Multi-view imaging technology obtains rich scene information by capturing images from different angles, which can provide key visual data for fields such as autonomous driving, intelligent manufacturing and robot navigation. This paper first summarizes the components of common multi-view imaging systems, their working principles and implementation methods, and provides an in-depth analysis of the significant advantages of different multi-view imaging systems and their limitations from the key dimensions of dynamic imaging adaptability, imaging accuracy, cost-effectiveness, and comprehensive system performance. Then for the visual image enhancement technology, the application and effect in improving the quality of multi-view imaging are discussed by combining traditional image processing methods and deep learning techniques. Finally, the current status and future trends of the development of multi-view imaging technology are considered, and forward-looking predictions are made in the development directions of hardware innovation, algorithm optimisation and multi-modal data fusion.
In underwater optical imaging applications, the strong scattering effect of particles in the water on reflected light often leads to poor imaging results. To address this issue, a pseudo-polarization de-scattering imaging method based on a single image is proposed, building on the foundation of underwater polarization difference imaging. By separating the spectral information of turbid underwater images, a pair of virtual orthogonal polarization images is constructed, which are then processed for polarization de-scattering to obtain a clear underwater image. Theoretical analysis and experimental results demonstrate that the proposed method outperforms the original images in complex underwater environments and under various distance conditions. Compared to the original images, the processed results show significant improvements in the following metrics: natural image quality evaluation (NIQE) increased by more than 50%, root mean square contrast (RMSC) increased by more than 1.5 times, and information entropy increased by more than 10%. Moreover, the enhancement effect of the method becomes more pronounced as the turbidity of the underwater environment increases. Additionally, compared to traditional underwater polarization de-scattering methods, the proposed method offers advantages such as fast processing speed and wide applicability.
Photoacoustic imaging is an efficient, non-invasive biomedical imaging technique that combines the high contrast of optical imaging with the deep tissue penetration of ultrasound imaging. By reducing the effects of optical scattering, it provides clear internal imaging views. This paper discusses traditional photoacoustic imaging techniques, including photoacoustic tomography, photoacoustic microscopy, photoacoustic endoscopy, and photoacoustic molecular functional imaging. It also highlights four novel photoacoustic imaging technologies: photoacoustic elastography, photoacoustic-guided wavefront shaping, polarization photoacoustic imaging, and optical detection methods for photoacoustic signals. Compared to traditional methods, these new approaches incorporate advanced optical control and signal processing techniques to improve imaging accuracy and resolution. The main challenges faced by new photoacoustic imaging technologies include improving imaging speed, enhancing signal detectability, and optimizing system user-friendliness. This paper summarizes key scientific achievements in photoacoustic imaging for achieving high resolution and deep tissue imaging and provides an outlook for future development. In the future, photoacoustic imaging technology is expected to overcome current limitations through further hardware innovations and algorithm optimizations, particularly in real-time imaging, system simplicity. With the development of multimodal imaging systems, photoacoustic imaging may be combined with other imaging techniques, such as magnetic resonance imaging (MRI), computed tomography (CT), or positron emission tomography (PET), to provide more comprehensive biomedical imaging solutions.
To enhance the measurement accuracy of a compact full-Stokes vector aperture-division polarimetric camera, a series of polarimetric image processing techniques have been proposed and established. These techniques specifically encompass dark current correction, bilateral filtering for noise reduction, image distortion correction, polarization parameter calibration, and channel image registration, followed by experimental research on polarimetric imaging. The results demonstrate that these techniques effectively mitigate the impact of various non-ideal factors on the camera’s imaging process. After image processing, the reprojection errors of the four polarization channels are all less than 0.2 pixels, and the average structural similarity index (SSIM) between the four polarimetric sub-images is improved by 15.2%. This signifies a significant enhancement in the accuracy of polarimetric information measurement.
Infrared polarization imaging detection technology introduces polarization information on the basis of traditional intensity information, which can effectively improve target detection and recognition capabilities under specific conditions. It has advantages such as high signal-to-noise ratio, anti camouflage, and anti-interference, and has broad application potential and good development prospects in target reconnaissance, detection, and strike fields. This article first introduces the theory of surface polarization of objects and related phenomena, especially the discovery of high-temperature polarization phenomenon of targets, which expands new fields for polarization detection applications.Based on the theory of target polarization, the research results of target polarization characteristics under different environments and application backgrounds were analyzed. Secondly, the development of infrared polarization detectors and the latest progress in target infrared polarization imaging detection in recent years were reviewed. The new requirements for infrared polarization detection technology in the current complex battlefield environment were summarized, including breaking through the bottleneck of real-time high-precision imaging technology, strengthening cloud and fog penetration, and anti occlusion interference performance.Finally, based on the summary of the target polarization mechanism, target polarization characteristics, and the development trend of polarization detector technology, it is proposed to deepen the theoretical research on target surface polarization, promote the development of high-precision infrared polarization detector preparation technology, explore multi-dimensional information fusion processing, and further look forward to the future development and application prospects of infrared polarization detection technology in military fields such as complex target recognition, anti stealth operations, and battlefield monitoring.
Polarization spectral imaging technology provides an effective solution to the imaging problems in complex scenes by combining intensity, polarization, and spectral information. Division-of-focal-plane polarization spectral imaging technology has become a significant development direction in this field due to its high compactness and strong real-time performance. This paper first reviews the development history of polarization spectral imaging technology and systematically compares the advantages and disadvantages of related technologies. Then, it focuses on the research progress of the division-of-focal-plane polarization spectral imaging system, providing a detailed overview of polarization spectral splitting elements, polarization spectral demosaicking algorithms, and existing polarization spectral image databases. It also systematically summarizes the core advantages of this technology, including high compactness, strong real-time performance, and low power consumption. Finally, it summarizes the applications of polarization spectral imaging technology in military reconnaissance, space exploration, medical diagnosis, and remote sensing detection. The analysis indicates that this technology has broad prospects in fields such as target detection, environmental monitoring, and medical diagnosis, but it still faces challenges such as low spatial resolution and insufficient accuracy in reconstructing polarization information currently. Based on this, future research should focus on optimizing the design and fabrication of polarization spectral splitting elements, improving demosaicking algorithms for high-quality image restoration, and further expanding its application capabilities in dynamic scenes and complex environments.
Multi-frame blind deconvolution (MFBD) is one of the current mainstream image restoration algorithms. It uses less frames (less than 20 frames) of degraded images to restore the high-resolution images. MFBD uses an iterative optimization method to obtain the optimal estimates of the target by minimizing the cost function. There are two main optimization strategies for the MFBD algorithm, namely the joint iteration strategy and the alternating iteration strategy. Currently, there are few publicly available research reports comparing the advantages and disadvantages of these two strategies. At the same time, the point spread function (PSF) parameterization method can also affect the restoration results. In order to obtain the optimal iteration strategies and parameterization methods, two iterative strategies are adopted with three different PSF parameterization methods based on the MFBD, to conduct comparative analysis on the restoration results under different signal-to-noise ratios and different initial value conditions through the normalized mean squared error(NMSE) and frequency spectrum curve of the result. Simulation experiments have shown that the joint iteration strategy with phase parameterization is able to handle more various complex degraded types. The mean square errors of the restoration results for three types of degraded images are 0.046, 0.194 and 0.342, respectively, which is the least compared with the joint iteration strategy with other PSF parameterization. For the alternating iteration strategy, only the gray matrix parameterization can obtain acceptable results (mean square errors of 0.109, 0.159, 0.332, respectively), but the spectral curve indicates that there is an amplification problem of iterative noise. In summary, joint iteration with phase parameterization can obtain better restoration results and handle more complex degraded situation.
Lead-free metal halide biperovskite is composed of non-toxic elements, stable in air and has a long carrier lifetime. The physical properties of bismuth based Cs2MBiX6(M=Cu, Ag, Au, X=Cl, Br, I) double perovskite materials with excellent photovoltaic properties were calculated theoretically.In order to analyze the effects of different lead-free metal halides on battery performance, first-principles calculations were performed to systematically investigate the crystal structures,electronic structures and optical properties of four materials Cs2AgBiI6, Cs2AuBiCl6, Cs2CuBiBr6, and Cs2AgBiBr6.Finally, the absorption rate, carrier collection efficiency, external quantum efficiency, short-circuit current density, open circuit voltage and volt-ampere characteristics for the layered architecture consists of FTO/c-TiO2/Cs2MBiX6/spiro-OMeTAD/Au structure perovskite solar cell are analyzed by performing equivalent optical admittance method. The results show that:when the thickness of the absorption layer is 0.6 μm.The short-circuit current densities of perovskite solar cells prepared with Cs3AgBiI6, Cs2AuBiCl6, Cs2CuBiBr6 and Cs2AgBiBr6 are 27.6, 26.0, 22.3 and 10.9 mA/cm2, respectively, corresponding to open circuit voltages of 0.83, 0.87, 1.08 and 1.1 V. The photoelectric conversion efficiency of the device is 19.3%, 16.6%, 21.3% and 10.9%, respectively.It is found that 4 kinds of materials have high thermodynamic stability, suitable band gap and high absorption coefficient of ~105cm-1 in the visible light range, and the cell with optimized device structure also has considerable photoelectric conversion efficiency.
The cavitation phenomenon of centrifugal pumps will seriously affect the hydraulic performance of the pump, especially the use of higher speed semi-open impeller high-speed miniature pumps, the impact of its tip clearance on the cavitation performance of the impeller is more significant, and is the main problem faced by its current research and application. The high-speed miniature semi-open impeller centrifugal pump applied to the thermal management system of airborne equipments is taken as the research object, and its full-flow field cavitation simulation is carried out. Using a combination of numerical simulation and experimental study, the cavitation performance of the centrifugal pump is investigated under different inlet cavitation margins and different tip clearance ratios (0.05, 0.08, 0.11 and 0.14). The results show that: the effective cavitation margin of the experimental pump increases with the increase of flow rate; the necessary cavitation margin of the pump decreases by 0.10 m for every 0.1 mm increase in the tip clearance, when the tip clearance ratio is increased by 0.03, resulting in a decrease in the anti-cavitation performance of the pump. Under different tip clearance, the smaller the tip clearance is the smaller the tip leakage flow can be obtained,the possibility of leakage vortex is reduced, improving the anti-cavitation performance of the pump.