Quantitative Error Assessment in Pattern Matching: Effects of Intensity Pattern Noise, Interpolation, Strain and Image Contrast on Motion Measurements

Abstract: Basic concepts in probability are employed to develop analytic formulae for both the expectation (bias) and variance for image motions obtained during subset‐based pattern matching. Specifically, the expectation and variance in image motions in the presence of uncorrelated Gaussian intensity noise for each pixel location are obtained by optimising a least squares intensity matching metric. Results for both 1D and 2D image analyses clearly quantify both the bias and the covariance matrix for image motion estimates as a function of: (a) interpolation method, (b) sub‐pixel motion, (c) intensity noise, (d) contrast, (e) level of uniaxial normal strain and (f) subset size. For 1D translations, excellent agreement is demonstrated between simulations, theoretical predictions and experimental measurements. The level of agreement confirms that the analytical formulae can be used to provide a priori estimates for the ‘quality’ of local, subset‐based measurements achievable with a given pattern. For 1D strain with linear interpolation, theoretical predictions are provided for the expectation and co‐variance matrix for the local displacement and strain parameters. For 2D translations with bi‐linear interpolation, theoretical predictions are provided for both the expectation and the co‐variance matrix for both displacement components. Theoretical results in both cases show that the expectations for the local parameters are biased and a function of: (a) the interpolation difference between the translated and reference images, (b) magnitude of white noise, (c) decimal part of the motion and (d) intensity pattern gradients. For 1D strain, the biases and the covariance matrix for both parameters are directly affected by the strain parameter p₁ as the deformed image is stretched by (1 + p₁). For 2D rigid body motion case, the covariance matrix for measured motions is shown to have coupling between the motions, demonstrating that the directions of maximum and minimum variability do not generally coincide with the x and y directions.     

Increased basal transepidermal water loss leads to elevation of some but not all stratum corneum serine proteases

There are indications of elevation of some inflammatory serine proteases in barrier damaged skin (e.g. plasmin and urokinase). Moreover, many other serine protease activities are present such as desquamatory enzymes as well as a newly detected tryptase‐like serine protease. However, the activities of these proteases have never been correlated with stratum corneum (SC) barrier function. The activity of extractable key serine proteases (SC trypsin‐like kallikreins, SC chymotrypsin‐like kallikreins, SC tryptase‐like serine protease, urokinase and plasmin) was measured from the outermost layers of SC obtained from facial tape strippings in clinically normal subjects. The protein content of the tape strippings was quantified by absorption measurements with the novel infrared densitometer SquameScan^TM 850A and the protease activities by the use of fluorogenic peptide substrates. SC barrier function, SC hydration and skin surface pH were measured using AquaFlux^TM, NOVA dermal phase meter and Skin‐pH‐Meter^®, respectively. As expected, SC hydration was reduced with increased transepidermal water loss (TEWL) values indicative of barrier impairment. Surprisingly, SC chymotrypsin‐like activity showed no correlation with hydration or TEWL, whereas all other enzymes positively correlated with impaired barrier function and some were statistically significant: SC trypsin‐like kallikreins (R² = 0.66, P < 0.01), SC tryptase‐like enzyme (R² = 0.95, P < 0.001), plasmin (R² = 0.86, P < 0.001) and urokinase (R² = 0.50, P < 0.05). All enzymes except urokinase also negatively correlated with SC hydration. Elevated levels of SC serine proteases have been associated with some dermatological disorders, such as atopic dermatitis, psoriasis and rosacea but these results indicate that these enzymes are also elevated with milder forms of barrier disruption, which is not clinically evident as irritated skin. As these proteases are elevated in the SC, they will also be elevated in the epidermis where they can be involved in neurogenic inflammation and epidermal barrier impairment via activation of the protease‐activated receptors. These results highlight the need for using serine protease inhibitors especially for urokinase and plasmin, SC tryptase‐like serine protease and possibly SC trypsin‐like kallikreins even in milder forms of barrier damage.     

A 375-mW Quadrature Bandpass ∆Σ ADC With 8.5-MHz BW and 90-dB DR at 44 MHz

A quadrature bandpass DeltaSigma ADC for a multistandard TV tuner achieves a total dynamic range of 90 dB over an 8.5-MHz passband centered on 44 MHz while consuming 375 mW. The fourth-order continuous-time ADC uses active-RC resonators configured in a modified feedforward architecture     

Cardiac anisotropy: is it negligible regarding noninvasive activation time imaging?

The aim of this study was to quantify the effect of cardiac anisotropy in the activation-based inverse problem of electrocardiography. Differences of the patterns of simulated body surface potential maps for isotropic and anisotropic conditions were investigated with regard to activation time (AT) imaging of ventricular depolarization. AT maps were estimated by solving the nonlinear inverse ill-posed problem employing spatio-temporal regularization. Four different reference AT maps (sinus rhythm, right-ventricular and septal pacing, accessory pathway) were calculated with a bidomain theory based anisotropic finite-element heart model in combination with a cellular automaton. In this heart model a realistic fiber architecture and conduction system was implemented. Although the anisotropy has some effects on forward solutions, effects on inverse solutions are small indicating that cardiac anisotropy might be negligible for some clinical applications (e.g., imaging of focal events) of our AT imaging approach. The main characteristic events of the AT maps were estimated despite neglected electrical anisotropy in the inverse formulation. The worst correlation coefficient of the estimated AT maps was 0.810 in case of sinus rhythm. However, all characteristic events of the activation pattern were found. The results of this study confirm our clinical validation studies of noninvasive AT imaging in which cardiac anisotropy was neglected.     

Design and evaluation of a telemonitoring concept based on NFC-enabled mobile phones and sensor devices

Utilization of information and communication technologies such as mobile phones and wireless sensor networks becomes more and more common in the field of telemonitoring for chronic diseases. Providing elderly people with a mobile-phone-based patient terminal requires a barrier-free design of the overall user interface including the setup of wireless communication links to sensor devices. To easily manage the connection between a mobile phone and wireless sensor devices, a concept based on the combination of Bluetooth and near-field communication technology has been developed. It allows us initiating communication between two devices just by bringing them close together for a few seconds without manually configuring the communication link. This concept has been piloted with a sensor device and evaluated in terms of usability and feasibility. Results indicate that this solution has the potential to simplify the handling of wireless sensor networks for people with limited technical skills.     

Quantitative composition of volatile constituents in cultivated strawberries,Fragaria ananassa cv. senga sengana,senga litessa and senga gourmella

The volatile components of cultivated strawberries Fragaria ananassa cv. Senga Sengana, Senga Litessa and Senga Gourmella were studied by gas chromatography-mass spectrometry. Employing standard-controlled aroma separation by combined vacuum distillation-liquid-liquid extraction, as well as prefractionation on silica gel, the aroma substances of freshly harvested and deep-frozen strawberries from two growing seasons were quantitatively determined by gas chromatography. Methyl and ethyl butanoate, methyl and ethyl hexanoate, trans-2-hexenyl acetate, trans-2-hexenal, trans-2-hexen-1-ol as well as 2,5-dimethyl-4-methoxy-3(2H)-furanone were identified as main volatile components. In comparison to Senga Litessa and Senga Gourmella, Senga Sengana showed higher amounts of aroma compounds. In general, deep-freezing resulted in decreases of the concentrations of most of the aroma substances, but higher amounts of 2,5-dimethyl-4-methoxy-3(2H)-furanone were found in deep-frozen berries than in the freshly harvested ones.     

Sesquiterpene hydrocarbons from grapes (author''s transl)

Leucocyte ascorbic acid was estimated in patients with abnormal leucocyte states and other haematological disorders. Levels below the normal range were found in most cases of chronic myeloid leukaemia and chronic lymphatic leukaemia. Subnormal levels were found in more than a third of patients with acute leukaemias, lymphomas, glandular fever, myelofibrosis, and polycythaemia, and in the same proportion of patients receiving cytotoxic drugs, and also in those with a polymorph leucocytosis and those with purpura. Most patients with anaemia but a normal leucocyte count, and those with myelomatosis had normal levels. The majority of pregnant women tested had subnormal levels. In a wide variety of leucocyte disorders the leucocyte ascorbic acid may not be an accurate index of the body's Vitamin C status. The results also support the supposition that leucocyte ascorbic acid is mostly carried by normal mature polymorphs.     

Linalool disaccharides as flavour precursors from green coffee beans (<Emphasis Type="Italic">Coffea arabica</Emphasis>)

Two linalool disaccharides, isolated from green coffee beans (Coffea arabica), were identified as 3(S)-linalool-3-O-#-D-glucopyranosyl-#-D-apiofuranoside and 3(S)-linalool-3-O-#-D-glucopyranosyl-!-L-arabinopyranoside. The structures were established by one- and two-dimensional ¹H and ¹³C NMR spectra as well as by ESI MS/MS spectra.