Phase Difference Pixel Sensitivity Ratio Correction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In image capturing apparatuses with phase difference pixels, changes in incident angle and light amount due to lens replacement affect focusing precision, leading to sensitivity deviations and reduced focusing accuracy.
Innovation Solution
An image capturing apparatus and method that calculate a sensitivity ratio for phase difference pixels, correcting sensitivity deviations by integrating light receiving sensitivity within specific incident angle ranges, allowing for high-precision phase difference AF processing despite lens changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If lens replacement is performed to increase adaptability, then versatility is improved, but sensitivity deviation occurs due to changes in incident angle and light amount
Solution Approach 1:
The patent calculates sensitivity ratios based on incident angle ranges corresponding to different F numbers and image heights. When a lens is replaced, the system identifies the new lens's F number and image height, then calculates appropriate sensitivity ratios for those specific parameters to correct the phase difference pixel outputs, maintaining measurement precision across different lens configurations
Solution Approach 2:
The patent pre-calculates and stores sensitivity ratio data in a table for various combinations of F numbers and image heights. When lens replacement occurs, the system quickly retrieves the appropriate pre-calculated sensitivity ratios based on the new lens parameters, enabling rapid correction without real-time complex calculations
2Adaptability or versatility
If phase difference pixels are used to enable phase difference AF, then focusing capability is improved, but sensitivity deviation reduces focusing precision when incident angle changes
Solution Approach 1:
The patent implements a feedback mechanism where the calculated sensitivity ratios are applied to correct the output values of phase difference pixels. The control unit uses these corrected values to determine accurate focus positions, compensating for sensitivity deviations caused by varying incident angles and maintaining high focusing precision across different shooting conditions
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 high-precision focusing control by accurately correcting sensitivity deviations between phase difference pixels, maintaining focusing accuracy even during lens replacement.
Implementation Method 1
Some pixels of a plurality of pixels formed and arranged in a light receiving region in a two-dimensional array pattern are formed by a phase difference pixel (also referred to as a focus detecting pixel) in an image sensor installed in an image capturing apparatus
Data Source
Figure 1
Figure 2
Figure 3
AI summary
An image capturing apparatus includes: an image capturing element in which a plurality of pixels are formed and arranged and phase difference pixels are formed within an effective pixel region; a photographing lens; and a control unit which analyzes a captured image signal by the image capturing element, obtains a phase difference amount from detection signals of two of the phase difference pixels that make a pair, and performs a focusing control of the photographing lens, in which the control unit is configured to calculate, as the sensitivity ratio, an average value of a ratio of a value of the light receiving sensitivity (I) of the pixel other than the phase difference pixels (2) and a value of the light receiving sensitivity (L, R) of the phase difference pixel (2), detected at a predetermined angle within the range (X) of the incident angle acquired at a plurality of points and to correct a deviation in light receiving sensitivity between the two phase difference pixels.