Phase unwrapping method based on rank information filtering

Abstract

The invention discloses a phase unwrapping method based on rank information filtering, and the method combines a local phase gradient estimation technology based on AMPM with a rank information filter, builds a phase unwrapping program based on rank information filtering, and converts an interferogram phase unwrapping problem into a state estimation problem under a rank information filtering framework. An H-infinity operator is introduced to optimize a state variable information matrix, and the state variable estimation precision is improved; a fast path tracking strategy based on heap ordering is utilized to guide a phase unwrapping path, and it is ensured that a phase unwrapping program based on rank information filtering unwraps an interferogram along a path from a high-quality pixel to a low-quality pixel. Simulation data and actual measurement data experiment results show that the algorithm is effective, and a stable result can be obtained from a noise winding interference pattern.

Description

technical field

[0001] The invention relates to the field of phase unwrapping, and relates to phase unwrapping based on rank information filtering, in particular to a phase unwrapping method based on rank information filtering. Background technique

[0002] Phase unwrapping is one of the important steps in data processing of interferometric synthetic aperture radar (InSAR), optical interferometry, synthetic aperture sonar (InSAS) and magnetic resonance imaging. Due to the periodicity of the trigonometric function, the interferometric phase of the characterizing target parameter obtained from interferometry is limited to its phase principal value (-π, π] interval, commonly known as the winding phase; recovering the true value of the target parameter from the winding phase Interferometric phase, which is the so-called phase unwrapping. Ideally, phase unwrapping can be achieved by adding an integer multiple of 2π to the winding phase. However, phase jumps, phase noise, radar sh...

Examples

Embodiment

[0070] A phase unwrapping method based on rank information filtering, comprising the steps of:

[0071] 1) According to the existing nonlinear filtering phase unwrapping model, the local phase gradient estimation technology based on AMPM is combined with the rank information filter to establish a phase unwrapping model based on the rank information filtering, and the interferogram phase unwrapping problem is transformed into is the state estimation problem under the framework of rank information filtering;

[0072] Using the relationship between the interferogram adjacent pixels to unwrap the phase, the interferogram phase unwrapping system equation can be expressed as follows:

[0073]

[0074]

[0075] where x k Represents the unwrapping phase of interferogram k pixel as the state variable to be evaluated; μ k-1 Indicates the real phase gradient of the k-1 pixel in the interferogram, and its estimated value can be obtained by using the AMPM-based local gradient estim...

technical field

[0001] The invention relates to the field of phase unwrapping, and relates to phase unwrapping based on rank information filtering, in particular to a phase unwrapping method based on rank information filtering. Background technique

[0002] Phase unwrapping is one of the important steps in data processing of interferometric synthetic aperture radar (InSAR), optical interferometry, synthetic aperture sonar (InSAS) and magnetic resonance imaging. Due to the periodicity of the trigonometric function, the interferometric phase of the characterizing target parameter obtained from interferometry is limited to its phase principal value (-π, π] interval, commonly known as the winding phase; recovering the true value of the target parameter from the winding phase Interferometric phase, which is the so-called phase unwrapping. Ideally, phase unwrapping can be achieved by adding an integer multiple of 2π to the winding phase. However, phase jumps, phase noise, radar sh...

Examples

Embodiment

[0070] A phase unwrapping method based on rank information filtering, comprising the steps of:

[0071] 1) According to the existing nonlinear filtering phase unwrapping model, the local phase gradient estimation technology based on AMPM is combined with the rank information filter to establish a phase unwrapping model based on the rank information filtering, and the interferogram phase unwrapping problem is transformed into is the state estimation problem under the framework of rank information filtering;

[0072] Using the relationship between the interferogram adjacent pixels to unwrap the phase, the interferogram phase unwrapping system equation can be expressed as follows:

[0073]

[0074]

[0075] where x k Represents the unwrapping phase of interferogram k pixel as the state variable to be evaluated; μ k-1 Indicates the real phase gradient of the k-1 pixel in the interferogram, and its estimated value can be obtained by using the AMPM-based local gradient estim...

Images