Defective Pixel Detection in Divided Image Sensors
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Solution Overview
Problem
Conventional image capturing apparatuses with solid-state image sensors having divided pixels face challenges in accurately detecting defective pixels, leading to potential erroneous corrections and unnecessary alteration of actual image signals.
Innovation Solution
An image capturing apparatus with an image sensor featuring microlenses shared by multiple photoelectric conversion units, employing a method where each photoelectric conversion unit is sequentially evaluated by comparing its output with signals from neighboring units, ensuring accurate detection of defective pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional defective pixel detection method comparing pixel output with neighboring pixels is used, then the detection process is simple, but the detection accuracy deteriorates when using divided pixels due to focus detection functionality
Solution Approach 1:
The invention segments the detection process into two distinct phases: a first detection using a conventional method comparing each divided pixel's output with neighboring pixels, and a second detection using a specialized method that accounts for focus detection functionality. This segmentation allows the system to handle the complexity of divided pixels while maintaining overall detection accuracy.
Solution Approach 2:
The invention performs preliminary focus detection before the final defective pixel detection. By first determining the focus state of each divided pixel and then using this information to guide the detection process, the system prepares the detection environment in advance, enabling accurate differentiation between focus-related variations and actual pixel defects.
2Productivity
If a simple comparison method is used to detect defective pixels, then the processing is fast, but normal pixels may be erroneously identified as defective in divided pixel structures
Solution Approach 1:
The invention performs preliminary focus detection before the final defective pixel detection. By first determining the focus state of each divided pixel and then using this information to guide the detection process, the system prepares the detection environment in advance, enabling accurate differentiation between focus-related variations and actual pixel defects.
Solution Approach 2:
The invention uses feedback from the first detection results and focus detection information to adjust and refine the second detection process. The system continuously compares detected values with reference values and adjusts detection thresholds based on focus state, improving reliability while maintaining processing efficiency.
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
This approach enhances the accuracy of defective pixel detection, minimizing errors in image signal corrections and maintaining the integrity of incident light-based image data.
Implementation Method 1
an image sensor including a plurality of pixels each having a microlens and a plurality of photoelectric conversion units that share the microlens
Data Source
AI summary
An image capturing apparatus comprises: an image sensor including a plurality of pixels each having a microlens and a plurality of photoelectric conversion means, and defective pixel detection means for detecting defective photoelectric conversion means from among the plurality of photoelectric conversion means, wherein the defective pixel detection means determines defective photoelectric conversion means by comparing an output signal output from photoelectric conversion means of a subject, sequentially taken from the plurality of photoelectric conversion means, for detection with first signals from photoelectric conversion means included in pixels neighboring the pixel including the photoelectric conversion means of the subject for detection, each position of the photoelectric conversion means included in the neighboring pixels corresponding to a position of the photoelectric conversion means of the subject for detection with respect to the microlens.