Imaging Device Phase Difference Pixel Signal Combination
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing imaging devices face challenges in achieving accurate and efficient automatic focus adjustment, particularly in low brightness conditions, where pixel combination methods degrade accuracy and noise reduction is limited, and contrast AF schemes prolong processing time.
Innovation Solution
The implementation of an imaging device with phase difference pixels arranged in a two-dimensional manner, where signal charges from adjacent pixels are combined and averaged to detect phase differences, allowing for accurate focus adjustment regardless of brightness levels, while maintaining cost-effectiveness and space efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If pixel combination is performed in low brightness conditions, then noise reduction is achieved, but AF processing accuracy degrades
Solution Approach 1:
The imaging element is divided into multiple pixel regions, with specific pixels (e.g., first and second pixels) designated for phase difference detection while others are used for noise reduction through combination. This segmentation allows simultaneous achievement of noise reduction and accuracy maintenance by processing different pixel groups differently.
Solution Approach 2:
Different processing methods are applied to different pixel regions: phase difference detection is performed on specific pixel pairs to maintain accuracy, while adjacent pixels are combined for noise reduction in low brightness conditions. This local quality approach ensures each region receives the appropriate processing for its function.
2Measurement precision
If contrast AF scheme is used, then focus adjustment is achieved, but processing time increases
Solution Approach 1:
Phase difference detection is performed preliminarily using dedicated pixels to determine focus state, eliminating the need for time-consuming contrast adjustment procedures. The system calculates phase differences directly from pixel signals, providing faster focus determination while maintaining accuracy.
Solution Approach 2:
The mechanical/iterative contrast adjustment process is replaced with direct phase difference calculation using pixel signal processing. This substitution of the detection mechanism from contrast-based iterative adjustment to phase-based direct measurement significantly reduces processing time.
3Object-affected harmful factors
If more pixels are combined for noise reduction, then signal-to-noise ratio improves, but processing complexity increases
Solution Approach 1:
Instead of combining all pixels for noise reduction, only specific adjacent pixels are combined in a partial manner. This selective combination achieves sufficient noise reduction for the phase difference detection function without the excessive processing complexity that would result from combining all pixels.
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 noise and improves signal-to-noise ratio, enabling faster and more accurate automatic focus adjustment without requiring new hardware, even in low brightness conditions, while maintaining stability and accuracy.
Implementation Method 1
an automatic focus adjustment unit configured to detect a phase difference between a voltage signal of the first pixel and a voltage signal of the second pixel subjected to arithmetic mean
Data Source
AI summary
An imaging device of an aspect of the invention, when reading, as voltage signals, signal charges output from a first pixel receiving a light on a partial area biased to a predetermined direction from a light axis of a light flux passing an exit pupil of an imaging optical system and a second pixel arranged so as to be adjacent to the first pixel and receiving a light on a partial area biased to an opposite direction to the predetermined direction from the light axis, combines and reads the signal charges of adjacent first-number pixels with respect to the first pixel and the second pixel, and calculates an arithmetic mean of adjacent second-number voltage signals with respect to the combined and read voltage signals of the first pixel and the second pixel.