Variational Registration of Multiple Images with the SVD based SqN Distance Measure

Image registration, especially the quantification of image similarity, is an important task in image processing. Various approaches for the comparison of two images are discussed in the literature. However, although most of these approaches perform very well in a two image scenario, an extension to a multiple images scenario deserves attention. In this article, we discuss and compare registration methods for multiple images. Our key assumption is, that information about the singular values of a feature matrix of images can be used for alignment. We introduce, discuss and relate three recent approaches from the literature: the Schatten q-norm based SqN distance measure, a rank based approach, and a feature volume based approach. We also present results for typical applications such as dynamic image sequences or stacks of histological sections. Our results indicate that the SqN approach is in fact a suitable distance measure for image registration. Moreover, our examples also indicate that the results obtained by SqN are superior to those obtained by its competitors.Comment: 12 pages, 5 figures, accepted at the conference "Scale Space and Variational Methods" in Hofgeismar, Germany 201

A new framework for morphological and morphometric study of fish species based on groupwise registration of otolith images.

Morphology of bones, teeth, and some particular structures are widely used for categorizing species and studying their evolution. In this paper, we used groupwise registration to provide a representative image from the set of the image samples that represents its typical morphology. We also provided perturbation map which indicates the deviation of each point through the morphology of structures in different species. The perturbation map can be further exploited for determining appropriate landmarks for morphometric analysis. Knowing the deformation between the prototype and each image sample from the species, the framework allows for automatic detection of corresponding points. Once the user puts a landmark on the prototype image, the corresponding points on all the image samples will be determined. This maximizes the accuracy in measuring the morphological indices by eliminating the human error due to uncertainty in locating landmarks

A soluble conducting polymer of 2,5-di(thiophen-2-yl)-1-p-tolyl-1H-pyrrole and its electrochromic device

A monomer 2,5-di(thiophen-2-yl)-1-p-tolyl-1H-pyrrole was synthesized via reaction of 1,4-di(2-thienyl)-1,4-butanedione and p-toluidine in the presence of catalytical amount of p-toluenesulfonic acid. Chemical polymerization of the monomer yielded a soluble polymer. The average molecular weight was determined by gel permeation chromatography as number average molecular weight (Mn) 2.5 x 10(3) g/mol. The monomer was also electrochemically polymerized in the presence of LiClO4, NaClO4 (1:1) as the supporting electrolyte in acetonitrile. Cyclic Voltammetry, Fourier Transform Infra Red, Nuclear Magnetic Resonance, Scanning Electron Microscopy and Ultraviolet-Visible Spectroscopy were employed for the characterization of the polymer. Spectroelectrochemistry analysis of homopolymer revealed an electronic transition at 428 nm which corresponds to pi-pi* transition. Switching ability of the homopolymer was evaluated by kinetic studies upon measuring the percent transmittance (%T) at the maximum contrast point, indicating that poly(2,5-di(thiophen-2-yl)-l-p-tolyl-IH-pyrrole) is a suitable material for electrochromic devices

Benzyl substituted benzotriazole containing conjugated polymers: Effect of position of the substituent on electrochromic properties

New classes of EDOT coupled-benzotriazole bearing pi-conjugated monomers containing benzyl units on electron-withdrawing benzotriazole moiety were synthesized. The effect of structural differences on electrochemical and optoelectronic properties of the resulting polymers (PBBTES and PBBTEA) was investigated. The results showed that the insertion of benzyl substituent to benzotriazole from different positions changes the electronic structure of polymer which results in completely different electrochemical and optical properties. PBBTES has a very low oxidation potential (0.13V) compared to the oxidation potential of PBBTEA (0.98 V). Spectroelectrochemical analyses revealed that PBBTES is blue in its neutral state with a pi-pi* transition at 625 nm whereas PBBTEA is orange in its neutral state with a pi-pi* transition at 477 nm. The band gap (E(g)) values for PBBTES and PBBTEA were calculated as 1.48 eV and 1.57 eV, respectively. PBBTEA can be switched between blue neutral state and light blue oxidized state while PBBTEA reveals orange color at the neutral state and gray color at oxidized state

Electrochromic properties of a novel low band gap conductive copolymer

A copolymer of 2,5-di(thiophen-2-yl)-1-p-tolyl-1H-pyrrole (DTTP) with 3,4-ethylene dioxythiophene (EDOT) was electrochemically synthesized. The resultant copolymer P(DTTP-co-EDOT) was characterized via cyclic voltammetry, FTIR, SEM, conductivity measurements and spectroelectrochemistry. Copolymer film has distinct electrochromic proper-ties. It has four different colors (chestnut, khaki, camouflage green, and blue). At the neutral state; gimel(max) due to the pi-pi* transition was found to be 487 nm and E-g was calculated as 1.65 eV. Double potential step chronoamperometry experiment shows that copolymer film has good stability, fast switching time (less than 1 s) and good optical contrast (20%). An electrochromic device based on P(DTTP-co-EDOT) and poly(3,4-ethylenedioxythiophene) (PEDOT) was constructed and characterized. The device showed reddish brown color at -0.6 V when the P(DTTP-co-EDOT) layer was in its reduced state; whereas blue color at 2.0 V when PEDOT was in its reduced state and P(DTTP-co-EDOT) layer was in its oxidized state. At 0.2 V intermediate green state was observed. Maximum contrast (%Delta T ) and switching time of the device were measured as 18% and 1 s at 615 nm. ECD has good environmental and redox stability

Multichromic polymers of benzotriazole derivatives: Effect of benzyl substitution

Two electroactive monomers 1-benzyl-4,7-di(thiophen-2-yl))-2H-benzo[d][1,2,3]triazole (BBTA) and 2-benzyl-4,7-di(thiophen-2-yl))-2H-benzo[d][1,2,3]triazole (BBTS) were synthesized with satisfactory yields. The effect of substitution site on electrochemical and optical properties was investigated with cyclic voltammetry and spectroelectrochemical studies. Results showed that position of pendant group alters the electronic structure of the resulting polymer causing different optical and electrochemical behaviors. Symmetrically positioned benzyl unit on benzotriazole moiety resulted in a neutral state red polymer. PBBTS, having multi-colored property in its different oxidized and reduced states. Its analogue PBBTA exhibited maximum absorption at 390 nm in its neutral state and also revealed multicolored electrochromic property upon stepwise oxidation. Very different optical band gap values were calculated: 1.55 eV and 2.25 eV for PBBTS and PBBTA, respectively

Fast Groupwise 4D Deformable Image Registration for Irregular Breathing Motion Estimation

Tumor heterogeneity can be assessed quantitatively by analyzing dynamic contrast-enhanced imaging modalities potentially leading to improvement in the diagnosis and treatment of cancer, for example of the lung. However, the acquisition of standard lung sequences is often compromised by irregular breathing motion artefacts, resulting in unsystematic errors when estimating tissue perfusion parameters. In this work, we illustrate implicit deformable image registration that integrates the Demons algorithm using the local correlation coefficient as a similarity measure, and locally adaptive regularization that enables incorporation of both spatial sliding motions and irregular temporal motion patterns. We also propose a practical numerical approximation of the regularization model to improve both computational time and registration accuracy, which are important when analyzing long clinical sequences. Our quantitative analysis of 4D lung Computed Tomography and Computed Tomography Perfusion scans from clinical lung trial shows significant improvement over state-of-the-art pairwise registration approaches