Noise Suppression in Image Capture Using Adaptive Flash Illuminance
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Solution Overview
Problem
Current methods for reducing noise introduced by ambient light in captured images are costly in terms of processing speed and expense, and overpowering ambient light with a flash increases complexity and cost.
Innovation Solution
An image capture system that digitally suppresses noise by capturing images with and without flash, determining pure flash illuminance, and applying adaptive noise suppression levels based on this illuminance, using a lower power flash and processing units to enhance images efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a flash is used to overpower ambient light, then image quality is improved, but device complexity and cost increase
Solution Approach 1:
The patent captures two images - one with flash illumination and one without - then digitally processes them to separate flash and ambient light components. This copying approach allows the system to use a simple flash while achieving the effects of a complex lighting system through computational methods.
Solution Approach 2:
The patent replaces the mechanical/optical approach of using a high-power flash to overpower ambient light with a digital signal processing approach. By capturing images at different illumination conditions and processing them algorithmically, the system achieves superior image quality without requiring a complex or high-cost flash system.
2Measurement precision
If digital methods are used to remove ambient light noise, then image quality is improved, but processing cost and time increase
Solution Approach 1:
The patent segments the image processing task by separating the flash illumination component from the ambient light component through directional lighting and captured images. This segmentation allows for targeted processing of only the relevant flash components, reducing overall processing time and computational cost.
Solution Approach 2:
The system performs preliminary capture of images under different illumination conditions (with and without flash) before final processing. This preliminary action provides pre-processed data that simplifies subsequent noise removal operations, reducing the computational burden and time required for ambient light elimination.
Data Source
AI summary
A method and apparatus apply one of a plurality of different levels of noise suppression to a pixel based on a difference between illuminance values for the pixel in the presence of (a) both a flash and ambient light and (b) without the flash.