Convolutional neural networks (CNNs) have facilitated substantial progress on various problems in computer vision and image processing. However, applying them to image fusion has remained challenging ...due to the lack of the labelled data for supervised learning. This paper introduces a deep image fusion network (DIF-Net), an unsupervised deep learning framework for image fusion. The DIF-Net parameterizes the entire processes of image fusion, comprising of feature extraction, feature fusion, and image reconstruction, using a CNN. The purpose of DIF-Net is to generate an output image which has an identical contrast to high-dimensional input images. To realize this, we propose an unsupervised loss function using the structure tensor representation of the multi-channel image contrasts. Different from traditional fusion methods that involve time-consuming optimization or iterative procedures to obtain the results, our loss function is minimized by a stochastic deep learning solver with large-scale examples. Consequently, the proposed method can produce fused images that preserve source image details through a single forward network trained without reference ground-truth labels. The proposed method has broad applicability to various image fusion problems, including multi-spectral, multi-focus, and multi-exposure image fusions. Quantitative and qualitative evaluations show that the proposed technique outperforms existing state-of-the-art approaches for various applications.
Motivated by the mechanism of inhibitory synapses, a new kind of spiking neural P (SNP) system rules, called inhibitory rules, is introduced in this paper. Based on this, a new variant of SNP systems ...is proposed, called spiking neural P systems with inhibitory rules (SNP-IR systems). Different from the usual firing rules in SNP systems, the firing condition of an inhibitory rule not only depends on the state of the neuron associated with the rule but also is related to the states of other neurons. Moreover, from the perspective of topological structure, the new variant is shown as a directed graph with inhibitory arcs, and therefore seems to have more powerful control. The computational completeness of SNP-IR systems is discussed. In particular, it is proved that SNP-IR systems are Turing universal number accepting/generating devices. Moreover, we obtain a small universal function-computing device for SNP-IR systems consisting of 100 neurons.
•We propose a new kind rule, inhibitory rules, inspired from mechanism of inhibitory synapse.•We propose a new variant, spiking neural P systems with inhibitory rules (SNP-IR systems, in short).•We prove that SNP-IR systems as both number generating and number accepting devices are Turing universal.•We construct a small universal function computing device consisting of 100 neurons for SNP-IR systems.
Background
Chronic Neck Pain (CNP) among rotary-wing aircrew is thought to stem from night vision goggles (NVG) and counterweight (CW) systems which displace the centre of mass of the head. This ...investigation aimed to quantify the loads acting on the neck as a function of movement magnitude (MM), helmet conditions, and movement axes in rapid movements.
Methods
Cervical spine kinematics during rapid head repositioning tasks for flexion-extension (FE) and axial rotation (AR) movements were measured from 15 males and 15 females. Participants moved in either a 35° (Near MM) or 70° arc (Far MM), while donning a helmet, helmet with NVG, helmet with NVG and a typical CW, and a CW Liner (CWL). Measured EMG from three muscles bilaterally and used to drive a biomechanical model to quantify the compression and shear acting at the C5-C6 joint.
Results
In AR, the NVGs were associated with the largest compression magnitudes, 252 (24) N. CW conditions decreased the maximum compression to 249 (53) N. For FE, the compression was 340 N for the Far MM trials and 246 N for Near MMs. Changing the helmet configuration only modestly influenced these magnitudes in FE.
Conclusion
Every 30° of MM increased compression by 57 to 105 N. The reduction of the moment of inertia by 16% in the CWL did not reduce reaction forces. Joint loads scaled proportionately with head-supported weight by a factor of 2.05. The magnitudes of loads suggest a cumulative loading pathway for CNP development.
Image fusion is an important task for computer vision as a diverse range of applications are benefiting from the fusion operation. The existing image fusion methods are largely implemented at the ...pixel level, which may introduce artifacts and/or inconsistencies, while the computational complexity is relatively high. In this article, we propose a symmetric encoder-decoder with residual block (SEDRFuse) network to fuse infrared and visible images for night vision applications. At the training stage, the SEDRFuse network is trained to create a fixed feature extractor. At the fusing stage, the trained extractor is utilized to extract the intermediate and compensation features, which are generated by the residual block and the first two convolutional layers from the input source images, respectively. Two attention maps, which are derived from the intermediate features, are then multiplied by the intermediate features for fusion. The salient compensation features obtained through elementwise selection are passed to the corresponding deconvolutional layers for processing. Finally, the fused intermediate features and the selected compensation features are decoded to reconstruct the fused image. Experimental results demonstrate that the proposed fusion solution, i.e., SEDRFuse, outperforms the state-of-the-art fusion methods in terms of both subjective and objective evaluations.
Near‐infrared (NIR) organic solid‐state lasers play an essential role in applications ranging from laser communication to infrared night vision, but progress in this area is restricted by the lack of ...effective excited‐state gain processes. Herein, we originally proposed and demonstrated the cascaded occurrence of excited‐state intramolecular proton transfer for constructing the completely new energy‐level systems. Cascading by the first ultrafast proton transfer of <430 fs and the subsequent irreversible second proton transfer of ca. 1.6 ps, the stepwise proton transfer process favors the true six‐level photophysical cycle, which supports efficient population inversion and thus NIR single‐mode lasing at 854 nm. This work realizes longest wavelength beyond 850 nm of organic single‐crystal lasing to date and originally exploits the cascaded excited‐state molecular proton transfer energy‐level systems for organic solid‐state lasers.
Six‐level energy systems are constructed through the cascaded occurrence of excited‐state intramolecular proton transfer consisting of a first ultrafast proton transfer of <430 fs and a following dominant and irreversible proton transfer of ca. 1.6 ps, which support the NIR single‐mode lasing at 854 nm for exploiting energy‐level systems of OSSLs, especially at the NIR region from 780 to 2500 nm.
Near‐infrared (NIR) phosphor‐converted light‐emitting diodes (pc‐LEDs) hold great potential for applications ranging from night vision to non‐destructive detection. However, it remains a ...long‐standing challenge to develop NIR phosphors simultaneously with longer‐wavelength broadband emissions and higher efficiency. Herein, ultra‐broadband Ga4GeO8:Cr3+ (GGO:Cr3+) phosphors are developed, with the NIR emission covering 700–1300 nm. Furthermore, tunable emission bands peaking from 835 to 980 nm are achieved simply by varying the Cr3+ concentration. Particularly, emission maxima (λmax) of GGO:xCr3+ shift from 850 to 900 nm without intensity loss when increasing x values between 0.02 and 0.10. An internal quantum yield of 60% is achieved for GGO:0.02Cr3+ (λmax ≈ 850 nm, full width at half maximum (FWHM) ≈215 nm). The origin of tunable ultra‐broadband emissions of GGO:Cr3+ is revealed on the basis of structural and time‐resolved spectroscopic analysis. The pc‐LED fabricated by GGO:0.02Cr3+ exhibits a maximum NIR output power of ≈56 mW at 400 mA drive current, and its application in high‐penetration quality analysis of fruits is also demonstrated. The results indicate that GGO:Cr3+ phosphors have high promise for practical applications in NIR pc‐LED devices.
Novel Ga4GeO8:Cr3+ near‐infrared (NIR) phosphors with multiple Cr3+ centers are developed showing efficient ultra‐broadband emissions in the 700–1300 nm range. Meanwhile, tunable emissions peaking from 835 to 980 nm are achieved by increasing the Cr3+ concentration. High‐penetration spectroscopic analysis on inner quality of fruits is also demonstrated using the fabricated high‐power NIR phosphor‐converted light‐emitting diodes (pc‐LEDs).
Metasurface provides a powerful platform to correct the chromatic aberration of conventional lenses in a flexible, integratable, and ultra‐compact manner. Mid‐wavelength infrared has promised many ...exciting applications ranged from molecular fingerprint detection to low‐light‐level night vision. Developing broadband achromatic metalens in mid‐wavelength infrared becomes necessary to meet the increasingly urgent demands on high performance photonic devices. Here, we demonstrate the broadband achromatic metalenses from 3.5 to 5 µm with all‐silicon metasurfaces. Large phase dispersion control range is achieved to realize metalenses with both large numerical apertures and sample sizes while maintaining high focusing efficiency. The experimental results verify the diffraction‐limited achromatic focusing and imaging of the metalenses in mid‐wavelength infrared. Additionally, we also demonstrate the versatility by successfully implementing the generation of the broadband achromatic focusing optical vortex (L = 2). This work represents a solid step toward practical implementation of metalens and may find applications in mid‐wavelength infrared imaging and detections.
Broadband achromatic metalenses with multiple functions based on an all‐silicon platform are demonstrated in mid‐wavelength infrared. This work endows polarization‐switchable varifocal metalens via dispersion‐engineered metasurfaces. With this general achromatism, high‐performance metadevices for focusing, imaging, and wavefront‐steering are achieved. It represents a significant step forward in the development of efficient and functional achromatic metalens to meet diverse applications in mid‐wavelength infrared.
In order to address the discontinuity caused by the direct application of the infrared and visible image fusion anti-halation method to a video, an efficient night vision anti-halation method based ...on video fusion is proposed. The designed frame selection based on inter-frame difference determines the optimal cosine angle threshold by analyzing the relation of cosine angle threshold with nonlinear correlation information entropy and de-frame rate. The proposed time-mark-based adaptive motion compensation constructs the same number of interpolation frames as the redundant frames by taking the retained frame number as a time stamp. At the same time, considering the motion vector of two adjacent retained frames as the benchmark, the adaptive weights are constructed according to the interframe differences between the interpolated frame and the last retained frame, then the motion vector of the interpolated frame is estimated. The experimental results show that the proposed frame selection strategy ensures the maximum safe frame removal under the premise of continuous video content at different vehicle speeds in various halation scenes. The frame numbers and playing duration of the fused video are consistent with that of the original video, and the content of the interpolated frame is highly synchronized with that of the corresponding original frames. The average FPS of video fusion in this work is about six times that in the frame-by-frame fusion, which effectively improves the anti-halation processing efficiency of video fusion.
This paper proposes an effective infrared and visible image fusion method based on a texture conditional generative adversarial network (TC-GAN). The constructed TC-GAN generates a combined texture ...map for capturing gradient changes in image fusion. The generator in the TC-GAN is designed as a codec structure for extracting more details, and a squeeze-and-excitation module is applied to this codec structure to increase the weight of significant texture information in the combined texture map. The generator loss function is designed by combing the gradient loss and adversarial loss to retain the texture information of the source images. The discriminator brings the texture of the generated image closer to the visible image. To obtain significant texture information from the source images, a multiple decision map-based fusion strategy is proposed using a combined texture map and an adaptive guided filter. Extensive experiments on the public TNO and RoadScene datasets demonstrate that the proposed method is superior to other state-of-the-art algorithms in terms of a subjective evaluation and quantitative indicators.
Organic emitters have been widely developed since the demonstration of high efficiency in pure organic emitters represented by thermally activated delayed fluorescent (TADF) emitters. Pure ...organic‐based TADF emitters are found to harvest all singlet and triplet excitons for radiative transition processes, like phosphorescent emitters that utilize all generated excitons for light emission by strong spin–orbit coupling. Red, green, and blue organic emitters are investigated, but major interest is focused on green and blue organic emitters. However, recent studies are being directed to red and even near‐infrared emitters because of their wide applications in bioimaging, sensors, telecommunications, and night vision. Although the external quantum efficiency of the red and near‐infrared TADF organic light‐emitting diodes (OLEDs) is low, the external quantum efficiency of red OLEDs has been advanced to close to 30% and that of near‐infrared OLEDs to the 10% level. Therefore, more attention is being paid to red and near‐infrared TADF emitters. In this work, recent progress of the red and near‐infrared TADF emitters is reviewed to understand the molecular design principle and the molecular structure–photophysical characteristics and molecular structure–device performance relationships. In addition, future prospect of the red and near‐infrared TADF emitters is proposed.
This report covers recent progress of red and near‐infrared thermally activated delayed fluorescent emitters in terms of photophysical properties and device performances. Molecular design strategy of the red and near‐infrared emitters for high efficiency is discussed and future prospects of the red and near‐infrared thermally activated delayed fluorescent emitters are proposed.
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