Image Processing for Phase Difference Pixels with Mixed Exposure
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Solution Overview
Problem
When phase difference pixels and normal pixels have different exposure times, it leads to image blurring differences, causing image degradation, especially when photographing moving objects in low-light conditions.
Innovation Solution
An image processing apparatus and method that estimates image blur amounts, calculates exposure time differences, and adjusts mixing ratios based on detected light amounts to correct image data, ensuring consistent image quality between functional and non-functional pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the exposure time of phase difference pixels is extended to improve focus detection in low-light conditions, then the focus detection capability is improved, but image degradation occurs due to difference in image blurring amounts between phase difference pixels and normal pixels
Solution Approach 1:
The patent changes the exposure time parameter differently for phase difference pixels versus normal pixels. Specifically, phase difference pixels use a first exposure time (longer) optimized for focus detection, while normal pixels use a second exposure time (shorter) optimized for image quality, resolving the contradiction between focus detection capability and image quality
Solution Approach 2:
The patent segments the imaging process by separating the exposure control for phase difference pixels from that of normal pixels. This allows independent optimization of exposure parameters for each pixel type, enabling phase difference pixels to have extended exposure for better focus detection while normal pixels maintain standard exposure for image quality
2Illumination intensity
If different exposure times are applied to phase difference pixels and normal pixels, then focus detection performance in low-light conditions is improved, but image degradation occurs when photographing moving objects
Solution Approach 1:
The patent applies different exposure quality characteristics to different pixel types: phase difference pixels receive extended exposure optimized for low-light focus detection, while normal pixels receive standard exposure optimized for image consistency. This local differentiation resolves the contradiction between low-light performance and image consistency
Data Source
AI summary
An image processing apparatus performs image processing on image data obtained by using an imaging element comprising a plurality of pixels which comprise a first pixel and a second pixel, wherein two different types of exposure times are applied between the first pixel and the second pixel. A blur amount estimation unit estimates an image blur amount. An exposure time difference calculation unit calculates an exposure time difference. A mixing ratio calculation unit determines a first ratio using a light amount detected by the first pixel to be a target and a second ratio using a light amount detected by the second pixel positioned around the first pixel based on the exposure time difference and the image blur amount. A correction unit corrects the image data based on the image blur amount, the exposure time difference, the first ratio, and the second ratio.