Towards a full-reference, information-theoretic quality assessment method for X-ray images

This work aims at defining an information-theoretic quality assessment technique for cardiovascular X-ray images, using a full-reference scheme (relying on averaging a sequence to obtain a noiseless reference). With the growth of advanced signal processing in medical imaging, such an approach will enable objective comparisons of the quality of processed images. A concept for describing the quality of an image is to express it in terms of its information capacity. Shannon has derived this capacity for noisy channel coding. However, for X-ray images, the noise is signal-dependent and non-additive, so that Shannon's theorem is not directly applicable. To overcome this complication, we exploit the fact that any invertible mapping on a signal does not change its information content. We show that it is possible to transform the images in such a way that the Shannon theorem can be applied. A general method for calculating such a transformation is used, given a known relation between signal mean and noise standard deviation. After making the noise signal-independent, it is possible to assess the information content of an image and to calculate an overall quality metric (e.g. information capacity) which includes the effects of sharpness, contrast and noise. We have applied this method on phantom images under different acquisition conditions and computed the information capacity for those images. We aim to show that the results of this assessment are consistent with variations in noise, contrast and sharpness, introduced by system settings and image processing

Detection of Object Throwing Behavior in Surveillance Videos

Anomalous behavior detection is a challenging research area within computer vision. Progress in this area enables automated detection of dangerous behavior using surveillance camera feeds. A dangerous behavior that is often overlooked in other research is the throwing action in traffic flow, which is one of the unique requirements of our Smart City project to enhance public safety. This paper proposes a solution for throwing action detection in surveillance videos using deep learning. At present, datasets for throwing actions are not publicly available. To address the use-case of our Smart City project, we first generate the novel public 'Throwing Action' dataset, consisting of 271 videos of throwing actions performed by traffic participants, such as pedestrians, bicyclists, and car drivers, and 130 normal videos without throwing actions. Second, we compare the performance of different feature extractors for our anomaly detection method on the UCF-Crime and Throwing-Action datasets. The explored feature extractors are the Convolutional 3D (C3D) network, the Inflated 3D ConvNet (I3D) network, and the Multi-Fiber Network (MFNet). Finally, the performance of the anomaly detection algorithm is improved by applying the Adam optimizer instead of Adadelta, and proposing a mean normal loss function that covers the multitude of normal situations in traffic. Both aspects yield better anomaly detection performance. Besides this, the proposed mean normal loss function lowers the false alarm rate on the combined dataset. The experimental results reach an area under the ROC curve of 86.10 for the Throwing-Action dataset, and 80.13 on the combined dataset, respectively

NADPH-induced chemiluminescence and lipid peroxidation in kidney microsomes

NADPH-induced chemiluminescence and lipid peroxidation in kidney microsomes. Lipid peroxidation and reactive oxygen species have been shown to affect diverse biological processes potentially important in renal disease. We therefore examined NADPH-induced chemiluminescence (CL) and lipid peroxidation (LP) by renal cortical and, in some experiments, medullary microsomes. We further examined the role of reactive oxygen species in these processes by the use of enzymatic and chemical scavengers. Cortical microsomes gave a marked NADPH-induced CL accompanied by LP. The time course of LP closely paralleled the CL response. Cortical microsomal CL and LP increased with increasing concentrations of protein (0.3 to 1.8 mg) and NADPH (0.1 to 3.0mM); NADH could not substitute for NADPH. Using similar amounts of protein and NADPH concentrations, cortical CL was significantly higher than medullary CL at all time points examined (peak cortical CL: 490 ± 25 × 103 cpm/mg protein, N = 4; peak medullary CL: 226 ± 61 × 103 cpm/mg protein, N = 4). Cortical LP was similarly higher at all time points, values corresponding to peak CL being 44.7 ± 3 nmoles/mg protein for cortex and 29.9 ± 0.8 nmoles/mg protein for medulla. Para-chloromercuribenzoate (PCMB), an inhibitor of NADPH-cytochrome P450 reductase, caused a marked inhibition of the microsomal CL and LP whereas SKF 525A, an inhibitor of cytochrome P450, had a relatively minor effect. Marked inhibition of NADPH induced CL and LP was observed with chelators EDTA and 1,10-phenanthroline. The addition of NADPH to microsomes prepared with sucrose-EDTA and washed in a Chelex-treated buffer gave a negligible CL and LP response; the responses were restored by the addition of iron. Scavengers of superoxide anion (superoxide dismutase), hydrogen peroxide (catalase), and the hydroxyl radical (sodium benzoate, tryptophan) had a relatively minor effect on CL and LP. Singlet oxygen quenchers sodium azide and 1,4-diazabicyclo (2.2.2) octane (DABCO) caused an incomplete inhibition of CL and LP responses and then only after the first 30min. Taken together, these data suggest that other free radical mechanisms are likely to be important in the CL and LP responses. These results which demonstrate the production of excited states and LP by renal microsomes suggest that their role in renal disease deserves further study.Chemiluminescence induite par le NADPH et peroxydation des lipides dans les microsomes de rein. Il a été montré que la peroxydation des lipides et le type d'oxygène réactif modifient diversement les processus biologiques potentiellement importants dans les maladies rénales. C'est pourquoi nous avons examiné la chemiluminescence (CL) induite par le NADPH, et la peroxydation (LP) des lipides par des microsomes corticaux et dans quelques expériences, médullaires rénaux. Nous avons ensuite examiné le rôle du type d'oxygène réactif dans ces processus en utilisant des agents métabolisants enzymatiques et chimiques. Les microsomes corticaux donnaient une CL marquée induite par le NADPH accompagnée par une LP. Dans le temps, la LP était étroitement parallèle à la réponse CL. La CL et la LP microsomiales corticales s'élevaient avec l'accroissement des concentrations de protéines (0, 1 à 1,8 mg) et de NADPH (0,1 à 3,0mM); le NADH ne pouvait so substituer au NADPH. En utilisant des quantités identiques de protéines et de NADPH, la CL corticale était significativement plus élevée que la CL médullaire à tous les temps examinés (pic de CL corticale: 490 ± 25 × 103 cpm/mg protéine, N = 4, pic de CL médullaire: 226 ± 61 × 103 cpm/mg protéine, N = 4). De même la LP corticale était plus élevée à tous les temps, les valeurs correspondant au pic de CL étant de 44,7 ± 3 nmoles/mg protéine pour le cortex et de 29,9 ± 0,8 nmoles/mg protéine pour la médullaire. Le parachloromercuribenzoate (PCMB), un inhibiteur de la réductase NADPH-cytochrome P450a entraîné une inhibition marquée de la CL et de la LP microsomiales tandis que le SKF 525 A, un inhibiteur du cytochrome P450, avait un effet relativement minime. Une inhibition marquée de la CL induite par le NADPH et de la LP a été observée avec des chélateurs tels l'EDTA et le 1,10-phénanthroline. L'addition de NADPH à des microsomes préparés dans du sucrose-EDTA et lavés dans un tampon traité au Chelex entraînait une réponse CL et LP négligeable; les réponses étaient restaurées par l'addition de fer. Les agents métabolisants l'anion superoxide (dismutase superoxide), le peroxide d'hydrogène (catalase), et le radical hydroxylé (benzoate de sodium, tryptophane) avaient un effet relativement minime sur CL et LP. Les capteurs d'oxygène singulet comme l'azide de sodium et le 1,4-diazabicyclo (2.2.2) octane (DABCO) entraînaient une inhibition incomplète des réponses CL et LP et cela seulement après les 30 premières min. Prises dans leur ensemble, ces données suggèrent que d'autres mécanismes par radicaux libres sont probablement importants dans les réponses CL et LP. Ces résultats, qui démontrent la production d'états excités et de LP par des microsomes rénaux, suggèrent que leur rôle dans les maladies rénales nécessite d'autres études

An apprach to generate large and small leptonic mixing angles

We take up the point of view that Yukawa couplings can be either 0 or 1, and the mass patterns of fermions are generated purely from the structure of the Yukawa matrices. We utilize such neutrino as well as charged leptonic textures which lead to (maximal) mixing angles of $\pi/4$ in each sector for relevant transitions. The combined leptonic CKM mixing angles are $\pi/4 \pm \pi/4$ which lead to very small $\sin^2 2 \Theta$ relevant to solar neutrino and LSND experiments. We propose that on the other hand the absence of the charged leptonic partner of the sterile neutrino maintains the angle $\pi/4$ from the neutrino sector for the transition $\nu_\mu \leftrightarrow \nu_s$ and hence atmospheric neutrino anomaly is explained through maximal mixing

Generalized stochastic Schroedinger equations for state vector collapse

A number of authors have proposed stochastic versions of the Schr\"odinger equation, either as effective evolution equations for open quantum systems or as alternative theories with an intrinsic collapse mechanism. We discuss here two directions for generalization of these equations. First, we study a general class of norm preserving stochastic evolution equations, and show that even after making several specializations, there is an infinity of possible stochastic Schr\"odinger equations for which state vector collapse is provable. Second, we explore the problem of formulating a relativistic stochastic Schr\"odinger equation, using a manifestly covariant equation for a quantum field system based on the interaction picture of Tomonaga and Schwinger. The stochastic noise term in this equation can couple to any local scalar density that commutes with the interaction energy density, and leads to collapse onto spatially localized eigenstates. However, as found in a similar model by Pearle, the equation predicts an infinite rate of energy nonconservation proportional to $\delta^3(\vec 0)$, arising from the local double commutator in the drift term.Comment: 24 pages Plain TeX. Minor changes, some new references. To appear in Journal of Physics