Bank Celik (turtlethumb94)

With the prevailing application of new materials and the higher requirements for the quality and efficiency of production in the equipment manufacturing industry, traditional assembly methods can hardly meet the needs of large-scale production, especially in the field of high-precision assembly. Robot assembly guided by visual perception has become the key of the research in the field of engineering technology. It requires higher accuracy of robot visual perception and the control over force, position and so on. However, in 3C assembly, most products are made of transparent materials such as glass. Because of the transparency and specular reflection of the surface, 3D reconstruction of transparent objects is a very difficult problem in computer vision, in that the traditional visual perception methods could not be accurate enough. The present research proposes a bionic active sensing algorithm for 3D perception and reconstruction and realizes high-precision 3D by applying the registration algorithm. The purpose is to solve the problems existing in the traditional visual perception method, such as difficulties in achieving active sensing, low accuracy of point clouds registration, and complex computation. The results of the experiments show that the present method is efficient and accurate in 3D reconstruction. It reduces the planar reconstruction error to 0.064 mm and the surface reconstruction error to 0.177 mm.Terahertz time-domain spectroscopy (THz-TDS) employs a mechanical stage to introduce the time delay between pump and probe optical pulses during the sampling process of the time-domain electric field of a terahertz pulse. The positioning error and limited resolution of a mechanical delay stage cause an inaccurate sampling of a terahertz pulse. In this study, we numerically and experimentally investigated the influence of delay stage positioning error on the major characteristics of THz-TDS, such as bandwidth and dynamic range of the system, along with the signal-to-noise ratio (SNR) of the intensity spectra. We demonstrate that the positioning error in the delay stage not only reduces bandwidth and dynamic range of the measurement system but also decreases the SNR of the intensity spectra.Freeform optics offers more degrees of freedom to optical design that can benefit from a compact package size and a large field of view for imaging systems. Motivated by the advances in modern optical fabrication and metrology, freeform optics has been found in many applications. In this paper, we will describe the challenging optical design, fabrication, metrology, and assembly of an all-aluminum unobscured two-mirror freeform imaging telescope. The telescope has a large field of view of 20∘×15∘. The freeform aluminum mirrors are manufactured by diamond turning based on a feedback modification strategy. The freeform mirrors are measured by a computer-generated hologram-based interferometric null test method. All-aluminum configuration has the advantages of being athermal and cost-effective.Existing photonic couplers are limited by either large footprint or long interaction length. Here a highly efficient and ultracompact three-port trench-based coupler (TBC) is proposed on an InP platform in terms of the frustrated total internal reflection principle. A single slash-shaped narrow trench located at the "T" intersection of two InP/InGaAsP multiquantum well ridge waveguides forms the coupler. The finite-difference time-domain numerical method is utilized to optimize the parameterization of the couplers, such as splitting ratios and efficiency versus trench widths, lengths, locations, and angles. A single-mode 2 µm wide ridge waveguide coupler having a high aspect ratio trench filled with Al2O3 was fabricated and characterized at 1.55 µm wavelength. CX-5461 concentration The "trench-first" fabrication process is optimized to reduce its inherent insertion loss (IL), showing the IL within a range of 0.3-0.5 dB. The devices can outperfo