Roof type classifier

Roof type is a crucial information for wind hazard analyses of buildings because it is a key attribute needed for consideration of wind effects on structures.

There are three major roof types, as shown in Table 2.2.1, that are widely used in the world: flat, gabled, hipped.

Table 1.2.1 Roof prototypes
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Fig. 1.2.1 Flat
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Fig. 1.2.2 Gabled
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Fig. 1.2.3 Hipped

Correspondingly, a typical satellite image of each roof type is shown in Table 1.2.2.

Table 1.2.2 Example satellite images of different roof types
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Fig. 1.2.4 Flat
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Fig. 1.2.5 Gabled
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Fig. 1.2.6 Hipped

Satellite images are a scalable source for inferring roof type information. In the attempt to determine roof type for every building in a region, a ConvNet classifier is trained to take a satellite image of a building and predicts its roof type. A training data set of 6,000 satellite images (2,000 for each roof type: flat, gabled, hipped) is collected. Specifically, ResNet [HZRS16], which is a widely-used ConvNet architecture for image feature recognition, is employed.

The architecture of the model is shown in Fig. 1.2.14. In this module, we used a 50-layer ResNet.

ResNet

Fig. 1.2.7 ResNet