2,302 research outputs found
Improving Sonar Image Patch Matching via Deep Learning
Matching sonar images with high accuracy has been a problem for a long time,
as sonar images are inherently hard to model due to reflections, noise and
viewpoint dependence. Autonomous Underwater Vehicles require good sonar image
matching capabilities for tasks such as tracking, simultaneous localization and
mapping (SLAM) and some cases of object detection/recognition. We propose the
use of Convolutional Neural Networks (CNN) to learn a matching function that
can be trained from labeled sonar data, after pre-processing to generate
matching and non-matching pairs. In a dataset of 39K training pairs, we obtain
0.91 Area under the ROC Curve (AUC) for a CNN that outputs a binary
classification matching decision, and 0.89 AUC for another CNN that outputs a
matching score. In comparison, classical keypoint matching methods like SIFT,
SURF, ORB and AKAZE obtain AUC 0.61 to 0.68. Alternative learning methods
obtain similar results, with a Random Forest Classifier obtaining AUC 0.79, and
a Support Vector Machine resulting in AUC 0.66.Comment: Author versio
SONIC: Sonar Image Correspondence using Pose Supervised Learning for Imaging Sonars
In this paper, we address the challenging problem of data association for
underwater SLAM through a novel method for sonar image correspondence using
learned features. We introduce SONIC (SONar Image Correspondence), a
pose-supervised network designed to yield robust feature correspondence capable
of withstanding viewpoint variations. The inherent complexity of the underwater
environment stems from the dynamic and frequently limited visibility
conditions, restricting vision to a few meters of often featureless expanses.
This makes camera-based systems suboptimal in most open water application
scenarios. Consequently, multibeam imaging sonars emerge as the preferred
choice for perception sensors. However, they too are not without their
limitations. While imaging sonars offer superior long-range visibility compared
to cameras, their measurements can appear different from varying viewpoints.
This inherent variability presents formidable challenges in data association,
particularly for feature-based methods. Our method demonstrates significantly
better performance in generating correspondences for sonar images which will
pave the way for more accurate loop closure constraints and sonar-based place
recognition. Code as well as simulated and real-world datasets will be made
public to facilitate further development in the field
Improving Generalization of Synthetically Trained Sonar Image Descriptors for Underwater Place Recognition
Autonomous navigation in underwater environments presents challenges due to
factors such as light absorption and water turbidity, limiting the
effectiveness of optical sensors. Sonar systems are commonly used for
perception in underwater operations as they are unaffected by these
limitations. Traditional computer vision algorithms are less effective when
applied to sonar-generated acoustic images, while convolutional neural networks
(CNNs) typically require large amounts of labeled training data that are often
unavailable or difficult to acquire. To this end, we propose a novel compact
deep sonar descriptor pipeline that can generalize to real scenarios while
being trained exclusively on synthetic data. Our architecture is based on a
ResNet18 back-end and a properly parameterized random Gaussian projection
layer, whereas input sonar data is enhanced with standard ad-hoc
normalization/prefiltering techniques. A customized synthetic data generation
procedure is also presented. The proposed method has been evaluated extensively
using both synthetic and publicly available real data, demonstrating its
effectiveness compared to state-of-the-art methods.Comment: This paper has been accepted for publication at the 14th
International Conference on Computer Vision Systems (ICVS 2023
Forward-Looking Sonar Patch Matching:Modern CNNs, Ensembling, and Uncertainty
Application of underwater robots are on the rise, most of them are dependent on sonar for underwater vision, but the lack of strong perception capabilities limits them in this task. An important issue in sonar perception is matching image patches, which can enable other techniques like localization, change detection, and mapping. There is a rich literature for this problem in color images, but for acoustic images, it is lacking, due to the physics that produce these images. In this paper we improve on our previous results for this problem (Valdenegro-Toro et al, 2017), instead of modeling features manually, a Convolutional Neural Network (CNN) learns a similarity function and predicts if two input sonar images are similar or not. With the objective of improving the sonar image matching problem further, three state of the art CNN architectures are evaluated on the Marine Debris dataset, namely DenseNet, and VGG, with a siamese or two-channel architecture, and contrastive loss. To ensure a fair evaluation of each network, thorough hyper-parameter optimization is executed. We find that the best performing models are DenseNet Two-Channel network with 0.955 AUC, VGG-Siamese with contrastive loss at 0.949 AUC and DenseNet Siamese with 0.921 AUC. By ensembling the top performing DenseNet two-channel and DenseNet-Siamese models overall highest prediction accuracy obtained is 0.978 AUC, showing a large improvement over the 0.91 AUC in the state of the art
The Marine Debris Dataset for Forward-Looking Sonar Semantic Segmentation
Accurate detection and segmentation of marine debris is important for keeping the water bodies clean. This paper presents a novel dataset for marine debris segmentation collected using a Forward Looking Sonar (FLS). The dataset consists of 1868 FLS images captured using ARIS Explorer 3000 sensor. The objects used to produce this dataset contain typical house-hold marine debris and distractor marine objects (tires, hooks, valves,etc), divided in 11 classes plus a background class. Performance of state of the art semantic segmentation architectures with a variety of encoders have been analyzed on this dataset and presented as baseline results. Since the images are grayscale, no pre-trained weights have been used. Comparisons are made using Intersection over Union (IoU). The best performing model is Unet with ResNet34 backbone at 0.7481 mIoU
Toward autonomous exploration in confined underwater environments
Author Posting. © The Author(s), 2015. This is the author's version of the work. It is posted here by permission of John Wiley & Sons for personal use, not for redistribution. The definitive version was published in Journal of Field Robotics 33 (2016): 994-1012, doi:10.1002/rob.21640.In this field note we detail the operations and discuss the results of an experiment conducted
in the unstructured environment of an underwater cave complex, using an autonomous underwater vehicle (AUV). For this experiment the AUV was equipped with two acoustic
sonar to simultaneously map the caves’ horizontal and vertical surfaces. Although the
caves’ spatial complexity required AUV guidance by a diver, this field deployment successfully demonstrates a scan matching algorithm in a simultaneous localization and mapping (SLAM) framework that significantly reduces and bounds the localization error for fully
autonomous navigation. These methods are generalizable for AUV exploration in confined
underwater environments where surfacing or pre-deployment of localization equipment are
not feasible and may provide a useful step toward AUV utilization as a response tool in
confined underwater disaster areas.This research work was partially sponsored by the EU FP7-Projects: Tecniospring-
Marie Curie (TECSPR13-1-0052), MORPH (FP7-ICT-2011-7-288704), Eurofleets2 (FP7-INF-2012-312762),
and the National Science Foundation (OCE-0955674)
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