapixel solid-state color imaging device is divided into unit areas for pixel adding and all the pixels for the same color are added together in each unit area. Accordingly, the percentage of utilized pixels is raised to 100% and aliasing noise to low frequencies in a high-frequency video signal is greatly suppressed by a spatial LPF (low pass filter) effect of the pixel addition in the area units.