476 research outputs found
Image Forgery Localization Based on Multi-Scale Convolutional Neural Networks
In this paper, we propose to utilize Convolutional Neural Networks (CNNs) and
the segmentation-based multi-scale analysis to locate tampered areas in digital
images. First, to deal with color input sliding windows of different scales, a
unified CNN architecture is designed. Then, we elaborately design the training
procedures of CNNs on sampled training patches. With a set of robust
multi-scale tampering detectors based on CNNs, complementary tampering
possibility maps can be generated. Last but not least, a segmentation-based
method is proposed to fuse the maps and generate the final decision map. By
exploiting the benefits of both the small-scale and large-scale analyses, the
segmentation-based multi-scale analysis can lead to a performance leap in
forgery localization of CNNs. Numerous experiments are conducted to demonstrate
the effectiveness and efficiency of our method.Comment: 7 pages, 6 figure
Implementing an ICC printer profile visualization software
Device color gamut plays a crucial role in ICC-based color management systems. Accurately visualizing a device\u27s gamut boundary is important in the analysis of color conversion and gamut mapping. ICC profiles contain all the information which can be used to better understand the capabilities of the device. This thesis project has implemented a printer profile visualization software. The project uses A2B 1 tag in a printer profile as gamut data source, then renders gamut of device the profile represents in CIELAB space with a convex hull algorithm. Gamut can be viewed interactively from any view points. The software also gets the gamut data set using CMM with different intent to do color conversion from a specified printer profile to a generic lab profile (short for A2B conversion) or from a generic CIELAB profile to a specified printer pro file and back to the generic CIELAB profile (short for B2A2B). Gamut can be rendered as points, wire frame or solid surface. Two-dimension a*b* and L*C* gamut slice analytic tools were also developed. The 2D gamut slice algorithm is based on dividing gamut into small sections according to lightness and hue angle. The point with maximum chroma on each section can be used to present a*b* gamut slice on a constant lightness plane or L*C* gamut slice on a constant hue angle plane. Gamut models from two or more device profiles can be viewed in the same window. Through the comparison, we can better understand the device reproduction capacities and proofing problems. This thesis also explained printer profile in details, and examined what gamut data source was the best for gamut visualization. At the same time, some gamut boundary descriptor algorithms were discussed. Convex hull algorithm and device space to CIELAB space mapping algorithm were chosen to render 3D gamut in this thesis project. Finally, an experiment was developed to validate the gamut data generated from the software. The experiment used the same method with profile visualization software to get gamut data set source from Photoshop 6.0. The results of the experiment were showed that the data set derived from visualization software was consistent with those from Photoshop 6.0
The spectral picture of Bergman Toeplitz operators with harmonic polynomial symbols
In this paper, it is shown that some new phenomenon related to the spectra of
Toeplitz operators with bounded harmonic symbols on the Bergman space. On the
one hand, we prove that the spectrum of the Toeplitz operator with symbol
is always connected for every polynomial with degree less
than . On the other hand, we show that for each integer greater than
, there exists a polynomial of degree such that the spectrum of the
Toeplitz operator with symbol has at least one isolated point but
has at most finitely many isolated points. Then these results are applied to
obtain a new class of non-hyponormal Toeplitz operators with bounded harmonic
symbols on the Bergman space for which Weyl's theorem holds.Comment: 21 page
Toeplitz operators on -spaces of a tree
Let be a rooted, countable infinite tree without terminal vertices. In
the present paper, we characterize the spectra, self-adjointness and positivity
of Toeplitz operators on the spaces of -summable functions on . Moreover,
we obtain a necessary and sufficient condition for Toeplitz operators to have
finite rank on such function spaces
ZeroGen: Zero-shot Multimodal Controllable Text Generation with Multiple Oracles
Automatically generating textual content with desired attributes is an
ambitious task that people have pursued long. Existing works have made a series
of progress in incorporating unimodal controls into language models (LMs),
whereas how to generate controllable sentences with multimodal signals and high
efficiency remains an open question. To tackle the puzzle, we propose a new
paradigm of zero-shot controllable text generation with multimodal signals
(\textsc{ZeroGen}). Specifically, \textsc{ZeroGen} leverages controls of text
and image successively from token-level to sentence-level and maps them into a
unified probability space at decoding, which customizes the LM outputs by
weighted addition without extra training. To achieve better inter-modal
trade-offs, we further introduce an effective dynamic weighting mechanism to
regulate all control weights. Moreover, we conduct substantial experiments to
probe the relationship of being in-depth or in-width between signals from
distinct modalities. Encouraging empirical results on three downstream tasks
show that \textsc{ZeroGen} not only outperforms its counterparts on captioning
tasks by a large margin but also shows great potential in multimodal news
generation with a higher degree of control. Our code will be released at
https://github.com/ImKeTT/ZeroGen.Comment: 17 pages, preprin
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