Abstract:Terrain classification is a hot topic in polarimetric synthetic aperture radar (PolSAR) image interpretation that aims at assigning a label to every pixel and forms a label matrix for a PolSAR image. From the perspective of human interpretation, classification is not in terms of pixels, but decomposed perceptual groups and structures. Therefore, a new perspective of label matrix completion is proposed to treat the classification task as a label matrix inversion process. Firstly, a matrix completion framework is built to avoid processing the large-scale PolSAR image data for traditional feature and classifier learning. Secondly, a light network is used to obtain the known labels for the complete task by uniform down-sampling of the entire image that aims to keep the shape of regions in a PolSAR image and reduce the computational complexity. Finally, the zeroth- and first-order label information is proposed as the prior distribution for label matrix completion to keep the structure and texture. The experiments are tested on real PolSAR images, which demonstrates that the proposed method can realize excellent classification results with less computation time and labeled pixels. Classification results with different down-sampling rates in the light network also prove the robustness of this method.Keywords: PolSAR image; label matrix completion; uniform sampling; terrain classification
LABEL MATRIX 8.0 FULL.rarl
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There are plenty of ways to gauge the performance of your classification model but none have stood the test of time like the confusion matrix. It helps us evaluate how our model performed, where it went wrong and offers us guidance to correct our path.
A Confusion matrix is an N x N matrix used for evaluating the performance of a classification model, where N is the number of target classes. The matrix compares the actual target values with those predicted by the machine learning model. This gives us a holistic view of how well our classification model is performing and what kinds of errors it is making.
And suddenly the Confusion matrix is not so confusing any more! This article should give you a solid base on how to intepret and use a confusion matrix for classification algorithms in machine learning.
Use decomposition objects to efficiently solve a linear system multiple times with different right-hand sides. decomposition objects are well-suited to solving problems that require repeated solutions, since the decomposition of the coefficient matrix does not need to be performed multiple times.
If A is full and B issparse then mldivide converts B toa full matrix and uses the full algorithm path (above) to computea solution with full storage. If A is sparse, thestorage of the solution x is the same as that of B and mldivide followsthe algorithm path for sparse inputs,shown below.
The mldivide function shows improved performance when solving linear systems A*x = b with a small coefficient matrix A. The performance improvement applies to real matrices that are 16-by-16 or smaller, and complex matrices that are 8-by-8 or smaller.
We have many options to multiply a chain of matrices because matrix multiplication is associative. In other words, no matter how we parenthesize the product, the result will be the same. For example, if we had four matrices A, B, C, and D, we would have:
However, the order in which we parenthesize the product affects the number of simple arithmetic operations needed to compute the product, or the efficiency. For example, suppose A is a 10 30 matrix, B is a 30 5 matrix, and C is a 5 60 matrix. Then,
Given an array p[] which represents the chain of matrices such that the ith matrix Ai is of dimension p[i-1] x p[i]. We need to write a function MatrixChainOrder() that should return the minimum number of multiplications needed to multiply the chain.
is the standard CSR representation where the column indices forrow i are stored in indices[indptr[i]:indptr[i+1]] and theircorresponding values are stored in data[indptr[i]:indptr[i+1]].If the shape parameter is not supplied, the matrix dimensionsare inferred from the index arrays.
The entries of a matrix can be specified as a flat list ofelements, a list of lists (i.e., a list of rows), a list of Sagevectors, a callable object, or a dictionary having positions askeys and matrix entries as values (see the examples). If you passin a callable object, then you must specify the number of rows andcolumns. You can create a matrix of zeros by passing an empty listor the integer zero for the entries. To construct a multiple ofthe identity (\(cI\)), you can specify square dimensions and pass in\(c\). Calling matrix() with a Sage object may return something thatmakes sense. Calling matrix() with a NumPy array will convert thearray to a matrix.
Two logical vectors can be used to index a matrix. In such situation, rows and columns where the value is TRUE is returned. These indexing vectors are recycled if necessary and can be mixed with integer vectors.
Enable Use overlay and the timestamps and/or labels willbe drawn in a non-destructive graphic overlay. Use the commands in theImage>Overlay submenu to hide, show or remove the overlay.Note that previously added overlays will be removed and virtual stackscan only have overlay labels.
Apart from the in silico comparisons and cultivation methods currently used, a set of isotope-probing techniques is available to directly test functional hypotheses within complex microbial communities. These methods encompass DNA-, RNA-, protein-, and lipid-stable isotope probing (SIP) [127] as well as FISH-micro-autoradiography, FISH-NanoSIMS, and FISH-Raman micro-spectroscopy, with the latter three methods offering single cell resolution [128, 129]. Recently, a microfluidic Raman activated cell sorting (RACS) platform was developed [130]. In a recent study, Lee and coworkers allowed cells from mouse colon microbiota to metabolize an unlabeled compound of interest (mucin) in a presence of deuterated water [130]. Subsequently, the deuterium labeled cells that actively metabolized mucin were sorted out from the complex microbiomes using the RACS platform and further analyzed by the means of single-cell genomics and cultivation methods. This method allows linking microbial metabolic phenotypes to their genotypes in a novel cultivation-free way, and so makes it possible to process from the microbial potential directly to the microbial function (Fig. 5). Despite its advancements, the throughput of this functional sorting platform is still limited, and complementary novel technological solutions such as the combination of FISH and bioorthogonal noncanonical amino acid tagging (BONCAT) [131] will contribute to the more urgently required phenotype-centric studies in microbiome research.
Simply put, the density matrix is an alternative way of expressing quantum states. However, unlike the state-vector representation, this formalism allows us to use the same mathematical language to describe both the more simple quantum states we've been working with so far (pure states), as well as the mixed states that consist of ensembles of pure states.
Now, all we have done so far is show a different way to represent quantum states, but there is no apparent advantage in doing so. To understand why the density matrix representation is beneficial, we need to learn about the concept of mixed states.
Here we have explicitly used the subscripts $A$ and $B$ to label the qubits associated with registers $q_1$ and $q_0$, respectively. Now, let's assume that right after preparing our state $ \psi_AB \rangle $ we perform a measurement on register $q_1$, as shown below:
So how do we, in general, represent the final state in register $q_0$ (labeled as $\psi_B$ in the diagram), not for a specific measurement outcome in $q_1$, but for an arbitrary result of this measurement process?
Although this way of expressing $\psi_B$ (or any general mixed state) is perfectly valid, it turns out to be somewhat inconvenient. Since a mixed state can consist of a myriad of pure states, it can be difficult to track how the whole ensemble evolves when, for example, gates are applied to it. It is here that we turn to the density matrix representation.
So, going back to our example, we know that since the two possible outcomes of state $\psi_B$ are $ 0_B \rangle $ or $ 1_B \rangle $, both with classical probability of occurence of $1/2$, we can construct the following density matrix for this state:
From this example, we can see how the density matrix representation can help us construct useful and realistic models that capture the effects of non-ideal (noisy) environmental or external sources on both ideal quantum states and quantum gates.
A very natural question to ask at this point is: How do mixed states evolve under unitary operations? It can be shown, with little effort, that if an initial arbitrary state $\psi_j \rangle$ with probability of occurrence $p_j$ evolves into the state $\hat U\psi_j \rangle$ after a unitary evolution, then the evolution of a density matrix, consisting of an essemble of normalized states $\\psi_j \rangle \_j = 1^n$ with probabilities $\p_j\_j = 1^n$, is given by:
On the other hand, the off-diagonal terms of the matrix are a measure of the coherence between the different basis states of the system. In other words, they can be used to quantify how a pure superposition state could evolve (decohere) into a mixed state. 2ff7e9595c
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