As shown in Figure 7 (a), the CMOS photographic system, the frosted glass screen, the pinhole and the lens are assembled in accordance with the theoretical optical path. Each element is adjusted to be coaxial and of equal altitude and in alignment with the resolution panel used as object (as shown in Figure 7 (b)). The distance between the pin-hole and the photographic system is carefully adjusted to enable the pictures on frosted glass screen observed clearly through the CMOS photographic system. The pictures are displayed on the computer screen as shown in Figure 7 (c). We change the position (related to the pin-hole) of the screen t, the pin-hole diameter d, the lens diameter D, the focal length f and other parameters successively, and make further analysis of each parameter of the picture by computer software, such as MATLAB and ToupView.
Abstract: For a wide field of view (FoV) wavefront coding athermalized infrared imaging system with a single decoding kernel, the off-axis aberration tends to cause artefacts. In order to correct off- axis aberration, many pieces of lenses will reduce the transmission efficiency and increase the weight and cost. To meet requirements for wide FoV, wide operating temperature and low weight of infrared imaging systems, this paper reports a wide-FoV wavefront coding athermalized infrared imaging system with a two-piece lens. Its principle, design, manufacture, measurement and performance validation are successively discussed. This paper constructs an optimization problem which maximizes the weighted mean of PSF consistency for both the FoV and operating temperature range. The two-piece lens contains four surfaces, where three aspheric surfaces are introduced to reduce optical off-axis aberrations and a cubic surface is introduced to achieve athermalization. The optical phase mask containing an aspheric surface and a cubic surface is manufactured by nano-metric machining of ion implanted material (NiIM) . Experimental results validate that our wide-FoV wavefront coding athermalized infrared imaging system has a full FoV of 26.10° and an operating temperature over -20°C to +70°C.
For testing, each IOL was placed within a model eye system. The haptics of the samples were rotationally oriented at random to compensate for the single slit measurement. The model cornea was an aberration-free achromatic doublet – as specified in ISO 11979–2 – so that any aberration observed or the effect of any aberra- tion on image quality would result only from the IOL. In each instance, the IOL was placed in an IOL holder (11.0–13.0 mm) before being inserted into the model eye, which was filled with deionized water. Each IOL was positioned so that the lens’s anterior side faced the incident light, and the IOL holder guaranteed tilt-free orientation of the lens during the testing procedure. The collimated light passing through the artificial cornea was focused on the IOL, thereby simulating the vergence of a human eye, and the device could automatically detect the optical axis of each IOL. Measurements were performed at ambient temperature as recommended by the ISO standard because the IOL dimensions do not deviate appreciably from those under in situ conditions.
that holds the lens is aligned with the OA and attached to the fixed kinematic mount base. The finished module is integrated into the instrument as follows: plug the fixed kinematic mount base into the instrument; the floating kinematic lens unit is then mounted into the fixed kinematic base and held in position by engaging air pressure on a pneumatic cylinder. The instrument system requires the plano-convex lens to be aligned with and posi- tioned on the system OA. A tolerance of ±3 µm apex decenter from the OA and ±0.1 ˚ tilt angle of the plano- surface normal away from the OA is necessary. Therefore, common types of lower-precision techniques, such as simple spring clips or burnished cell mounting, are not sufficient . Active optical alignment and specially de- signed mechanical fixtures (i.e. kinematic constraining each of the six degrees of freedom) are needed to achieve the highest precision of the lens position. The rest of the paper is organized as follows. Section 2 briefly reviews the optical alignment system design and simulations. Section 3 presents the optomechanical design of the kine- matic mount module and process development for the prototype fabrication. Section 4 introduces the testing re- sults and analysis, followed by the summaries in Section 5.
Fig. 5 Error Comparison Of Coordinates And Angle Obviously, the mean errors in x, or y orientation are reduced after correcting distortion (as blue line shown in Fig.5.(1), Fig.5(2), respectively), and at the same time, the angle errors also are reduced. However, the error curves are not velvet, especially, the angle errors are also important for the turning of robot field. And the symmetries of the error curves are not good, especially for angle error curve. Because the sixth column is consistent with the optical axis of the camera, those error curves in Fig.5 should have good symmetry about this column. But, the results shown in Fig.5 indicate that the errors may affect the accuracy and stability of the vision navigation system for field robot.
The principle on which this set up works is that the governing equation for a system with forcing functions are the same as those of an undamped system with base excitation. The frequency of excitation is varied through a variable speed drive which mainly consists of two exactly identical wooden tapered rollers driven by means of flexible belt, the position of which could easily be altered through a pulley which can be slided on a bridge.
2466 Conversely, the concave end just filled with the resin, i.e., the planoconvex-lens end, showed a gradual decay in coupling efficiency over a separation of ~400µm. In the case of the concave end overfilled with resin, i.e., the biconvex-lens end, the coupling efficiency increased to its maximum at a working distance of 150µm. It exhibited the longitudinal tolerance of ±150µm at 0.5 dB less than the maximum. For reference, the coupling efficiency was also measured with a vacant concave-end fiber. In this case, the output power was rapidly decreased as we moved the launch position away from the POF endface. These results of coupling efficiency on the various fiber ends are analogous to those shown in Fig. 16. This means that the acceptable emission angle is comparable to experiments performed with coupling efficiency as affected by working distance. The output optical field of the lensed end was found to be distinct from that generated by the fiber without a lens. The laser light at 830 nm was launched into the polished end of the POF and the output end of the POF was formed into various profiles.
Results of Hyperbolic-Secant pulse propagation in a single- mode optical fiber communication system are presented. Dispersion results in pulse broadening which limits the information carrying capacity of the fiber. Hyperbolic-Secant pulse propagation model is obtained using split-step Fourier Method from nonlinear Schrodinger Equation. It was found that hyperbolic-secant pulse has a much more uniform pulse broadening and also experience less pulse broadening when compared to a Gaussian pulse at same propagation distance.
As long as monofocal IOLs remain the primary lens of choice, surgeons are most likely to choose those lenses that are easiest to implant, have the fewest unwanted visual side effects (thereby improving patient outcomes), and have been shown to be biocompatible and safe. We therefore have undertaken a review of the literature to provide an analysis of the advantages and disadvantages of the enVista lens and to stimulate an open discussion about monofocal IOLs.
Abstract—A full-duplex radio-over-ﬁber (ROF) transport system employing semiconductor optical ampliﬁer (SOA)-based opticalsingle sideband (SSB) modulation technique is proposed and demonstrated. For our proposed approach, it is relatively simple to implement as it requires only one SOA to generate optical SSB signal. Over an- 80 km single-mode ﬁber (SMF) transmission, low bit error rate (BER), clear eye diagram, and low third-order intermodulation distortion to carrier ratio (IMD 3 /C) were achieved. Our proposed full-duplex ROF
To our knowledge, the propagation of MBG beams through misaligned optical systems has not been studied yet. In this paper, we use the generalized diffraction in- tegral introduced by Wang and Ronchi , and all our previous work, in this field, to develop the analytical solution of the propagation of MBG beams traveling through any misaligned opticalsystem. For illustration, we apply our solution to the particular case of the propa- gation of MBG beams through a misaligned lens. More interestingly, we demonstrate that our analytical result is a generated formalism which allows for retrieving the solution of the propagation of pure Bessel, Gaussian and of Bessel-Gaussian beams through a misaligned opticalsystem  as particular cases.
We could estimate the working distance from the pupil diameter and the NA. We can estimate the WD using the following equation WD = D/2NA (see 3.1). The pupil diameter of the lens was measured to be 2.00 ( ± 0.02) cm, giving a WD ≈ 2.9 (± 0.4 ) cm. The specified working distance is 20 mm, which is al- most 15 times smaller. We don’t understand why the difference is so large and the only explanations that come to mind are: The lens is not fully used and as such the effective diameter is much smaller; Compound lenses are intricate and equation 3.1 simply does not hold in those cases. It is interesting to find out what the reason is, but this goes beyond the scope of this thesis.
(7) By summarizing the radiation ﬁelds of all the triangular elements, the far ﬁeld of the horn is obtained. Next, ray-tracing method is processed to simulate the electromagnetic ﬁeld propagating in the lens. Normally, ray-tracing method includes two steps: (1) obtaining all the ray paths based on Snell’s law; (2) calculating electric ﬁelds of all rays. Considering that the circular aperture plane is the projection plane of the curved surface of the lens, we split the aperture plane into triangular elements by using ANSYS ﬁrst, and the x , y coordinates of each node are given by the software. Then the value of z coordinate of each node is calculated by substituting t = x 2 + y 2 into formula (3). Thus the curved
Methods: The Lens Opacities Classification System III (LOCS III) was used to grade nuclear opalescence (NO), along with different methods of lens densitometry evaluation (absolute scale from 0% to 100%): three-dimensional (3D), linear, and region of interest (ROI) modes. Cumula- tive dissipated energy (CDE) and total ultrasound (US) time were recorded and correlated with the different methods of cataract grading. Significant correlations were evaluated using Pearson or Spearman correlation coefficients according to data normality.
Sophisticated lens modelling and source reconstruction techniques have recently been developed to overcome this problem. Wallington et al. (1996) introduced the idea of a pixellated background source, where each pixel value is treated as an independent parameter, thus avoiding any as- sumption on the shape of the source surface brightness dis- tribution. Warren & Dye (2003) showed that with this ap- proach the problem of reconstructing the background source, for a fixed lens mass model, is reduced to the inversion of a matrix. The best-fitting lens model parameters can then be explored via standard Monte Carlo techniques. In or- der to avoid unphysical solutions, the method introduces a regularization term that forces a certain degree of smooth- ness in the reconstructed source. The weight assigned to this regularization term is set by Bayesian analysis (Suyu et al. 2006). Further improvements to the method include pixel sizes adapting to the lens magnification pattern (Dye & Warren 2005; Vegetti & Koopmans 2009; Nightingale & Dye 2015) and non-smooth lens mass models (Vegetti & Koopmans 2009; Hezaveh et al. 2016) in order to detect dark matter sub-structures in the foreground galaxy acting as the lens.
FibreOptical communication system gets the high attention due to economic advantages, and high information capacity. This systemhas multiplexing, demultiplexing, filtering, amplificati- on, correlation and optical signal processing is much faster than electrical signal processing, it can be directly done in optical domain. In optical fibre communication system OCDMA is one of the type of multiplexing technique in which this can be achieved by assigning different code sequences for different users. According to principle of working OCDMA is classified in two categories that are incoherent and coherent, incoherent is an intensity based and coherent which is phase shift based OCDMA technique, but due to overall performance coherent typegets more attraction for practicalthan
understanding would advance applications in laser dicing, drilling, cutting and large volume ablation [7, 61–63]. Research of high-pressure and high temperature phases of materials as well as WDM conditions would benefit basic science and applications from the concept outlined in this memorandum. Optical pump with fs-laser Bessel beam combined with synchronised X-ray probe with exceptional optical flux, sub-micron beam size, rather high X-ray photon energy in the keV-range and ultrashort pulse length ∼10 fs, allows one, to investigate the atomic motion via X-ray diffraction with extremely high spatial and temporal resolution. Recently emerging of X-FELs with pulse duration of 10–25 fs and the photon energy ∼8 keV currently available at the European X-FEL at DESY in Germany, with up to 17 keV to be expected in near future at the LCLS at the SLAC National Acceleration Laboratory in US, and with 7–15 keV at the SACLA at the RIKEN SPring-8 center in Japan are the ideal sources to be used as a probe pulse to uncover the processes of formation of unusual transient material states in the conditions far from thermodynamic equilibrium.
A Foldscope made out of an optical magnifying lens that can be amassed from a punched sheet of cardstock, a round glass focal point, a light producing diode and a diffuser board, alongside a watch battery that powers the LED. The Foldscope gauges 8 grams and arrives in a pack with different focal points that give amplification from 140X to 2,000X. The amplification control is sufficient to empower the spotting of life forms. A Foldscope can be imprinted on a standard A4 sheet of paper and gathered shortly. Prakash claims that the Foldscope can endure brutal conditions, incorporating being tossed in water or dropped from a five-story building.