Multi-color Space Research Articles

Star-galaxy separation in the AKARI NEP deep field

Context: It is crucial to develop a method for classifying objects detected in deep surveys at infrared wavelengths. We specifically need a method to separate galaxies from stars using only the infrared information to study the properties of galaxies, e.g., to estimate the angular correlation function, without introducing any additional bias. Aims. We aim to separate stars and galaxies in the data from the AKARI North Ecliptic Pole (NEP) Deep survey collected in nine AKARI / IRC bands from 2 to 24 {\mu}m that cover the near- and mid-infrared wavelengths (hereafter NIR and MIR). We plan to estimate the correlation function for NIR and MIR galaxies from a sample selected according to our criteria in future research. Methods: We used support vector machines (SVM) to study the distribution of stars and galaxies in the AKARIs multicolor space. We defined the training samples of these objects by calculating their infrared stellarity parameter (sgc). We created the most efficient classifier and then tested it on the whole sample. We confirmed the developed separation with auxiliary optical data obtained by the Subaru telescope and by creating Euclidean normalized number count plots. Results: We obtain a 90% accuracy in pinpointing galaxies and 98% accuracy for stars in infrared multicolor space with the infrared SVM classifier. The source counts and comparison with the optical data (with a consistency of 65% for selecting stars and 96% for galaxies) confirm that our star/galaxy separation methods are reliable. Conclusions: The infrared classifier derived with the SVM method based on infrared sgc- selected training samples proves to be very efficient and accurate in selecting stars and galaxies in deep surveys at infrared wavelengths carried out without any previous target object selection.

The Color Recognition of Jet Fuel Silver Corrosion Images Based on Color Difference Formula

This article introduces the basic theoretical knowledge of the multi-color space and its color difference formula. By research and experiment, it validates that HSV and CIE L * a * b * color space and its corresponding color difference formula, which are used in the color recognition of jet fuel silver corrosion image, and their results are mostly in accordance with the recognition results by the naked eyes. And it also proves the feasibility of these two methods for the color recognition of jet fuel silver corrosion. Silver strip corrosion experiment must be tested as one of jet fuel corrosion detection items in jet fuel accepting, providing and storage process. The examination, whether jet fuel is qualified or not, is mainly due to silver corrosion’s color judgment. For computer visual system, the color is the character of object surface, and it is mankind recognition system to the object surface, light shine and visual condition’s comprehensive effect, and it has important function in the picture’s partition and identifying field. The color that is put up by visible light is continuous, and in order to measure and calculate conveniently, some scholars successively establish more than ten color spaces, which are mainly divided three types, by the HSV color space with RGB, HIS, and Munsell color spaces etc. According to particular application color space, YUV and YIQ and CMY color space are adopted by the television system, and CIE color space then includes CIE, XYZ, Lab and Luv etc. This article comparatively studies representative color space as well as RGB, HIS, CMY, YUV and CIE Lab color spaces, which are used for jet fuel silver strip corrosion image’s color recognition accuracy, and this article finally ensures a kind of color space and color difference formula which are applied to jet fuel silver strip corrosion image’s color recognition.

THE ASSEMBLY HISTORY OF DISK GALAXIES. I. THE TULLY-FISHER RELATION TO z {approx_equal} 1.3 FROM DEEP EXPOSURES WITH DEIMOS

We present new measures of the evolving scaling relations between stellar mass, luminosity and rotational velocity for a morphologically inclusive sample of 129 disk-like galaxies with z{sub AB} < 22.5 in the redshift range 0.2 <z < 1.3, based on spectra from DEep Imaging Multi-Object Spectrograph on the Keck II telescope, multi-color Hubble Space Telescope (HST) Advanced Camera for Surveys photometry, and ground-based K{sub s} -band imaging. A unique feature of our survey is the extended spectroscopic integration times, leading to significant improvements in determining characteristic rotational velocities for each galaxy. Rotation curves are reliably traced to the radius where they begin to flatten for {approx}90% of our sample, and we model the HST-resolved bulge and disk components in order to accurately de-project our measured velocities, accounting for seeing and dispersion. We demonstrate the merit of these advances by recovering an intrinsic scatter on the stellar mass Tully-Fisher relation a factor of two to three less than in previous studies at intermediate redshift and comparable to that of locally determined relations. With our increased precision, we find that the relation is well established by (z) {approx} 1, with no significant evolution to (z) {approx} 0.3, {Delta}M{sub *} {approx} 0.04 {+-}more » 0.07 dex. A clearer trend of evolution is seen in the B-band Tully-Fisher relation corresponding to a decline in luminosity of {Delta}M{sub B} {approx} 0.85 {+-} 0.28 magnitudes at fixed velocity over the same redshift range, reflecting the changes in star formation over this period. As an illustration of the opportunities possible when gas masses are available for a sample such as ours, we show how our dynamical and stellar mass data can be used to evaluate the likely contributions of baryons and dark matter to the assembly history of spiral galaxies.« less

Implementation of a hand mouse based on a hand recognition method using multi-color spaces and two cameras

Implementation of a hand mouse based on a hand recognition method using multi-color spaces and two cameras

Detailed cluster mass and light profiles of A1703, A370 and RXJ1347−11 from deep Subaru imaging

Weak lensing work can be badly compromised by unlensed foreground and cluster members which dilute the true lensing signal. We show how the lensing amplitude in multi-colour space can be harnessed to securely separate cluster members from the foreground and background populations for three massive clusters, A1703 (z=0.258), A370 (z=0.375) and RXJ1347-11 (z=0.451) imaged with Subaru. The luminosity functions of these clusters when corrected for dilution, show similar faint-end slopes, \alpha ~= -1.0, with no marked faint-end upturn to our limit of M_R ~= -15.0, and only a mild radial gradient. In each case, the radial profile of the M/L ratio peaks at intermediate radius, ~=0.2r_{vir}, at a level of 300-500(M/L_R)_\odot, and then falls steadily towards ~100(M/L_R)_{\odot} at the virial radius, similar to the mean field level. This behaviour is likely due to the relative paucity of central late-type galaxies, whereas for the E/S0-sequence only a mild radial decline in M/L is found for each cluster. We discuss this behaviour in the context of detailed simulations where predictions for tidal stripping may now be tested accurately with observations.

A multi color space approach for texture classification: experiments with Outex, Vistex and Barktex image databases

A multi color space approach for texture classification: experiments with Outex, Vistex and Barktex image databases

Adaptive mouth region detection algorithm based on multi-color spaces

Mouth region detection is the prerequisite of lipreading.In this paper,an adaptive mouth region detection algorithm was proposed based on multi-color spaces.The algorithm combined color edge detection in RGB color space and threshold segmentation in HSV color space.Furthermore,according to the mouth position of the face,an adaptive lip localization method was introduced to detect the position of mouth baseline automatically.Then the rectangular area of mouth region was detected by projection method.Experimental results show that the proposed algorithm can locate mouth region fast,accurately and robustly.

Design of high performance multimedia software for a mobile device with hardware accelerators

This paper describes the design of multimedia software for a mobile device consisting of software and hardware decoders and accelerators for achieving the best video performance. The hardware system of the mobile device consists of multi format codec subsystem and color space converter. The multi format codec (MFC) supports the encoding and decoding of video/image data in five different formats. The multimedia software is designed so that it makes use of the hardware accelerators in the most efficient way. In the case of video formats that are not supported by the MFC, the multimedia application makes use of software video decoders. The paper gives an analysis of several design configurations and brings out the best design in terms of performance and processor usage for displaying video on mobile devices. An experimental analysis and results is given that demonstrates the efficiency and usefulness of the design.

QSO number counts to B < 24.5 from hubble space telescope WFPC2 images

We have conducted a survey for faint quasars to B < 24.5, z < 2.1 based on archival high-latitude Hubble Space Telescope Wide Field Planetary Camera 2 (WFPC2) images covering 0.04 deg 2 of the sky in three filters spanning 2300–9600 Å. Taking advantage of the superb 0.1″ resolution of WFPC2, we have developed an approach to select quasar candidates based on their morphology and position in multicolor space. We derive cumulative surface densities and compare them with our previous survey in the Groth–Westphal Strip and other faint quasar surveys that utilize very different selection approaches. In most cases the agreement with these surveys is good, however, we find approximately twice as many quasar candidates to B = 24.5 as the COMBO-17 survey. Although we are confident that our approach eliminates most contaminating stars and galaxies, spectroscopic follow-up will be required to determine the level of residual contamination and confirm or refute this excess.

Color control of the multi-color printing device

Conventional color-printing systems often use inks of three hues, such as CMY, CMYK and CMYKLcLm, but in order to obtain more realistic color reproductions, the ink set of more than three hues has been adopted by some color-printing systems. It is difficult, however, to model the composed color with the multiple inks when the number of the output ink hues exceeds three due to the none-unique mapping between the color spaces of the CIE Lab and the multi-color printing device. In this paper, we propose a fine color-printing method for multi-color printing device with the ink set of more than three hues. The proposed approach has good color expression ability and provides fine control of the printed color. By dividing the output color space into several subspaces, our method allows one-to-one mapping between the standard color space and the multi-color output color space. It has been proved effective when applied to the digital inkjet printer—Mutoh8000.

ICA-based multi-colour space texture classification system

Presented is a novel method which uses independent component analysis (ICA) for systematically partitioning and combining textural features extracted from different colour spaces, in a multiple classifier based system, for colour texture classification. Results obtained illustrate that the proposed ICA-based feature-partitioning and classifier combination system produces more accurate results compared to a system that combines classifiers applied to features extracted from individual colour spaces.

High-Redshift Quasars Found in Sloan Digital Sky Survey Commissioning Data

We present photometric and spectroscopic observations of 15 high-redshift quasars (z > 3.6) discovered from ~140 deg2 of five-color (u', g', r', i', and z') imaging data taken by the Sloan Digital Sky Survey (SDSS) during its commissioning phase. The quasars are selected by their distinctive colors in SDSS multicolor space. Four of the quasars have redshifts higher than 4.6 (z = 4.63, 4.75, 4.90, and 5.00, the latter being the highest redshift quasar yet known). In addition, two previously known z > 4 objects were recovered from the data. The quasars all have i* < 20 and have luminosities comparable to that of 3C 273. The spectra of the quasars have similar features (strong, broad emission lines and substantial absorption blueward of the Lyα emission line) seen in previously known high-redshift quasars. Although the photometric accuracy and image quality fail to meet the final survey requirements, our success rate for identifying high-redshift quasars (17 quasars from 27 candidates) is much higher than that of previous multicolor surveys. However, the numbers of high-redshift quasars found is in close accord with the number density inferred from previous surveys.

Quasar Candidates in the Hubble Deep Field

We focus on the search for unresolved faint quasars and AGN in the crude combine images using a multicolor imaging analysis that has proven very successful in recent years. Quasar selection was carried out both in multicolor space and in profile space, defined as the multi-parameter space formed by the radial profiles of the objects in the different images. By combining the dither frames available for each filter, we were able to obtain well-sampled radial profiles of the objects and measure their deviation from that of a stellar source. We also generated synthetic quasar spectra in the range 1.0 3.5. We find more quasar candidates than previous work because of our more extensive modeling and use of all of the available color information. (abridged)

Three‐dimensional Parameterization of the Stellar Locus with Application to QSO Color Selection

A straightforward method for parameterizing and visualizing a locus of points in n-space is presented. The algorithm applies directly to the problem of distinguishing QSOs from Galactic stars in multicolor space. When applied to an existing four-filter data set (photometric errors of σ ~ 0.1 mag and BJ ≲ 21.5), it recovers 95% of the known QSOs, with 76% of the candidate sources yielding QSOs. If only the non-ultraviolet excess candidates are considered, it recovers 69% of the 13 known QSOs, with 47% of the candidate sources yielding QSOs. The completeness and efficiency will differ depending on the depth and accuracy of the photometric data. The algorithm scales well to large data sets and allows astrophysical information about the location of QSOs in color space to be easily added to improve efficiency. Three-dimensional visualization of the high-accuracy photometry (σ < 0.01 mag) of the Catalogue of WBVR Magnitudes of Northern Sky Bright Stars (V < 7.2) yields the first look at the intrinsic width in the Galactic star color distribution. The stellar locus is found to populate a ribbon-like subset of color-color-color space. In the G to early-K star region, the cross section of the stellar locus has a FWHM of 0.07 mag in the wide direction. We attribute the majority of the width to metallicity differences between the stars, although there may be some contribution from other sources such as differential reddening. The FWHM in the thin direction is 0.03 mag or less. The locus is parameterized from late-B stars through M stars. We reproduce the metallicities of 64 F and G dwarfs with an rms error of 0.13. The distribution of bright stars along the locus is also presented. The algorithm can be applied to parameterize any one-dimensional set of data that is distributed in n-dimensional space.

A Deep Multicolor Survey. II. Initial Spectroscopy and Comparison with Expected Quasar Number Counts

We have used the KPNO 4-meter Mayall telescope to image 0.83 square degrees of sky in six fields at high galactic latitude in six filters spanning 3000-10000\AA to magnitude limits ranging from 22.1 to 23.8. As a first use of this database, we have conducted a multicolor survey for quasars. We discuss various methods of selecting outliers in different color-color diagrams and multicolor space that have been used to identify quasars at all redshifts from their colors alone. We discuss the initial results of our program of spectroscopic identification which has so far resulted in the identification of over forty faint quasars, including one at z$>$4, a similar number of compact narrow-emission-line galaxies, and a number of unusual and potentially interesting stars. We use these spectroscopic results, along with extensive simulations of quasar spectra, to study the efficiency of our candidate selection procedures. Finally, we compare the number counts of our quasars and quasar candidates to the expected numbers based on previous studies of the quasar luminosity function. The agreement of our observations with these expectations is good in most cases. However, we do estimate that our survey contains more quasars with B$ $3 quasars than expected from the results of Warren, Hewett, \& Osmer (1994), both at the 3$\sigma$ level. Additional spectroscopic observations will be required to confirm or refute these excesses.

Slicing Through Multicolor Space: Galaxy Redshifts from Broadband Photometry

As a means of better understanding the evolution of optically selected galaxies we consider the distribution of galaxies within the multicolor space $U$, $B_J$, $R_F$ and $I_N$. We find that they form an almost planar distribution out to $B_J =22.5$ and $z<0.3$. The position of a galaxy within this plane is dependent on its redshift, luminosity and spectral type. While in the original $U$, $B_J$, $R_F$ and $I_N$ space these properties are highly correlated we can define an optimal rotation of the photometric axes that makes much of this information orthogonal. Fitting the observed spectroscopic redshifts with a quadratic function of the four magnitudes we show that redshifts for galaxies can be estimated to an accuracy better than $\Delta z =0.05$. This dispersion is due to the photometric uncertainties within the photographic data. Assuming no galaxy evolution we derive a set of simulated galaxy fluxes in the U, J, F and N passbands. Using these data we investigate how the redshift is encoded within the broadband magnitudes and the intrinsic dispersion of the photometric-redshift relation. We find that the signal that defines a galaxy's photometric redshift is not related to specific absorption or emission lines but comes from the break in the overall shape of the galaxy continuum at around 4000 \AA. Using high signal-to-noise photometric data we estimate that it is possible to achieve an intrinsic dispersion of less than $\Delta z =0.02$.

A CATALOG OF QSO CANDIDATES FROM A BVRI CCD SURVEY OF THE NORTH ECLIPTIC POLE

ABSTRACT Twenty-five QSO candidates with B </= 22.0 have been selected from a 0.33 sq. deg. BVRI CCD survey of the North Ecliptic Pole. Those stellar-like objects which departed significantly from the locus defined by stars in a multi-color space were identified as candidates. We looked unsuccessfully for objects which might have been anomalously fainter than the limiting magnitude in one or more bands. Two of the candidates near the red end of the stellar locus may be M or K dwarf stars, and two candidates with the V - I > 1.0 may be unresolved galaxies. The completeness of the survey, estimated from the fraction of QSOs with colors indistinguishable from stars, is about 50% to B = 21.60. Contamination by main-sequence stars, white dwarf stars, blue sub-dwarf stars, and galaxies is about 20%.