Showing papers on "Polarimetry published in 2011"

Tissue polarimetry: concepts, challenges, applications, and outlook

Abstract: Polarimetry has a long and successful history in various forms of clear media. Driven by their biomedical potential, the use of the polarimetric approaches for biological tissue assessment has also recently received considerable attention. Specifically, polarization can be used as an effective tool to discriminate against multiply scattered light (acting as a gating mechanism) in order to enhance contrast and to improve tissue imaging resolution. Moreover, the intrinsic tissue polarimetry characteristics contain a wealth of morphological and functional information of potential biomedical importance. However, in a complex random medium-like tissue, numerous complexities due to multiple scattering and simultaneous occurrences of many scattering and polarization events present formidable challenges both in terms of accurate measurements and in terms of analysis of the tissue polarimetry signal. In order to realize the potential of the polarimetric approaches for tissue imaging and characterization/diagnosis, a number of researchers are thus pursuing innovative solutions to these challenges. In this review paper, we summarize these and other issues pertinent to the polarized light methodologies in tissues. Specifically, we discuss polarized light basics, Stokes-Muller formalism, methods of polarization measurements, polarized light modeling in turbid media, applications to tissue imaging, inverse analysis for polarimetric results quantification, applications to quantitative tissue assessment, etc.

The Imaging Magnetograph eXperiment (IMaX) for the Sunrise Balloon-Borne Solar Observatory

Abstract: The Imaging Magnetograph eXperiment (IMaX) is a spectropolarimeter built by four institutions in Spain that flew on board the Sunrise balloon-borne solar observatory in June 2009 for almost six days over the Arctic Circle. As a polarimeter, IMaX uses fast polarization modulation (based on the use of two liquid crystal retarders), real-time image accumulation, and dual-beam polarimetry to reach polarization sensitivities of 0.1%. As a spectrograph, the instrument uses a LiNbO3 etalon in double pass and a narrow band pre-filter to achieve a spectral resolution of 85 mA. IMaX uses the high-Zeeman-sensitive line of Fe i at 5250.2 A and observes all four Stokes parameters at various points inside the spectral line. This allows vector magnetograms, Dopplergrams, and intensity frames to be produced that, after reconstruction, reach spatial resolutions in the 0.15 – 0.18 arcsec range over a 50×50 arcsec field of view. Time cadences vary between 10 and 33 s, although the shortest one only includes longitudinal polarimetry. The spectral line is sampled in various ways depending on the applied observing mode, from just two points inside the line to 11 of them. All observing modes include one extra wavelength point in the nearby continuum. Gauss equivalent sensitivities are 4 G for longitudinal fields and 80 G for transverse fields per wavelength sample. The line-of-sight velocities are estimated with statistical errors of the order of 5 – 40 m s−1. The design, calibration, and integration phases of the instrument, together with the implemented data reduction scheme, are described in some detail.

White-light channeled imaging polarimeter using broadband polarization gratings

Abstract: A white-light snapshot channeled linear imaging (CLI) polarimeter is demonstrated by utilizing polarization gratings (PGs). The CLI polarimeter is capable of measuring the two-dimensional distribution of the linear Stokes polarization parameters by incorporating two identical PGs, in series, along the optical axis. In this configuration, the general optical shearing functionality of a uniaxial crystal-based Savart plate is realized. However, unlike a Savart plate, the diffractive nature of the PGs creates a linear dependence of the shear versus wavelength, thus providing broadband functionality. Consequently, by incorporating the PG-based Savart plate into a Savart plate channeled imaging polarimeter, white-light interference fringes can be generated. This enables polarimetric image data to be acquired at shorter exposure times in daylight conditions, making it more appealing over the quasi-monochromatic channeled imaging polarimeters previously described in the literature. Furthermore, the PG-based device offers significantly more compactness, field of view, optical simplicity, and vibration insensitivity than previously described white-light CLI polarimeters based on Sagnac interferometers. Included in this paper are theoretical descriptions of the linear (S0, S1, and S2) and complete (S0, S1, S2, and S3) channeled Stokes imaging polarimeters. Additionally, descriptions of our calibration procedures and our experimental proof of concept CLI system are provided. These are followed by laboratory and outdoor polarimetric measurements of S0, S1, and S2.

Single-shot, dual-wavelength digital holography based on polarizing separation

Abstract: We describe what we believe to be a new digital holographic configuration that can be utilized for both single-shot, dual-wavelength, off-axis geometry and imaging polarimetry. To get the feasibility of the single-shot, dual-wavelength, off-axis geometry, a sample with a nominal step height of 1.34 μm is used. Undesirable noises that strongly affect the measurement have been suppressed successfully by using a modified flat fielding method for the dual-wavelength scheme. And also, the experiment is conducted on a nanopattern sample on the basis of a single image acquisition to show the imaging polarimetry capability. The proposed scheme can provide a real-time solution for measuring three-dimensional objects having a high abrupt height difference with moderate accuracy. Furthermore, it can be used as a fast polarization imaging measurement tool.

POLARIZED REFLECTED LIGHT FROM THE EXOPLANET HD189733b: FIRST MULTICOLOR OBSERVATIONS AND CONFIRMATION OF DETECTION

Abstract: We report the first multicolor polarimetric measurements (UBV bands) for the hot Jupiter HD189733b and confirm our previously reported detection of polarization in the B band. The wavelength dependence of polarization indicates the dominance of Rayleigh scattering with a peak in the blue B and U bands of ~10–4 ± 10–5 and at least a factor of two lower signal in the V band. The Rayleigh-like wavelength dependence, also detected in the transmitted light during transits, implies a rapid decrease of the polarization signal toward longer wavelengths. Therefore, the nondetection by Wiktorowicz, based on a measurement integrated within a broad passband covering the V band and partly covering the B and R bands, is inconclusive and consistent with our detection in B. We discuss possible sources of the polarization and demonstrate that effects of incomplete cancellation of stellar limb polarization due to starspots or tidal perturbations are negligible as compared with scattering polarization in the planetary atmosphere. We compare the observations with a Rayleigh-Lambert model and determine effective radii and geometrical albedos for different wavelengths. We find a close similarity of the wavelength-dependent geometrical albedo with that of the Neptune atmosphere, which is known to be strongly influenced by Rayleigh and Raman scattering. Our result establishes polarimetry as a reliable means for directly studying exoplanetary atmospheres.

Evaluation of C-band polarization diversity and polarimetry for wetland mapping

Abstract: Wetlands provide important ecological benefits at both local and regional scales, thus wetland conservation and effective management are goals at many levels of government. Radar systems are a useful data source for providing information about wetlands and thus play a complementary role to optical data in wetland mapping and monitoring applications. This paper explores the use of polarization diversity and polarimetry for wetland classification and mapping using airborne CV-580 C-band synthetic aperture radar (SAR) data. The results show that dual polarization with an HH polarized component is superior to single polarization but does not contain as much information for wetland classification as full polarimetry. However, polarization ratios using HH are adequate for mapping water and flooded and nonflooded vegetation for a generalized land-cover map. The implications of this research are discussed with respect to wetland classification and land cover information needs for waterfowl-productivity estimates ...

Polarimetric Phased-Array Radar for Weather Measurement: A Planar or Cylindrical Configuration?

Abstract: This paper suggests a cylindrical configuration for agile beam polarimetric phased-array radar (PPAR) for weather surveillance. The most often used array configuration for PAR is a planar array antenna. The planar configuration, however, has significant deficiencies for polarimetric measurements, as well as other limitations, such as increases in beamwidth, decreases of sensitivity, and changes in the polarization basis when the beam scans off its broadside. The cylindrical polarimetric phased-array radar (CPPAR) is proposed to avoid these deficiencies. The CPPAR principle and potential performance are demonstrated through theoretical analysis and simulation. It is shown that the CPPAR has the advantage of a scan-invariant polarization basis, and thus avoids the inherent limitations of the planar PPAR (i.e., PPPAR).

Combined spectral and polarimetry imaging and diagnostics

Abstract: Combined spectral and polarimetry imaging and diagnostic techniques are disclosed, including an imaging system that simultaneously records spatially co- registered spectral and polarization information from an image of a target scene such as an ocular structure or material or device in an around the eye. Image acquisition and image calibration by such an imaging system or an imaging spectrometer or polarimeter are also disclosed. Methods of data storage and image display relevant to medical practice in general and ophthalmology practice specifically are further disclosed.

The Lunar Mini-RF Radars: Hybrid Polarimetric Architecture and Initial Results

Abstract: The two mini-radio-frequency (mini-RF) radars flown in near-polar lunar orbits (on Chandrayaan-1 and the Lunar Reconnaissance Orbiter) were the first of their kind, hybrid-polarimetric. This new paradigm transmits circular polarization, and receives coherently on orthogonal linear polarizations. The resulting data support calculation of the 2 × 2 covariance matrix of the backscattered field, from which follow the four Stokes parameters. These are the basis of science products from the observations, which include images that are traditional in radar astronomy, as well as polarimetric decompositions. The instruments all have mass less than 15 kg, antenna areas of about 1 m2, and modest power and spacecraft accommodation requirements. Data quality and instrument characteristics suggest that hybrid polarity is highly desirable for future exploratory radar missions in the Solar system.

A Fundamental Figure of Merit for Radio Polarimeters

Abstract: Many modern radio applications, such as astronomy and remote sensing, require high-precision polarimetry. These applications put exacting demands on radio polarimeters (antenna systems that can measure the state of polarization of radio sources), and in order to assess their polarimetric performance, a figure of merit (FoM) would be desirable. Unfortunately, we find that the parameter commonly used for this purpose, the cross-polarization ratio, is not suitable as a polarimetry FoM unless it is given in an appropriate coordinate system. This is because although the cross-polarization ratio is relevant for raw, uncalibrated polarimetry, in general it is not relevant to the quality of the polarimetry after polarimetric calibration. However, a cross-polarization ratio can be constructed from invariants of the Jones matrix (the matrix that describes the polarimetric response of a polarimeter) that quantifies polarimetric performance even after calibration. We call this cross-polarization ratio the intrinsic cross-polarization ratio (IXR) and conclude that it is a fundamental FoM for polarimeters. We then extend the IXR concept from the Jones calculus to the Mueller calculus and also to interferometers, and we give numerical examples of these parameters applied to the Parkes radio telescope, the Westerbork synthesis radio telescope, and the Effelsberg telescope.

Data-reduction techniques for high-contrast imaging polarimetry. Applications to ExPo

Abstract: Context. Imaging polarimetry is a powerful tool for detecting and characterizing exoplanets and circumstellar environments. Polarimetry allows a separation of the light coming from an unpolarized source such as a star and the polarized source such as a planet or a protoplanetary disk. Future facilities like SPHERE at the VLT or EPICS at the E-ELT will incorporate imaging polarimetry to detect exoplanets. The Extreme Polarimeter (ExPo) is a dual-beam imaging polarimeter that can currently reach contrast ratios of 10 5 , enough to characterize circumstellar environments. Aims. We present the data-reduction steps for a dual-beam imaging polarimeter that can reach contrast ratios of 10 5 . Methods. The data obtained with ExPo at the William Herschel Telescope (WHT) are analyzed. Instrumental artifacts and noise sources are discussed for an unpolarized star and for a protoplanetary disk (AB Aurigae). Results. The combination of fast modulation and dual-beam techniques allows us to minimize instrumental artifacts. A proper data processing and alignment of the images is fundamental when dealing with high contrasts. Imaging polarimetry proves to be a powerful method to resolve circumstellar environments even without a coronagraph mask or an adaptive optics system.

A Generalized Radar Backscattering Model Based on Wave Theory for Multilayer Multispecies Vegetation

Abstract: A generalized radar scattering model based on wave theory is described. The model predicts polarimetric radar backscattering coefficients for structurally complex vegetation comprised of multiple species and layers. Compared to conventional two-layer crown-trunk models, modeling of actual forests has been improved substantially, allowing better understanding of microwave interaction with vegetation. The model generalizes an existing single-species discrete scatterer model and, by including scattering and propagation effects through judiciously defined vegetation layers, enables its application to an arbitrary number of species types. The scatterers within each layer are modeled as finite cylinders or disks having arbitrary size, density, and orientation, as in the predecessor model. The distorted Born approximation is used to represent the propagation through each layer, while scattering from each is modeled as a linear superposition of scattering from its respective random collection of scatterers. Interactions of waves within and between each layer and direct scattering from the ground are accounted for. Validation of the model is presented based on its application to 23 wooded savanna sites located in Queensland, Australia, and comparison with Advanced Land Observing Satellite (ALOS) Phased Arrayed L-band Synthetic Aperture Radar (PALSAR) and National Aeronautics and Space Administration (NASA) Jet Propulsion Laboratory (JPL) Airborne Synthetic Aperture Radar (AIRSAR) data. Results indicate good agreement between simulated and actual backscattering coefficients, particularly at HH and VV polarizations. More discrepancies are found at HV polarizations and can be explained by uncertainties in the knowledge of input parameters, such as inaccuracies in the surface model, surface roughness parameterization, and soil moisture.

Inferring microstructure and turbulence properties in rain through observations and simulations of signal spectra measured with Doppler–polarimetric radars

Abstract: Doppler radars are able to measure important parameters of the target velocity. In contrast, polarimetric radars are very sensitive to features of the target shape and orientation relative to the radar beam direction. This chapter describes a novel Doppler–polarimetric approach to radar remote sensing. The combination of the Doppler ability and polarization diversity in the radar technology enables more comprehensive investigations of objects and phenomena in radar coverage. The discussion is adapted to the case of atmospheric remote sensing. A special case of cloud and precipitation observations is considered in greater detail. Mathematical models of signals and spectra of Doppler–polarimetric returns are discussed. It is demonstrated (theoretically, by simulation, and by real data processing) that important parameters of dynamic characteristics and microstructure of meteorological objects can be retrieved from Doppler–polarimetric observations. These results lead to new interesting and important applications like turbulence intensity measurement, drop size distribution estimation, recognition of type of scatterers, detection of hail zones, etc.

Analysis and Modeling on co- and Cross-Polarized Urban Radio Propagation for Dual-Polarized MIMO Wireless Systems

Abstract: Cross-polarization coupling is an important radio propagation characteristic in dual-polarized multiple-input multiple output (MIMO) systems. Still, few studies analyze the polarimetric properties of the radio channel in relation to the actual propagation conditions and processes taking place in urban environment. The topic is studied in the present paper with the aid of dual-polarized MIMO measurements and ray tracing simulations. Several scenarios are considered, and the impact of the different propagation characteristics (LOS, NLOS, link-distance, presence of diffuse-scattering, angular distribution of the signal, etc.) on cross-polarization coupling is analyzed. Generally, a fairly high degree of coupling is observed due to multipath propagation and especially to diffuse scattering. Surprisingly, it does not appear to depend on link distance.

Geologic Studies of Planetary Surfaces Using Radar Polarimetric Imaging

Abstract: Radar is a useful remote sensing tool for studying planetary geology because it is sensitive to the composition, structure, and roughness of the surface and can penetrate some materials to reveal buried terrain. The Arecibo Observatory radar system transmits a single sense of circular polarization, and both senses of circular polarization are received, which allows for the construction of the Stokes polarization vector. From the Stokes vector, daughter products such as the circular polarization ratio, the degree of linear polarization, and linear polarization angle are obtained. Recent polarimetric imaging using Arecibo has included Venus and the Moon. These observations can be compared to radar data for terrestrial surfaces to better understand surface physical properties and regional geologic evolution. For example, polarimetric radar studies of volcanic settings on Venus, the Moon, and Earth display some similarities, but also illustrate a variety of different emplacement and erosion mechanisms. Polarimetric radar data provide important information about surface properties beyond what can be obtained from single-polarization radar. Future observations using polarimetric synthetic aperture radar will provide information on roughness, composition, and stratigraphy that will support a broader interpretation of surface evolution.

Classification of Tropical Vegetation Using Multifrequency Partial SAR Polarimetry

Abstract: This letter presents a case study addressing the comparison between different synthetic aperture radar (SAR) partial polarimetric options for tropical-vegetation cartography. These options include compact polarization (CP), dual polarization (DP), and alternating polarization (AP). They are all derived from fully polarimetric (FP) SAR data acquired by the airborne SAR (AIRSAR) sensor over the French Polynesian Tubuai Island. The classification approach is based on the support vector machine algorithm and is further validated by several ground surveys. For a single frequency band, FP data give significantly better results than any other partial polarimetric configuration. Among the partial polarimetric architectures, the CP mode performs best. In addition, the DP mode shows better performance than the AP mode, highlighting the value of the polarimetric differential phase. The combination of different frequency bands (P-, L-, and C-bands) holds the most significant improvement: The multifrequency diversity adds generally more information than the multipolarization diversity. A noticeable result is the major contribution of the C-band at VV polarization (the only polarization available at C-band with the AIRSAR data set used in this letter) to the classification performance, due to its ability to discriminate between Pinus and Falcata.

Passive Polarimetric Imagery-Based Material Classification Robust to Illumination Source Position and Viewpoint

Abstract: Polarization, a property of light that conveys information about the transverse electric field orientation, complements other attributes of electromagnetic radiation such as intensity and frequency. Using multiple passive polarimetric images, we develop an iterative, model-based approach to estimate the complex index of refraction and apply it to target classification.

Prototyping for the Spectropolarimeter for Planetary EXploration (SPEX): calibration and sky measurements

Abstract: We present the Spectropolarimeter for Planetary EXploration (SPEX), a high-accuracy linear spectropolarimeter measuring from 400 to 800 nm (with 2 nm intensity resolution), that is compact (~ 1 liter), robust and lightweight. This is achieved by employing the unconventional spectral polarization modulation technique, optimized for linear polarimetry. The polarization modulator consists of an achromatic quarter-wave retarder and a multiple-order retarder, followed by a polarizing beamsplitter, such that the incoming polarization state is encoded as a sinusoidal modulation in the intensity spectrum, where the amplitude scales with the degree of linear polarization, and the phase is determined by the angle of linear polarization. An optimized combination of birefringent crystals creates an athermal multiple-order retarder, with a uniform retardance across the field of view. Based on these specifications, SPEX is an ideal, passive remote sensing instrument for characterizing planetary atmospheres from an orbiting, air-borne or ground-based platform. By measuring the intensity and polarization spectra of sunlight that is scattered in the planetary atmosphere as a function of the single scattering angle, aerosol microphysical properties (size, shape, composition), vertical distribution and optical thickness can be derived. Such information is essential to fully understand the climate of a planet. A functional SPEX prototype has been developed and calibrated, showing excellent agreement with end-to-end performance simulations. Calibration tests show that the precision of the polarization measurements is at least 2 • 10-4. We performed multi-angle spectropolarimetric measurements of the Earth's atmosphere from the ground in conjunction with one of AERONET's sun photometers. Several applications exist for SPEX throughout the solar system, a.o. in orbit around Mars, Jupiter and the Earth, and SPEX can also be part of a ground-based aerosol monitoring network.

Characterization of telescope polarization properties across the visible and near-infrared spectrum Case study: the Dunn Solar Telescope

Abstract: Accurate astrophysical polarimetry requires a proper characterization of the polarization properties of the telescope and instrumentation employed to obtain the observations. Determining the telescope and instrument Muller matrix is becoming increasingly difficult with the increase in aperture size, precision requirements and instrument complexity of new and upcoming projects. We have carried out a detailed multi-wavelength characterization of the Dunn Solar Telescope (DST) at the National Solar Observatory/Sacramento Peak as a case study and explore various possibilites for the determination of its polarimetric properties. We show that the telescope model proposed in this paper is more suitable than that in previous work in that it describes better the wavelength dependence of aluminum-coated mirrors. We explore the adequacy of the degrees of freedom allowed by the model using a novel mathematical formalism. Finally, we investigate the use of polarimeter calibration data taken at different times of the day to characterize the telescope and find that very valuable information on the telescope properties can be obtained in this manner. The results are also consistent with the entrance window polarizer measurements. This general method opens interesting possibilities for the calibration of future large-aperture telescopes and precision polarimetric instrumentation.

Polarimetry noise in fiber-based optical coherence tomography instrumentation

Abstract: High noise levels in fiber-based polarization-sensitive optical coherence tomography (PS-OCT) have broadly limited its clinical utility. In this study we investigate contribution of polarization mode dispersion (PMD) to the polarimetry noise. We develop numerical models of the PS-OCT system including PMD and validate these models with empirical data. Using these models, we provide a framework for predicting noise levels, for processing signals to reduce noise, and for designing an optimized system.

A cryogenic waveplate rotator for polarimetry at mm and submm wavelengths

Abstract: Context. Polarimetry at mm and submm wavelengths is the new frontier of research in cosmic microwave background and interstellar dust studies. Polarimeters working in the IR to MM range need to be operated at cryogenic temperatures to limit the systematic effects related to the emission of the polarization analyzer. Aims. We study the effect of the temperature of the different components of a waveplate polarimeter and describe a system able to rotate a birefringent crystal at 4 K in a completely automated way. Methods. We simulate the main systematic effects related to the temperature and non-ideality of the optical components in a Stokes polarimeter. To limit these effects, a cryogenic implementation of the polarimeter is mandatory. In our system, the rotation produced by a step motor running at room temperature is transmitted down to cryogenic temperatures by means of a long shaft and gears running on custom cryogenic bearings. Results. Our system is able to rotate a birefringent crystal at 4 K in a completely automated way and dissipates only a few mW in the cold environment. A readout system based on optical fibers allows us to control the rotation of the crystal to better than 0.1 ◦ . Conclusions. This device fulfills the stringent requirements for operations in cryogenic space experiments, such as the forthcoming PILOT, BOOMERanG and LSPE.

Fourier transform hyperspectral imaging polarimeter for remote sensing

Abstract: Theory and simulations of a novel hyperspectral imaging polarimeter for remote sensing are presented. The spectropolarimeter is formed by cascading two laser servocontrol modified wave plates (MWP) and a polarization interference imaging spectrometer (PIIS). Using the phase modulation of the MWPs, this setup enables PIIS, originally developed by C. Zhang, to be extended for full polarization detection without dividing the interference fringes into channels as that in Oka's original channeled polarimeter. In this way, we can get the polarization information with higher spectral resolution. Besides, the data can be acquired with simpler operation. Aside from this feature, the configuration retains the advantages of both elements: the high precision phase modulation of the MWPs and the high spectral, spatial resolution, and higher throughput of the PIIS. A design example with spectral resolution 100 cm−1 and range 0.4-1.0 μm is given.

Polarimetric Doppler Radar Observations of Kelvin–Helmholtz Waves in a Winter Storm

Abstract: Kelvin–Helmholtz waves were observed by the Twin Lakes, Oklahoma (KTLX), Weather Surveillance Radar-1988 Doppler (WSR-88D); the Norman, Oklahoma (KOUN), polarimetric WSR-88D; and the polarimetric Collaborative Adaptive Sensing of the Atmosphere (CASA) radars on 30 November 2006 during a winter storm in central Oklahoma. The life cycle and structure of the waves are analyzed from the radar data, and the nearby atmospheric conditions are examined. The initial perturbations associated with the waves are first evident only in the radars’ radial velocity fields. As the waves mature, perturbations become discernable in the reflectivity factor Z and spectrum width (SW) fields of both radars, and in the differential reflectivity Zdr and, to a lesser extent, the cross-correlation coefficient ρhv fields of KOUN. As the waves break and begin to dissipate, the perturbations subside.A dual-Doppler analysis is synthesized to examine the kinematic structure of the waves and to relate the polarimetric observation...

Optical polarimetry for noninvasive glucose sensing enabled by Sagnac interferometry.

Abstract: Optical polarimetry is used in pharmaceutical drug testing and quality control for saccharide-containing products (juice, honey). More recently, it has been proposed as a method for noninvasive glucose sensing for diabetic patients. Sagnac interferometry is commonly used in optical gyroscopes, measuring minute Doppler shifts resulting from mechanical rotation. In this work, we demonstrate that Sagnac interferometers are also sensitive to optical rotation, or the rotation of linearly polarized light, and are therefore useful in optical polarimetry. Results from simulation and experiment show that Sagnac interferometers are advantageous in optical polarimetry as they are insensitive to net linear birefringence and alignment of polarization components.

Assessment of System Polarization Quality for Polarimetric SAR Imagery and Target Decomposition

Abstract: The quality of polarimetric synthetic aperture radar (PolSAR) imagery and its polarimetric decompositions depends on the accuracy of polarimetric observations of the SAR system and its calibration. Polarization distortions on the polarimetric measurement can be incurred due to nonideal system polarization quality and propagation factors, such as channel imbalance, crosstalk, and Faraday rotation at lower frequencies. All these distortions have varying impacts on different target types as well as different decomposition methods. In this paper, we assess the polarization quality of the PolSAR system in the context of polarimetric imagery analysis and quantify the various effects of polarization distortions on polarization target decompositions. A generic metric is defined to measure the polarization purity of the system. Considering the fact that target decomposition plays an important role in imagery analysis, we apply several widely used decomposition methods to showcase the polarimetric system requirement based on the defined metric. We demonstrate that this metric can be used for radar system design and polarimetric data calibration.