With the development of infrared detection technology and the improvement of military remote sensing needs, infrared object detection networks with low false alarms and high detection accuracy have been a research focus. However, due to the lack of texture information, the false detection rate of infrared object detection is high, resulting in reduced object detection accuracy. To solve these problems, we propose an infrared object detection network named Dual-YOLO, which integrates visible image features. To ensure the speed of model detection, we choose the You Only Look Once v7 (YOLOv7) as the basic framework and design the infrared and visible images dual feature extraction channels. In addition, we develop attention fusion and fusion shuffle modules to reduce the detection error caused by redundant fusion feature information. Moreover, we introduce the Inception and SE modules to enhance the complementary characteristics of infrared and visible images. Furthermore, we design the fusion loss function to make the network converge fast during training. The experimental results show that the proposed Dual-YOLO network reaches 71.8% mean Average Precision (mAP) in the DroneVehicle remote sensing dataset and 73.2% mAP in the KAIST pedestrian dataset. The detection accuracy reaches 84.5% in the FLIR dataset. The proposed architecture is expected to be applied in the fields of military reconnaissance, unmanned driving, and public safety.

The natural compound eye has received much attention in recent years due to its remarkable properties, such as its large field of view (FOV), compact structure, and high sensitivity to moving objects. Many studies have been devoted to mimicking the imaging system of the natural compound eye. The paper gives a review of state-of-the-art artificial compound eye imaging systems. Firstly, we introduce the imaging principle of three types of natural compound eye. Then, we divide current artificial compound eye imaging systems into four categories according to the difference of structural composition. Readers can easily grasp methods to build an artificial compound eye imaging system from the perspective of structural composition. Moreover, we compare the imaging performance of state-of-the-art artificial compound eye imaging systems, which provides a reference for readers to design system parameters of an artificial compound eye imaging system. Next, we present the applications of the artificial compound eye imaging system including imaging with a large FOV, imaging with high resolution, object distance detection, medical imaging, egomotion estimation, and navigation. Finally, an outlook of the artificial compound eye imaging system is highlighted.

An optical zoom imaging system that can vary the magnification factor without displacing the object and the image plane has been widely used. Nonetheless, conventional optical zoom imaging systems suffer slow response, complicated configuration, vulnerability to misalignment during zoom operation, and are incompatible for miniaturized applications. This review article focuses on state-of-the-art research on novel optical zoom imaging systems that use adaptive liquid lenses. From the aspect of the configuration, according to the amount of the adaptive liquid lenses, we broadly divide the current optical zoom imaging systems using adaptive liquid lenses into two configurations: multiple adaptive liquid lenses, and a single adaptive liquid lens. The principles and configurations of these optical zoom imaging systems are introduced and represented. Three different working principles of the adaptive liquid lens (liquid crystal, polymer elastic membrane, and electrowetting effect) adopted in the optical zoom imaging systems are reviewed. Some representative applications of optical zooming imaging systems using adaptive liquid lenses are introduced. The opportunities and challenges of the optical zoom imaging systems using adaptive liquid lenses are also discussed. This review aims to provide a snapshot of the current state of this research field for attracting more attention to put forward the development of the next-generation optical zoom imaging systems.

A stick-slip/inchworm hybrid rotary piezomotor based on a symmetric triangular driving mechanism, which can simultaneously achieve the benefits of both stick-slip and inchworm motors, was reported in this letter. It is based on the principle of stick-slip motors, and, inspired by the clamping-releasing actions from inchworm motors, it employs a symmetric triangular driving mechanism to generate a clamping action during the stick phase and a releasing action during the slip phase. Compared with stick-slip motors, it involves a clamping action during the stick phase and a releasing action during the slip phase, thus resulting in a larger driving force. Compared with inchworm motors, which require active control and coordination of clamping/releasing modules with feeding modules, it involves the control and operation of only one feeding piezoactuator without any actively controlled clamping/releasing module. Therefore, the control is easier, and a much larger operation frequency and driving speed can be achieved. Under the sawtooth waveform voltage of 90 V at 2600 Hz with a self-holding torque of 4 N m, the prototype achieved a no-load speed higher than 0.6 rad/s, a load torque capacity larger than 1.8 N m, and a weight carrying capacity more than 100 kg for both clockwise and anticlockwise directions. Compared with load torque capacity and weight carrying capacity in the reported stick-slip and inchworm rotary piezomotors, the current levels in terms of the same driving speed have been improved over 60 times and 12 times, respectively, in the proposed hybrid motor.

Stick-slip piezoelectric actautors are promising actautors with prinicipally unlimited stroke and positioning resolution. However, it is challenged with a low load capacity, which limits the field of application. Various types of compliant driving foot were proposed in literature to improve the load capacity but the improved load capacity is direction-dependent. To improve the load capacity in both forward and backward directions, this paper proposes an approach via a shared driving foot. The basic idea is to employ two piezoelectric actuators and a shared driving foot to work in a way that either forward or backward driving is a stick-slip process and both involve a clamping action during the ‘stick’ phase and a releasing action during the ‘slip’ phase, so that a large driving force/load capacity can be achieved in both driving directions. Following this approach, a shared driving foot was proposed and designed. Finite element simulations were carried out and have validated that the designed driving foot can realize the proposed approach as desired. A prototype was built and tested and the effectiveness of the proposed approach has been validated by experiments. Under the sawtooth waveform voltage of 100 V at 1 kHz, the prototype achieved a free-load forward and backward driving speed as large as 18.6 mm s ⁻¹ and 16 mm s ⁻¹ respectively and a load capacity larger than 2 kg for both driving directions. Under a driving load of 2 kg, it can still move stably with forward and backward driving speeds of 1.8 mm s ⁻¹ and 0.6 mm s ⁻¹ respectively.