We developed an intelligent innovative orientation method to improve the accuracy of polarization compasses in harsh conditions: weak skylight polarization patterns resulting from unfavorable weather conditions (e.g., haze, sandstorms) or locally destroyed skylight polarization conditions caused by occlusions (e.g., buildings, trees). First, the skylight polarization status was determined with the degree of linear polarization threshold analysis method and a bionic polarization enhancement sensing model was constructed to simulate the enhanced perception mechanism identified in the Syrphidae visual neural pathway, highly efficient in dark or weakly illuminated environments. The bionic model successfully enhanced the information content extracted from weak polarization patterns. Second, polarization pixel interferences, caused by occlusions under locally destroyed skylight polarization conditions, were removed with a convolutional neural network for image segmentation and the sky area of interest was identified. Finally, the incomplete angle of polarization map derived after image segmentation was fitted using our optimized adaptive antisymmetric ring algorithm. On the basis of the strong angle-of-polarization antisymmetry along the solar meridian, information extracted from the sparse and irregular polarization pixels was analyzed to derive a high-accuracy polarization orientation solution. The whole method intelligently realizes pattern analysis and deep learning intelligent processing, efficiently rotates to manage polarization disorientation. The experimental results demonstrated the performance of the proposed method in compensating for reduced orientation accuracy under degraded polarization conditions, its robustness against perturbations, and its beneficial impact on the environmental adaptability of bionic polarization compasses.

Autonomous velocity measurement technology based on optical flow plays an important role in applications of the Internet of Things. However, robust velocity measurement results need to provide a robust optical flow field and distance to the ground, especially for complex ground scenes. To solve this problem, this article proposes a visual velocity measurement method based on a$3\times3$camera-array multiaperture biomimetic compound-eye imaging system. The multiaperture optical flow field is first obtained from compound-eye through multiscale analysis and Bayes threshold processing. The real distance to the ground is then obtained by extracting the disparity information of nine apertures for adaptive depth estimation. The velocity measurement error is less than 0.6 m/s in low-altitude (8 and 13 m) flight scenarios with multiple obstacles.

In an actual indoor acoustic environment, the signal processing technique to extract the low-noise and low-reverberation speech signal of a particular speaker from the mixed audio signals is crucial for the back-end speech recognition, speech emotion perception judgment, voiceprint recognition, and other artificial intelligence systems that can be used for IoT connectivity. This paper proposes a method solving the problem of speaker source separation in the presence of both noise and reverberation by using two-step networks for separation, denoising and dereverberation. To ensure the high quality of the input signal used in the dereverberation stage, various separation networks such as Sepfomer were used as training targets with different signals types, and exhibited good convergence in the training set, an obvious separation effect in the validation set, and good generalization. An improved dereverberation method based on time convolution network (TCN-WPE) is proposed. This method uses various improvement strategies such as employing the scale-invariant signal-to-distortion ratio (SISDR) as the network loss function, adopting a transposition mechanism for the input signal, and employing an additional residual mechanism in the network unit, and significantly improves the dereverberation compared with the traditional WPE and DNN-WPE. The Sepformer with the best separation and denoising effect was cascaded with the TCN-transposed-residual. The experiments confirmed that the proposed method can achieve high-quality speaker speech separation and enhancement within a limited corpus, which enables it to be used in IoT-oriented applications such as automatic speech recognition systems.

Accurately obtaining the navigation information of the device is crucial for realizing various emerging Internet of Things (IoT) applications, and a multi-source fusion navigation system is the key to achieving this goal. A distributed integrated inertial navigation system (INS), polarization compass (PC), and geomagnetic compass (MAG) enhanced direction approach is presented to improve the accuracy and robustness of the multisource fusion navigation system in complex environments. To estimate the time-varying measurement noise covariance in a nonlinear multi-source fusion navigation system, the traditional federated Kalman filter (FKF) is improved. In the FKF framework, the third-order spherical radial cubature rule and variational Bayesian theory are introduced, and a variational Bayesian federated cubature Kalman filter (VBFCKF) is proposed. Furthermore, a distributed information monitoring and compensation algorithm based on residuals is developed to address issues like anomalous measured values and asynchronous multi-rate problems. Finally, an experimental platform for unmanned vehicle navigation is designed, and the tests are conducted to confirm the efficacy of the suggested approach. The experimental results show that the system can precisely estimate values based on the measurement quality of sub-filters during navigation. It effectively adjusts measurement noise covariance during updates, thereby mitigating the negative impact of interferences like occlusions and electromagnetic noise on the multi-source fusion navigation system in complex environments. This can strengthen the accuracy and robustness of the navigation system.

Autonomous orientation technology has major engineering significance for intelligent transportation systems (ITS) especially for the intelligent vehicle. The sky polarization characteristics offer a wealth of navigation data. At present, the most advanced polarization navigators can output this navigation information and do not require complex optical structures. However, these current navigation methods are limited severely by the sky conditions, and it is difficult to achieve orientation accurately under interference from reflected light. Here, we report a sky recognition algorithm based on a region prior approach to reduce the influence of the reflected light. Furthermore, to solve the sun fuzzy problem, a morphometric template matching in transform domain (MTMTD) strategy is proposed based on the angle of polarization (AOP). The application scope and practicability of the method are improved effectively by using all the effective pixels as a navigation unit. In addition, this method turns these pixels into curves, which means that even when only one pixel is observed, the sun fuzzy problem can be solved exactly. Our results efficiently verify the feasibility of the proposed strategy, which may provide an interesting solution for heading measurement of intelligent vehicle.

Accurate and reliable navigation data is a key component in Internet of Things (IoT). High-precision and stable autonomous orientation has attracted considerable attention regarding environments in which the global navigation satellite system signal is unreliable. This study proposed a robust orientation method based on the atmospheric polarization mode called weather weighting sparse coding that includes weather classification, sparse coding, and fitting. In comparison with previous studies, the proposed method is effective in restoring the angle-of-polarization image and achieving accurate orientation under complex weather. Specifically, to achieve high-precision orientation in complex weather, a polarization compass was designed, which used the characteristics of the different levels of destruction of atmospheric polarization images under different weather conditions for classification and denoising. The proposed strategy was used to process atmospheric polarization images obtained in complex weather. Experimental results showed that the orientation accuracy was better than 0.31° (root-mean-square error) under conditions of overcast, sandstorms, clear with overexposed areas, and smog with tree-obscured and overexposed areas.