nils-herrmann/clean_scirepeval huggingface dataset:
Multiresolution stochastic models for the efficient solution of large-scale space-time estimation problems

The successful application of a previously developed tree-based multiscale estimation framework to large-scale static estimation problems has proven the statistical flexibility and the computational efficiency of the framework. However, the estimation of processes evolving in time remains a considerable challenge. We address this challenge by investigating multiscale models for the steady-state estimation of dynamic systems. In particular, we build such models for 1-D and 2-D heat diffusion processes, making use of a canonical correlations realization technique. The problem of the assimilation of satellite altimetric measurements of the dynamic ocean surface over time is also addressed.
A Bayesian Information Flow Approach to Image Segmentation

A novel Bayesian information flow approach is presented for accurate image segmentation, formulated as a maximum a posteriori (MAP) problem as per the popular Mumford-Shah (MS) model. The model is solved using an iterative Bayesian estimation approach conditioned on the flow of information within the image, where the flow is based on inter-pixel interactions and intra-region smoothness constraints. In this way, a localized and accurate Bayesian estimate of the underlying piece-wise constant regions within an image can be found, even under high noise and low contrast situations. Experimental results using 2-D images show that the proposed Bayesian information flow approach is capable of producing more accurate segmentations when compared to state-of-the-art segmentation methods, especially under scenarios with high noise levels and poor contrast.
Multi-scale tensor vector field active contour

Two major challenges faced in active contours are poor capture range and high sensitivity towards noise. Recently, the concept of tensor vector convolution (TVF) was introduced and shown to be promising in handling these challenges. However, in the presence of high noise levels, TVF may have difficulty in converging to the desired object boundary, particularly if the distance is great between the initial contour and the object boundary. To tackle this challenge, the concept of a multi-scale tensor vector field (MTVF) active contour is introduced to further reduce noise sensitivity. Comparing the performance of MTVF with multi-scale gradient vector field and multi-scale vector field convolution demonstrates that MTVF is more resilient to high noise levels as well as significantly reducing computation time.
Foveated multiscale models for large-scale estimation

Efficient, large-scale estimation methods such as nested dissection or multiscale estimation rely on a divide-and-conquer strategy, in which a statistical problem is conditionally broken into smaller pieces. This conditional decorrelation is not possible for arbitrarily large problems due to issues of computational complexity and numerical stability. Given the growing interest in global-scale-remote sensing problems (or even three-dimensional problems), in this summary we develop a class of estimators with more promising asymptotic computational properties.
Incremental shape reconstruction using stereo image sequences

The limitations of estimating structure from either stereo or motion alone can be addressed by the use of stereo image sequences; however, many existing techniques for processing stereo sequences rely on having accurate feature correspondences initially. We present an iterative feature matching and shape reconstruction algorithm. The proposed method simultaneously resolves matching ambiguities by multiple hypothesis testing and develops an incrementally accurate and dense representation of the reconstructed object. This approach uses minimal domain specific constraints and can be easily generalised. The method's potential is demonstrated in a space vision application.
BRINT: A binary rotation invariant and noise tolerant texture descriptor

Local Binary Pattern (LBP) and its variants are effective and popular descriptors for texture classification. Most LBP like descriptors have disadvantages including sensitiveness to noise and inability to capture long distance texture information. In this paper we propose a simple, efficient, yet robust multi-resolution descriptor to texture classification - Binary Rotation Invariant and Noise Tolerant (BRINT). The proposed descriptor is very fast to build, very compact while remaining robust to illumination variations, rotation changes and noise. We develop a novel and simple strategy - averaging before binarization - to compute a local binary descriptor based on the conventional LBP approach. Points are sampled in a circular neighborhood, but keeping the number of bins in a single-scale LBP histogram constant and small by averaging over several contiguous pixels in the circle. There is no need for pre-training, no texton dictionary, and no tuning of parameters to deal with different datasets. Experiments on the Outex test suite demonstrate that the proposed approach is very robust to noise and significantly outperforms the state-of-the-art in terms of classifying noise corrupted textures.
Analysis of corneal images for assessing contact lens trauma

Contact lens wearers are often affected by a condition known as conjuctival hyperaemia. This condition is characterised by dilated blood vessels visible in the sclera (the white portion of the eye). Optometrists need to be able to detect changes in the level of redness and to repeatably assess the absolute levels of redness found in a patient's eye in order to prescribe and evaluate treatment. The goal of this paper is to develop an automated method for grading the level of redness in human eyes. The selected features examine the average redness and length of arterial edges. The computed features are correlated with expert data collected to train the redness estimator.
Statistical fusion and sampling of scientific images

Porous media are an important class of heterogeneous materials possessing complex random structures. Due to the limitation in measuring high resolution real samples, studying different physical properties of porous media requires the reconstruction of artificial samples. In many cases of significant interest, we have a two-scale reconstruction, in which only the large scales are resolved by low resolution measurements, leaving fine scales to be inferred from statistical models. In this paper we propose a statistical fusion approach for a two-scale porous media reconstruction, in which low resolution measurements are fused with high resolution samples, with synthetic realizations generated by posterior sampling.
Data fusion of sea-surface temperature data

The problem of data fusion, the merging of data taken by different sensors, becomes ever more relevant with the launch of each new remote-sensing platform. One example of considerable current interest in the climate change community is the production of an improved sea surface temperature (SST) map. In particular, two state-of-the-art instruments - the Along Track Scanning Radiometer (ATSR) and AVHRR - share complementary features: ATSR allows excellent cloud discrimination and atmospheric correction based on its dual-view scanning geometry, but observes only narrow swaths of ocean; AVHRR suffers from low-wavenumber atmospheric distortions and cloud contamination, but has extensive global coverage. The authors propose a methodology for combining ocean skin temperatures from the ATSR and AVHRR instruments to produce a continuous analysis at one-sixth degree spatial and three-day temporal resolutions, together with reliable error estimates, from the fusion of multiple datasets with arbitrary sampling characteristics, resulting in estimated temperatures which unite the precision of ATSR with the superior coverage afforded by AVHRR.
A structure-guided conditional sampling model for video resolution enhancement

In this paper, a novel approach is introduced to video resolution enhancement based on a structure-guided conditional sampling model. The proposed conditional sampling model is composed of hybrid models to handle strongly structured and weakly structured regions separately. To accomplish this, a binary hidden field indicating image structure is introduced into the conditional reconstruction process for estimating the high resolution video frames from the low resolution video frames. Preliminary results show that the proposed approach has the potential to produce high resolution video frames with improved image quality when compared to existing structure-guided video resolution enhancement approaches.
A new Bayesian source separation approach to blind decorrelation of SAR data

In this paper, a novel approach for performing blind decorrelation of SAR data is proposed. A patch-wise computation of the point-spread function (PSF) is performed directly from the SAR data to account for spatial nonstationarities present in SAR. The problem of estimating the PSF is formulated as an additive source separation problem in the frequency domain, and is subsequently solved using a Bayesian least squares estimation approach based on a Fisher-Tippett log-scatter model. Experimental results using both simulated SAR data and real RADARSAT-2 SAR sea-ice data showed that the proposed decorrelation approach can successfully learn the correct PSF and significantly reduce the correlation in SAR data.
A Combined Bayesshrinkwavelet-Ridgelet Technique for Image Denoising

In this paper a combined Bayesshrink wavelet-ridgelet de-noising method is presented. In our previous work we have showed that Bayesshrink ridgelet performs better than Visushrink ridgelet and Visushrink wavelet. Although our Bayesshrink ridgelet technique performs somewhat poorer in comparison with Bayesshrink wavelet, based on SNR, visually it produces smoother results, especially for images with straight lines. In the proposed method Bayesshrink wavelet is combined with Bayesshrink ridgelet denoising method which performs better than each filter individually. The proposed combined denoising method gains the advantage of each filter in its specific domain, i.e., wavelet for natural and ridgelet for straight regions, and produces better and smoother results, both visually and in terms of SNR
Scalable multi-neighborhood learning for convolutional networks

In this paper we explore the role of scale for improved feature learning in convolutional networks. We propose multi-neighborhood convolutional networks, designed to learn image features at different levels of detail. Utilizing nonlinear scale-space models, the proposed multi-neighborhood model can effectively capture fine-scale image characteristics (i.e., appearance) using a small-size neighborhood, while coarse-scale image structures (i.e., shape) are detected through a larger neighborhood. In addition, we introduce a scalable learning method for the proposed multi-neighborhood architecture and show how one can use an already-trained single-scale network to extract image features at multiple levels of detail. The experimental results demonstrate the superior performance of the proposed multi-scale multi-neighborhood models over their single-scale counterparts without an increase in training cost.
Stem-Cell Localization: A Deconvolution Problem

Hematopoietic Stem Cells (HSCs) form blood and immune cells and are responsible for the constant renewal of blood. To produce new blood cells, HSCs proliferate and differentiate to different blood cell types continuously during their lifetime. Hence they are of substantial interest in stem cell therapy and cancer research. To classify HSCs to different groups, they must be observed/tracked over time and their key features including cell size, shape, and motility must be extracted. The manual tracking is an onerous task and automated methods are in high demand. The first stage of an semi-automatic/automatic tracking system is cell segmentation. In our previous work we addressed the cell segmentation/localization problem. Modelling adjacent or splitting cells is very challenging and our previous methods might fail to accurately model a group of adjacent cells or a splitting cell. In this paper we address this issue and propose a deconvolution method to precisely model individual HSCs as well as adjacent (splitting) HSCs. An optimization algorithm is combined with a template matching method to segment cell regions and locate the cell centers.
Efficient Deep Feature Learning and Extraction via StochasticNets

Deep neural networks are a powerful tool for feature learning and extraction. One area worth exploring in feature extraction using deep neural networks is efficient neural connectivity formation for faster feature learning and extraction. Motivated by findings of stochastic synaptic connectivity formation in the brain as well as the brain's uncanny ability to efficiently represent information, we propose the efficient learning and extraction of features via StochasticNets, where sparsely-connected deep neural networks can be formed via stochastic connectivity between neurons. Experimental results show that features learned using deep convolutional StochasticNets, with fewer neural connections than conventional deep convolutional neural networks, can allow for better or comparable classification accuracy than conventional deep neural networks. Finally, it was also shown that significant gains in feature extraction speed can be achieved in embedded applications using StochasticNets.
A probabilistic framework for image segmentation

A new probabilistic image segmentation model based on hypothesis testing and Gibbs random fields is introduced. First, a probabilistic difference measure derived from a set of hypothesis tests is introduced. Next, a Gibbs/Markov random field model endowed with the new measure is then applied to the image segmentation problem to determine the segmented image directly through energy minimization. The Gibbs/Markov random fields approach permits us to construct a rigorous computational framework where local and regional constraints can be globally optimized. Results on grayscale and color images are encouraging.
Undecimated hierarchical active contours for oct image segmentation

A limitation of Optical Coherence Tomography (OCT) image segmentation is the poor signal-to-noise ratio of the imaging process, particularly because images are sampled quickly, at high resolutions, and in-vivo. Furthermore, speckle noise is generated by the reflections of the OCT LASER. Because OCT is widely used in imaging the cornea, retina, and skin, OCT layer segmentation is of key interest in all applications. In this paper, a multi-resolution parametric active contour is used for OCT segmentation. The proposed method uses an undecimated wavelet transform to obtain scale-dependent noise reduction, while the active contour is initialized with a generalized Hough transform. Experimental results show that the proposed method outperforms classical as well as state-of-the-art methods and segments OCT images with high level of accuracy.
Extended local binary pattern fusion for face recognition

This paper presents a simple, novel, yet highly effective approach for robust face recognition. Given LBP-like descriptors based on local accumulated pixel differences, Angular Differences (AD) and Radial Differences (RD), the local differences are decomposed into complementary components of signs and magnitudes. The proposed descriptors have desirable features: (1) robustness to lighting, pose, and expression; (2) computation efficiency; (3) encoding of both microstructures and macrostructures; (4) consistent in form with traditional LBP, thus inheriting the merits of LBP; and (5) no required training, improving generalizability. From a given face image, we obtain six histogram features, each of which is obtained by concatenating spatial histograms extracted from nonoverlapping subregions. The Whitened PCA technique is used for dimensionality reduction, followed by Nearest Neighbor classification. We have evaluated the effectiveness of the proposed method on the Extended Yale B and CAS-PEAL-R1 databases. The proposed method impressively outperforms other well known systems, including what we believe to be the best reported performance for the the CAS-PEAL-R1 lighting probe set with a recognition rate of 72.3%.
Motion estimation of sparse, remotely-sensed fields

Sea surface temperature (SST) can be estimated from remotely-sensed images. Because of the sparsity of the available observation it is ideal to do estimation using dynamic methods (such as Kalman filtering). To model dynamics of SST accurately we need to know the motion of sea current. The traditional video motion estimation problem is straightforward, in some ways, because there are so few constraints. That is, the motion vectors are pretty much arbitrary, and successive image frames are densely pixellated, have the same number of pixels, with similar noise statistics. However there are many motion estimation problems, particularly in the area of remote sensing, which do not share these properties. In this paper we investigate the problem of determining the motion field of the sea surface, based on infrared measurements of surface temperature. This problem is challenging in that only a subset of the whole domain is measured at each point in time; specifically, only a few stripes are imaged. In addition, because of clouds, the measured subset varies from time to time. The quality (level of noise) can also vary from pixel to pixel. Our research is based on the following assumptions and observations: the motion field should be smooth and ideally divergence-free, i.e. the motion field is close to time-stationary. Based on these assumptions we choose to use optical flow method for this motion problem. We handle difficulty of data sparcity by pre-estimation to get a dense field. Pre-estimation can be refined by integrating this motion estimation result.
Improved fine structure modeling via guided stochastic clique formation in fully connected conditional random fields

Markov random fields (MRFs) and conditional random fields (CRFs) are influential tools in image modeling, particularly for applications such as image segmentation. Local MRFs and CRFs utilize local nodal interactions when modeling, leading to excessive smoothness on boundaries (i.e., the short-boundary bias problem). Recently, the concept of fully connected conditional random fields with stochastic cliques (SFCRF) was proposed to enable long-range nodal interactions while addressing the computational complexity associated with fully connected random fields. While SFCRF was shown to provide significant improvements in segmentation accuracy, there were still limitations with the preservation of fine structure boundaries. To address these limitations, we propose a new approach to stochastic clique formation for fully connected random fields (G-SFCRF) that is guided by the structural characteristics of different nodes within the random field. In particular, fine structures surrounding a node are modeled statistically by probability distributions, and stochastic cliques are formed by considering the statistical similarities between nodes within the random fields. Experimental results show that G-SFCRF outperforms existing fully connected CRF frameworks, SFCRF, and the principled deep random field framework for image segmentation.
Combining sorted random features for texture classification

This paper explores the combining of powerful local texture descriptors and the advantages over single descriptors for texture classification. The proposed system is composed of three components: (i) highly discriminative and robust sorted random projections (SRP) features; (ii) a global Bag-of-Words (BoW) model; and (iii) the use of multiple kernel Support Vector Machines (SVMs) combining multiple features. The proposed system is also very simple, stemming from (1) the effortless extraction of the SRP features, (2) the simple orderless histogramming in the BoW model, (3) a strategy with low computational complexity for multiple kernel SVMs. We have tested our texture classification system on three popular and challenging texture databases and find that the SVMs combining of SRP features produces outstanding classification results, outperforming the state-of-the-art for CUReT (99.37%) and KTH-TIPS (99.29%), and with highly competitive results for UIUC (98.56%).
Multiply-rooted multiscale models for large-scale estimation

Divide-and-conquer or multiscale techniques have become popular for solving large statistical estimation problems. The methods rely on defining a state which conditionally decorrelates the large problem into multiple subproblems, each more straightforward than the original. However this step cannot be carried out for asymptotically large problems since the dimension of the state grows without bound, leading to problems of computational complexity and numerical stability. In this paper, we propose a new approach to hierarchical estimation in which the conditional decorrelation of arbitrarily large regions is avoided, and the problem is instead addressed piece-by-piece. The approach possesses promising attributes: it is not a local method-the estimate at every point is based on all measurements; it is numerically stable for problems of arbitrary size; and the approach retains the benefits of the multiscale framework on which it is based: a broad class of statistical models, a stochastic realization theory, an algorithm to calculate statistical likelihoods, and the ability to fuse local and nonlocal measurements.
Towards random field modeling of wavelet statistics

The paper investigates the statistical characterization of signals and images in the wavelet domain. In particular, in contrast to common decorrelated-coefficient models, we find that the correlation between wavelet scales can be surprisingly substantial, even across several scales. We investigate possible choices of statistical-interaction models. One efficient and fast strategy which describes the wavelet-based statistical correlations is illustrated. Finally, the effectiveness of the proposed tool towards an efficient hierarchical MRF (Markov random field) modeling of within-scale neighborhoods and across-scale dependencies is demonstrated.
Efficient Globally Optimal Registration of Remote Sensing Imagery via Quasi-Random Scale-Space Structural Correlation Energy Functional

A novel energy functional for automatic registration of remote sensing imagery based on quasi-random scale-space structural correlation is presented. The structural correlation energy functional takes advantage of the fact that, for many types of remote sensing imagery, there exist common structures at different scales even if the acquired images have very different intensity characteristics. The proposed energy functional also takes advantage of the noise robustness and feature localization properties of quasi-random scale-space theory. An efficient globally exhaustive optimization strategy in the frequency domain is developed for registering remote sensing imagery based on the proposed energy functional. Promising test results on interband, intraband, and intermodal remote sensing image sets show that the proposed method has the advantage of being robust to differing sensing conditions and large misalignments.
Hierarchical Markov models for wavelet-domain statistics

There is a growing realization that modeling wavelet coefficients as statistically independent may be a poor assumption. Thus, this paper investigates two efficient models for wavelet coefficient coupling. Spatial statistics which are Markov (commonly used for textures and other random imagery) do not preserve their Markov properties in the wavelet domain; that is, the wavelet-domain covariance P/sub w/ does not have a sparse inverse. The main theme of this work is to investigate the approximation of P/sub w/ by hierarchical Markov and non-Markov models.