Flash Image Correction with Spatially Varying Brightness
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing flash modules in consumer electronics devices cause uneven illumination due to their proximity to cameras, leading to undesirable illumination variations in captured images.
Innovation Solution
A method and device for performing spatially-varying brightness correction by decomposing flash images into flash and ambient contribution images, using depth maps, reflectivity maps, and contextual information to adjust brightness, and recomposing them to generate corrected flash images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a flash module is positioned close to the camera to fit in consumer electronic devices, then device compactness is improved, but illumination uniformity deteriorates
Solution Approach 1:
The illumination correction is achieved by segmenting the image into different depth layers using a depth map, then applying spatially-varying brightness adjustments to different segments. This allows targeted correction of illumination non-uniformity in different spatial regions without requiring physical separation of the flash and camera.
Solution Approach 2:
The patent applies local quality by performing spatially-varying brightness adjustments where different regions of the image receive different brightness corrections based on their depth and illumination characteristics. The flash contribution image is adjusted locally according to depth map information, ensuring each region is corrected according to its specific illumination conditions.
2Productivity
If flash illumination is used to capture images in low light conditions, then image capture capability is improved, but illumination variation deteriorates
Solution Approach 1:
The patent performs preliminary action by capturing a depth map and separating the flash contribution image from the ambient contribution image before final image synthesis. This preliminary separation allows for targeted brightness adjustment of the flash component, correcting illumination variations before the images are recombined into the final output.
Solution Approach 2:
The depth map serves as an intermediary that mediates between the flash illumination and the final image correction. By using depth information as an intermediate layer, the system can accurately determine which regions received excessive flash illumination and apply appropriate corrections, separating the flash effect from the ambient lighting effects.
3Illumination intensity
If spatially-varying brightness adjustment is applied to correct flash illumination, then illumination uniformity is improved, but image processing complexity deteriorates
Solution Approach 1:
The image processing is simplified by segmenting the correction task into distinct components: depth map generation, flash contribution separation, and brightness adjustment. Each component handles a specific aspect of the correction, making the overall complex process more manageable and efficient through modular segmentation of the correction workflow.
Data Source
AI summary
Embodiments disclosed herein are directed to devices and methods for performing spatially-varying brightness correction of a flash image. The spatially-varying brightness correction utilizes a set of images that includes one or more images captured under flash illumination and one or more images captured without flash illumination, which are used to decompose one of the flash images or an image generated therefrom into a flash contribution image and an ambient contribution image. The flash contribution image and the ambient contribution image are recombined to generate a corrected flash image, and information about the flash module and/or scene is used to adjust the relative contributions of these images during recombination.