Image Frame Flicker Correction Using Rolling-Shutter Luminance Analysis
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Flicker or banding occurs in image frames captured using rolling shutters due to varying light levels caused by the periodicity of alternating current lighting sources, leading to uneven luminance across different sensor elements, which affects image quality.
Innovation Solution
A device with an image sensor and processing circuitry determines a flicker correction parameter based on the luminance of a set of captured frames, applying it to generate additional frames with reduced flicker before display, using a buffer to store luminance information and a single read command to optimize efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If rolling shutter is used to capture image frames, then the image sensor can capture different portions of the sensor at different times, but flicker or banding occurs due to varying light levels across different rows or columns
Solution Approach 1:
The system captures a first set of image frames before the main image capture sequence to determine flicker correction parameters. These parameters are calculated based on luminance variations across the first set of frames, allowing the rolling shutter to compensate for lighting periodicity before actual image capture begins, thereby reducing flicker while maintaining capture capability
Solution Approach 2:
The system modifies exposure parameters dynamically based on determined flicker correction parameters. By adjusting exposure timing or duration according to the calculated parameters, the system compensates for luminance variations caused by alternating current lighting, achieving uniform luminance across different rows or columns while preserving rolling shutter functionality
2Manufacturing precision
If flicker correction is applied after image capture, then correction can be performed, but processing time and power consumption increase
Solution Approach 1:
The system performs flicker correction parameter determination before the main image capture sequence by analyzing a first set of image frames. This preliminary action allows the correction parameters to be ready in advance, eliminating the need for time-consuming post-processing and reducing overall processing time while maintaining correction accuracy
Solution Approach 2:
The system continuously captures image frames and processes them to determine flicker correction parameters in real-time during the capture sequence. This continuous processing approach ensures that correction parameters are always current and accurate, eliminating the need for separate post-processing steps and optimizing both timing and power consumption
3Measurement precision
If multiple read commands are used to retrieve luminance information from buffer, then complete data can be retrieved, but processing efficiency decreases
Solution Approach 1:
The system combines multiple read commands into a single read operation to retrieve luminance information for multiple image frames simultaneously from the buffer. This merging approach maintains complete luminance data retrieval while significantly improving processing efficiency by reducing the number of memory access operations and associated overhead
Data Source
AI summary
A device for image processing includes an image sensor configured to capture a first set of image frames; a buffer configured to store information indicative of luminance of each image frame of the first set of image frames; and processing circuitry configured to: retrieve, from the buffer, the information indicative of luminance of each image frame of the first set of image frames; determine a flicker correction parameter based on the luminance across each of the first set of image frames; and generate additional image frames that are for display based on the flicker correction parameter.