Flexible Pixel Summing for High Dynamic Range Imaging
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Image sensors face challenges in capturing high dynamic range images due to limited dynamic range, resulting in loss of details in bright and dark areas, and existing algorithms that vary integration times introduce motion artifacts.
Innovation Solution
An image sensor with pixels grouped into subsets, where charge is summed from multiple pixels using transfer transistors connected to a common node, allowing for flexible pixel summing and asymmetrical high dynamic range imaging with a single integration time across all pixels, combining un-summed and summed charges to produce a high dynamic range image.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If integration times of pixels are varied to improve dynamic range, then detail capture in bright and dark areas is improved, but motion artifacts and blurring occur in the final image
Solution Approach 1:
The pixel array is divided into multiple independently controllable groups, where each group can have its integration time independently adjusted. This segmentation allows different regions to capture light for different durations, enabling detailed capture in both bright and dark areas without introducing motion artifacts across the entire image, as each group's data can be processed separately to maintain temporal consistency.
Solution Approach 2:
Different integration times are applied to different spatial regions (groups of pixels) based on local lighting conditions. Brighter regions use shorter integration times to avoid saturation, while darker regions use longer integration times to capture sufficient light. This local quality approach maintains image reliability by ensuring each region is optimized for its specific conditions without introducing global motion artifacts.
2Measurement precision
If multiple images are combined to produce high dynamic range image, then dynamic range is improved, but motion artifacts and blurring are introduced
Solution Approach 1:
The image sensor divides the pixel array into multiple groups that can be independently controlled. Each group captures image data with the same integration time, ensuring temporal consistency within each group. The final high dynamic range image is constructed by combining data from these groups, which eliminates motion artifacts while maintaining improved dynamic range through the segmented capture approach.
Solution Approach 2:
Multiple image datasets from different pixel groups are merged to produce the final high dynamic range image. Since all groups use the same integration time, the merging process combines spatial information without introducing temporal inconsistencies or motion artifacts, thus improving dynamic range while maintaining image stability.
3Adaptability or versatility
If pixels are grouped into subsets with common nodes for charge summing, then flexible pixel summing is enabled, but device complexity increases
Solution Approach 1:
Multiple pixels within each group share common readout circuitry and control signals, merging functions to reduce overall complexity. The pixel groups are organized with shared resources, allowing flexible summing operations while avoiding the complexity of completely independent pixel structures. This merging approach enables adaptability through group-level control while maintaining manageable device complexity.
Solution Approach 2:
The pixel group structure implements multi-functionality where the same hardware infrastructure supports both individual pixel readout and flexible summing operations. The common nodes and control mechanisms serve multiple purposes, enabling the system to adapt to different imaging requirements without requiring separate dedicated circuitry for each function, thus balancing versatility with complexity management.
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 image detail capture across varying light conditions without motion artifacts, as all pixels have the same integration time, improving the dynamic range and reducing unwanted blurring.
Implementation Method 1
Each pixel can include a photodetector and a transfer transistor
Data Source
AI summary
An image sensor can include pixels that are grouped into subsets of pixels, with each subset including three or more pixels. A method for asymmetrical high dynamic range imaging can include capturing an image of a subject scene using a single integration time for all of the pixels. In a subset of pixels, charge in N pixels is read out and summed together. N represents a number that is between two and one less than a total number of pixels in the subset. Un-summed charge is read out from one pixel in the subset. The un-summed charge and the summed charge are combined when producing a high dynamic range image.