When using ground-based medium wave infrared measurement system, gray value drift is one of the significant errors in radiation calibration and measurement. By investigating the dependence between the ambient temperature with the output gray value of infrared system, the law of gray drift with ambient temperature was summarized, the reason of gray drift was found, the relationship between ambient temperature and gray drift was deduced, and a method based on ambient temperature was proposed to compensate the gray value drift. The results indicated that the method in this paper can compensate gray value drift effectively and reduce the gray value drift caused by ambient temperature.

Image super-resolution (SR) refers to the reconstruction of a high-resolution (HR) image from single or multiple observed degraded low-resolution (LR) images for the purpose of improving image's visual effects and getting more available information. We propose an image super-resolution algorithm based on collaborative representation and clustering in this paper. In the training stage, the image samples are clustered according to the image features and multiple dictionaries are trained by using the differences of image features, which overcomes the shortcoming of lack of expressiveness of traditional single-dictionary training methods. Moreover, projection matrices between different HR and LR image clustering are computed via collaborative representation, which accelerate the speed of image reconstruction. Experiments demonstrate that compared with other methods, the proposed method not only enhanced PSNR and SSIM metrics for reconstructed images but also improved image's visual effects.

Using STM32 microprocessor, a non-invasive skin cholesterol detection system based on absorption spectroscopy was designed. The relative cholesterol content of human skin was indirectly obtained by absorption spectrum information of colored products which was detected by micro-spectrometer. The system was designed with a high-precision adjustable LED constant current source, and the fluctuation range of LED light intensity is controlled within ±1%. A liquid limit device with a simple structure, a small amount of reagents, and no need for an exact detection reagent volume was also designed to achieve accurate measurement of the measured liquid concentration. By detecting the concentration of CuSO4 solution, the accuracy of the system for quantitative detection of different concentrations of solution was verified. Using this system to detect the skin cholesterol of patients with atherosclerotic disease and control population, the test results have statistically significant differences, which preliminarily verifies that system can be used for human skin cholesterol detection.

To solve the obstacle avoidance problem in plant protection UAV in operation, especially for farmland areas, a technology based on structured light vision was proposed. Based on the laser triangulation principle, through the special optical path design between the semiconductor laser and CCD sensor, an optical detection system to detect front obstacle information was designed. The line structured light emitted by the laser was reflected by the surface of the obstacle and was imaged on the CCD target surface. Through the image acquisition, processing and calculation, the distance, azimuth, width and other parameter information of front obstacle were extracted. Experiments show that this method can effectively detect the distance, azimuth and width of the obstacle in the unknown environment. The deviation of distance detection is less than 0.06 m.

Compressed sensing technology for atmospheric turbulence wavefront slope measurement can greatly improve the wavefront signal measurement speed, while reducing the pressure of wavefront measurement system hardware. Different from the existing wavefront slope measurement method, the compressed sensing wavefront measurement increase a process which from sparse measurement of wavefront slope value to the reconstruction of the wavefront slope signal. Therefore, a fast and accurate wavefront slope reconstruction algorithm is needed if the compressed sensing technology is used for wavefront measurement. Smoothed L0 Norm (SL0) algorithm is an optimized iterative reconstruction algorithm with approximate L0 norm estimation, and compared with other algorithms, it is not necessary to know the sparsity of the signal in advance, and the calculation is low and the estimation accuracy is high. Based on the SL0 algorithm, this paper implements a subregion parallel algorithm- Block-Smoothed L0 Norm (B-SL0) which can quickly and accurately reconstruct the signal by measuring the wavefront slope signal in subarea and parallel operations through theoretical analysis and experiments. The experimental results show that B-SL0 is significantly better than other existing reconstruction algorithms in the calculation time and accuracy, and explore the feasibility of compressed sensing technology for measurement of atmospheric turbulence wavefront preliminarily.

In grinding and polishing of the aspherical and freeform surface, the CCOS technology is widely used. It commonly uses constant pressure during polishing, and thus the desired amount of material to be remove depends on the dwell time. This paper focuses on the variable pressure CCOS polishing technology. It adds one more degree of freedom to the polishing process, in which the desired amount of material to be removed is controlled by both the polishing pressure and the dwell time. Firstly, a mathematical model was established for the variable pressure polishing process. Then, the stability and response speed of the output force of the polishing tool, and the stability of removal function was measured and analyzed. Finally, a material removal experiment that applied sinusoidal force was carried out on a K9 material mirror. Results show that frequency of the measured force is the same as that of the ideal sinusoidal polishing force, with a standard deviation of the force error being about 0.35 N. Its effect on PV and RMS of the finish surface is less than 9%. The spatial period of the measured surface profile is the same as that of surface profile obtained by simulation of the sinusoidal polishing process. The surface profile error is within 17%. In this paper, variable pressure polishing was achieved, and its effectiveness for optical processing was verified.

On the development trend of opening low altitude airspace in our country and the protection requirements for key areas, combined with the latest optoelectronic technology, a fast search method to detect low slow small target for low altitude airspace was presented, and a set of prototype system was developed. The system uses a linear CCD camera mounted on a high-precision one-dimensional turntable to collect 360-degree panoramic images of low altitude airspace. The image data is transmitted to the data processing workstation in real time through gigabit Ethernet slide ring. The data processing workstation detects small targets in the area above the skyline and figures out the orientation of target. Preliminary observation experiments of the prototype are conducted, the result shows that the system can detect low slow small target in broad low airspace in all directions. In the case of good atmospheric transparency, it can detect unmanned aerial vehicle (UAV) in size of 300 mm×300 mm×200 mm within 2300 m. The accuracy of the direction of measurement is 60 arcsecond. This research provides an effective mean to solve the problem of searching and finding low slow small targets.

Tight focus of azimuthally polarized wave finds its applications in optical super-resolution, particle trapping and so on. To overcome the disadvantages of conventional optics, including bulky size and difficult for integration, a binary-amplitude (0, 1) super-oscillatory planar lens is designed for sub-diffraction focusing of azimuthally polarized wave at wavelength of 632.8 nm. The lens radius is 650λ, and its focal length is 200λ. The corresponding numerical aperture is 0.96. The experimental results demonstrate the generation of a hollow spot with circular ring shape on the focal plane. The inner full-width-at-half-maximum of the hollow spot is 0.368λ, smaller than the super-oscillatory criterion (0.398λ), and the maximum sidelobe ratio is about 36.7%. Such planar lenses are easy to fabricate. Their small size and ultra-thin thickness make them promising in system minimization and integration for different applications, such as optical microscopy, optical trapping and ultra-high density data storage.

In order to solve the two difficult problems of the poor processing controllability and the low surface accuracy of quartz aspheric microlens array processing, a fabrication method of quartz aspheric microlens array for turning mask is proposed. This method mainly uses single point diamond turning technology and reactive ion etching technology, studies the turning and etching properties of the mask material, and optimizes the mask material by experiment. Finally, the fabrication of an aspherical glass microlens array with an area of 5 mm×5 mm was carried out. The experimental results are compared with the expected parameters. The analysis shows that the error root mean square of the quartz glass component is 1.155 nm, and the surface accuracy error is 0.47%.

A new method of wavefront sensing based on fiber coupling in the fiber laser array has been proposed. The scheme and the recovery process of this sensor are introduced. Numerical simulations of detecting the turbulence- induced aberrations utilizing such method and experiments of recovering static aberrations with 7-element adaptive fiber optics collimator (AFOC) array are presented. Numerical results show that such sensor could effectively recover the wavefront with turbulence-induced aberrations. For hexagonal array with different units, the optimum reconstructed Zernike mode is also different. Smaller array filled factor leads to larger recovery residual error. Compared with array filled factor of 1.0, value of 0.8 is easy to obtain and brings in recovery residual error increment less than 10%. Experimental results reveal that RMS less than 0.075 μm of the recovery residual error is obtained when detecting the static aberration with 7-element AFOC array with filled factor of 0.875. The aberration is with RMS of 0.433 μm and mainly includes Zernike modes of low orders like defocus. Results here validate the effectiveness of the wavefront sensing method proposed here. Such method would get further application in systems like laser array propagating and turbulence aberrations correcting.