Image Sensor Phase Detection Pixel Line Correlation
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Solution Overview
Problem
Existing image pickup apparatuses using image sensor phase difference detection methods face challenges in achieving accurate focus detection in two-dimensional focus detection areas without excessively long calculation times, particularly for specific objects like transverse lines, and require complex calculations.
Innovation Solution
An image pickup apparatus with a two-dimensionally arranged pixel structure that produces paired image signals from each pixel line, shifts these signals to calculate correlation data, and aggregates this data across multiple pixel lines to determine defocus amounts efficiently, reducing calculation time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If paired image signals are produced from all pixels in a two-dimensional focus detection area, then focus detection accuracy is improved, but calculation time increases excessively
Solution Approach 1:
The focus detection area is divided into multiple pixel lines, and paired image signals are produced separately for each pixel line. This segmentation allows the calculation to be performed in a structured manner, improving efficiency while maintaining accuracy across the entire two-dimensional area.
Solution Approach 2:
The patent processes pixel data by treating each pixel line as a separate one-dimensional signal, then aggregates results across multiple lines to achieve two-dimensional focus detection. This dimensional approach simplifies the calculation by breaking down the complex 2D problem into manageable 1D components.
2Loss of time
If paired image signals are produced by compressing two-dimensional pixel outputs into one dimension, then calculation time is reduced, but focus detection performance deteriorates for specific objects
Solution Approach 1:
Instead of compressing all 2D pixel data into a single 1D signal, the patent segments the data by processing each pixel line separately while preserving the two-dimensional structure. This maintains detection performance for various object orientations while keeping calculation efficient.
Solution Approach 2:
The patent performs correlation calculations for each pixel line individually rather than attempting to process all pixels simultaneously. This partial processing approach ensures adequate detection performance without the excessive computational burden of full 2D processing.
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
Enables accurate focus detection in two-dimensional areas for various objects without prolonged calculation times by simplifying the focus detection process through correlation data aggregation.
Implementation Method 1
an image sensor configured to include plural pixels to photoelectrically convert paired object images respectively formed by light fluxes passing through mutually different areas in an exit pupil of an image capturing optical system
Data Source
AI summary
The image pickup apparatus includes an image sensor photoelectrically converting paired object images formed by light fluxes from mutually different pupil areas of an image capturing optical system, a signal producing part producing, by using output from each of plural pixel lines in a focus detection area in the image sensor, paired image signals corresponding to the paired object images for each pixel line, a calculating part calculating a defocus amount by using the paired image signals produced for each pixel line. The calculating part shifts the paired image signals relatively, produce first correlation data showing change of a correlation value of the paired image signals according to their relative shift amount, adds the first correlation data produced for the respective plural pixel lines to produce second correlation data, and calculates the defocus amount from the second correlation data.