Camera Anti-Flicker Signal Processing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional anti-flicker techniques for cameras are ineffective in high-brightness environments, as they require exposure times that are integer multiples of the flicker period, leading to visible flicker issues due to oscillating background illumination.
Innovation Solution
A camera system with a sensor and image signal processor that captures first and second image data with a time delay based on the flicker period, differentiates and normalizes the data to calculate oscillation amplitudes, and uses these to eliminate flicker, generating flicker-eliminated image data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the exposure time for each row is set to an integer multiple of the flicker period, then the flicker problem is solved for conventional lighting conditions, but the exposure time becomes too long for high-brightness background illumination
Solution Approach 1:
The patent applies dynamics by making the exposure time adaptive rather than fixed. The exposure time is dynamically adjusted based on the brightness level of the background illumination. For high-brightness environments, the exposure time is shortened to a fraction of the flicker period, while for conventional lighting, it maintains the integer multiple relationship. This dynamic adjustment resolves the contradiction between maintaining flicker elimination effectiveness and adapting to different illumination conditions.
Solution Approach 2:
The patent changes the exposure time parameter based on the brightness condition. Instead of using a fixed exposure time that is an integer multiple of the flicker period, the system modifies the exposure time parameter to be adaptively determined. For high-brightness background illumination, the exposure time is set to a shorter duration, and the anti-flicker processing is applied during image signal processing to maintain flicker elimination effectiveness.
2Duration of action of moving object
If the exposure time for each row is reduced to half the flicker period for high-brightness illumination, then the exposure time is shortened, but the integrated value of background illumination varies between rows causing visible flicker
Solution Approach 1:
The patent introduces an intermediary processing step between image capture and final output. The anti-flicker processing unit acts as an intermediary that receives the captured image data and applies correction algorithms to eliminate flicker artifacts. This intermediary processing allows the system to use shorter exposure times for high-brightness illumination while still achieving effective flicker elimination through post-processing.
Solution Approach 2:
The patent replaces the mechanical approach of adjusting exposure time to match flicker periods with an electronic signal processing approach. Instead of mechanically synchronizing the exposure timing with the illumination flicker frequency, the system uses electronic image signal processing to detect and correct flicker artifacts. This substitution allows flexible exposure time adjustment without being constrained by the need to match flicker periods.
Data Source
AI summary
A camera and an image capturing method with anti-flicker capability. The camera has a camera sensor and an image signal processor. The camera sensor captures first and second image data separated by a time delay which depends on a flicker period of background illumination. The image signal processor differentiates the first and the second image data along rows to obtain first and second differentiated image data, respectively, normalizes the first and second image data to obtain for each column an oscillation amplitude, normalizes the first and second differentiated image data to obtain for each column an oscillation amplitude, and obtains flicker-eliminated image data based on the first and second image data, the first and second differentiated image data, and the oscillation amplitudes obtained from normalizing the first and second image data and the oscillation amplitudes obtained from normalizing the first and second differentiated image data.