Shaped Illumination for Vignetting Compensation in Imaging Systems
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Imaging systems often suffer from vignetting, leading to non-uniform signal-to-noise ratios (SNRs) due to varying sensing efficiency across the field of view, which conventional digital image processing cannot effectively address, especially in applications like time-of-flight cameras and machine vision imaging.
Innovation Solution
An imaging system that includes an illuminator providing shaped illumination with higher intensity at areas of lower sensing efficiency, ensuring uniform SNRs across the field of view by matching the illumination distribution to the image capture system's capabilities and sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional digital image processing is used to correct vignetting, then the appearance of the image is improved, but the signal-to-noise ratio deteriorates
Solution Approach 1:
The illumination pattern is pre-configured to compensate for vignetting effects before image capture. The illuminator is designed with a specific angular distribution that brightens peripheral areas, so that when the image is captured, the sensing efficiency variation is compensated and uniform SNR is achieved directly from the captured data without requiring post-processing
2Device complexity
If uniform illumination is used across the field of view, then the illumination system is simple, but the sensing efficiency variation causes non-uniform SNR
Solution Approach 1:
The illumination system provides non-uniform illumination with different intensity levels at different locations in the field of view. The illuminator is designed to emit light with an angular distribution that creates higher intensity at peripheral angles where sensing efficiency is lower, and lower intensity at central angles where sensing efficiency is higher, achieving uniform SNR across the image
Data Source
AI summary
A system including an image capture system with a sensing efficiency that varies over a field of view of the image capture system may employ shaped illumination to compensate for the variation in the sensing efficiency. An illuminator may be configured to illuminate the field of view of the image capture system with illumination shaped to have higher intensity where the sensing efficiency is lower, e.g., at the periphery of the field over view. The imaging system may thus provide image data with more uniform signal-to-noise ratios. Image data from an illuminated scene may be manipulated using data from a non-illuminated scene to produce improved image data.