Phase Difference Detection Pixel Arrangement for Accurate Defocus Measurement
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Solution Overview
Problem
Existing imaging devices face challenges in enhancing the quality of captured images and accuracy of phase difference detection for focusing control, as methods that connect detection signals from phase difference detection pixels in different rows can introduce errors and are not effective when image matching is low.
Innovation Solution
An imaging device with a specific arrangement of signal detection units, including first and second signal detection units with different positions and pitches, and a frequency determination unit that selects between two defocus amount generation processes based on the presence of high-frequency components in the subject image, allowing for accurate focusing control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of phase difference detection pixels increases, then the accuracy of phase difference detection is improved, but the quality of captured image deteriorates
Solution Approach 1:
The imaging surface is segmented into multiple blocks, with phase difference detection pixels arranged in specific patterns within each block. This segmentation allows the system to achieve accurate phase difference detection while maintaining good image quality by distributing the detection pixels across multiple blocks rather than concentrating them in one area.
Solution Approach 2:
Different regions of the imaging surface have different pixel arrangements optimized for their specific functions. Phase difference detection pixels are strategically placed in certain blocks with specific patterns, while other areas maintain normal imaging pixel distributions, achieving local optimization for both detection accuracy and image quality.
2Manufacturing precision
If the number of phase difference detection pixels arranged in phase difference detection direction decreases, then the quality of captured image is improved, but the accuracy of phase difference detection deteriorates
Solution Approach 1:
The patent transitions from one-dimensional arrangement considerations to two-dimensional block-based arrangements. By organizing phase difference detection pixels in specific two-dimensional patterns within blocks rather than simply increasing their linear arrangement, the system achieves accurate detection with fewer pixels in the detection direction, thereby improving image quality.
3Measurement precision
If connection of detection signals from phase difference detection pixels in different rows is performed, then the accuracy of phase difference detection is improved, but errors are introduced when image matching is low
Solution Approach 1:
The system dynamically selects between different defocus amount generation processes based on image matching conditions. When image matching is high, connection of detection signals from different rows is performed to improve accuracy. When image matching is low, the system switches to an alternative process that does not perform connection, thereby maintaining reliability under varying conditions.
Data Source
AI summary
A phase difference AF processing unit (19) connects detection signals of phase difference detection pixels (52A) in an AF area (53), connects detection signals of phase difference detection pixels (52B) in the AF area (53), and performs a correlation operation with respect to detection signal groups after connection to generate a defocus amount when it is determined that a subject image formed in the AF area (53) includes a high frequency component. The phase difference AF processing unit (19) performs a correlation operation with respect to detection signal groups of phase difference detection pixels (52A, 52B) in each pair line in the AF area (53) to generate the defocus amount when it is determined that the subject image formed in the AF area (53) does not include a high frequency component.