204 research outputs found
Expediting Building Footprint Segmentation from High-resolution Remote Sensing Images via progressive lenient supervision
The efficacy of building footprint segmentation from remotely sensed images
has been hindered by model transfer effectiveness. Many existing building
segmentation methods were developed upon the encoder-decoder architecture of
U-Net, in which the encoder is finetuned from the newly developed backbone
networks that are pre-trained on ImageNet. However, the heavy computational
burden of the existing decoder designs hampers the successful transfer of these
modern encoder networks to remote sensing tasks. Even the widely-adopted deep
supervision strategy fails to mitigate these challenges due to its invalid loss
in hybrid regions where foreground and background pixels are intermixed. In
this paper, we conduct a comprehensive evaluation of existing decoder network
designs for building footprint segmentation and propose an efficient framework
denoted as BFSeg to enhance learning efficiency and effectiveness.
Specifically, a densely-connected coarse-to-fine feature fusion decoder network
that facilitates easy and fast feature fusion across scales is proposed.
Moreover, considering the invalidity of hybrid regions in the down-sampled
ground truth during the deep supervision process, we present a lenient deep
supervision and distillation strategy that enables the network to learn proper
knowledge from deep supervision. Building upon these advancements, we have
developed a new family of building segmentation networks, which consistently
surpass prior works with outstanding performance and efficiency across a wide
range of newly developed encoder networks. The code will be released on
https://github.com/HaonanGuo/BFSeg-Efficient-Building-Footprint-Segmentation-Framework.Comment: 13 pages,8 figures. Submitted to IEEE Transactions on Neural Networks
and Learning System
PiCoCo: Pixelwise Contrast and Consistency Learning for Semisupervised Building Footprint Segmentation
Building footprint segmentation from high-resolution
remote sensing (RS) images plays a vital role in urban planning, disaster response, and population density estimation. Convolutional
neural networks (CNNs) have been recently used as a workhorse for
effectively generating building footprints. However, to completely
exploit the prediction power of CNNs, large-scale pixel-level annotations are required. Most state-of-the-art methods based on CNNs
are focused on the design of network architectures for improving
the predictions of building footprints with full annotations, while
few works have been done on building footprint segmentation with
limited annotations. In this article, we propose a novel semisupervised learning method for building footprint segmentation, which
can effectively predict building footprints based on the network
trained with few annotations (e.g., only 0.0324 km2 out of 2.25-km2
area is labeled). The proposed method is based on investigating
the contrast between the building and background pixels in latent
space and the consistency of predictions obtained from the CNN
models when the input RS images are perturbed. Thus, we term the
proposed semisupervised learning framework of building footprint segmentation as PiCoCo, which is based on the enforcement of
Pixelwise Contrast and Consistency during the learning phase. Our
experiments, conducted on two benchmark building segmentation
datasets, validate the effectiveness of our proposed framework as
compared to several state-of-the-art building footprint extraction
and semisupervised semantic segmentation methods
Deep Learning for Building Footprint Generation from Optical Imagery
Auf Deep Learning basierende Methoden haben vielversprechende Ergebnisse für die Aufgabe der Erstellung von Gebäudegrundrissen gezeigt, aber sie haben zwei inhärente Einschränkungen. Erstens zeigen die extrahierten Gebäude verschwommene Gebäudegrenzen und Klecksformen. Zweitens sind für das Netzwerktraining massive Annotationen auf Pixelebene erforderlich. Diese Dissertation hat eine Reihe von Methoden entwickelt, um die oben genannten Probleme anzugehen. Darüber hinaus werden die entwickelten Methoden in praktische Anwendungen umgesetzt
Reducing the Burden of Aerial Image Labelling Through Human-in-the-Loop Machine Learning Methods
This dissertation presents an introduction to human-in-the-loop deep learning methods for remote sensing applications. It is motivated by the need to decrease the time spent by volunteers on semantic segmentation of remote sensing imagery. We look at two human-in-the-loop approaches of speeding up the labelling of the remote sensing data: interactive segmentation and active learning. We develop these methods specifically in response to the needs of the disaster relief organisations who require accurately labelled maps of disaster-stricken regions quickly, in order to respond to the needs of the affected communities. To begin, we survey the current approaches used within the field. We analyse the shortcomings of these models which include outputs ill-suited for uploading to mapping databases, and an inability to label new regions well, when the new regions differ from the regions trained on. The methods developed then look at addressing these shortcomings. We first develop an interactive segmentation algorithm. Interactive segmentation aims to segment objects with a supervisory signal from a user to assist the model. Work within interactive segmentation has focused largely on segmenting one or few objects within an image. We make a few adaptions to allow an existing method to scale to remote sensing applications where there are tens of objects within a single image that needs to be segmented. We show a quantitative improvements of up to 18% in mean intersection over union, as well as qualitative improvements. The algorithm works well when labelling new regions, and the qualitative improvements show outputs more suitable for uploading to mapping databases. We then investigate active learning in the context of remote sensing. Active learning looks at reducing the number of labelled samples required by a model to achieve an acceptable performance level. Within the context of deep learning, the utility of the various active learning strategies developed is uncertain, with conflicting results within the literature. We evaluate and compare a variety of sample acquisition strategies on the semantic segmentation tasks in scenarios relevant to disaster relief mapping. Our results show that all active learning strategies evaluated provide minimal performance increases over a simple random sample acquisition strategy. However, we present analysis of the results illustrating how the various strategies work and intuition of when certain active learning strategies might be preferred. This analysis could be used to inform future research. We conclude by providing examples of the synergies of these two approaches, and indicate how this work, on reducing the burden of aerial image labelling for the disaster relief mapping community, can be further extended
Building Section Instance Segmentation with Combined Classical and Deep Learning Methods
In big cities, the complexity of urban infrastructure is very high. In city centers, one construction can consist of several building sections of different heights or roof geometries. Most of the existing approaches detect those buildings as a single construction in the form of binary building segmentation maps or as one instance of object-oriented segmentation. However, reconstructing complex buildings consisting of several parts requires a higher level of detail. In this work, we present a methodology for individual building section instance segmentation on satellite imagery. We show that fully convolutional networks (FCNs) can tackle the issue much better than the state-of-the-art Mask-RCNN. A ground truth raster image with pixel value 1 for building sections and 2 for their touching borders was generated to train models on predicting both classes as a semantic output. The semantic outputs were then post-processed with the help of morphology and watershed labeling to generate segmentation on the instance level. The combination of a deep learning-based approach and a classical image processing algorithm allowed us to fulfill the segmentation task on the instance level and reach high-quality results with an mAP of up to 42 %
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