WDR Image Synthesis Flicker Evaluation and Dynamic Mixing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing wide dynamic range (WDR) processing techniques face issues with image distortion and flicker when synthesizing short and long exposure images, particularly in dynamic environments, leading to suboptimal results when dealing with moving subjects and flickering light sources.
Innovation Solution
A method and apparatus for calculating a flicker-evaluation value to dynamically determine flicker occurrence at each pixel, allowing for the selection of a long exposure image to avoid flicker, and accurately detecting flicker areas, thereby ensuring WDR processing without flicker in moving pictures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If short exposure image is used for WDR synthesis, then dynamic range is improved, but flicker occurs in the synthesized image
Solution Approach 1:
The image is divided into multiple regions based on flicker detection results. The apparatus calculates a flicker evaluation value for each pixel and segments the image into flicker-affected regions and non-flicker regions. This allows different processing strategies to be applied to different parts of the image, maintaining WDR effect in non-flicker regions while avoiding flicker in other regions.
Solution Approach 2:
Different quality characteristics are applied to different regions of the image. In regions where flicker is detected, the apparatus uses only the long exposure image or applies weighted combination with minimal short exposure contribution. In regions without flicker, the full WDR synthesis is performed. This local quality approach ensures that each region has the optimal characteristics for its specific condition.
2Object-affected harmful factors
If long exposure image is used for WDR synthesis, then flicker is reduced, but image distortion and contour doubling occur when subjects move
Solution Approach 1:
The apparatus dynamically adjusts the mixing ratio between long and short exposure images based on the flicker evaluation value and motion detection results. Rather than using a fixed ratio, the system continuously adapts the contribution of each exposure image based on local conditions, allowing optimal balance between flicker reduction and motion handling.
Solution Approach 2:
The apparatus changes the mixing ratio parameter dynamically based on flicker evaluation and motion detection. When motion is detected in a region, the system adjusts the weight given to long and short exposure images to minimize distortion while still reducing flicker. This parameter change approach allows flexible optimization of both flicker and distortion issues.
3Measurement precision
If multiple frames are captured for flicker detection, then flicker detection accuracy is improved, but response time to flicker light source changes is delayed
Solution Approach 1:
The apparatus performs preliminary flicker detection using a small number of initial frames to establish baseline flicker characteristics. This preliminary action allows the system to prepare flicker evaluation parameters in advance, enabling faster response when flicker conditions change. The system uses this preliminary information to make quicker decisions about image synthesis strategies.
Solution Approach 2:
The apparatus implements continuous feedback by monitoring flicker evaluation values in real-time and adjusting the image synthesis process accordingly. When flicker conditions change, the system receives feedback from ongoing frame analysis and immediately adjusts the mixing ratio and synthesis strategy. This feedback mechanism maintains both detection accuracy and rapid response to changing light conditions.
Data Source
AI summary
An apparatus and a method for calculating a flicker-evaluation value through a wide dynamic range (WDR) system. The apparatus includes: a first calculator configured to calculate a first difference between a pixel value of a long exposure image of a current frame and a pixel value of a long exposure image of a previous frame; an average calculator configured to calculate an average of the pixel value of the long exposure image of the current frame and the pixel value of the long exposure image of the previous frame; a second calculator configured to calculate a second difference between a pixel value of a short exposure image of the current frame and the average calculated by the average calculator; and a flicker-evaluation value calculator configured to calculate a flicker-evaluation value which indicates a flicker strength using the first difference and the second difference.