Multi-exposure Imaging System Eliminates Rolling Shutter Flicker
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Solution Overview
Problem
Multi-exposure imaging systems face exacerbated rolling shutter flicker issues due to the shorter exposure duration of short exposure images, especially under unstable ambient light conditions with flickering AC lighting, which worsens the flicker problem.
Innovation Solution
A method and apparatus that capture both long and short exposure images, calculate an exposure ratio, and use a flicker gain detector to accumulate pixel values and generate a flicker gain, which is then used to compensate the short exposure image, effectively eliminating rolling shutter flicker by multiplying its pixel values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a short exposure image is captured to increase dynamic range, then the dynamic range is improved, but the rolling shutter flicker is exacerbated
Solution Approach 1:
The patent introduces a flicker gain detector as an intermediary component that processes the short exposure image to calculate and apply a flicker gain factor. This mediator detects the flicker effect and compensates for it by adjusting the pixel values, thereby allowing the short exposure image to maintain its dynamic range advantage while eliminating the flicker artifact.
Solution Approach 2:
The patent changes the parameter of pixel values in the short exposure image by applying a calculated flicker gain factor. By modifying the intensity parameter of each pixel based on the detected flicker pattern, the system maintains the dynamic range benefits of short exposure while compensating for the flicker effect through parameter adjustment.
2Duration of action of moving object
If the exposure duration is reduced to capture short exposure images, then the dynamic range is enhanced, but the flicker problem worsens
Solution Approach 1:
The patent performs preliminary action by capturing both long exposure and short exposure images before final processing. The flicker gain detector analyzes the short exposure image to detect flicker patterns, and the flicker gain factor is calculated in advance so that it can be applied to compensate for the flicker effect, allowing the short exposure duration to be maintained while preventing flicker degradation.
Solution Approach 2:
The patent implements feedback by using the short exposure image to detect flicker patterns and calculate a flicker gain factor, which is then fed back to adjust the pixel values of the short exposure image. This feedback loop allows the system to adapt to the specific flicker conditions and maintain image quality despite the reduced exposure duration.
Data Source
AI summary
A method for eliminating flicker of a multi-exposure imaging system is provided. The method includes the steps of: capturing a long exposure image based on a long exposure from a scene; capturing a short exposure image based on a short exposure from the scene; obtaining an exposure ratio of the long exposure to the short exposure; generating a long accumulated value by accumulating pixel values of a portion of the long exposure image; generating a short accumulated value by accumulating pixel values of a portion of the short exposure image corresponding to the portion of the long exposure image; and generating a flicker gain according to the long average value, the short average value and the exposure ratio.