2,727 research outputs found

    Faithful completion of images of scenic landmarks using internet images

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    Abstract—Previous works on image completion typically aim to produce visually plausible results rather than factually correct ones. In this paper, we propose an approach to faithfully complete the missing regions of an image. We assume that the input image is taken at a well-known landmark, so similar images taken at the same location can be easily found on the Internet. We first download thousands of images from the Internet using a text label provided by the user. Next, we apply two-step filtering to reduce them to a small set of candidate images for use as source images for completion. For each candidate image, a co-matching algorithm is used to find correspondences of both points and lines between the candidate image and the input image. These are used to find an optimal warp relating the two images. A completion result is obtained by blending the warped candidate image into the missing region of the input image. The completion results are ranked according to combination score, which considers both warping and blending energy, and the highest ranked ones are shown to the user. Experiments and results demonstrate that our method can faithfully complete images

    Ultrasonic frogs show extraordinary sex differences in auditory frequency sensitivity

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    Acoustic communication plays an important role in the reproductive behavior of anurans. Males of concave-eared torrent frog (_Odorrana tormota_) have ultrasonic communication capacity 1, 2, but it is unknown whether females communicate with ultrasound. Here we show that _O. tormota_ exhibits great sex differences in the auditory frequency sensitivity. Acoustic playback experiments demonstrated that the male's advertisement calls evoke gravid females' positive phonotaxis and vocal responses, whereas ultrasonic components of the male's calls (frequencies above 20 kHz) do not elicit female phonotaxis or vocalization. The behavioral study was complemented by electrophysiological recordings from the auditory midbrain and by laser Doppler vibrometer measurements of the tympanic membrane's response to acoustic stimuli. These measurements revealed that females have an upper frequency limit up to 16 kHz (threshold 107 dB SPL) and no ultrasound sensitivity, unlike males which have an upper frequency limit of up to 35 kHz (87 dB SPL). Single units in the female auditory midbrain have the best excitatory frequencies (BEFs) peaked around 5 kHz, corresponding to the fundamental frequency (F0) of male's most calls, whereas the male auditory midbrain units have BEFs mostly above 8 kHz, largely consistent with the F0 of female courtship calls. Females have a frequency sensitive bandwidth (10 dB above threshold) ranged from 2 to 6 kHz, narrower than that males have (5-20 kHz). The velocity amplitude of the tympanic membranes peaked around 5 kHz in females, whereas 7 kHz in males. The results suggest that the frog species O. tormota is an example of a vertebrate, which demonstrates well phonotaxis and extraordinary sex differences in hearing

    Dichlorido(4,5-diaza­fluoren-9-one-κ2 N,N′)palladium(II)

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    The structure of the title compound, [PdCl2(C11H6N2O)], shows a nearly square-planar geometry for the PdII atom within a Cl2N2 donor set

    In-silico design of novel myocilin inhibitors for glaucoma therapy

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    Purpose: To explore newer computational approaches in the design of novel myocilin inhibitors for the treatment of glaucoma.Methods: An in-silico virtual screening technique based on simulation of molecular docking was utilised to design a novel myocilin inhibitors for the treatment of  glaucoma. The designed novel molecules were theoretically evaluated to predict their pharmacokinetic properties and toxic effects. Lead molecules were screened out in virtual screening technique on the basis of low binding energies obtained in AutoDock based molecular docking simulation.Results: Out of ten top lead compounds screened, ZINC01729523 and ZINC04692015 were promising, having shown potent inhibition of myocilin, good pharmacokinetic properties and absence of any toxic effects.Conclusion: In-silico virtual screening of molecular libraries containing a large number of ligands is very useful for short-listing of potential lead molecules for further structure-based discovery of antiglaucoma-drugs.Keywords: Glaucoma, Myocilin, Docking, Virtual-screening, Autodock, Ligand, Drug desig

    Efficient, edge-aware, combined color quantization and dithering

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    Abstract—In this paper we present a novel algorithm to simultaneously accomplish color quantization and dithering of images. This is achieved by minimizing a perception-based cost function which considers pixel-wise differences between filtered versions of the quantized image and the input image. We use edge aware filters in defining the cost function to avoid mixing colors on opposite sides of an edge. The importance of each pixel is weighted according to its saliency. To rapidly minimize the cost function, we use a modified multi-scale iterative conditional mode (ICM) algorithm which updates one pixel a time while keeping other pixels unchanged. As ICM is a local method, careful initialization is required to prevent termination at a local minimum far from the global one. To address this problem, we initialize ICM with a palette generated by a modified median-cut method. Compared to previous approaches, our method can produce high quality results with fewer visual artifacts but also requires significantly less computational effort. Index Terms—Color quantization, dithering, optimization-based image processing. I
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