A background memory model for hyperspectral anomaly detection

Hyperspectral images (HSIs) have a wealth of continuous spectrum information, covering hundreds of bands from visible light to infrared wavelengths. The data characteristics of HSIs give it a unique advantage in harnessing the inherent attributes of the spectrum in image processing. This advantage is conducive to making full use of spatial and spectral information and detecting targets in the region of interest. However, due to the high dimensionality of hyperspectral data, the complexity of actual scenes, and the limited number of labeled samples, hyperspectral anomaly detection faces the problem of indistinct background and anomalies and low detection accuracy. Therefore, we propose a background memory model for hyperspectral anomaly detection. First, the pseudo background and anomaly vectors are obtained through an unsupervised rough inspection method based on density estimation. Second, we design a background memory generation adversarial network model based on anomalous prominent regular term constraints. Moreover, we expand the distance between the false background and false anomalies in a weak supervision-pseudo-label manner. Thus, the network has a strong background generation ability while the effect on anomaly reconstruction is weakened, which reduces the generalization of background and anomaly reconstruction and enhances the difference and discrimination between background and anomaly. We also perform adversarial learning in the feature domain and image domain to improve sample generation ability, enabling better learning of the distribution of input samples and strengthening the capability to generate background. Finally, a nonlinear background suppression method is introduced to reduce the false alarm rate and further improve the detection accuracy. The experimental results show that our model has a better detection effect on different datasets than other detection algorithms. HSIs have continuous spectral information of hundreds of bands, which make it possible to capture the deep and intrinsic characteristics in a spectrum. However, due to the high dimension of HSI, the complexity of the scene, and the limitation of labeled samples, hyperspectral anomaly detection remains a challenge. To solve the abovementioned problem, we propose a generative adversarial network with anomaly-highlighted regularization and train it in a weakly supervised manner. We aim to separate the anomaly and background vectors to make the difference more obvious and obtain a more accurate detection map. In this paper, we propose a background memory generative adversarial network for hyperspectral anomaly detection. First, we obtain the pseudo background and anomalies through unsupervised coarse detection based on density estimation as the input of the network. Next, to reduce anomaly contamination in background estimation, we impose the constraint of anomaly-highlighted regularization to expand the distance between the background and anomaly. In the weak supervised pseudo labeling training mode, the network can reconstruct background vectors well but gains poor performance for anomaly reconstruction. Besides, there are two discriminators in the latent and reconstruction domains, which aim to improve the ability of background generation and estimation. Finally, we perform nonlinear background suppression on the detection map as post-processing to reduce the false alarm rate. Compared with other new algorithms with good performance, the proposed method has better detection results in both quantitative and qualitative aspects of different datasets. The AUC score of (Pd, Pf) achieves the highest value across different datasets and outperforms other algorithms and has the advantage of an order of magnitude. For example, the AUC score of (Pd, Pf) achieves 0.99771 for the ABU-1 dataset, while the AUC score of (Pf, τ) is 0.00258, which outperforms the second-best algorithm AED with scores of 0.99760 and 0.02230, respectively. The visual results are consistent with the qualitative results as well. The ROC curve locates near the upper left corner. Under the same false alarm rate, the proposed method has the highest accuracy for most datasets, obtaining higher detection probability and lower false alarm rate, and has better detection performance. The box plot likewise reveals that the background and anomaly of this method are more separable. In this paper, we propose a generative adversarial network memorizing background for hyperspectral anomaly detection. Different from our previous work, we obtain the pseudo background and anomaly vector adaptively in an unsupervised manner to solve the problem of the small number of anomaly samples and lack of prior information. Based on weakly supervised pseudo-labeling learning, we aim to model a hyperspectral anomaly and background vector. As a result, the network can reconstruct background data well but performs poorly on anomaly vector reconstruction. We also apply the constraint of highlighting an anomaly regular term in the network to enhance the separability between background and anomaly. Finally, we perform post-processing of nonlinear background suppression to reduce the false alarm rate under the same detection accuracy. Experimental results show that the proposed method can achieve better detection performance than other algorithms on different datasets. © 2024 Science Press. All rights reserved.