Image Sensor Crosstalk Noise Compensation via Adaptive Pixel Processing
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Solution Overview
Problem
Optical crosstalk between image sensing elements in digital cameras, caused by manufacturing design constraints and defects, degrades image quality by affecting adjacent sensing elements, especially in devices with both image sensing and phase detection elements.
Innovation Solution
An image sensor and processing method that compensates image data based on exposure, system gain, and sharpness information, using a sensing array with image sensing and phase detection elements, and a processing circuit to generate a processed raw image by determining whether to compensate image data of current pixels and applying compensation when specific conditions are met.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If image sensing elements are made smaller to enable miniaturization of digital cameras, then portability and convenience are improved, but optical crosstalk between adjacent sensing elements increases, degrading image quality
Solution Approach 1:
The patent introduces an intermediate processing step between light capture and final image formation. A crosstalk estimation model predicts the crosstalk noise pattern, and this estimation is used as an intermediary to guide the compensation process, effectively separating the crosstalk removal function from the standard image processing pipeline
Solution Approach 2:
The patent implements a feedback mechanism where the estimated crosstalk noise is fed back into the image processing system to adjust and refine the compensation process. The system continuously monitors image quality metrics and adjusts compensation parameters accordingly, creating a closed-loop control system that adaptively reduces crosstalk while preserving image details
2Measurement precision
If phase detection sensing elements are integrated into the image sensor array, then auto-focusing precision is improved, but optical crosstalk affecting image quality increases due to manufacturing design constraints
Solution Approach 1:
The patent segments the sensing array into distinct functional regions - image sensing elements and phase detection elements - and applies different processing strategies to each. By identifying and separating PD pixel locations, the system can selectively compensate only those image pixels affected by PD element crosstalk, rather than processing the entire array uniformly
Solution Approach 2:
The patent applies local quality by making the crosstalk compensation adaptive to local image characteristics. Different regions of the image receive different compensation intensities based on local sharpness metrics and estimated crosstalk levels, preserving edges and details in high-contrast regions while aggressively filtering crosstalk in smooth regions
3Ease of manufacture
If incident light is not effectively confined to the generated sensing element, then manufacturing design flexibility is improved, but optical crosstalk increases, adversely affecting adjacent sensing elements and degrading image quality
Solution Approach 1:
The patent converts the harmful effect of optical crosstalk into a beneficial signal by using the crosstalk pattern itself as information. The system estimates the crosstalk contribution based on adjacent pixel values and uses this estimation to reconstruct the true signal, effectively turning the manufacturing limitation into a characterizable and correctable phenomenon
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
Effectively reduces optical crosstalk noise, improving image quality by adapting to different ambient conditions and scene contexts through data compensation, particularly in smooth regions where crosstalk is more noticeable.
Implementation Method 1
An image sensor including an array of image sensing pixels is used primarily in the digital camera that receives and converts incident light into electrical signals
Data Source
AI summary
A method, an image sensor, and an image processing device for crosstalk noise reduction are proposed. The method is applicable to an image sensor having a sensing array of image sensing elements and PD sensing elements and includes the following steps. A raw image generated by the sensing array is obtained. Whether to compensate image data of a current image pixel among image pixels corresponding to the image sensing elements is determined based on a first condition associated with at least one of an exposure and a system gain of the image sensor, a second condition associated with pixel coordinates of PD pixels corresponding to the PD sensing elements, and a third condition associated with sharpness information of the raw image. The image data of the current image pixel is compensated in response to the three conditions being satisfied. A processed raw image including the compensated image data is generated.