scholarly journals Structural Similarity Measurement Based Cost Function for Stereo Matching of Automotive Applications

2020 ◽  
Vol 6 (8) ◽  
pp. 77
Author(s):  
Oussama Zeglazi ◽  
Mohammed Rziza ◽  
Aouatif Amine ◽  
Cédric Demonceaux
Keyword(s):  
Stereo Matching ◽  
Road Traffic ◽  
Structural Information ◽  
Structural Similarity ◽  
Natural Scenes ◽  
Human Visual Perception ◽  
Adaptive Aggregation ◽  
Aggregation Technique ◽  
Image Gradients ◽  
Two Stages

The human visual perception uses structural information to recognize stereo correspondences in natural scenes. Therefore, structural information is important to build an efficient stereo matching algorithm. In this paper, we demonstrate that incorporating the structural information similarity, extracted either from image intensity (SSIM) directly or from image gradients (GSSIM), between two patches can accurately describe the patch structures and, thus, provides more reliable initial cost values. We also address one of the major phenomenons faced in stereo matching for real world scenes, radiometric changes. The performance of the proposed cost functions was evaluated within two stages: the first one considers these costs without aggregation process while the second stage uses the fast adaptive aggregation technique. The experiments were conducted on the real road traffic scenes KITTI 2012 and KITTI 2015 benchmarks. The obtained results demonstrate the potential merits of the proposed stereo similarity measurements under radiometric changes.

Fused Image Quality Measure Based on Structural Similarity

2011 ◽  
Vol 255-260 ◽  
pp. 2072-2076
Author(s):  
Yi Yong Han ◽  
Jun Ju Zhang ◽  
Ben Kang Chang ◽  
Yi Hui Yuan ◽  
Hui Xu
Keyword(s):  
Image Fusion ◽  
Structural Information ◽  
Similarity Index ◽  
Structural Similarity ◽  
Reference Image ◽  
Human Visual Perception ◽  
Subjective Evaluations ◽  
Fused Image ◽  
Fusion Methods ◽  
Image Quality Measure

Under the assumption that human visual perception is highly adapted for extracting structural information from a scene, we present a new approach using structural similarity index for assessing quality in image fusion. The advantages of our measures are that they do not require a reference image and can be easily computed. Numerous simulations demonstrate that our measures are conform to subjective evaluations and can be able to assess different image fusion methods.

scholarly journals Objective Numerical Evaluation of Diffuse, Optically Reconstructed Images Using Structural Similarity Index

Biosensors ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 504
Author(s):  
Vicky Mudeng ◽  
Minseok Kim ◽  
Se-woon Choe
Keyword(s):  
Structural Information ◽  
Optical Tomography ◽  
Similarity Index ◽  
Structural Similarity ◽  
Similarity Score ◽  
Human Visual Perception ◽  
Structural Similarity Index ◽  
Non Invasive ◽  
Numerical Assessment ◽  
Sharpness Parameter

Diffuse optical tomography is emerging as a non-invasive optical modality used to evaluate tissue information by obtaining the optical properties’ distribution. Two procedures are performed to produce reconstructed absorption and reduced scattering images, which provide structural information that can be used to locate inclusions within tissues with the assistance of a known light intensity around the boundary. These methods are referred to as a forward problem and an inverse solution. Once the reconstructed image is obtained, a subjective measurement is used as the conventional way to assess the image. Hence, in this study, we developed an algorithm designed to numerically assess reconstructed images to identify inclusions using the structural similarity (SSIM) index. We compared four SSIM algorithms with 168 simulated reconstructed images involving the same inclusion position with different contrast ratios and inclusion sizes. A multiscale, improved SSIM containing a sharpness parameter (MS-ISSIM-S) was proposed to represent the potential evaluation compared with the human visible perception. The results indicated that the proposed MS-ISSIM-S is suitable for human visual perception by demonstrating a reduction of similarity score related to various contrasts with a similar size of inclusion; thus, this metric is promising for the objective numerical assessment of diffuse, optically reconstructed images.

scholarly journals Structure and lipid-mediated remodelling mechanism of the Na+/H+ exchanger NHA2

2021 ◽  
Author(s):  
Rei Matsuoka ◽  
Roman Fudim ◽  
Sukkyeong Jung ◽  
Chenou Zhang ◽  
Andre Bazzone ◽  
...  
Keyword(s):  
Ion Exchange ◽  
Structural Information ◽  
Salt Bridge ◽  
Structural Similarity ◽  
Ion Binding ◽  
Transport Activity ◽  
Regulation Of Transport ◽  
Fine Tune ◽  
Exchange Activity

Na+/H+ exchangers catalyse an ion-exchange activity that is carried out in most, if not all cells. SLC9B2, also known as NHA2, correlates with the long-sought after sodium/lithium (Na+/Li+) exchanger linked to the pathogenesis of diabetes mellitus and essential hypertension in humans. Despite its functional importance, structural information and the molecular basis of its ion-exchange mechanism have been lacking. Here, we report the cryo EM structures of bison NHA2 in detergent and in nanodiscs at 3.0 and 3.5 Å resolution, respectively. NHA2 shares closest structural similarity to the bacterial electrogenic Na+/H+ antiporter NapA, rather than other mammalian SLC9A members. Nevertheless, SSM-based electrophysiology results with NHA2 show the catalysis of electroneutral rather than electrogenic ion exchange, and the ion binding site is quite distinctive, with a tryptophan arginine-glutamate triad separated from the well established ion-binding aspartates. These triad residues fine-tune ion binding specificity, as demonstrated by a salt-bridge swap mutant that converts NHA2 into a Li+ specific transporter. Strikingly, an additional N terminal helix in NHA2 establishes a unique homodimer with a large ~ 25 Å intracellular gap between protomers. In the presence of phosphatidylinositol lipids, the N-terminal helix rearranges and closes this gap. We confirm that dimerization of NHA2 is required for activity in vivo, and propose that the N- terminal helix has evolved as a lipid-mediated remodelling switch for regulation of transport activity.

A compensating total variation image denoising model combining L1 and L2 norm

2020 ◽  
pp. 002072092092330
Author(s):  
Liqiong Zhang ◽  
Min Li ◽  
Xiaohua Qiu
Keyword(s):  
Image Denoising ◽  
Total Variation ◽  
Structural Information ◽  
Signal To Noise Ratio ◽  
Similarity Index ◽  
Structural Similarity ◽  
Isotropic Diffusion ◽  
Model Combining ◽  
L2 Norm ◽  
Staircase Effect

To overcome the “staircase effect” while preserving the structural information such as image edges and textures quickly and effectively, we propose a compensating total variation image denoising model combining L1 and L2 norm. A new compensating regular term is designed, which can perform anisotropic and isotropic diffusion in image denoising, thus making up for insufficient diffusion in the total variation model. The algorithm first uses local standard deviation to distinguish neighborhood types. Then, the anisotropic diffusion based on L1 norm plays the role of edge protection in the strong edge region. The anisotropic and the isotropic diffusion simultaneously exist in the smooth region, so that the weak textures can be protected while overcoming the “staircase effect” effectively. The simulation experiments show that this method can effectively improve the peak signal-to-noise ratio and obtain the higher structural similarity index and the shorter running time.

scholarly journals Structural basis for the transformation pathways of the sodium naproxen anhydrate–hydrate system

IUCrJ ◽  
2014 ◽  
Vol 1 (5) ◽  
pp. 328-337 ◽  
Author(s):  
Andrew D. Bond ◽  
Claus Cornett ◽  
Flemming H. Larsen ◽  
Haiyan Qu ◽  
Dhara Raijada ◽  
...  
Keyword(s):  
Solid State ◽  
Density Functional ◽  
Structural Information ◽  
Structural Similarity ◽  
Structural Basis ◽  
X Ray Diffraction ◽  
Functional Theory ◽  
Face To Face ◽  
Transformation Pathways ◽  
Dehydration Processes

Crystal structures are presented for two dihydrate polymorphs (DH-I and DH-II) of the non-steroidal anti-inflammatory drug sodium (S)-naproxen. The structure of DH-I is determined from twinned single crystals obtained by solution crystallization. DH-II is obtained by solid-state routes, and its structure is derived using powder X-ray diffraction, solid-state13C and23Na MAS NMR, and molecular modelling. The validity of both structures is supported by dispersion-corrected density functional theory (DFT-D) calculations. The structures of DH-I and DH-II, and in particular their relationships to the monohydrate (MH) and anhydrate (AH) structures, provide a basis to rationalize the observed transformation pathways in the sodium (S)-naproxen anhydrate–hydrate system. All structures contain Na+/carboxylate/H2O sections, alternating with sections containing the naproxen molecules. The structure of DH-I is essentially identical to MH in the naproxen region, containing face-to-face arrangements of the naphthalene rings, whereas the structure of DH-II is comparable to AH in the naproxen region, containing edge-to-face arrangements of the naphthalene rings. This structural similarity permits topotactic transformation between AH and DH-II, and between MH and DH-I, but requires re-organization of the naproxen molecules for transformation between any other pair of structures. The topotactic pathways dominate at room temperature or below, while the non-topotactic pathways become active at higher temperatures. Thermochemical data for the dehydration processes are rationalized in the light of this new structural information.

scholarly journals RNA Packaging Motor: From Structure to Quantum Mechanical Modelling and Sequential-Stochastic Mechanism

2008 ◽  
Vol 9 (3-4) ◽  
pp. 351-369 ◽  
Author(s):  
Jelena Telenius ◽  
Anders E. Wallin ◽  
Michal Straka ◽  
Hongbo Zhang ◽  
Erika J. Mancini ◽  
...  
Keyword(s):  
Conformational Changes ◽  
Atp Hydrolysis ◽  
Structural Information ◽  
Molecular Motor ◽  
Structural Similarity ◽  
Binding Pocket ◽  
Reaction Coordinate ◽  
Rna Packaging ◽  
Cooperative Action ◽  
Empty Capsid

The bacteriophages of theCystoviridaefamily package their single stranded RNA genomic precursors into empty capsid (procapsids) using a hexameric packaging ATPase motor (P4). This molecular motor shares sequence and structural similarity with RecA-like hexameric helicases. A concerted structural, mutational and kinetic analysis helped to define the mechanical reaction coordinate,i.e.the conformational changes associated with RNA translocation. The results also allowed us to propose a possible scheme of coupling between ATP hydrolysis and translocation which requires the cooperative action of three consecutive subunits. Here, we first test this model by preparing hexamers with defined proportions of wild type and mutant subunits and measuring their activity. Then, we develop a stochastic kinetic model which accounts for the catalytic cooperativity of the P4 hexamer. Finally, we use the available structural information to construct a quantum-chemical model of the chemical reaction coordinate and obtain a detailed description of the electron density changes during ATP hydrolysis. The model explains the results of the mutational analyses and yields new insights into the role of several conserved residues within the ATP binding pocket. These hypotheses will guide future experimental work.

scholarly journals Mice use robust and common strategies to discriminate natural scenes

2017 ◽  
Author(s):  
Yiyi Yu ◽  
Riichiro Hira ◽  
Jeffrey N. Stirman ◽  
Waylin Yu ◽  
Ikuko T. Smith ◽  
...  
Keyword(s):  
Gabor Filter ◽  
Discrimination Performance ◽  
Structural Similarity ◽  
Orientation Dependence ◽  
Natural Scenes ◽  
Natural Environments ◽  
Natural Scene ◽  
Image Metrics ◽  
Screen System ◽  
Mouse Vision

AbstractMice use vision to navigate and avoid predators in natural environments. However, the spatial resolution of mouse vision is poor compared to primates, and mice lack a fovea. Thus, it is unclear how well mice can discriminate ethologically relevant scenes. Here, we examined natural scene discrimination in mice using an automated touch-screen system. We estimated the discrimination difficulty using the computational metric structural similarity (SSIM), and constructed psychometric curves. However, the performance of each mouse was better predicted by the population mean than SSIM. This high inter-mouse agreement indicates that mice use common and robust strategies to discriminate natural scenes. We tested several other image metrics to find an alternative to SSIM for predicting discrimination performance. We found that a simple, primary visual cortex (V1)-inspired model predicted mouse performance with fidelity approaching the inter-mouse agreement. The model involved convolving the images with Gabor filters, and its performance varied with the orientation of the Gabor filter. This orientation dependence was driven by the stimuli, rather than an innate biological feature. Together, these results indicate that mice are adept at discriminating natural scenes, and their performance is well predicted by simple models of V1 processing.

ALGORITHMS OF STRUCTURAL AND PARAMETRICAL TUNING OF ADAPTIVE OBSERVERS

2020 ◽  
Vol 13 (2) ◽  
pp. 39-47
Author(s):  
Konstantin Mukhanov
Keyword(s):  
Nonlinear System ◽  
Nonlinear Systems ◽  
Structural Information ◽  
Structural Parameters ◽  
Adaptive Algorithms ◽  
Parametric Identification ◽  
Adaptive Observers ◽  
Structural Stage ◽  
Two Stages

This paper deals with the identification of nonlinear systems of adaptive observers (AO). The process of building an AH consists of two stages – structural and parametric. At the structural stage, the class of nonlinearity and its structural parameters are estimated. In the process of parametric identification, the adjustment of the obtained parameters of the nonlinear system takes place. Considered two cases of application of structural information. The main focus is on the case of insufficient structural information. Adaptive algorithms for setting the parameters of AO are proposed. A procedure for estimating uncertainty is proposed.

scholarly journals Deep Color Transfer for Color-Plus-Mono Dual Cameras

Sensors ◽  
2020 ◽  
Vol 20 (9) ◽  
pp. 2743
Author(s):  
Hae Woong Jang ◽  
Yong Ju Jung
Keyword(s):  
Image Fusion ◽  
Stereo Matching ◽  
Color Image ◽  
Structural Information ◽  
Just Noticeable Difference ◽  
Color Transfer ◽  
Fused Image ◽  
Visual Artifacts ◽  
Transfer Method ◽  
Deep Learning Model

A few approaches have studied image fusion using color-plus-mono dual cameras to improve the image quality in low-light shooting. Among them, the color transfer approach, which transfers the color information of a color image to a mono image, is considered to be promising for obtaining improved images with less noise and more detail. However, the color transfer algorithms rely heavily on appropriate color hints from a given color image. Unreliable color hints caused by errors in stereo matching of a color-plus-mono image pair can generate various visual artifacts in the final fused image. This study proposes a novel color transfer method that seeks reliable color hints from a color image and colorizes a corresponding mono image with reliable color hints that are based on a deep learning model. Specifically, a color-hint-based mask generation algorithm is developed to obtain reliable color hints. It removes unreliable color pixels using a reliability map computed by the binocular just-noticeable-difference model. In addition, a deep colorization network that utilizes structural information is proposed for solving the color bleeding artifact problem. The experimental results demonstrate that the proposed method provides better results than the existing image fusion algorithms for dual cameras.

scholarly journals Using the Natural Scenes’ Edges for Assessing Image Quality Blindly and Efficiently

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Saifeldeen Abdalmajeed ◽  
Jiao Shuhong
Keyword(s):  
Image Quality ◽  
Image Quality Assessment ◽  
Signal To Noise Ratio ◽  
Structural Similarity ◽  
Natural Image ◽  
Natural Scenes ◽  
Signal To Noise ◽  
Enhanced Sensitivity ◽  
Full Reference ◽  
Distortion Type

Two real blind/no-reference (NR) image quality assessment (IQA) algorithms in the spatial domain are developed. To measure image quality, the introduced approach uses an unprecedented concept for gathering a set of novel features based on edges of natural scenes. The enhanced sensitivity of the human eye to the information carried by edge and contour of an image supports this claim. The effectiveness of the proposed technique in quantifying image quality has been studied. The gathered features are formed using both Weibull distribution statistics and two sharpness functions to devise two separate NR IQA algorithms. The presented algorithms do not need training on databases of human judgments or even prior knowledge about expected distortions, so they are real NR IQA algorithms. In contrast to the most general no-reference IQA, the model used for this study is generic and has been created in such a way that it is not specified to any particular distortion type. When testing the proposed algorithms on LIVE database, experiments show that they correlate well with subjective opinion scores. They also show that the introduced methods significantly outperform the popular full-reference peak signal-to-noise ratio (PSNR) and the structural similarity (SSIM) methods. Besides they outperform the recently developed NR natural image quality evaluator (NIQE) model.

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