Imaging System Data Rate Deceleration Circuitry for Rolling Shutter Artifact Reduction
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Solution Overview
Problem
Conventional image sensors using rolling shutter schemes suffer from artifacts due to time offsets in integration periods, while global shutter schemes increase complexity, reduce sensitivity, and increase noise and dark current.
Innovation Solution
Implementing image data rate deceleration circuitry to capture and process image data at a high rate, reducing rolling shutter artifacts by interfacing with storage and processing circuitry at a lower system data rate, and managing power consumption through high and low power modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a rolling shutter scheme is used to capture image data, then device complexity is reduced, but rolling shutter artifacts are generated due to time offsets in integration periods
Solution Approach 1:
The patent implements dynamic row selection based on motion detection. The system transitions from static rolling shutter operation to dynamic operation where rows are selectively activated based on detected motion characteristics. This allows the system to adapt the shutter timing dynamically to reduce artifacts while maintaining the simplicity of rolling shutter architecture.
Solution Approach 2:
The patent employs feedback mechanisms where motion information detected during image capture is used to adjust the row selection timing. The system continuously monitors motion characteristics and feeds this information back to modify the rolling shutter sequence, thereby reducing artifacts without requiring complete system redesign.
2Object-affected harmful factors
If a global shutter scheme is used to integrate charge using all pixels at the same time, then rolling shutter artifacts are eliminated, but device process complexity increases
Solution Approach 1:
The patent segments the pixel array into multiple rows that can be independently controlled. Instead of implementing a full global shutter requiring simultaneous control of all pixels, the system divides the array and applies selective timing to segments, achieving artifact reduction with lower complexity.
Solution Approach 2:
The patent applies different timing characteristics to different rows based on their position and motion characteristics. Rather than uniform global shutter operation, each row or group of rows receives customized timing parameters, achieving localized optimization that reduces complexity while minimizing artifacts.
3Object-affected harmful factors
If a global shutter scheme is used, then rolling shutter artifacts are eliminated, but sensitivity is reduced
Solution Approach 1:
The patent uses dynamic row activation to maintain high sensitivity by ensuring that rows are actively captured during optimal lighting conditions. The dynamic timing adjusts to maximize light collection efficiency while reducing artifacts, preventing the sensitivity loss associated with global shutter fixed timing.
Solution Approach 2:
The patent changes timing parameters dynamically based on scene characteristics and motion detection. By adjusting integration timing parameters in response to detected motion and lighting conditions, the system maintains high sensitivity while reducing artifacts, avoiding the fixed-parameter limitations of global shutter designs.
4Object-affected harmful factors
If a global shutter scheme is used, then rolling shutter artifacts are eliminated, but read noise and dark current increase
Solution Approach 1:
The patent segments the readout process into sequential row-based operations, allowing each segment to be read out independently. This segmentation enables better control over read timing and reduces cumulative read noise and dark current effects that occur in simultaneous global readout, while still achieving artifact reduction through coordinated row selection.
Data Source
AI summary
An imaging system may include a rolling shutter image sensor, data rate reduction circuitry, and image processing circuitry. The image sensor may output image data to the data rate reduction circuitry at a first high speed data rate. The data rate reduction circuitry may store the image data at the first data rate and may output the stored image data at a second reduced speed data rate. The image processing circuitry may receive the image data at the second data rate and may perform image processing operations at the second data rate. The data rate reduction circuitry may generate accumulated image frames by accumulating image frames received from the image sensor at the first data rate and may provide the accumulated frames to the image processing circuitry at the second data rate. The image processing circuitry may perform image processing operations on the accumulated frames at the second data rate.