Search

Homography estimation is regarded as one of the key challenges in image alignment, where the goal is to estimate the projective transformation between two images on the same plane. Unsupervised learning methods are gradually becoming popular due to their excellent performance and lack of need for labeled data. However, in regional scenes with repeated textures, there may be ambiguity in the correspondence between local features, affecting homography estimation accuracy. This paper proposes a new unsupervised deep homography method RTHEN to solve such problems. In order to effectively obtain repeated texture features, a multi-scale Feature pyramid Siamese network (FPSN) is designed. Specifically, we dynamically allocate the weights of recited texture features through a dynamic attention module and introduce a channel attention module to provide rich contextual information for repeated texture areas. We propose a hard triplet loss function based on overlap constraints to optimize the matching results. At the same time, we collected a repetitive texture image dataset (RTID) for homography estimation training and evaluation. Experimental results show that our method outperforms existing learning methods in repetitive texture scenes and offers competitive performance with state-of-the-art traditional methods. • An unsupervised method is employed for homography estimation. • The issue of mismatching in repetitive textures is effectively addressed. • Formulated a loss function with overlap constraints to enhance estimation results. • Curated a dataset of repeated texture images for training and model evaluation. [ABSTRACT FROM AUTHOR]

• A method for single-object tracking of fish was proposed. • The problems of similar interference, occlusion and image blur are solved. • The model has good performance in aquaculture environment. • Tracking of fish will improve fish welfare. In aquaculture, tracking fish helps to obtain information about their growth, behavior, location and health, etc. However, there are some problems in the process of fish tracking. Firstly, to solve the noise problem of underwater images, we use the contrast limited adaptive histogram equalization (CLAHE) to carry out local histogram equalization in each small block, which increases the image contrast while retaining more details. This operation enhances the contrast of the image while suppressing noise to solve the problem of noisy images. Then, to solve the problems of similarity interference, occlusion and scale variation among fish, we propose a new method for fish single object tracking in aquaculture environments, called SiamFCA, by combining the coordinated attention mechanism (CA). The method is based on the siamese network framework and uses a modified AlexNet to extract the depth features of image pairs. And through the coordinate attention mechanism, the model can learn the relationship between different objects more accurately, which can improve the accuracy and robustness of the model when dealing with complex image scenes. Finally, the correlation operation between classification and regression is performed based on the region proposal network (RPN). By classifying, region suggestions can be labeled as positive or negative samples, and regression can calibrate the position and size of the region proposal to match targets more accurately. The experimental results show that the precision and success rate of the algorithm are 84.2 % and 62.4 %, respectively, which are better than the tracking methods such as SiamRPN and DaSiamRPN, etc. The SiamFCA runs at 83 fps, which meets the demand of real-time fish tracking in aquaculture. [ABSTRACT FROM AUTHOR]

• A survey of machine vision for fish tracking in aquaculture. • A taxonomy of the techniques and classify the papers based on the taxonomy. • An analysis of fish detection and tracking methods. • A review of the application of fish tracking technology in fish research. • Summarized the datasets that can be used for fish tracking. In aquaculture, Behavioral monitoring of fish contributes to scientific management and reduces the threat of loss from disease and stress. Fish tracking technology plays an important role in behavior monitoring. It can pay attention to the movement of fish at any time and discover various abnormal behaviors in time. As a non-invasive method, computer vision is a powerful tool for fish tracking.. Its tracking principle is to establish the relationship between fish positions in a continuous video sequence and get the complete movement trajectory of the fish. Nevertheless, computer vision modeling used for fish tracking is riddled with many challenges, such as fish deformation, frequent occlusion, scale change, etc. Around these difficult issues, many scholars have carried out the research. In this paper, we review the progress of tracking algorithms in fish research. Then, methods for fish tracking before deep learning are introduced. Further, a detailed discussion of fish tracking methods employing deep learning such as tracking-by-detection, deep features combined with correlation filtering methods, Siamese networks, etc. Furthermore, we summarize datasets that can be used as fish tracking and give evaluation metrics in target tracking algorithms. In addition, experimental data of several mainstream tracking algorithms on a public tracking dataset are given. Finally, we discuss the outstanding findings and look forward to the fish tracking method combined with Transformer, aiming to provide a reference for accelerating the promotion of smart fishery and precision farming. [ABSTRACT FROM AUTHOR]