Improving detection accuracy of low-resolution objects remains a challenging task in the field of photoelectric detection, and image super-resolution (SR) is one of the vital processing methods that contribute to improving detection accuracy. Current infrared SR algorithms are mostly based on fixed integer scaling factors, but in practical applications, the ability to represent images at arbitrary resolutions is crucial for object detection. This study proposes a method named YOLOArbSR based on arbitrary-scale SR reconstruction to address the problem of low detection accuracy in low-resolution shortwave infrared images. We optimized the super-resolution algorithm to accommodate arbitrary scale factor for detecting infrared targets using the implicit representation function. Furthermore, we introduce a local texture estimator (LTE) and tune the network hyperparameters. Experiments on the practical dataset obtained from the experimental infrared system show that our proposed method is superior to existing technologies in improving the accuracy of infrared detection.
It’s widely agreed that optical characteristics at crystal boundary may change comparing to the internal part of bulk crystal but, as far as we know, sometimes the phenomenon, for example, the variation of susceptibility usually can’t be intuitively, simply presented in experiments. Recently, we observe a kind of special harmonic generation which is at the same wavelength as incident light. Besides, this kind of harmonic generation behaves in a similar way with nonlinear Cherenkov radiation, thus we call it linear Cherenkov radiation (LCR). We theoretically predict and calculate the phase-matching scheme and radiation path of LCR. In our experiment, we employ a polished KDP to verify our theory about the conversion of polarization in this process, and the phenomenon also help to rule out the possibility of birefringence at boundary. Combining with the coupling wave equation, we can derive new elements in linear susceptibility tensor according to the polarization states of incident light and LCR. The result tells us the linear susceptibility at the KDP boundary is assuredly different from that in bulk crystal, and this is mainly because of the breakdown of crystal symmetry at boundary, in our opinion. The existence of LCR is evidence of the variation of linear susceptibility. And in return, we could use this phenomenon to probe the non-zero elements in the tensor.
KEYWORDS: Wavefronts, Adaptive optics, High power lasers, Beam controllers, Control systems, Wavefront distortions, National Ignition Facility, Mirrors, Sensors, Wavefront aberrations
Experiment of entire beam wavefront compensation was carried out in a beamline of a high power laser facility, and two adaptive optics systems with different intentions were applied in the chosen beamline. After correction, the far-filed irradiance distribution is concentrated evidently and the entrance rate of 3ω focal spot to a 500-μm hole is improved to be about 95% under number kilojoules energy.
Beam alignment of multi-pass amplification is based on cavity mirror alignment. To optimize multi-segmental parallel cavity mirror alignment arithmetic of high power solid-state lasers, propose a new type of arithmetic of multi-pass beam path cavity mirror based on diffraction symmetry, and the accuracy of multi-pass amplification beam path alignment is improved by 10μrad up to 3.96μrad. The arithmetic avoids low accuracy of CM alignment caused by poor image quality, It makes SG-Ⅲ facility operate long term and properly.
Chirp pulse amplification (CPA) has been promoted as an effective way to explore the intensity frontier. High order dispersion induced by the stretcher and materials in the CPA system, which deteriorates both the pulse duration and temporal contrast, however, can not be absolutely compensated by the compressor. Placed at the Fourier plane of a 4f zero-dispersion stretcher consisting of a grating, the deformable mirror (DM) has been demonstrated as the modulator to compensate high order dispersion. Using the method of ray tracing, the relation between spectrum and position on DM has been obtained. It shows that the resolution of the deformable mirror can be controlled by adjusting the focal length and incident angle. We have simulated a typical Ti:sappire CPA system to revise the spectral phase by the DM. The result illustrates that if the spectral phase can be compensated, the temporal contrast will be improved by 2 order of magnitude.
A novel method based on diffraction theory to control the far-field irradiance profile by deformable mirror is presented.
Special near-field phase which determines the contour of the focal spot is obtained by a high spatial frequency
deformable mirror. Numerical simulations show that, we can control the far-field intensity envelope as CPP by
adopting adaptive optics technique when the spatial resolution of deformable mirror is high enough, here 16×16
actuators in 320mm×320mm aperture. The coupling coefficient is an important factor influencing control effect, and
its best value range is round 0.6.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.