Contents
What is phase retrieval problem?
Abstract: The phase retrieval problem arises in applications of electromagnetic theory in which wave phase is apparently lost or impractical to measure and only intensity data are available. The mathematics of the problem provides unusual insights into the nature of electromagnetic fields.
Why do we do phase retrieval?
Phase retrieval is a key component of coherent diffraction imaging (CDI). In this way, phase retrieval allows for the conversion of a diffraction pattern into an image without an optical lens. Using phase retrieval algorithms, it is possible to characterize complex optical systems and their aberrations.
What is phase reconstruction?
Abstract: Phase reconstruction, which estimates phase from a given amplitude spectrogram, is an active research field in acoustical signal processing with many applications including audio synthesis. The experimental results confirm that the proposed method outperformed the direct phase estimation by a DNN.
How do you solve phase problems?
There are several ways to retrieve the lost phases. The phase problem must be solved in x-ray crystallography, neutron crystallography, and electron crystallography. Not all of the methods of phase retrieval work with every wavelength (x-ray, neutron, and electron) used in crystallography.
What is a phase in XRD?
A phase is a crystalline solid with a regular 3-dimensional arrangement of the atoms. The measured diffraction peak positions and intensities are like a fingerprint of a particular crystalline phase. This is also known as qualitative phase analysis.
How do you determine phase from XRD data?
The measured diffraction peak positions and intensities are like a fingerprint of a particular crystalline phase. Identification is accomplished by comparison of the measured pattern with the entries in reference databases using a search-match algorithm. This is also known as qualitative phase analysis.
What are crystalline phases?
Liquid crystalline phases, also referred to as mesophases, are surfactant-based systems that comprise properties of both liquids and solids. They show the flow behavior of liquids but likewise exhibit a birefringent, ordered crystalline structure. Such lyotropic liquid crystalline systems are known as microemulsions.
Which is an example of a phase retrieval problem?
Phase retrieval is the process of algorithmically finding solutions to the phase problem. Given a complex signal where x is an M -dimensional spatial coordinate and k is an M -dimensional spatial frequency coordinate.
How is phase retrieval used in diffraction imaging?
Phase retrieval is a key component of coherent diffraction imaging (CDI). In CDI, the intensity of the diffraction pattern scattered from a target is measured. The phase of the diffraction pattern is then obtained using phase retrieval algorithms and an image of the target is constructed.
How does shrinkwrap help with phase retrieval problem?
The shrinkwrap technique periodically updates the estimate of the support by low-pass filtering the current estimate of the object amplitude (by convolution with a Gaussian) and applying a threshold, leading to a reduction in the image ambiguity. The phase retrieval is an ill-posed problem.