Ingrid Daubechies | Duke University (original) (raw)

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Papers by Ingrid Daubechies

Monthly Notices of the Royal Astronomical Society, 2005

We present a new method for component separation aimed at extracting Sunyaev-Zel'dovich (SZ) gala... more We present a new method for component separation aimed at extracting Sunyaev-Zel'dovich (SZ) galaxy clusters from multifrequency maps of cosmic microwave background (CMB) experiments. This method is designed to recover non-Gaussian, spatially localized and sparse signals. We first characterize the cluster non-Gaussianity by studying it on simulated SZ maps. We then apply our estimator on simulated observations of the Planck and Atacama Cosmology Telescope (ACT) experiments. The method presented here outperforms multifrequency Wiener filtering, both in the reconstructed average intensity for given input and in the associated error. In the absence of point source contamination, this technique reconstructs the ACT (Planck) bright (big) cluster central y parameter with an intensity that is about 84 (43) per cent of the original input value. The associated error in the reconstruction is about 12 and 27 per cent for the 50 (12) ACT (Planck) clusters considered. For ACT, the error is dominated by beam smearing. In the Planck case, the error in the reconstruction is largely determined by the noise level: a noise reduction by a factor of 7 would imply almost perfect reconstruction and 10 per cent error for a large sample of clusters. We conclude that the selection function of Planck clusters will strongly depend on the noise properties in different sky regions, as well as the specific cluster extraction method assumed.

Journal of Mathematical Physics, 1983

Thermal analysis of high intensity organic light-emitting diodes based on a transmission matrix a... more Thermal analysis of high intensity organic light-emitting diodes based on a transmission matrix approach J. Appl. Phys. 110, 124516 (2011) A novel compensation method of insertion losses for wavelet inverse-transform processors using surface acoustic wave devices Rev. Sci. Instrum. 82, 115003 Large-scale symmetry-adapted perturbation theory computations via density fitting and Laplace transformation techniques: Investigating the fundamental forces of DNA-intercalator interactions

IEEE Signal Processing Magazine, 2000

IEEE Transactions on Pattern Analysis and Machine Intelligence, 2000

Super-resolution methods form high-resolution images from low-resolution images. In this paper, w... more Super-resolution methods form high-resolution images from low-resolution images. In this paper, we develop a new Bayesian nonparametric model for super-resolution. Our method uses a beta-Bernoulli process to learn a set of recurring visual patterns, called dictionary elements, from the data. Because it is nonparametric, the number of elements found is also determined from the data. We test the results on both benchmark and natural images, comparing with several other models from the research literature.

IEEE Transactions on Information Theory, 2002

We introduce the concept of "democracy," in which the individual bits in a coarsely quantized rep... more We introduce the concept of "democracy," in which the individual bits in a coarsely quantized representation of a signal are all given "equal weight" in the approximation to the original signal. We prove that such democratic representations cannot achieve the same accuracy as optimal nondemocratic schemes.

Constructive Approximation, 1996

Constructive Approximation, 1999

Abstract. We study the smoothness of the limit function for one-dimensional unequally spaced inte... more Abstract. We study the smoothness of the limit function for one-dimensional unequally spaced interpolating subdivision schemes. The new grid points introduced at every level can lie in irregularly spaced locations between old, adjacent grid points and not only midway ...

Applied and Computational Harmonic Analysis, 1998

Invertible wavelet transforms that map integers to integers have important applications in lossle... more Invertible wavelet transforms that map integers to integers have important applications in lossless coding. In this paper we present two approaches to build integer to integer wavelet transforms. The first approach is to adapt the precoder of Laroiaet al.,which is used in ...

In this paper, we investigate the minimax properties of Stein block thresholding in any dimension... more In this paper, we investigate the minimax properties of Stein block thresholding in any dimension d with a particular emphasis on d = 2. Towards this goal, we consider a frame coefficient space over which minimaxity is proved. The choice of this space is inspired by the characterization provided in [L. Borup, M. Nielsen, Frame decomposition of decomposition spaces, J. Fourier Anal. Appl. 13 (1) (2007) 39-70] of family of smoothness spaces on R d , a subclass of so-called decomposition spaces [H.G. Feichtinger, Banach spaces of distributions defined by decomposition methods, II, Math. Nachr. 132 (1987) 207-237]

ABSTRACT The art of Jan van Eyck is renowned for its capacity to reveal with extreme accuracy the... more ABSTRACT The art of Jan van Eyck is renowned for its capacity to reveal with extreme accuracy the materiality of object surfaces. The interaction of light with the surface of materials results in reflected light that carries to the viewer the information on the quality of the surface material. Apparently Jan van Eyck understands that seeing a visual object has more to do with tracing perceptually what kind of light is falling on the object and where it comes from than with any conceptual identification of the object. Tracing the light back to its source is in vision studies known as inverse optics. In a visual display, the light source is particularly revealed by the highlights which are mirroring that source. In his pictures Jan van Eyck uses these highlights as anchor points to indicate where in the visual scene the highest lightness is to be found. With further understanding of the physics involved, he carefully observes the specific fall off of the intensity of reflected light around highlights to characterize particular materials. His special sensibility for highlights might have originated in his involvement with the production of miniatures in illuminated books where, depending on the locations of light source and viewer and orientation of the illuminated page, gilded segments can drastically change in brightness. We will compare color and luminance distribution properties around highlights in some Eyckian pictures with comparable pictures of contemporaries (Campin, Van der Weyden) with special attention to metals and gold brocade.