In the past few years, transformers have attracted the attention of many scholars due to their excellent performance in fields such as natural language and machine vision. However, the transformer's self-attention mechanism makes it difficult to extract long-distance contextual information and is difficult to apply to semantic segmentation tasks with high-resolution remote sensing images. Therefore, we propose a bionic eye movement transformer model with visual perception capabilities for cross-domain semantic segmentation of high-resolution remote sensing images. Specifically, we designed three different bionic eye movement attention models to enhance the transformer's ability to extract long-distance contextual features. Experiments conducted on two international standard remote sensing image data sets show that our proposed bionic eye movement transformer has excellent cross-domain semantic segmentation capabilities.
In this paper, a visualization system was proposed based on ultrasound excitation from a Q-switched pulsed YAG laser. The ultrasonic wave was received by a piezoelectric transducer. The electrical time-domain signal was analyzed in the Fourier-domain in order to detect a hole-like reflector in an austenitic stainless steel specimen. At a given receiver position, a piezoelectric transducer received the ultrasonic wave signal. The electrical time-domain signal was analyzed in the Fourier-domain. The experimental research on the influence of the relative position distance between the laser excitation spot and the defect of the test specimen was conducted. The experimental results showed a significant geometrical imaging of the reflector shape with the scanned data. Therefore, a quantitative laser ultrasound visualization system was realized along with the spectral analysis. It will provide a new method of defects detection and sizing.
It briefly introduces the international development status of the high resolution for air-to-ground remote sensing satellite.
High resolution for the air-to-ground observation is also the civil and martial pursuing target. Because of the rising cost
along with the large-diameter telescope, the weight, cubage will also become large. Nowadays, how to get high
resolution with light weight, small cubage launch and large diameter is one of the important research directions in many
countries. We raise a method of large field-of-view and high resolution optical synthesis telescope which can solve this
problem. It is a co-phased segment mirrors which synthetic aperture diameter is about 1 m. Four 50cm diameter segment
mirrors can fulfill the requirement. It is folded during its launch and is spread after it reaches to its working spot. In this
way, it can reach the requirement of low launch weight, small launch cubage and can get high resolution observation.
This method contains the key technologies of real-time UV coverage, optics design optimization, co-phase measurement
and adjustment, micro-displacement sensor technology, the optics design and structure design. We explore the
technology which can fulfill field-of-view of 1.86° and the resolution of 0.4m. We will discuss the UV-coverage method
which includes the aperture arrangement, the relationship between the aperture number and the synthetic aperture
diameter. There are much more detail calculation and analysis to it. Something is discussed about its structure design and
optics design in the paper.
KEYWORDS: Thin films, Signal processing, Sensing systems, Spectrum analysis, Spectroscopy, Optical fibers, Beam splitters, Data processing, Ocean optics, Signal to noise ratio
In order to determine the properties of thin films with the required performance and reliability, a sensing system for
dynamic monitoring is proposed to measure the thickness of thin films. The system is based on the principle of
white-light interference, and is combination of spectrum analysis and optical fiber techniques. When two reflected lights
interfere within white-light coherent length range, relationship of between interference intensity and the wavelength of
incident light is achieved according to the equation of interference light's intensity. According to different thickness of
film, the relevant method is selected to calculate the thickness of thin film. So the interference can be analyzed in
spectral domain. The scheme of the system is set up including white-light source, multi-mode optical fiber, beam splitter,
spectrometer. With the help of optical fiber, the interference pattern is captured by spectrometer. When thickness of thin
film is varying, spectra curve will shift. The original spectra curve is processed in the computer. In order to determine
accurate extreme points, many methods of curve processing are used to decrease the noise. The spectra curve is
smoothed by signal processing method called empirical mode decomposition (EMD). This method is suitable for
non-linear and non-stationary data processing. The experimental data is contrast to the calibrated value. The results
show that the relative error of this method is lower 1%. This method has advantages over other measuring methods, such
as higher accuracy, low-cost instrument, extensive measurement range, simple structure and non-destructive.
In recent years, because of the emerging requirements for increasing autonomy, the controller of uninhabited air vehicles
must be augmented with a very sophisticated autopilot design which is capable of tracking complex and agile
maneuvering trajectory. This paper provides a simplified control system framework to solve UAV maneuvering
trajectory tracking problem. The flight control system is divided into three subsystems including command generation,
transformation and allocation. According to the kinematics equations of the aircraft, flight path angle commands can be
generated by desired 3D position from path planning. These commands are transformed to body angular rates through
direct nonlinear mapping, which is simpler than common multi-loop method based on time scale separation assumption.
Then, by using weighted pseudo-inverse method, the control surface deflections are allocated to follow body angular
rates from the previous step. In order to improve the robustness, a nonlinear disturbance observer-based approach is used
to compensate the uncertainty of system. A 6DOF nonlinear UAV model is controlled to demonstrate the performance of
the trajectory tracking control system. Simulation results show that the control strategy is easy to be realized and the
precision of tracking is satisfying.
Aperture Masking Interferometry (AMI) is one of the high-resolution astronomical image observation technologies. It is also an important research way to the Optical Aperture Synthesis (OAS). The theory of OAS is simply introduced and AMI simulation method is raised. The mathematics model is built and the interferogram fringes are got. The aperture mask u-v coverage is discussed and one image reconstruction method is done. The reconstructed image result is got with CLEAN method. Shortcoming of this work is also referred and the future research work is mentioned at last.
The role of the tip-tilt mirror in the stellar interferometer is introduced. Tip-tilt mirror construction, work theory and mechanical design are discussed in detail. According to the facilities we already have had, we designed two sets of measurement system to measure two important parameters: tip-tilt mirror movement range and its frequency response. The result was given which shows good quality of this tip-tilt mirror we design.
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