203,389 research outputs found
Digital Color Imaging
This paper surveys current technology and research in the area of digital
color imaging. In order to establish the background and lay down terminology,
fundamental concepts of color perception and measurement are first presented
us-ing vector-space notation and terminology. Present-day color recording and
reproduction systems are reviewed along with the common mathematical models
used for representing these devices. Algorithms for processing color images for
display and communication are surveyed, and a forecast of research trends is
attempted. An extensive bibliography is provided
The relation between color spaces and compositional data analysis demonstrated with magnetic resonance image processing applications
This paper presents a novel application of compositional data analysis
methods in the context of color image processing. A vector decomposition method
is proposed to reveal compositional components of any vector with positive
components followed by compositional data analysis to demonstrate the relation
between color space concepts such as hue and saturation to their compositional
counterparts. The proposed methods are applied to a magnetic resonance imaging
dataset acquired from a living human brain and a digital color photograph to
perform image fusion. Potential future applications in magnetic resonance
imaging are mentioned and the benefits/disadvantages of the proposed methods
are discussed in terms of color image processing.Comment: 13 pages, 3 figures, short paper, submitted to Austrian Journal of
Statistics compositional data analysis special issue, first revision, fix
rendering error in fig
Color camera computed tomography imaging spectrometer for improved spatial-spectral image accuracy
Computed tomography imaging spectrometers ("CTIS"s) having color focal plane array detectors are provided. The color FPA detector may comprise a digital color camera including a digital image sensor, such as a Foveon X3.RTM. digital image sensor or a Bayer color filter mosaic. In another embodiment, the CTIS includes a pattern imposed either directly on the object scene being imaged or at the field stop aperture. The use of a color FPA detector and the pattern improves the accuracy of the captured spatial and spectral information
METACOW: A public-domain, high-resolution, fully-digital, noise-free, metameric, extended-dynamic-range, spectral test target for imaging system analysis and simulation
Standard, easily accessible, test targets have long served the field of color imaging as a foundation for comparison of the performance of various imaging systems and algorithms and the open and meaningful exchange of research results. This paper details the creation and application of a new digital color test target useful for research and development of color imaging systems. The target has several advantages over previous types of targets that include spatial resolution, dynamic range, spectral resolution, metameric properties, lack of noise, and continuous tonal variations. All these features can be important for visual assessment, computational analysis, and colorimetric evaluation. This target, known as METACOW, is freely available to all performing research in color imaging
Simultaneous two-color imaging in digital holographic microscopy
We demonstrate the use of two-color digital holographic microscopy (DHM) for imaging microbiological subjects. The use of two wavelengths significantly reduces artifacts present in the reconstructed data, allowing us to image weakly scattering objects in close proximity to strongly-scattering objects. We demonstrate this by reconstructing the shape of the flagellum of a single-cell eukaryotic parasite Leishmania mexicana in close proximity to a more strongly-scattering cell body. Our approach also yields a reduction of approximately one third in the axial position uncertainty when tracking the motion of swimming cells at low magnification, which we demonstrate with a sample of Escherichia coli bacteria mixed with polystyrene beads. The two-wavelength system that we describe introduces minimal additional complexity into the optical system, and provides significant benefits
Specialized Color Targets for Spectral Reflectance Reconstruction of Magnified Images
Digital images are used almost exclusively instead of film to capture visual information across many scientific fields. The colorimetric color representation within these digital images can be relayed from the digital counts produced by the camera with the use of a known color target. In image capture of magnified images, there is currently no reliable color target that can be used at multiple magnifications and give the user a solid understanding of the color ground truth within those images. The first part of this dissertation included the design, fabrication, and testing of a color target produced with optical interference coated microlenses for use in an off-axis illumination, compound microscope. An ideal target was designed to increase the color gamut for colorimetric imaging and provide the necessary Block Dye spectral reflectance profiles across the visible spectrum to reduce the number of color patches necessary for multiple filter imaging systems that rely on statistical models for spectral reflectance reconstruction.
There are other scientific disciplines that can benefit from a specialized color target to determine the color ground truth in their magnified images and perform spectral estimation. Not every discipline has the luxury of having a multi-filter imaging system. The second part of this dissertation developed two unique ways of using an interference coated color mirror target: one that relies on multiple light-source angles, and one that leverages a dynamic color change with time. The source multi-angle technique would be used for the microelectronic discipline where the reconstructed spectral reflectance would be used to determine a dielectric film thickness on a silicon substrate, and the time varying technique would be used for a biomedical example to determine the thickness of human tear film
The Cut & Enhance method : selecting clusters of galaxies from the SDSS commissioning data
We describe an automated method, the Cut & Enhance method (CE) for detecting
clusters of galaxies in multi-color optical imaging surveys. This method uses
simple color cuts, combined with a density enhancement algorithm, to up-weight
pairs of galaxies that are close in both angular separation and color. The
method is semi-parametric since it uses minimal assumptions about cluster
properties in order to minimize possible biases. No assumptions are made about
the shape of clusters, their radial profile or their luminosity function. The
method is successful in finding systems ranging from poor to rich clusters of
galaxies, of both regular and irregular shape. We determine the selection
function of the CE method via extensive Monte Carlo simulations which use both
the real, observed background of galaxies and a randomized background of
galaxies. We use position shuffled and color shuffled data to perform the false
positive test. We have also visually checked all the clusters detected by the
CE method. We apply the CE method to the 350 deg^2 of the SDSS (Sloan Digital
Sky Survey) commissioning data and construct a SDSS CE galaxy cluster catalog
with an estimated redshift and richness for each cluster. The CE method is
compared with other cluster selection methods used on SDSS data such as the
Matched Filter (Postman et al. 1996, Kim et al. 2001), maxBCG technique (Annis
et al. 2001) and Voronoi Tessellation (Kim et al. 2001). The CE method can be
adopted for cluster selection in any multi-color imaging surveys.Comment: 62 pages, 32 figures, Accepted for publication in the Astronomical
Journal, "the CE galaxy cluster catalog can be downloaded from,
http://astrophysics.phys.cmu.edu/~tomo/ce/
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