Showing papers in "Optics and Laser Technology in 2006"
TL;DR: Critical areas were outlined in this report, where colour design can be utilised and applied, for the benefit of all users, from ambience to essential legal requirements such as colour contrast for the visually impaired.
Abstract: Little information or guidance has been available to assist the development of a hospital's visual environment. A report on lighting and colour design schemes, accessible to non professionals with responsibility for refurbishment strategies, was required by NHS Estates. Firstly, 20 hospitals were audited to establish a picture of current practice and to identify key issues where colour design could broadly enhance the environment for patients, staff and visitors. Critical areas were outlined in this report, where colour design can be utilised and applied, for the benefit of all users, from ambience to essential legal requirements such as colour contrast for the visually impaired. Provision of staff relaxation rooms that are different in terms of colour and lux levels from immediate work spaces, or thoughtfully designed areas for patients awaiting intensive treatment, have been shown to have some beneficial effects on a sense of well being. Colour and design have not been established as a definite cure for sickness and ill health, but certainly monotony and poor conditions in premises that have not been refurbished with any care, have had a detrimental affect on recovery rates and staff morale. The realisation that a well balanced and attractive environment is of major importance to patients’ health is, in no way new; Florence Nightingale observed that ‘a variety of form and brilliance of colour in the objects presented to patients are an actual means of recovery’.
180 citations
TL;DR: In this article, the origins and composition of the earliest earth pigments used by primitive man to decorate the walls of caves through to the synthetic pigments developed in more recent times.
Abstract: Human beings have had an inherent urge to leave their mark in the form of works of art since prehistoric times. This has driven the quest for new and better pigments with which to make paints. This paper describes the origins and composition of earliest earth pigments used by primitive man to decorate the walls of caves through to the synthetic pigments developed in more recent times. Despite modern technology, the artist's palette remains a mixture of the pigments used by cave artists, natural pigments used in the middle ages, and modern organic compounds.
148 citations
TL;DR: In this article, the optical nonlinearity exhibited by zinc tetraphenyl porphyrin at low laser powers is utilized to design an optical limiter for low threshold operation.
Abstract: The increasing use of low power cw lasers in various applications calls for the design of optical limiters with low thresholds. To this end, the optical nonlinearity exhibited by zinc tetraphenyl porphyrin at low laser powers is utilized to design an optical limiter for low threshold operation. The basic parameter responsible for limiting action, the nonlinear refractive index of the medium, is measured using the Z-scan technique and found to have a value of - 1.4 × 10 - 7 cm 2 / W at the helium–neon laser wavelength of 632.8 nm. The origin of nonlinearity is explained on the basis of the thermal lens model. It is shown that effective optical limiting at desired threshold values can be achieved by the optimal choice of aperture size and experimental geometry.
113 citations
TL;DR: In this article, a two-colour implementation of thermographic phosphor thermometry is described, based on the intensity ratio of emissions from two distinct lines in the spectrum, which can be used to measure surface temperatures and heat transfer in gas turbines.
Abstract: Thermographic phosphor thermometry enables surface temperatures to be measured over a wide range extending from sub 0 °C to in excess of 1400 °C by utilising the temperature-dependent luminescent properties of lanthanide-doped ceramics. The technique is particularly advantageous where surface temperatures are high due to the difficulty in applying conventional techniques and is therefore particularly well suited to the study of surface temperatures and heat transfer in gas turbines. The paper describes a two-colour implementation of the technique based on the intensity ratio of emissions from two distinct lines in the spectrum. An imaging system based on a single CCD camera has been developed and is described as are the image processing routines. YAG:Dy and YSZ:Dy phosphors were calibrated over a temperature range from 300 to 900 K with a repeatability in the data of around ±0.6%. The response of the phosphors and the performance of the imaging system were demonstrated in a transient heating/cooling study of ceramic and metallic plates.
112 citations
TL;DR: In this article, the most relevant devices currently used in order to achieve electrically stimulated generations of colours from electroactive polymers, either as coloured light emissions from the material or as modifications of its intrinsic colour properties are reviewed.
Abstract: This paper focuses on the most relevant devices currently used in order to achieve electrically stimulated generations of colours from electroactive polymers, either as coloured light emissions from the material or as modifications of its intrinsic colour properties. For this purpose, most relevant materials, fundamental principles of operations, latest developments and current applications of organic-based electrochromic, electroluminescent and lasing devices are reviewed here. The very promising performances resulting from the analysis of state-of-the-art products, and in particular of those which are currently approaching commercial applications, suggest likely roles played by such devices for niche applications in the very near future.
107 citations
TL;DR: For example, the fly-eye antireflector as mentioned in this paper is an example of an animal reflector that has been taken through to the manufacture stage, although only one optical device in animals has been made through the manufacturing stage.
Abstract: Over the past 30 years, optics well known to the physicist have been identified in their multitudes in nature. Multilayer reflectors, diffraction gratings, liquid crystals and structures that scatter light—devices explained using “simple” optical theory—have been found in animals with a diversity of designs. For many years the potential to employ these designs commercially has been clear, although only one optical device in animals has been taken through to the manufacture stage—the fly-eye antireflector. Now, with the beginnings of “complex” optical study in biological specimens, and consequent identification of photonic band gaps, animal reflectors are being taken seriously as promising first stages in the design process of optical engineers. However, natural photonic crystals are often highly complex structures at the nano-scale that may lie beyond the limits of current engineering. This in turn justifies the study of cellular engineering—maybe we can also exploit the flawless processes of manufacture employed by animals.
85 citations
TL;DR: In the last decade thermochromic liquid crystals (TLC) and true-colour digital image processing have been successfully used in nonintrusive technical, industrial and biomedical studies and applications.
Abstract: In the last decade thermochromic liquid crystals (TLC) and true-colour digital image processing have been successfully used in non-intrusive technical, industrial and biomedical studies and applications. Thin coatings of TLCs at surfaces are utilized to obtain detailed temperature distributions and heat transfer rates for steady or transient processes. Liquid crystals also can be used to make visible the temperature and velocity fields in liquids by the simple expedient of directly mixing the liquid crystal material into the liquid (water, glycerol, glycol, and silicone oils) in very small quantities to use as thermal and hydrodynamic tracers. In biomedical situations e.g., skin diseases, breast cancer, blood circulation and other medical application, TLC and image processing are successfully used as an additional non-invasive diagnostic method especially useful for screening large groups of potential patients. The history of this technique is reviewed, principal methods and tools are described and some examples are also presented.
76 citations
TL;DR: In this paper, a modified method to design photonic crystal fibers with flattened dispersion characteristics was presented, by replacing the circular air-holes of the first central ring with elliptic airholes.
Abstract: We present a modified method to design photonic crystal fibers with flattened dispersion characteristics. By replacing the circular air-holes of the first central ring with elliptic air-holes, we observe a more flattened dispersion curve. Plane-wave expansion (PWE) method is used to analyze the dispersion property in a high-index core PCF. The simulation results are presented, and ultra-low and ultra-flattened dispersion curves over wide wavelength range are demonstrated.
71 citations
TL;DR: This paper will initially introduce the three main application fields of colour science: colour specification, colour-difference evaluation and colour appearance modelling.
Abstract: Although colour science has been widely used in a variety of industries over the years, it has not been fully explored in the field of product design. This paper will initially introduce the three main application fields of colour science: colour specification, colour-difference evaluation and colour appearance modelling. By integrating these advanced colour technologies together with modern colour imaging devices such as display, camera, scanner and printer, some computer systems have been recently developed to assist designers for designing colour palettes through colour selection by means of a number of widely used colour order systems, for creating harmonised colour schemes via a categorical colour system, for generating emotion colours using various colour emotional scales and for facilitating colour naming via a colour-name library. All systems are also capable of providing accurate colour representation on displays and output to different imaging devices such as printers.
49 citations
TL;DR: In this article, a modified contrast-stretching method was used to enhance a non-uniformly illuminated image, where low-frequency information of the image was processed by the conventional manipulation, while the highfrequency information was exaggerated by the log transformation.
Abstract: We demonstrate a modified contrast-stretching method to enhance a non-uniformly illuminated image. Low-frequency information of the image is processed by the conventional manipulation, while the high-frequency information is exaggerated by the log transformation. Characteristics in the picture are better enhanced compared to the traditional algorithm.
43 citations
TL;DR: This paper describes a novel method of incorporating concealed coding features in security holograms in the form of moire patterns, which need an encoded key hologram to decode them, so that these remain invisible to the counterfeiters thereby enhancing the anti-counterfeiting ability of security hologram.
Abstract: This paper describes a novel method of incorporating concealed coding features in security holograms in the form of moire patterns, which need an encoded key hologram to decode them. These concealed codes in the holograms are in turn recorded with an encoded feature, so that these remain invisible to the counterfeiters thereby enhancing the anti-counterfeiting ability of security holograms. These security features, which are specific kinds of moire patterns, can only be decoded by using an encoded key hologram in the final reading process. Though these type of security holograms are quite suitable for visual inspection, they possess high degree of anti-counterfeit ability and also do not require expensive reading machines. They can also be used as security codes for better protection against counterfeiting embossed holograms. Two different recording schemes for the formation of such security holograms and typical experimental results have been presented.
TL;DR: In this paper, a finite element modeling of laser-generated ultrasound in a coating-substrate system is presented, which entails a numerical formulation for the transient responses in terms of the characteristics of the source that originated the waves in the thermoelastic regime.
Abstract: Thermal and mechanical finite element modeling of laser-generated ultrasound in coating–substrate system is presented, which entails a numerical formulation for the transient responses in terms of the characteristics of the source that originated the waves in the thermoelastic regime. The formulation takes into account the temperature dependence of the material parameters and thermal diffusion from the source. Numerical results show that the temperature gradient field is equivalent to the body force source, namely, vertical forces propagate downward and horizontal forces outward in the specimen. Waveforms at the epicenter present fast oscillations immediately after the precursor, which are produced by multiple reflections of the longitudinal in the coating, the thickness of the coating has remarkable influence on the waveforms at the epicenter.
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TL;DR: This method was used to denoise a simulated speckle fringe patterns, a good fidelity value was obtained and it has provided a phase distribution with a good accuracy.
Abstract: This paper presents a stationary wavelet transform (SWT) method for speckle noise reduction in digital speckle pattern interferometry fringes The main advantage of SWT is its translation invariance, which makes it important in statistical image processing applications This method was used to denoise a simulated speckle fringe patterns, a good fidelity value was obtained Applied to the wavelet phase evaluation, it has provided a phase distribution with a good accuracy
TL;DR: The unpredictability of the evenness of colour developed on titanium surfaces for use in jewellery has led to a research project at Central Saint Martin's College of Art and Design (CSM) to investigate the detailed structure of the thin oxide films that produce the interference colours as discussed by the authors.
Abstract: The unpredictability of the evenness of colour developed on titanium surfaces for use in jewellery has led to a research project at Central Saint Martin's College of Art and Design (CSM) to investigate the detailed structure of the thin oxide films that produce the interference colours In the course of some initial investigations an unusual phenomenon was observed when a specific material was anodised Examination of the anodised surface by scanning electron microscopy (SEM) showed a profusion of flower-like ‘oxide growths’ developed in random orientations from about 30 V with increasing density up to 110 V In honour of the late Professor Harvey Flower these features are currently referred to as ‘Flower oxides’ or ‘flowers’ Further work is continuing to clarify the nature of these growth features and their structure and composition
TL;DR: An up-to-date progress of the international laser research and development is given in this paper, where the number of scientific publications and filed patents are considered as a figure of merit and based on these numbers the growth pace and important aspects are investigated.
Abstract: An up-to-date progress of the international laser research and development is given in this article. The number of scientific publications and filed patents are considered as a figure of merit and based on these numbers the growth pace and important aspects are investigated. We have used the Science Finder Scholar search engine, which indexes more than 4000 journals, in different languages, and represents most significant published materials in laser science and engineering. The growth of the laser and related fields are described in terms of resulting scientific publications for the period of 1990–2003. The share of top nations in scientific publications, and in particular laser publications in terms of their gross domestic product (GDP) is presented. It is noted that the four countries including the USA, Japan, Germany and China have a laser publication contribution of 58.9% while the rest of the world including 189 countries contribute 41.1%. However, for the case of patent, which is a more important factor, these four countries hold a share of 90.1% while the remaining nations have a small share of 9.9%. The USA heads all the nations in the number of scientific publications, citations, and laser publications, however, in terms of accepted laser patents Japan shows a big lead. Scientific scopes of the laser systems are presented and some requirements to be met in each field are described. The key points in this field of research, which might be helpful in the future development of the laser technology are discussed.
TL;DR: In this paper, a quasi-phase matched optical parametric oscillator (OPO) using periodically poled MgO-doped LiNbO 3 with different grating periods was presented.
Abstract: We report a compact quasi-phase-matched optical parametric oscillator (OPO) using periodically poled MgO-doped LiNbO 3 with different grating periods. The OPO is pumped by a diode-pumped passively Q-switched Nd:YAG laser providing 4.8-ns pulses at 5.4-kHz repetition rate. The OPO generates signal and idler wavelengths tunable in the ranges of 1.5– 1.7 μ m and 2.8– 3.6 μ m , respectively, by changing the crystal temperature between room temperature and 170 ∘ C . The temperature-dependent Sellmeier equation for the extraordinary refractive index of MgO-doped LiNbO 3 is modified in the Mid-IR region, which gives an accurate prediction of the experimental temperature-tuning results. The linewidth of the signal wave is in the range of 0.5–1.0 nm without any controlling element.
TL;DR: In this paper, a new theoretical method for searching the light-emitting diodes with the desired technological parameters is proposed, which is grounded on the complex use of molecular dynamics and quantum chemical methods for the prediction of the main directions of the design of the corresponding light sources.
Abstract: A new theoretical method for searching the light-emitting diodes with the desired technological parameters is proposed. This method is grounded on the complex use of molecular dynamics and quantum chemical methods for the prediction of the main directions of the design of the corresponding light sources. Comparison of the theoretical simulations and measured parameters is made. A crucial role of the solvents on the performed theoretical simulations was shown. It was found that several observed discrepancies between the theoretical simulations and experimental data may be explained within the red Stocks shifts of the emission spectra. Generally, the simulated spectra within a framework of the proposed approach describe well the observed experimental dependences. Depending on the substituted group (hydrogen, phenyl, methyl and their combination), we have established a correlation between the spectral shift of blue luminescence from 161 up to 3200 cm - 1 . A quantum efficiency (about 0.20%) allows to propose the investigated materials’ blue-light luminophore. The approach may be recommended for searching the organic chromophore for light-emitting diodes.
TL;DR: The overall results show that the developed conversion method reported here can be effectively used to obtain more in-depth and quantitative information out of the raw data for the PLIF experiments.
Abstract: The goal of this paper is to describe essential criteria for image analysis of planar laser-induced fluorescence (PLIF) signals. A new image file conversion method is introduced and some typical illustrative examples showing the potential applications of the method in PLIF experiments are presented. Analysis of row, column, and total pixel counts, and the dark noise related to an image are discussed. Image segmentation, averaging and background correction can be easily done by the reported method. In our analysis it is straightforward to inspect the pixel counts and check for saturation of the camera sensors. It is also feasible to obtain a particular row or column for interpretation and it offers an easy way to check the validity of the captured images. Furthermore, the method offers a sensitive technique to check pulse-to-pulse variation of the excitation laser by using frame-to-frame fluorescence image data comparison, which is more illustrative than power checking by other means. The overall results show that the developed conversion method reported here can be effectively used to obtain more in-depth and quantitative information out of the raw data for the PLIF experiments.
TL;DR: In this article, the authors examined the origins and philosophies behind the colour circles of Art, Perception, Science and Physiology with reference to Aristotle, Robert Boyle, Leonardo da Vinci, Goethe, Ewald Hering and Albert Munsell.
Abstract: Colour is not the domain of any one discipline be it art, philosophy, psychology or science. Each discipline has its own colour wheel and this presentation examines the origins and philosophies behind the colour circles of Art, Perception, Science and Physiology (after image) with reference to Aristotle, Robert Boyle, Leonardo da Vinci, Goethe, Ewald Hering and Albert Munsell. The paper analyses and discusses the differences between the four colour wheels using the Natural Colour System ® notation as the reference for hue (the position of colours within each of the colour wheels). Examination of the colour wheels shows the dominance of blue in the wheels of art, science and physiology particularly at the expense of green. This paper does not consider the three-dimensionality of colour space its goal was to review the hue of a colour with regard to its position on the respective colour wheels.
TL;DR: Here, a behavioural ecologist and an installation artist present bumblebees with reproductions of paintings highly appreciated in Western society, such as Van Gogh's Sunflowers to raise awareness for between-species differences in visual perception, and to provoke thinking about the implications of biology in human aesthetics.
Abstract: Flower colours have evolved over 100 million years to address the colour vision of their bee pollinators. In a much more rapid process, cultural (and horticultural) evolution has produced images of flowers that stimulate aesthetic responses in human observers. The colour vision and analysis of visual patterns differ in several respects between humans and bees. Here, a behavioural ecologist and an installation artist present bumblebees with reproductions of paintings highly appreciated in Western society, such as Van Gogh's Sunflowers. We use this unconventional approach in the hope to raise awareness for between-species differences in visual perception, and to provoke thinking about the implications of biology in human aesthetics and the relationship between object representation and its biological connotations.
TL;DR: In this paper, a theoretical approach to simulation of nonlinear optical absorption in zinc selenide crystals doped with cobalt (II) ions (ZnSe:Co 2+ ) was presented.
Abstract: The paper presents theoretical approach to simulation of nonlinear optical absorption in zinc selenide crystals doped with cobalt (II) ions (ZnSe:Co 2+ ), which was reported by us earlier (Opt. Laser Technology, V. 35, (2003), 169). We used ZnSe:Co 2+ crystals as saturable absorbers for generation of giant-pulse eye-safe laser radiation. It was found that minimal optical losses (maximal final transmission) occurred for ZnSe samples containing 1.6×10 19 cm −3 of Co 2+ ions. Band structure and photoinduced molecular dynamics simulations were performed to explain the parabolic dependence of optical losses versus Co 2+ concentration. The minimum was shown to be the result of photoinduced anharmonic electron–phonon interaction.
TL;DR: In this paper, two-component Particle Image Velocimetry (PIV) has been used to visualise the flow behavior for a circular cylinder on a plane end-wall.
Abstract: A cylinder attached to an end-wall normal to its axis is a common feature of many practical flow systems, e.g. in turbo-machinery or when a bridge is supported by a pillar from the bed of a river. In this situation, the nominally two-dimensional boundary layer flow incident upon the cylinder develops strong three-dimensional features and a very pronounced vortex structure may arise in the upstream flow close to the wall. For the appropriate Reynolds number range, the upstream vortical structure is nominally steady and is commonly referred to as the “horseshoe vortex system”. In contrast, the flow downstream is unsteady and periodic over a wide range of Reynolds numbers and vortices aligned with the cylinder axis are shed at a regular frequency into the wake. The generation of both these vortex systems requires energy to be extracted from the incident flow with the result that the drag force on the cylinder is increased. This paper concentrates on the upstream region of the cylinder and discusses an investigation in which two-component Particle Image Velocimetry (PIV) has been used to visualise the flow behaviour for a circular cylinder on a plane end-wall. The use of PIV has enabled two orthogonal velocity components to be measured in planes defined by the upstream flow direction and the axis of the cylinder. The third (out-of-plane) velocity component was then calculated by integrating the continuity equation. Subsequently, the velocity field information has been manipulated and converted into time-averaged information. Discussion of the measured results confirms that colour displays are an invaluable aid to understanding this complex fluid flow situation since they reveal substantially more information than grey-scale plots of the same data. In particular, the source of the horseshoe vortex system can be identified when colour plots of the time-averaged velocity and vorticity distributions are obtained. A limited amount of information on the unsteady vortex structures appearing in the end-wall region upstream of the cylinder is also presented. Finally, the experimental findings are discussed in relation to the results of previous workers.
TL;DR: In this article, the influence of energy density on laser hardening effect is analyzed and the simulation results can be regarded as a basis for choosing laser technological parameters, and the thermocouple temperature transducer is verified through the specimen surface temperature under the laser irradiation.
Abstract: Temperature field in the laser hardening process was numerically simulated by MSC.Marc software. The influence of energy density on laser hardening effect is analyzed. Simulation result is verified through the thermocouple temperature transducer measuring the specimen surface temperature under the laser irradiation. Experimental curves of temperature versus time are in agreement with simulation results. The simulation results can be regarded as a basis for choosing laser technological parameters.
TL;DR: In this article, a new laser transition at 1112 nm was obtained after analyzing the parameters of the main laser transitions in Nd:YAG and calculating the transmission loss of the cavity at 1064, 1319, and 946 nm.
Abstract: A new laser transition at 1112 nm was obtained after analyzing the parameters of the main laser transitions in Nd:YAG and calculating the transmission loss of the cavity at 1064, 1319, and 946 nm. The maximum output power of the fundamental wavelength was 610 mW, the fundamental wavelength light-to-light conversion efficiency was 38.1%, the maximum output at 556 nm was 109 mW intra-cavity frequency doubled by LBO, the SHG conversion efficiency was 17.8%, and the overall light-to-light efficiency was 6.8% for the pump power of 1.6 W.
TL;DR: In this paper, the authors demonstrate an efficient continuous-wave diode-pumped LBO laser emitting in the red (660.5 and 657 nm) by intracavity frequency doubling with a LBO crystal.
Abstract: We demonstrate an efficient continuous-wave diode-pumped Nd : YLF laser emitting in the red (660.5 and 657 nm) by intracavity frequency doubling with a LBO crystal. We obtained more than 1 W of average power (in two output beams) for 12 W of pump power with a TEM 00 mode. This power is to our knowledge the highest obtained with a frequency-doubled Nd : YLF laser emitting in the red. Comparison between “a-cut” and “c-cut” crystals has been carried out in terms of performance and wavelength emission.
TL;DR: In this paper, the optical properties of a-Ge 30 - x Sb x S 70 chalcogenide glass films were analyzed by the Wemple equation, which is based on the single-oscillator model.
Abstract: We have analyzed the optical properties of a- Ge 30 - x Sb x S 70 chalcogenide glass films ( x = 0 , 10 , 20 and 30 at%); the chalcogenide films were prepared by vacuum thermal evaporation. The optical-absorption data indicate that the absorption mechanism is non-direct transition. We found that the optical band gap, E opt , decreases from 2.04 ± 0.01 to 1.74 ± 0.01 eV, whereas the refractive index increases with increasing Sb content. Data are analyzed by the Wemple equation, which is based on the single-oscillator model.
TL;DR: In this paper, the fluorescence emission spectra of Cr:Nd:YAG crystal were measured and the effective stimulated emission cross-section of the crystal was obtained from −80 to +80°C.
Abstract: The fluorescence emission spectra of Cr:Nd:YAG crystal are measured and the effective stimulated emission cross-section of the crystal is obtained from −80 to +80 °C. A linear temperature dependence between −80 and +80 °C is reported for the 1.064-μm peak stimulated emission cross-section of Cr:Nd:YAG crystal.
TL;DR: In this paper, the optimal structural features in the peacock tail feather were analyzed and the results showed that the thin-film sandwich structure is ideal for producing optimal structural performance and optimal optical performance.
Abstract: This paper presents an analysis of the optimal structural features in the peacock tail feather. Peacock tail feathers are highly optimized in three respects. The feathers are highly efficient structures that can support their own weight in a deployed position. The feathers are also optimized for producing thin-film colours with a high degree of lustre. The feathers also have a structure which produces intricate patterns with a high degree of aesthetic merit. There are structural features that allow simultaneous optimization in the different areas of performance. In particular, the thin-film sandwich structure is ideal for producing optimal structural performance and optimal optical performance.
TL;DR: In this paper, a KrF excimer laser was applied to irradiate 304 stainless steel specimen distributed with copper particles (45 μ m ) to generate surface wave for copper particle removal.
Abstract: This paper is to investigate the mechanisms of micro-scale particle removal by surface wave, which was induced by a short pulse laser in a cleaning process. The authors analyzed the adhesive forces of particles on substrate surface and the clearance force produced by surface wave in laser cleaning. The physical model of particle removal by laser-induced surface wave was established to predict the removal area and the processing conditions of laser cleaning. In this research, a KrF excimer laser was applied to irradiate 304 stainless steel specimen distributed with copper particles ( 45 μ m ) to generate surface wave for copper particle removal. Considering that a time-varying and uniformly distributed heat source irradiates on material surface with thermao-elastic behavior, the displacement and acceleration of substrate induced by a pulsed laser were solved by an uncoupled thermal–mechanical analysis based on the finite element method. The processing parameters such as laser energy, laser spot size are discussed, respectively. A series of laser cleaning experiments were designed to compare with computation results. The results show that the removal area by surface wave beyond the laser spot increases with the laser energy and that, the surface acceleration decreases with the increase of the laser spot size.
TL;DR: Results presented show that this flexible new 3D technique for performing system calibration and measuring is more simple and robust in engineering than conventional measurement method.
Abstract: Aimed at the problems of inferior precision and bad maneuverability for three-dimensional (3D) measurement by projected fringe pattern, a flexible new 3D technique for performing system calibration and measuring was proposed. First, we analyzed the principle of conventional 3D measurement with projected fringe pattern, and pointed out the shortcoming of measurement system. Then, the CCD camera calibration technique is analyzed and we set up the perspective projection model which transforms the computer image coordinate to 3D world coordinate, and we get the coordinate of the CCD camera image lens. Third, the position of projection lens optical center can be obtained using the above model. At last, some experiment results presented show that this technique is more simple and robust in engineering than conventional measurement method.