Spectral measurements of two-dimensional color images

1999 ◽  
Author(s):  
Markku Hauta-Kasari ◽  
Kanae Miyazawa ◽  
Satoru Toyooka ◽  
Jussi P. S. Parkkinen
Keyword(s):  
Color Images ◽  
Two Dimensional ◽  
Spectral Measurements

Investigation of the Early Soot Formation Process in a Transient Spray Flame Via Spectral Measurements of Laser-Induced Emissions

2006 ◽  
Vol 7 (2) ◽  
pp. 93-101 ◽  
Author(s):  
T Aizawa ◽  
H Kosaka
Keyword(s):  
Formation Process ◽  
Soot Formation ◽  
Yttrium Aluminium Garnet ◽  
Two Dimensional ◽  
Spectral Measurements ◽  
Cross Sectional ◽  
Soot Particles ◽  
Nozzle Orifice ◽  
Spray Flame ◽  
Soot Precursors

In order to investigate the early soot formation process in a diesel spray flame, two-dimensional imaging and spectral measurements of laser-induced emission from soot precursors and soot particles in a transient spray flame achieved in a rapid compression machine (2.8 MPa, 710 K) were conducted. The 3rd harmonic (355 nm) and 4th harmonic (266 nm) Nd: YAG (neodymium-doped yttrium aluminium garnet) laser pulses were used as the light source for laser-induced fluorescence (LIF) from soot precursors and laser-induced incandescence (LII) from soot particles in the spray flame. The two-dimensional imaging covered an area between 30 and 55 mm downstream from the nozzle orifice. The results of two-dimensional imaging showed that strong laser-induced emission excited at 266 nm appears only on the laser incident side of the spray flame, in contrast to an entire cross-sectional distribution of the emission excited at 355 nm, indicating that 266 nm-excited emitters are stronger absorbers and more abundant than 355 nm-excited emitters in the spray flame. The spectral measurements were conducted at three different positions, 35, 45, and 55 mm downstream from the nozzle orifice, along the central axis of the spray, where LIF from soot precursors was observed in a previous two-dimensional imaging study. The spectra measured in upstream positions showed that broad emission peaked at around 400–500 nm, which is attributable to LIF from polycyclic aromatic hydrocarbons (PAHs). The spectra measured in downstream positions appeared very much like grey-body emission from soot particles.

scholarly journals A fractional corner anomaly reveals higher-order topology

Science ◽  
2020 ◽  
Vol 368 (6495) ◽  
pp. 1114-1118 ◽  
Author(s):  
Christopher W. Peterson ◽  
Tianhe Li ◽  
Wladimir A. Benalcazar ◽  
Taylor L. Hughes ◽  
Gaurav Bahl
Keyword(s):  
Charge Density ◽  
Higher Order ◽  
Order Topology ◽  
Two Dimensional ◽  
Spectral Measurements ◽  
Fractional Charge ◽  
Boundary Correspondence ◽  
Rotationally Symmetric ◽  
Topological Crystalline Insulators ◽  
Gap States

Spectral measurements of boundary-localized topological modes are commonly used to identify topological insulators. For high-order insulators, these modes appear at boundaries of higher codimension, such as the corners of a two-dimensional material. Unfortunately, this spectroscopic approach is only viable if the energies of the topological modes lie within the bulk bandgap, which is not required for many topological crystalline insulators. The key topological feature in these insulators is instead fractional charge density arising from filled bulk bands, but measurements of such charge distributions have not been accessible to date. We experimentally measure boundary-localized fractional charge density in rotationally symmetric two-dimensional metamaterials and find one-fourth and one-third fractionalization. We then introduce a topological indicator that allows for the unambiguous identification of higher-order topology, even without in-gap states, and we demonstrate the associated higher-order bulk-boundary correspondence.

Real-Time Text Detection in Color Images Based on Color Projection

2011 ◽  
Vol 480-481 ◽  
pp. 84-88
Author(s):  
Jian Jie Wu ◽  
Yu Hui Zhang
Keyword(s):  
Real Time ◽  
Production Line ◽  
Color Image ◽  
Detection Algorithm ◽  
Text Detection ◽  
Color Images ◽  
Two Dimensional ◽  
Defect Inspection ◽  
One Dimensional ◽  
Different Types

In SMT production line, different types of components may have the same shape but providing different functions. The only difference between these components is the text on surface of a component indicating its type. Therefore, not only geometry defect inspection but also text detection is needed in component inspection to avoid wrong use of components. Traditional algorithms based on pixel comparison of text image are time consuming and sensitive to tiny change of the text as well. A concise text detection algorithm based on color projection is proposed. The algorithm transfers two-dimensional color image to one-dimensional curve for comparison by projection of the text image, which greatly reduces the computing amount, increases speed and makes the algorithm less sensitive to displacement or rotation of the text. Experiments show that the algorithm can ensure effective real-time text detection.

Blind Steganography in Color Images by Double Wavelet Transform and Improved Arnold Transform

2016 ◽  
Vol 3 (3) ◽  
pp. 586 ◽  
Author(s):  
Mohammad Rasoul PourArian ◽  
Ali Hanani
Keyword(s):  
Wavelet Transform ◽  
Discrete Wavelet Transform ◽  
Color Image ◽  
Structural Similarity ◽  
Color Images ◽  
Encryption Algorithm ◽  
Discrete Wavelet ◽  
Two Dimensional ◽  
Arnold Transform ◽  
Hidden Data

<p>Steganography is a method which can put data into a media without a tangible impact on the cover media. In addition, the hidden data can be extracted with minimal differences. In this paper, two-dimensional discrete wavelet transform is used for steganography in 24-bit color images. This steganography is of blind type that has no need for original images to extract the secret image. In this algorithm, by the help of a structural similarity (SSIM) and a two-dimensional correlation coefficient, it is tried to select part of sub-band cover image instead of embedding location. These sub-bands are obtained by 3-levels of applying the DWT. Also to increase the steganography resistance against cropping or insert visible watermark, two channels of color image is used simultaneously. In order to raise the security, an encryption algorithm based on Arnold transform was also added to the steganography operation. </p>

scholarly journals The effect of some of spaces and sets of topology on the types of digital images

2021 ◽  
pp. 119-133
Author(s):  
Prof Hindrustum Shaaban ◽  
Alyaa Yousif Khudayir
Keyword(s):  
Digital Images ◽  
Three Dimensional ◽  
Color Images ◽  
Digital Topology ◽  
Two Dimensional ◽  
Matlab Software ◽  
Closed Set ◽  
Opposite Color

There is a growing interest in studying and improving the characteristics of images and objects in the e-commerce environment. Digital topology is concerned with dealing with the properties and features of two-dimensional (2D) or three-dimensional (3D) digital images such as borders, shapes, the intensity of illumination, and other characteristics. This paper aims to introduce and study new classes of fg-disconnected space and compactly fg-closed set, which could impact the brightness and brightness of the internal components of the types of color images, gray and binary. The paper also aims to find the effect of implementing fg-disconnected space and compactly fg-closed set to determine the brightness and brightness of the internal components of the types of color images, gray and binary. Each research plate contains 30 images of each type of image. Ten different images were chosen at the same time to be analyzed and executed using the proposed system based on MATLAB software. The study proved that higher brightness and light will disappear and delete the components of the image of any kind. This aimed to make the image white and opposite color, the greater darkness, and luminescence will make the picture color mysterious and turn to black.

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