Search results for "RGB"
showing 10 items of 116 documents
Developments in RGB photoelasticity
2006
In this paper the combined use of both RGB and phase stepping photoelasticity is proposed. The method is characterised by the following features: maximum measurable order greater than that of the RGB method, ability to determine the total fringe order without necessity of unwrapping.
Phase shifting photoelasticity in white light
2007
The availability of image acquisition systems has led to the development of digital photoelasticity both in monochromatic and white light. In particular white light has been used mainly with the following methods: Spectral Content Analysis, RGB photoelasticity and phase shifting photoelasticity. Phase shifting photoelasticity in the colour domain has been used effectively for the determination of the isoclinic parameter in order to reduce the influence of the isochromatic fringes. The method has been also proposed for the determination of the isochromatic fringe order. This paper concerns the general characteristics of phase shifting photoelasticity in the colour domain. Special attention i…
RGB photoelasticity applied to the analysis of membrane residual stress in glass
2011
The measurement of residual stresses is of great relevance in the glass industry. The analysis of residual stress in glass is usually made by photoelastic methods because glass is a photoelastic material. This paper considers the determination of membrane residual stresses in glass plates by automatic digital photoelasticity in white light (RGB photoelasticity). The proposed method is applied to the analysis of membrane residual stresses in some tempered glass. The proposed method can effectively replace manual methods based on the use of white light, which are currently provided by some technical standards.
A critical assessment of automatic photoelastic methods for the analysis of edge residual stresses in glass
2014
The measurement of residual stresses is of great importance in the glass industry. The analysis of residual stresses in the glass is usually carried out by photoelastic methods since the glass is a photoelastic material. This article considers the determination of membrane residual stresses of glass plates by digital photoelasticity. In particular, it presents a critical assessment concerning the automated methods based on gray-field polariscope, spectral content analysis, phase shifting, RGB photoelasticity, “test fringes” methods and “tint plate” method. These methods can effectively automate manual methods currently specified in some standards.
Photoelastic Analysis of Edge Residual Stresses in Glass by the Automated Tint Plate Method
2013
The analysis of residual stress in glass is usually carried out by means of photoelastic methods. This article considers the automation of the white light photoelastic method based on the use of a full-wave plate placed behind the glass plate. In particular, the method in based on the use of RGB photoelasticity in white light in conjunction with a full wave plate. The proposed method have been applied to the analysis of membrane residual stresses in tempered glass, showing that it can effectively replace manual methods of photoelastic analysis of residual stresses in glass when a low photoelastic retardation is present.
A review of automated methods for the collection and analysis of photoelastic data
1998
Photoelasticity is one of the most widely used full-field methods for experimental stress analysis. However, the collection of photoelastic parameters can be a long and tedious process. The advent of automated photoelastic systems has allowed the experimentalists to speed up the rate of analysis and to perform more complex investigations. This paper provides a survey of recent methods of automated photoelasticity developed in the last 20 years, i.e. methods of the fringe centres, half-fringe photoelasticity, phase-stepping photoelasticity, methods based on the Fourier transform, spectral content analysis (SCA) and RGB (red, green, blue) photoelasticity.
Multi-line NIR-RGB emission in Nd:LiNbO3 RPE optical waveguides
2007
Simultaneous generation of four spectral emission lines has been achieved in Nd-doped lithium niobate reverse proton exchange optical waveguide cavities. Using a pump at 800 nm, the four lines were found and they are due to lasing at 1.3735 combined with parametric conversion at 0.687, 0.574 and 0.4 mum.
RGB Photoelasticity: Review and Improvements
2010
: This paper considers the main developments of RGB photoelasticity with reference to the maximum measurable retardation. In this paper, a new procedure based on the standard error function evaluated on a subset of the calibration array is also proposed and experimentally tested. The experiments show that the filament lamp makes it possible to find retardations until approximately 4 fringe orders while the fluorescent lamp makes it possible to determine higher fringe orders (12 fringe orders in this paper) owing to the discrete spectrum of the source. The paper shows that, by using the incandescent lamp, the primary limiting factor is the lack of modulation of the R, G and B signals wherea…
Single-output color pattern recognition using a fractional correlator
1997
A novel method for performing color image pattern recogni- tion using a fractional correlator (FC) is proposed. The input plane is illuminated with three different coherent sources of wavelengths corre- sponding to RGB (red, green, and blue) colors. The output plane pro- vides a single output peak, which is a result of an incoherent addition between the three correlations obtained per each color. By using the fractional correlator, which is a partially space variant correlator, we achieve space-variance-controlled color pattern recognition. The use of the three-color illumination can drastically increase the discrimination ability of the suggested correlator. © 1997 Society of Photo-Optical…
Resolution improvement by single-exposure superresolved interferometric microscopy with a monochrome sensor
2011
Single-exposure superresolved interferometric microscopy (SESRIM) by RGB multiplexing has recently been proposed as a way to achieve one-dimensional superresolved imaging in digital holographic microscopy by a single-color CCD snapshot [Opt. Lett. 36, 885 (2011)]. Here we provide the mathematical basis for the operating principle of SESRIM, while we also present a different experimental configuration where the color CCD camera is replaced by a monochrome (B&W) CCD camera. To maintain the single-exposure working principle, the object field of view (FOV) is restricted and the holographic recording is based on image-plane wavelength-dispersion spatial multiplexing to separately record the thre…