What does "Coherent Diffraction Imaging" mean?
Table of Contents
Coherent Diffraction Imaging (CDI) is a technique used to capture images of tiny structures by analyzing the light that bounces off them. This method uses very bright and short bursts of light from special machines called X-ray Free Electron Lasers. CDI helps scientists look at nanostructures, which are incredibly small, in their natural gas form and see how they change over time with high detail.
How It Works
When light hits a sample, it scatters in different ways. Ideally, scientists could use a simple mathematical method called the Fourier Transform to figure out what the sample looks like from the scattered light. However, the tricky part is that they only get to see the intensity of the light, not the phase, which is lost during the measurement. To get back that lost information, scientists need special algorithms, which are like problem-solving recipes.
New Approach
To improve the way phase information is retrieved, a method called Memetic Phase Retrieval (MPR) combines traditional algorithms with evolutionary approaches. This new method has been tested using data from two different research facilities and has shown good performance, even in tough situations. It has been designed to be easy to use and is available for anyone in the imaging community to try out.
Low-Light Imaging
In cases where using a lot of light isn't possible, like with delicate samples, phase retrieval can become difficult due to noise that comes from low light levels. Some imaging techniques need a series of light measurements over time, which doesn’t work for capturing a single image. New methods that use deep learning and generative models have been effective in other imaging tasks but haven’t worked well in phase retrieval. A new approach called Low-dose Deep Image Prior (LoDIP) merges in-situ CDI with advanced generative models to improve phase retrieval for single images under low light conditions. This method has been shown to work better than previous techniques in real-world scenarios.