A towed instrument package for fisheries research in great barrier reef waters

A tethered remote instrument package (TRIP) has been developed for biological surveys over Queensland's continental shelf and slope. The present system, evolved from an earlier sled configuration, is suspended above the sea bed and towed at low speeds. Survey information is collected through video and film cameras while instrument and environmental variables are handled by a minicomputer. The operator was able to "fly" the instrument package above the substrate by using an altitude echosounder, forward-looking sonar and real-time television viewing. Unwanted movements of the viewing system were stabilized through a gyro-controlled camera-head panning system. the hydrodynamic drag of the umbilical presented a major control problem which could be overcome only by a reduction in towing speed. Despite the constraints of towing a device such as this through the coral reef environment, the package performed well during a recent biological survey where it was worked at 50% of its 350 m design depth.

Generation of optimum random pinhole arrays for multiple imaging

Through an analysis using the transfer function of a pinhole camera, the multiple imaging characteristics of photographic diffusers described by Grover and Tremblay [Appl. Opt.21,4500(1982)] is studied. It is found that only one pinhole diameter satisfies the optimum imaging condition for best contrast transfer at any desired spatial frequency. A simple method of generating random pinhole arrays with a controlled pinhole diameter is described. These pinhole arrays are later used to generate high frequency sinusoidal gratings from a coarse grid. The contrast in the final gratings is found to be reasonably high.

Repeatable Condition-Invariant Visual Odometry for Sequence-Based Place Recognition

This paper describes a vision-only system for place recognition in environments that are tra- versed at different times of day, when chang- ing conditions drastically affect visual appear- ance, and at different speeds, where places aren’t visited at a consistent linear rate. The ma- jor contribution is the removal of wheel-based odometry from the previously presented algo- rithm (SMART), allowing the technique to op- erate on any camera-based device; in our case a mobile phone. While we show that the di- rect application of visual odometry to our night- time datasets does not achieve a level of perfor- mance typically needed, the VO requirements of SMART are orthogonal to typical usage: firstly only the magnitude of the velocity is required, and secondly the calculated velocity signal only needs to be repeatable in any one part of the environment over day and night cycles, but not necessarily globally consistent. Our results show that the smoothing effect of motion constraints is highly beneficial for achieving a locally consis- tent, lighting-independent velocity estimate. We also show that the advantage of our patch-based technique used previously for frame recogni- tion, surprisingly, does not transfer to VO, where SIFT demonstrates equally good performance. Nevertheless, we present the SMART system us- ing only vision, which performs sequence-base place recognition in extreme low-light condi- tions where standard 6-DOF VO fails and that improves place recognition performance over odometry-less benchmarks, approaching that of wheel odometry.

The onset of warps in Spitzer observations of edge-on spiral galaxies

We analyse warps in the nearby edge-on spiral galaxies observed in the Spitzer/Infrared Array Camera (IRAC)4.5-mu m band. In our sample of 24 galaxies, we find evidence of warp in 14 galaxies. We estimate the observed onset radii for the warps in a subsample of 10 galaxies. The dark matter distribution in each of these galaxies are calculated using the mass distribution derived from the observed light distribution and the observed rotation curves. The theoretical predictions of the onset radii for the warps are then derived by applying a self-consistent linear response theory to the obtained mass models for six galaxies with rotation curves in the literature. By comparing the observed onset radii to the theoretical ones, we find that discs with constant thickness can not explain the observations; moderately flaring discs are needed. The required flaring is consistent with the observations. Our analysis shows that the onset of warp is not symmetric in our sample of galaxies. We define a new quantity called the onset-asymmetry index and study its dependence on galaxy properties. The onset asymmetries in warps tend to be larger in galaxies with smaller dis scalelengths. We also define and quantify the global asymmetry in the stellar light distribution, that we call the edge-on asymmetry in edge-on galaxies. It is shown that in most cases the onset asymmetry in warp is actually anticorrelated with the measured edge-on asymmetry in our sample of edge-on galaxies and this could plausibly indicate that the surrounding dark matter distribution is asymmetric.

Distributed Robotic Vision as a service

The vision sense of standalone robots is limited by line of sight and onboard camera capabilities, but processing video from remote cameras puts a high computational burden on robots. This paper describes the Distributed Robotic Vision Service, DRVS, which implements an on-demand distributed visual object detection service. Robots specify visual information requirements in terms of regions of interest and object detection algorithms. DRVS dynamically distributes the object detection computation to remote vision systems with processing capabilities, and the robots receive high-level object detection information. DRVS relieves robots of managing sensor discovery and reduces data transmission compared to image sharing models of distributed vision. Navigating a sensorless robot from remote vision systems is demonstrated in simulation as a proof of concept.

Characterisation of the efficacy of endodontic medications using a three-dimensional fluorescent tooth model: An ex vivo study

The purpose of this study was to establish a three-dimensional fluorescent tooth model to investigate bacterial viability against intra-canal medicaments across the thickness and surface of root dentine. Dental microbial biofilms (Enterococcus faecalis and Streptococcus mutans) were established on the external root surface and bacterial kill was monitored over time against intra-canal medicament (Ca(OH)2 ) using fluorescent microscopy in conjunction with BacLight SYTO9 and propidium iodide stains. An Olympus digital camera fitted to SZX16 fluorescent microscope captured images of bacterial cells in biofilms on the external root surface. Viability of biofilm was measured by calculating the total pixel area of green (viable bacteria) and red (non-viable bacteria) for each image using ImageJ® software. All data generated were assessed for normality and then analysed using a Mann-Whitney t-test. The viability of S. mutans biofilm following Ca(OH)2 treatment showed a significant decline compared with the untreated group (P = 0.0418). No significant difference was seen for E. faecalis biofilm between the Ca(OH)2 and untreated groups indicating Ca(OH)2 medicament is ineffective against E. faecalis biofilm. This novel three-dimensional fluorescent biofilm model provides a new clinically relevant tool for testing of medicaments against dental biofilms.

Maize kernel hardness classification by near infrared (NIR) hyperspectral imaging and multivariate data analysis.

The use of near infrared (NIR) hyperspectral imaging and hyperspectral image analysis for distinguishing between hard, intermediate and soft maize kernels from inbred lines was evaluated. NIR hyperspectral images of two sets (12 and 24 kernels) of whole maize kernels were acquired using a Spectral Dimensions MatrixNIR camera with a spectral range of 960-1662 nm and a sisuChema SWIR (short wave infrared) hyperspectral pushbroom imaging system with a spectral range of 1000-2498 nm. Exploratory principal component analysis (PCA) was used on absorbance images to remove background, bad pixels and shading. On the cleaned images. PCA could be used effectively to find histological classes including glassy (hard) and floury (soft) endosperm. PCA illustrated a distinct difference between glassy and floury endosperm along principal component (PC) three on the MatrixNIR and PC two on the sisuChema with two distinguishable clusters. Subsequently partial least squares discriminant analysis (PLS-DA) was applied to build a classification model. The PLS-DA model from the MatrixNIR image (12 kernels) resulted in root mean square error of prediction (RMSEP) value of 0.18. This was repeated on the MatrixNIR image of the 24 kernels which resulted in RMSEP of 0.18. The sisuChema image yielded RMSEP value of 0.29. The reproducible results obtained with the different data sets indicate that the method proposed in this paper has a real potential for future classification uses.

Family and guests at Aenny Catzenstein nee Gottschalk's 80th birthday party; London.

Dinner scene with Franz Mattheisen left, daughter Susan Mattheisen next to him, next daughter Maren Matthiesen, his wife Olga Matthiesen at the end of the table. Beatrice Durand is facing the camera

Gottschalk family on vacation in front of Kurhaus Brunig; Norderney, Germany.

From left to right: man with camera: Karl Gottschalk; sitting on stairs: Fritz Gottschalk, unidentified woman, Therese Gottschalk nee Molling, Hans Ludwig, Kurt Gottschalk, unidentified woman (maid?) and Elizabeth Gottschalk

Albert Einstein; California Portraits; Men

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Albert Einstein writing; California Portraits; Men

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Strategies for collecting screen-less oscillation data

Screen-less oscillation photography is the method of choice for recording three-dimensional X-ray diffraction data for crystals of biological macromolecules. The geometry of an oscillation camera is extremely simple. However, the manner in which the reciprocal lattice is recorded in any experiment is fairly complex. This depends on the Laue symmetry of the reciprocal lattice, the lattice type, the orientation of the crystal on the camera and to a lesser extent on the unit-cell dimensions. Exploring the relative efficiency of collecting X-ray diffraction data for different crystal orientations prior to data collection might reduce the number of films required to record most of the unique data and the consequent amount of time required for processing these films. Here algorithms are presented suitable for this purpose and results are reported for the 11 Laue groups, different lattice types and crystal orientations often employed in data collection.

Family and guests at Aenny Catzenstein nee Gottschalk's 80th birthday party; London.

Dinner scene with Franz Mattheisen left, daughter Susan Mattheisen next to him, next daughter Maren Matthiesen, his wife Olga Matthiesen at the end of the table. Beatrice Durand is facing the camera

Gottschalk family on vacation in front of Kurhaus Brunig; Norderney, Germany.

From left to right: man with camera: Karl Gottschalk; sitting on stairs: Fritz Gottschalk, unidentified woman, Therese Gottschalk nee Molling, Hans Ludwig, Kurt Gottschalk, unidentified woman (maid?) and Elizabeth Gottschalk

Albert Einstein; California Portraits; Men

Digital Image