Imaging Device Black Level Correction for Shading
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Solution Overview
Problem
Existing imaging devices face challenges in performing effective black level correction when outputting multiple types of data groups, such as focus detection data and captured image data, as the black level correction value for focus detection data may not follow shading, leading to poor image quality.
Innovation Solution
An imaging device with a pixel unit and signal processing unit that includes reference pixel regions driven in different modes to calculate correction values based on average values from these regions, allowing for suitable black level correction across various data groups.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If black level correction value is independently generated for each data group (focus detection data and captured image data), then the correction process can be simplified, but the black level correction value of focus detection data may not follow shading, leading to poor image quality
Solution Approach 1:
The reference pixel regions are divided into a first reference pixel region for focus detection data and a second reference pixel region for captured image data. Each region independently calculates correction values for its specific data type, allowing simplified processing while maintaining accuracy through targeted correction.
Solution Approach 2:
Different correction approaches are applied to different data groups based on their specific requirements. The first correction value is calculated specifically for focus detection data using the first reference pixel region, while the second correction value is calculated for captured image data using the second reference pixel region, ensuring each data type receives appropriate correction quality.
2Adaptability or versatility
If multiple types of data groups are output simultaneously (focus detection data and captured image data), then the imaging device functionality is enhanced, but the black level correction value may no longer follow shading, making it difficult to obtain good images
Solution Approach 1:
The pixel unit is segmented into different reference pixel regions that independently process different data groups. The first reference pixel region processes focus detection data while the second reference pixel region processes captured image data, allowing multi-functionality without compromising correction accuracy for each data type.
Solution Approach 2:
Different driving modes are applied to different reference pixel regions to optimize correction for each data type. The first reference pixel region uses a first driving mode suitable for focus detection data, while the second reference pixel region uses a second driving mode suitable for captured image data, maintaining high image quality across multiple output types.
3Ease of operation
If focus detection data is discretely read out while captured image data is output, then the data processing flexibility is improved, but the black level correction value of focus detection data may no longer follow shading
Solution Approach 1:
The reference pixel regions are segmented to independently handle different readout patterns. The first reference pixel region is dedicated to focus detection data with discrete readout, while the second reference pixel region handles captured image data, allowing flexible processing without compromising correction accuracy for either data type.
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
The solution enables suitable black level correction for both captured image data and focus detection data, improving image quality by accurately following shading and level differences, even when multiple data groups are output simultaneously.
Implementation Method 1
a pixel unit in which a plurality of unit pixels each including a plurality of photoelectric converters are arranged in a matrix
Data Source
AI summary
An imaging device includes a pixel unit where pixels including photoelectric converters are arranged, and a signal processing unit that processes signals from the pixel unit. The pixel unit includes a first region including pixels each driven in a first mode to read a signal based on charge generated by the photoelectric converters and a second region including the pixels each driven in a second mode to read more signals than in the first mode including a signal based on charges generated by a part of the photoelectric converters and a signal based on charges generated by the photoelectric converters. The signal processing unit calculates a first correction value based on an average of a first data group from the first region and a second correction value based on an average of a second data group from the second region by using the first correction value as an initial value.