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Abstract: We present a new endoscopic 3D scanning system based on Single Shot Structured Light. The proposed design makes it possible to build an extremely small scanner. The sensor head contains a catadioptric camera and a pattern projection unit. The paper describes the working principle and calibration procedure of the sensor. The prototype sensor head has a diameter of only 3.6mm and a length of 14mm. It is mounted on a flexible shaft. The scanner is designed for tubular cavities and has a cylindrical working volume of about 30mm length and 30mm diameter. It acquires 3D video at 30 frames per second and typically generates approximately 5000 3D points per frame. By design, the resolution varies over the working volume, but is generally better than 200μm. A prototype scanner has been built and is evaluated in experiments with phantoms and biological samples. The recorded average error on a known test object was 92μm. [Copyright &y& Elsevier]

Abstract: If electron spectroscopic techniques are applied in surface and interface science, quantification of surface sensitivity is of crucial interest. In this article, we present a systematic experimental investigation of the effective electron attenuation length (EAL) in organic materials, on the example of PTCDA. The effective attenuation length was determined in a comprehensive experiment over a wide range of energies especially in the range of interest for surface analysis. The overlayer method was used and proven to be adequate for the utilized model system PTCDA on Ag(111) since the preparation parameters could be controlled extremely well. Compared to calculations which we performed applying the TPP2M formula the results show the expected offset which is due to the additional elastic contribution in the measured values. Furthermore, a comparison with the widely used “universal curve” [1] shows that this description does not match the data on PTCDA very well. However, the curvature of the theoretical curve derived from the TPP2M approach [2] matches or our experimental EAL data reasonably good. [Copyright &y& Elsevier]

Abstract: We performed high-resolution photoemission experiments at different photon energies to investigate the valence band structure of 1ML of 1,4,5,8-naphthalene tetracarboxylic dianhydride (NTCDA) on Ag(111). Besides the known occupied molecular orbitals HOMO and HOMO−1 we observe a new state close to the Fermi level, which results from the interaction between NTCDA and the substrate, partially filling the lowest unoccupied orbital of the free molecule (LUMO) in the monolayer system. By tuning the photon energy through the carbon K-edge, a resonance like change of the spectral intensity at the HOMO and HOMO−1 energies is clearly revealed, which we use for an assignment of the individual spectral features to a predominant localization either at the naphthalene core or the anhydride group. [Copyright &y& Elsevier]

Abstract: One monolayer of Ag deposited on Cu(111) shows two kinds of characteristic reconstruction, depending on the conditions of the preparation: the incommensurate moiré structure appears for one monolayer prepared at 200K whereas a monolayer deposited at room temperature (or higher) exhibits a quasi-commensurate triangular structure. By high-resolution ARUPS measurements on the triangular structure we find an opening of a gap in the Shockley state band, which is a signature of the super-lattice. On the other hand, no gap opening is observed on the moiré structure. In addition, we show that the Shockley state plays an important role in the adsorption process of rare gas atoms on these surfaces. ARUPS experiments on adsorbed Xe on 0.6ML Ag/Cu(111) show clearly that the Xe atoms favor the adsorption on the Ag islands, before the Cu terraces will be covered at higher Xe exposure. [Copyright &y& Elsevier]

Abstract: In this paper, a novel real-time 3D and color sensor for the mid-distance range (0.1–3m) based on color-encoded structured light is presented. The sensor is integrated using low-cost of-the-shelf components and allows the combination of 2D and 3D image processing algorithms, since it provides a 2D color image of the scene in addition to the range data. Its design is focused on enabling the system to operate reliably in real-world scenarios, i.e. in uncontrolled environments and with arbitrary scenes. To that end, novel approaches for encoding and recognizing the projected light are used, which make the system practically independent of intrinsic object colors and minimize the influence of the ambient light conditions. The system was designed to assist and complement a face authentication system integrating both 2D and 3D images. Depth information is used for robust face detection, localization and 3D pose estimation. To cope with illumination and pose variations, 3D information is used for the normalization of the input images. The performance and robustness of the proposed system is tested on a face database recorded in conditions similar to those encountered in real-world applications. [Copyright &y& Elsevier]

Traditionally, most camera calibrations rely on a planar target with well-known marks. However, the localization error of the marks in the image is a source of inaccuracy. We propose the use of high-resolution digital displays as active calibration targets to obtain more accurate calibration results for all types of cameras. The display shows a series of coded patterns to generate correspondences between world points and image points. This has several advantages. No special calibration hardware is necessary because suitable displays are practically ubiquitious. The method is fully automatic, and no identification of marks is necessary. For a coding scheme based on phase shifting, the localization accuracy is approximately independent of the camera's focus settings. Most importantly, higher accuracy can be achieved compared to passive targets, such as printed checkerboards. A rigorous evaluation is performed to substantiate this claim. Our active target method is compared to standard calibrations using a checkerboard target. We perform camera, calibrations with different combinations of displays, cameras, and lenses, as well as with simulated images and find markedly lower reprojection errors when using active targets. For example, in a stereo reconstruction task, the accuracy of a system calibrated with an active target is five times better. [ABSTRACT FROM AUTHOR]

This paper addresses digital staining and classification of the unstained white blood cell images obtained with a differential contrast microscope. We have data coming from multiple domains that are partially labeled and partially matching across the domains. Using unstained images removes time-consuming staining procedures and could facilitate and automatize comprehensive diagnostics. To this aim, we propose a method that translates unstained images to realistically looking stained images preserving the inter-cellular structures, crucial for the medical experts to perform classification. We achieve better structure preservation by adding auxiliary tasks of segmentation and direct reconstruction. Segmentation enforces that the network learns to generate correct nucleus and cytoplasm shape, while direct reconstruction enforces reliable translation between the matching images across domains. Besides, we build a robust domain agnostic latent space by injecting the target domain label directly to the generator, i.e., bypassing the encoder. It allows the encoder to extract features independently of the target domain and enables an automated domain invariant classification of the white blood cells. We validated our method on a large dataset composed of leukocytes of 24 patients, achieving state-of-the-art performance on both digital staining and classification tasks. [ABSTRACT FROM AUTHOR]

Optical and electrochemical investigations of triarylamine redox centres attached to gold nanoparticles via a π-conjugated bridge show intervalence charge-transfer bands which prove to be surprisingly strong interchromophore interactions. [ABSTRACT FROM AUTHOR]

Optical and electrochemical investigations of triarylamine redox centres attached to gold nanoparticles viaa π-conjugated bridge show intervalence charge-transfer bands which prove to be surprisingly strong interchromophore interactions. [ABSTRACT FROM AUTHOR]