Automatic Flicker Correction in Image Capture Devices
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Image capture devices face flicker issues due to fluctuations in indoor lighting frequencies, leading to banding in captured images, as they do not instantaneously capture all image information and are affected by varying AC power frequencies worldwide.
Innovation Solution
Implementing automatic flicker detection and correction techniques that compare image frames to detect flicker, using a flicker correction unit to adjust the integration time of the image sensor array to an integer multiple of the illumination source frequency, thereby eliminating flicker by setting the integration time to match the detected frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the integration time is set to an integer multiple of the period of the illumination source to eliminate flicker, then flicker is reduced, but the device cannot adapt to different AC power frequencies (50 Hz or 60 Hz) and may experience flicker when the actual frequency differs from the anticipated frequency
Solution Approach 1:
The integration time is made dynamically adjustable rather than fixed. The system automatically detects the AC power frequency and adjusts the integration time to be an integer multiple of the detected frequency period, enabling adaptation to both 50 Hz and 60 Hz environments while maintaining flicker elimination
Solution Approach 2:
The system changes the integration time parameter based on the detected illumination source frequency. By detecting whether the environment uses 50 Hz or 60 AC power and setting the integration time accordingly (to an integer multiple of the period), the system resolves the contradiction between maintaining optimal flicker suppression and adapting to different frequency standards
2Reliability
If the integration time is set for a specific frequency (e.g., 60 Hz), then flicker is eliminated at that frequency, but flicker occurs when capturing imagery in a different frequency environment (e.g., 50 Hz)
Solution Approach 1:
The system incorporates frequency detection feedback to automatically determine the AC power frequency in the environment. Based on this feedback, the integration time is automatically adjusted to match the detected frequency, ensuring flicker elimination regardless of whether the environment uses 50 Hz or 60 Hz power
Solution Approach 2:
The integration time transitions from a static setting to a dynamic parameter that automatically adapts to the detected frequency. This dynamic adjustment allows the system to maintain optimal flicker suppression performance across different AC power frequency environments
Data Source
AI summary
The disclosure describes flicker detection and correction techniques to improve the quality of captured imagery, such as video or still images. In particular, this disclosure describes flicker correction techniques that compare different image frames to detect flicker. In some embodiments, the comparisons involves summing intensity values associated with rows within the frames and comparing the row sums to generate a difference signal. Detection and correction of flicker may be performed using a first derivative of the difference signal. The first derivative of the difference signal can be used in variety of ways to detect and correct flicker.