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Synthetic Aperture Radar (SAR) satellite data are widely used to monitor deformation phenomena impacting the Earth's surface (e.g. landslides, glacier motions, subsidence, and volcano deformations) and infrastructures (e.g. bridges, dams, buildings). The analysis is generally performed using the Differential SAR Interferometry (DInSAR) technique that exploits the phase information of SAR data. However, this technique suffers for lack of coherence among the considered stack of images, and it can only be adopted to monitor slow deformation phenomena. In the field of geohazards monitoring and glacier melting, the Offset Tracking technique has been also widely investigated. This approach is based on the amplitude information only but it reaches worse accuracy compared to DInSAR. To overcome the limitations of DIn-SAR and Offset Tracking, in the last decade, a new technique called Imaging Geodesy has been investigated exploiting the amplitude information and the precise orbit of the modern SAR platforms (i.e. TerraSAR-X, COSMO-SkyMed). In this study, an investigation of using COSMO-SkyMed data for Earth surface monitoring was performed. The developed approach was applied to a set of imagery acquired over the Corvara (Northern Italy) area, which is affected by a fast landslide with yearly displacements up to meters. Specifically, two well identifiable and stable human-made Amplitude Persistent Scatterers (APSs) were considered to estimate the residual errors of COSMO-SkyMed sensor during the acquisition period between 2010 and 2015. Then, the same methodology was applied to estimate the displacement of a Corner Reflector (CR) located in the landslide area. Finally, the results were compared to the available GPS reference trend showing a good agreement.

The problem of detecting significant brain activity upon stimulus in functional Magnetic Resonance Imaging (fMRI) data is tackled by a statistical data analysis for which the signal's amplitude is required. From literature, it is known that fMRI data follow a Rice distribution. Hence, for fMRI signal detection first the parameters of the Rice distribution need to be estimated. Different methods exist and each has their own pros and cons. In this paper, a novel estimation approach is presented in order to overcome the drawbacks of the existing methods. The proposed estimator is based on the harmonic median. Its performance is verified via a simulation experiment and compared with the state-of-the-art approaches.

Analyzing functional MRI data is often a hard task due to the fact that these periodic signals are strongly disturbed with noise. In many cases, the signals are buried under the noise and not visible, such that detection is quite impossible. However, it is well known that the amplitude measurements of such disturbed signals follow a Rice distribution which is characterized by two parameters. In this paper, an alternative Bayesian approach is proposed to tackle this two-parameter estimation problem. By incorporating prior knowledge into a mathematical framework, the drawbacks of the existing methods (i.e. the maximum likelihood approach and the method of moments) can be overcome. The performance of the proposed Bayesian estimator is analyzed theoretically and illustrated through simulations. Finally, the developed approach is successfully applied to measurement data for the analysis of functional MRI

The problem of detecting a periodic signal buried in zero-mean Gaussian noise is present in various fields of engineering. It is well-known that the amplitude of the disturbed signal follows a Rice distribution which is characterized by two parameters. In this paper, an alternative Bayesian approach is proposed to tackle this two-parameter estimation problem. By incorporating prior knowledge into a mathematical framework, the drawbacks of the existing methods (i.e., the maximum likelihood approach and the method of moments) can be overcome. The performance of the proposed Bayesian estimator is shown through simulations.

This paper reports the activities performed in the framework of the ESA contract 18432/04/NL/AR: Enhancement of diffusers BSDF Accuracy. This study was conducted to investigate properties of various diffusers. Diffusers are widely used in space instruments as part of the on-board absolute calibration. Knowledge of the behavior of the diffuser is therefore most important. From measurements of launched instruments in-orbit it has been discovered that when a diffuser is used in the vacuum of space the BSDF (Bi-directional Scattering Distribution Function) can change with respect to the one in ambient conditions. This is called the air/vacuum effect and has been simulated in this study by measuring the BSDF in a laboratory in ambient as well as vacuum conditions, results of this part of the study will be reported. Another effect on the BSDF is not related to the air/vacuum effect, but to the design parameters of the optical system and the scattering properties of the diffuser. The effect is called Spectral Features and is a noise like structure superimposed on the BSDF. To observe this effect, spectral and spatial (partially) coherence light is needed. High-resolution spectrometers provide the spectral coherence and a narrow field of view provides the spatial coherence. Modern space spectrometers have high spectral resolution and/or a small field of view (high spatial resolution). Different diffusers create different speckle patterns leading to different Spectral Features amplitudes. Therefore the choice of diffuser can be very critical with respect to the required absolute radiometric calibration of an instrument. Even if the Spectral Features are small it can influence the error budget of the retrieval algorithms for the level 2 products. In this presentation diffuser trade-off results are presented and the Spectral Features model applied to the optical configuration of the MERIS instrument is compared to in-flight measurements of MERIS. The introduction describes the use of diffusers in earth-observation satellites and why they cause spectral features. In Sec.2 the physical background of the spectral features, speckles, is discussed. Section 3 shows the results from air/vacuum effect measurements (SubSec.3.1), spectral features amplitude measurements on our in-house setup and simulations in a single graphical display (SubSec.3.2), and the measured and simulated results for the MERIS instrument (SubSec.3.3). The following sections deal with a description of the measuring setup and the model that has been made to do the simulations. Finally, in the discussion, topics like what is the best diffuser and what can be done to minimize the amplitude of the spectral features will be dealt with.

This paper reports the activities performed in the framework of the ESA contract 18432/04/NL/AR: Enhancement of diffusers BSDF Accuracy. This study was conducted to investigate properties of various diffusers. Diffusers are widely used in space instruments as part of the on-board absolute calibration. Knowledge of the behavior of the diffuser is therefore most important. From measurements of launched instruments in-orbit it has been discovered that when a diffuser is used in the vacuum of space the BSDF (Bi-directional Scattering Distribution Function) can change with respect to the one in ambient conditions. This is called the air/vacuum effect and has been simulated in this study by measuring the BSDF in a laboratory in ambient as well as vacuum conditions, results of this part of the study will be reported. Another effect on the BSDF is not related to the air/vacuum effect, but to the design parameters of the optical system and the scattering properties of the diffuser. The effect is called Spectral Features and is a noise like structure superimposed on the BSDF. To observe this effect, spectral and spatial (partially) coherence light is needed. High-resolution spectrometers provide the spectral coherence and a narrow field of view provides the spatial coherence. Modern space spectrometers have high spectral resolution and/or a small field of view (high spatial resolution). Different diffusers create different speckle patterns leading to different Spectral Features amplitudes. Therefore the choice of diffuser can be very critical with respect to the required absolute radiometric calibration of an instrument. Even if the Spectral Features are small it can influence the error budget of the retrieval algorithms for the level 2 products. In this presentation diffuser trade-off results are presented and the Spectral Features model applied to the optical configuration of the MERIS instrument is compared to in-flight measurements of MERIS. The introduction describes the use of diffusers in earth-observation satellites and why they cause spectral features. In Sec.2 the physical background of the spectral features, speckles, is discussed. Section 3 shows the results from air/vacuum effect measurements (SubSec.3.1), spectral features amplitude measurements on our in-house setup and simulations in a single graphical display (SubSec.3.2), and the measured and simulated results for the MERIS instrument (SubSec.3.3). The following sections deal with a description of the measuring setup and the model that has been made to do the simulations. Finally, in the discussion, topics like what is the best diffuser and what can be done to minimize the amplitude of the spectral features will be dealt with.