FPGA implementation of pipelined architecture for optical imaging distortion correction

Fast and efficient operation is a major challenge for complex image processing algorithms executed in hardware. This paper describes novel algorithms for correcting optical geometric distortion in imaging systems, together with the architectures used to implement them in FPGA-based hardware. The proposed architecture produces a fast, almost real-time solution for the correction of image distortion implemented using VHDL HDL with a single Xilinx FPGA XCS3 1000-4 device. Using dedicated SRLC16 shift registers to build the synchronous FIFOs is an ideal utilization of the device resources available. The experimental results show that the barrel distortion can be quickly corrected with a very low residual error. The design can also be applied to other imaging processing algorithms in optical systems. ©2006 IEEE.</p

FPGA implementation of pipelined architecture for optical imaging distortion correction

Fast and efficient operation is a major challenge for complex image processing algorithms executed in hardware. This paper describes novel algorithms for correcting optical geometric distortion in imaging systems, together with the architectures used to implement them in FPGA-based hardware. The proposed architecture produces a fast, almost real-time solution for the correction of image distortion implemented using VHDL HDL with a single Xilinx FPGA XCS3 1000-4 device. Using dedicated SRLC16 shift registers to build the synchronous FIFOs is an ideal utilization of the device resources available. The experimental results show that the barrel distortion can be quickly corrected with a very low residual error. The design can also be applied to other imaging processing algorithms in optical systems. ©2006 IEEE.</p

Quantum correlations from dynamically modulated optical nonlinear interactions

We investigate optical nonlinear interactions in a dynamic environment by studying generation of photons in spontaneous parametric down conversion inside a nonlinear cavity where the optical path length is periodically modulated in time. We show that the temporal dynamics of the cavity modify the nonlinear interaction and the generated continuous variable time-frequency entangled bi-photon state evolves into a tunable discrete higher dimensional state in the non-adiabatic modulation regime where the modulation time scales are much faster than the photon lifetime. In this regime, the system mimics effects of a quantum random walk in a photonic lattice with many associated effects including localized and delocalized wavefunctions of the generated photons. We also propose generation of time-frequency hyper-entangled states in the adiabatic limit. Our analysis shows that the proposed system is promising for applications in quantum simulation and information processing in the time-frequency domain

The GO classifications of assembled unigenes for <i>H</i>. <i>erectus</i> and <i>H</i>. <i>mohnikei</i>.

The GO classifications of assembled unigenes for H. erectus and H. mohnikei.</p

Image_1_Identification of neurohypophysial hormones and the role of VT in the parturition of pregnant seahorses (Hippocampus erectus).jpeg

Neurohypophysial hormones regulate the reproductive behavior of teleosts; however, their role in the gestation and parturition of ovoviviparous fishes with male pregnancy (syngnathids) remains to be demonstrated. In the present study, the complementary DNA (cDNA) sequences of arginine vasotocin (VT) and isotocin (IT) from the lined seahorse (Hippocampus erectus) were cloned and identified. We observed that the mature core peptides of seahorse VT and IT were conserved among teleosts. In the phylogenic tree, seahorse VT and IT were clustered independently with teleost VT and IT. The tissue distribution patterns of VT and IT were similar, and both were highly expressed in the brain, gills, and gonads. Interestingly, they were also expressed to some extent in the brood pouch. In situ hybridization revealed that VT and IT messenger RNA (mRNA) signals in the brain were mainly located in the preoptic area region of the hypothalamus. Intraperitoneal administration of the VT core peptide to pregnant seahorses induced premature parturition, stimulated gonadotropin release, increased serum estrogen levels, and decreased prolactin secretion. Moreover, VT injection upregulated the mRNA expression of the membrane estrogen receptor in the brood pouch. In summary, neurohypophysial hormones promote premature parturition by regulating estrogen synthesis through the hypothalamus–pituitary–gonad axis.</p

Far infrared to terahertz widely tunable narrow linewidth light source via surface-emitting periodically poled thin film lithium niobate waveguides

Generating widely tunable, continuous wave light at long wavelengths via difference frequency generation (DFG) remains challenging due to high absorption and dispersion. The relatively new platform of thin film lithium niobate enables high-confinement nonlinear waveguides, which could improve efficiency. We simulated DFG in thin film lithium niobate waveguides that are periodically poled for surface emission at 30 THz. Maximum efficiency for a 1 cm device is 9.16 $\times$ 10$^{-6}$ W$^{-1}$ assuming $d_{33}$ = 30 pm/V. The tuning range within 50$\%$ of efficiency at 30 THz is as wide as 25 THz, from 25 THz to 50 THz

Biosynthesis of unsaturated fatty acids pathways identified in <i>H</i>. <i>erectus</i>.

<p>Red boxes represent unigenes which are annotated to this pathway. Biosynthesis of unsaturated fatty acids pathways identified in <i>H</i>. <i>mohnikei</i> is the same as <i>H</i>. <i>erectus</i>.</p

Perfect soliton crystals on demand

Recent advance of soliton microcombs has shown great promise to revolutionize many important areas such as optical communication, spectroscopic sensing, optical clock, and frequency synthesis. A largely tunable comb line spacing is crucial for the practical application of soliton microcombs, which unfortunately is challenging to realize for an on-chip monolithic microresonator. The recently discovered perfect soliton crystal (PSC) offers a convenient route to tune the comb line spacing. However, excitation of a PSC is generally stochastic by its nature and accessing a certain PSC state requires delicate tuning procedure. Here we demonstrate the on-demand generation of PSCs in a lithium niobate microresonator. The unique device characteristics allow us to produce a variety of PCSs and to switch between different PSC states, deterministically and repetitively. We utilize the device to show arbitrary dialing of the comb line spacing from 1 to 11 times of the free-spectral range of the resonator. The demonstration of PCSs on demand may now open up a great avenue for flexibly controlling the repetition rate of soliton pulses, which would significantly enhance and extend the application potential of soliton microcombs for communication, signal processing, and sensing

The temporal evolution of population for the numerical solution (line) and the approximate analytical solution (dot) after applying a Gaussian single-cycle pulse

<p><strong>Figure 1.</strong> The temporal evolution of population for the numerical solution (line) and the approximate analytical solution (dot) after applying a Gaussian single-cycle pulse. The pulse width parameter is <em>T</em> = 0.7 <em>T</em>₀; \phi _0 = \frac{\pi }{2}; ω = ω_<em>eg</em> = 3 rad fs⁻¹. (a) The peak Rabi frequency of pulses is Ω₀ = 0.5 rad fs⁻¹. (b) The peak Rabi frequency of pulses is Ω₀ = 0.8 rad fs⁻¹.</p> <p><strong>Abstract</strong></p> <p>The interactions of sub-cycle and single-cycle pulses with two- or three-level quantum systems are studied, respectively. For the two-level quantum system, two cases in which the carrier frequency of pulses is in resonance and far from resonance with the atom are analysed. The ultrafast complete population transfer can be obtained. The sub-cycle pulse with a far off-resonant carrier frequency is found to be more suitable for the population transfer. The relation between the area of pulses and population transfer is clarified in the sub-cycle and single-cycle domain. For the Lambda-type three-level quantum system, more than 90% of population transfer can be achieved from one level to another. The scheme is insensitive to the variation of the laser parameters such as the peak Rabi frequency and the carrier frequency for both two- and three-level quantum systems.</p

Illustration of SampEn algorithm with the embedding dimension <i>m</i> = 2.

<p>The colored bands show the tolerance regions <i>r</i>. (a) Green arrow denotes template vector <i>u</i>(10) = [<i>x</i>(10), <i>x</i>(11)]. (b) Only vectors <i>u</i>(20) = [<i>x</i>(20), <i>x</i>(21)], <i>u</i>(35) = [<i>x</i>(35), <i>x</i>(36)] (red arrow) falling into these bands were counted to match the template vector: <i>u</i>(10) = [<i>x</i>(10), <i>x</i>(11)].</p