52 research outputs found

    Scratches Removal in Digitised Aerial Photos Concerning Sicilian Territory

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    In this paper we propose a fast and effective method to detect and restore scratches in aerial photos from a photographic archive concerning Sicilian territory. Scratch removal is a typical problem for old movie films but similar defects can be seen in still images. Our solution is based on a semiautomatic detection process and an unsupervised restoration algorithm. Results are comparable with those obtained with commercial restoration tools

    Illumination Correction on Biomedical Images

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    RF-Inhomogeneity Correction (aka bias) artifact is an important research field in Magnetic Resonance Imaging (MRI). Bias corrupts MR images altering their illumination even though they are acquired with the most recent scanners. Homomorphic Unsharp Masking (HUM) is a filtering technique aimed at correcting illumination inhomogeneity, but it produces a halo around the edges as a side effect. In this paper a novel correction scheme based on HUM is proposed to correct the artifact mentioned above without introducing the halo. A wide experimentation has been performed on MR images. The method has been tuned and evaluated using the simulated Brainweb image database. In this framework, the approach has been compared successfully against the Guillemaud filter and the SPM2 method. Moreover, the method has been successfully applied on several real MR images of the brain (0.18 T, 1.5 T and 7 T). The description of the overall technique is reported along with the experimental results that show its effectiveness in different anatomical regions and its ability to compensate both underexposed and overexposed areas. Our approach is also effective on non-radiological images, like retinal ones

    Second Opinion System for Intraoral Lesions

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    In this paper we present the prototype of a teledentistry system to perform the remote diagnosis of oral diseases. It makes use of a particular device called intra-oral (or dental) camera properly designed to shoot video and take pictures of the inner part of the mouth. The intra-oral cameras can be connected via USB to a common PC and they are very cheap, unlike the intra-oral photography kit for DSLR cameras. Usually this kind of devices are used in dentistry studies for local visualization by means of specialized software. The novelty of our system is that the real-time video produced by this device is canalized into a video streming by means of VideoLan client/server (VLC) and pictures can be sent by a current File Tranfer Protocol (FTP) service to realize a Second Opinion Syste

    Morphological Exponential Entropy Driven Hum on Knee MR Images

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    A very important artifact corrupting magnetic resonance images is the RF inhomogeneity. This kind of artifact generates variations of illumination which trouble both direct examination by the doctor and segmentation algorithms. Even if homomorphic filtering approaches have been presented in literature, none of them has developed a measure to determine the cut-off frequency. In this work we present a measure based on information theory with a large experimental setup aimed to demonstrate the validity of our approac

    Bias artifact suppression on MR volumes

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    RF-Inhomogeneity correction is a relevant research topic in the field of Magnetic Resonance Imaging (MRI). A volume corrupted by this artifact exhibits nonuni- form illumination both inside a single slice and between adjacent ones. In this work a bias correction technique is presented, which suppresses this artifact on MR vol- umes scanned from different body parts without any a-priori hypothesis on the artifact model. Theoretical foundations of the method are reported together with experimental results and a comparison is presented with both the 2D version of the algorithm and other techniques that are widely used in MRI literature

    Morphological Exponential Entropy Driven-HUM

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    This paper presents an improvement to the exponential entropy driven-homomorphic unsharp masking (E2D-HUM) algorithm devoted to illumination artifact suppression on magnetic resonance images. E2D-HUM requires a segmentation step to remove dark regions in the foreground whose intensity is comparable with background, because strong edges produce streak artifacts on the tissues. This new version of the algorithm keeps the same good properties of E2D-HUM without a segmentation phase, whose parameters should be chosen in relation to the imag
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