12,915 research outputs found
Enhancing Low-Light Images Using Infrared-Encoded Images
Low-light image enhancement task is essential yet challenging as it is
ill-posed intrinsically. Previous arts mainly focus on the low-light images
captured in the visible spectrum using pixel-wise loss, which limits the
capacity of recovering the brightness, contrast, and texture details due to the
small number of income photons. In this work, we propose a novel approach to
increase the visibility of images captured under low-light environments by
removing the in-camera infrared (IR) cut-off filter, which allows for the
capture of more photons and results in improved signal-to-noise ratio due to
the inclusion of information from the IR spectrum. To verify the proposed
strategy, we collect a paired dataset of low-light images captured without the
IR cut-off filter, with corresponding long-exposure reference images with an
external filter. The experimental results on the proposed dataset demonstrate
the effectiveness of the proposed method, showing better performance
quantitatively and qualitatively. The dataset and code are publicly available
at https://wyf0912.github.io/ELIEI/Comment: The first two authors contribute equally. The work is accepted by
ICIP 202
The last gasps of VY CMa: Aperture synthesis and adaptive optics imagery
We present new observations of the red supergiant VY CMa at 1.25 micron, 1.65
micron, 2.26 micron, 3.08 micron and 4.8 micron. Two complementary
observational techniques were utilized: non-redundant aperture masking on the
10-m Keck-I telescope yielding images of the innermost regions at unprecedented
resolution, and adaptive optics imaging on the ESO 3.6-m telescope at La Silla
attaining extremely high (~10^5) peak-to-noise dynamic range over a wide field.
For the first time the inner dust shell has been resolved in the near-infrared
to reveal a one-sided extension of circumstellar emission within 0.1" (~15
R_star) of the star. The line-of-sight optical depths of the circumstellar dust
shell at 1.65 micron, 2.26 micron, and 3.08 micron have been estimated to be
1.86 +/- 0.42, 0.85 +/- 0.20, and 0.44 +/- 0.11. These new results allow the
bolometric luminosity of VY~CMa to be estimated independent of the dust shell
geometry, yielding L_star ~ 2x10^5 L_sun. A variety of dust condensations,
including a large scattering plume and a bow-shaped dust feature, were observed
in the faint, extended nebula up to 4" from the central source. While the
origin of the nebulous plume remains uncertain, a geometrical model is
developed assuming the plume is produced by radially-driven dust grains forming
at a rotating flow insertion point with a rotational period between 1200-4200
years, which is perhaps the stellar rotational period or the orbital period of
an unseen companion.Comment: 25 pages total with 1 table and 5 figures. Accepted by Astrophysical
Journal (to appear in February 1999
Land classification of south-central Iowa from computer enhanced images
The author has identified the following significant results. Enhanced LANDSAT imagery was most useful for land classification purposes, because these images could be photographically printed at large scales such as 1:63,360. The ability to see individual picture elements was no hindrance as long as general image patterns could be discerned. Low cost photographic processing systems for color printings have proved to be effective in the utilization of computer enhanced LANDSAT products for land classification purposes. The initial investment for this type of system was very low, ranging from 200 beyond a black and white photo lab. The technical expertise can be acquired from reading a color printing and processing manual
Document Flash Thermography
This paper presents an extension of flash thermography techniques to the analysis of documents. Motivation for this research is to develop the ability to reveal covered writings in archaeological artifacts such as the Codex Selden or Egyptian Cartonnage. An emphasis is placed on evaluating several common existing signal processing techniques for their effectiveness in enhancing subsurface writings found within a set of test documents. These processing techniques include: contrast stretching, histogram equalization, image filters, contrast images, differential absolute contrast (DAC), thermal signal reconstruction (TSR), principal component thermography (PCT), dynamic thermal tomography (DTT), pulse phase thermography (PPT), and fitting-correlation analysis (FCA). The ability of flash thermography and the combined techniques to reveal subsurface writings and document strikeouts will be evaluated. In addition, the differences in flash thermography parameters are evaluated for most effective imaging of the two document subsets
A Dual Sensor Computational Camera for High Quality Dark Videography
Videos captured under low light conditions suffer from severe noise. A
variety of efforts have been devoted to image/video noise suppression and made
large progress. However, in extremely dark scenarios, extensive photon
starvation would hamper precise noise modeling. Instead, developing an imaging
system collecting more photons is a more effective way for high-quality video
capture under low illuminations. In this paper, we propose to build a
dual-sensor camera to additionally collect the photons in NIR wavelength, and
make use of the correlation between RGB and near-infrared (NIR) spectrum to
perform high-quality reconstruction from noisy dark video pairs. In hardware,
we build a compact dual-sensor camera capturing RGB and NIR videos
simultaneously. Computationally, we propose a dual-channel multi-frame
attention network (DCMAN) utilizing spatial-temporal-spectral priors to
reconstruct the low-light RGB and NIR videos. In addition, we build a
high-quality paired RGB and NIR video dataset, based on which the approach can
be applied to different sensors easily by training the DCMAN model with
simulated noisy input following a physical-process-based CMOS noise model. Both
experiments on synthetic and real videos validate the performance of this
compact dual-sensor camera design and the corresponding reconstruction
algorithm in dark videography
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