Dual-Pixel Autofocus Defective Pixel Correction
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Solution Overview
Problem
Image capturing equipment faces challenges in autofocus speed due to defective pixels, which affect the performance of phase difference AF methods, and existing correction techniques are not efficient in handling these defects effectively.
Innovation Solution
An image capturing apparatus with a dual-pixel system that includes a first and second obtaining unit to generate pixel values using different methods, a detecting unit to identify defective pixels, and a correcting unit to correct pixel values based on detected defects, allowing for accurate autofocus and image correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the image capturing element contains defective pixels, then the autofocus performance is degraded, but correcting defective pixels requires additional processing time and complexity
Solution Approach 1:
The patent applies preliminary action by detecting defective pixels in advance using the first image obtained by the first obtaining unit before the autofocus operation. The detected defective pixel information is stored and used to guide the correction process in the second image, avoiding real-time detection delays during autofocus execution.
Solution Approach 2:
The patent segments the image processing into two distinct pathways: the first obtaining unit generates a first image for defective pixel detection, while the second obtaining unit generates a second image for autofocus. This segmentation allows defective pixel correction to be performed independently on the autofocus image using information from the detection image, resolving the contradiction between reliability and complexity.
2Manufacturing precision
If defective pixels are detected and corrected, then image quality is improved, but the processing time increases
Solution Approach 1:
The system performs preliminary defective pixel detection using the first obtaining unit and first image before the main autofocus operation. The detected defective pixel positions are stored in advance, allowing the correcting unit to quickly identify and correct only the specific defective pixels in the second image without performing full-image analysis during time-critical autofocus execution.
Solution Approach 2:
Instead of processing the entire image for defective pixel detection during autofocus, the system applies partial action by using the first obtaining unit to detect defective pixels only in specific regions or using simplified detection methods. The correcting unit then applies correction only to the identified defective pixel locations in the second image, rather than processing the entire image, thus reducing processing time while maintaining image quality.
Data Source
AI summary
To perform high-accurate correction while securing high-speed process, an image capturing apparatus comprises: an image capturing element having plural unit pixels; a first obtainer obtaining a pixel value of a first image generated by a first method, based on an output signal of the image capturing element; a second obtainer obtaining a pixel value of a second image for autofocus generated by a second method different from the first method, based on the output signal of the image capturing element; a first detector detecting a defective pixel based on the pixel value of the first image; a second detector detecting a defective pixel based on information of the defective pixel detected by the first detector and the pixel value of the second image; and a corrector correcting the second image, by correcting the pixel value of the second image corresponding to the defective pixel detected by the second detector.