Image Processing Unit Phase Difference Focus Selection
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Solution Overview
Problem
In image pickup apparatuses with continuous shooting functionality, selecting well-focused images from a series of photos is challenging, especially when the subject is moving or at high magnification, as the depth of field is small, leading to difficulties in comparing and selecting well-focused images.
Innovation Solution
An image processing unit and method that utilize phase difference detection to calculate the difference in focus state across a series of images, allowing for the selection of the image with the highest focusing degree and controlling focus during continuous shooting to ensure proper image selection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If evaluation area is set for contrast-based focusing analysis, then well-focused images can be selected, but proper selection fails when subject is moving significantly or at high magnification
Solution Approach 1:
The invention changes the measurement parameter from contrast-based focusing analysis to phase difference detection. By detecting the phase difference between images captured by multiple photoelectric conversion units, the system can accurately measure focusing degree even when the subject is moving or at high magnification, resolving the contradiction between measurement precision and selection reliability
Solution Approach 2:
The invention replaces the mechanical/visual comparison method (contrast-based analysis requiring image alignment) with an optical/physical detection method (phase difference detection). This substitution eliminates the problem of image comparison failure when subjects move, as phase difference can be detected directly from the captured images without requiring manual or automated alignment
2Productivity
If continuous shooting is performed at high magnification, then more images are captured, but depth of field becomes small making focus selection difficult
Solution Approach 1:
The invention changes the detection parameter from contrast (which is insensitive to small focus changes at high magnification) to phase difference (which provides sensitive and quantitative measurement of focus state). This allows accurate focus detection even when depth of field is extremely small during continuous shooting at high magnification
Solution Approach 2:
The system provides feedback on the focusing degree for each captured image by calculating phase difference, allowing the user to identify which images are properly focused among multiple continuous shots. This feedback mechanism solves the difficulty of determining focus state when depth of field is minimal
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 the proper selection of well-focused images by locking focus during continuous shooting and determining the appropriate shooting mode based on magnification and camera stability, improving the chances of capturing images with the target in focus, especially in macro photography scenarios.
Implementation Method 1
a difference calculating section which calculates a difference from the in-focus state by focus detection through phase difference detection
Data Source
AI summary
An image processing unit which includes: an input section which inputs a plurality of images each of which is associated with a difference from an in-focus state detected in accordance with differences among images of a subject which is divided during production of each of the plurality of images, the images being produced in continuous shooting in which a series of images are produced continuously in time series; and a selecting section which selects an image with the highest focusing degree in accordance with the difference from the in-focus state from among the plurality of images.