Showing papers in "Optics and Lasers in Engineering in 2013"

TL;DR: A high-speed three-dimensional shape measurement technique for dynamic scenes by using bi-frequency tripolar pulse-width-modulation (TPWM) fringe projection to generate ideal fringe patterns with slight defocus is introduced.

TL;DR: A robust morphological methodology using edge detection is devised to evaluate the physical properties of different speckle patterns with image resolutions from 23 to 705 pixels/mm, to demonstrate that the pattern properties derived from the analysis can be used to indicate pattern quality and hence minimise DIC measurement errors.

TL;DR: A novel non-contact, full-field, three dimensional, multi-camera Digital Image Correlation (DIC) measurement system is proposed and the performance of the setup is tested in both static and dynamic cases to show the potential of the system.

TL;DR: A novel discrete fractional random transform based on 2D chaotic logistic maps and two chaotic random masks resulting from Chirikov standard map is proposed and double random phase encoding is utilized to complete encryption.

TL;DR: Both numerical simulations and real experiments reveal that the proposed technique is capable of reducing the bias error in measured displacement to a negligible degree for both noisy and noiseless images, even though a simple bicubic interpolation is used.

TL;DR: A kind of amplitude scrambling operation is designed and introduced into an image encryption process for scrambling amplitude distribution in order to save the space of storage and transmission of the key information.

TL;DR: In this article, a simple linear least squares algorithm is proposed to estimate the distortion coefficient from the distorted displacement results of rigid body, in-plane translation tests, which can be used to correct the distortion fields to obtain unbiased displacement and strain fields.

TL;DR: A novel property of the proposed scheme is its authentication ability which can detect whether the image is tampered during the transmission or not, particularly important in applications where image data or part of it contains highly sensitive information.

TL;DR: A fast PMP method based on phase-shifting and trifocal tensor that works well in measuring both static and dynamic objects; and the experimental system can perform fast 3D measurement of arbitrary shape objects with full spatial and temporal resolution.

TL;DR: A new method to accurately calibrate the telecentric imaging system by considering the major sources of lens distortions and the maximum distortion of the system reduces 26 times by the presented calibration technology.

TL;DR: A Digital Image Correlation-based single camera pseudo-stereo system that uses a biprism in front of the camera objective to split the scene into two equivalent lateral stereo views in the two halves of the sensor is presented and tested.

TL;DR: It is found that both the node-splitting and overlapping-mesh techniques can be applied to successfully capture the discontinuous displacement field of a propagating crack and the crack-path optimization is capable of locating the crack path with sub-pixel accuracy, reducing correlation residuals and thus increasing the robustness of the DIC analysis.

TL;DR: In this paper, the stability of the weld surface quality resulting from laser-arc hybrid welding of 4 mm thick steel was studied and the trends of stability in terms of top weld width variation were estimated by usi

TL;DR: In this paper, the results of applying a 3 mm thick cladding layer by laser melting Inconel 690 powder on top of a 10 mm thick plate of Inconels 600 alloy substrate were reported.

TL;DR: In this paper, the suitability of the laser cladding technique for manufacturing and repairing aeronautic components of Inconel 718 was evaluated, using a continuous wave Nd:YAG laser.

TL;DR: In this study, entropy and correlation coefficient are used as WDICA's fitness functions and the goal is to maximize the entropy and minimize correlation coefficients.

TL;DR: A novel color image encryption algorithm based on Arnold- and discrete Hartley transform in gyrator transform domain is proposed, which can be well protected under chosen- and known plaintext attacks.

TL;DR: In this article, the flow of molten metal on the front wall of a laser generated welding keyhole has been observed by high speed photography, optically measured by mapping the flow on the liquid surface and theoretically calculated.

TL;DR: A color image encryption algorithm is designed by using the affine transform in the gyrator transform domains to enhance the security of this encryption algorithm.

TL;DR: In this article, a comparison of welds obtained using the same process parameters in continuous and pulsed wave lasers is made, and the results show that when these parameters are used the two lasers show very dissimilar behaviours in terms of penetration depth.

TL;DR: Results show evidence of the de-noising effects and demonstrate that this method can effectively de- noise the noisy Lidar signals in strong background light and achieve improvement in the signal to noise ratio of system.

TL;DR: A novel integrated method to recover dynamic shapes from a wider view with less occlusion by taking most of the benefits of the two approaches, namely, a structured-light stereo approach for the acquisition of dynamic shape.

TL;DR: A color image encryption algorithm by using chaotic mapping and Hartley transform and an electro-optical encryption structure is designed, constituted by two selected color components of output in real number domain.

TL;DR: In this paper, the impact of lens distortions on strain measurements was investigated, and a uni-axial tensile test on a textile composite with spatially varying high strain gradients was performed, resulting in very accurate determined strains along the fibers of the material.

TL;DR: A framework to optimize the Bayer-dithering technique in phase domain by iteratively mutating the status (0 or 1) of a binary pixel and it is demonstrated that the proposed optimization technique can drastically reduce the phase error when the projector is nearly focused.

TL;DR: In this paper, a coupled methodology comprising of Finite Element Method (FEM) and Artificial Neural Network (ANN) has been used to develop a prediction model for the Laser Beam Percussion Drilling (LBPD) process.

TL;DR: Experimental results indicate that the proposed approach to automatic reconstruction of 3D building roof models can provide high-quality 3D roof models with diverse roof structure complexities.

TL;DR: This algorithm, by a new interferogram normalization procedure, can handle interferograms with variable spatiotemporal visibility overcoming the restriction and drawbacks from usual variable spatial visibility approaches.

TL;DR: In this paper, a second order response surface model was developed for each Da and Ta using hybrid approach of Taguchi methodology (TM) and response surface methodology (RSM), and the effect of input process parameters on each cut quality (Da and Ta) was also studied.

TL;DR: A vision measurement model of the LDS based on the perspective projection principle is presented, which is more comprehensive and avoids a linear approximation procedure, and the corresponding calibration method is easily complemented.