update!

README.md

@@ -17,20 +17,20 @@ Our dataset consists of large areas from two UK cities, covering about 6 km^2 of
 In the dataset, each 3D point is labeled as one of 13 semantic classes, such as *ground*, *vegetation*, 
 *car*, *etc.*. 
 
-<p align="center"> <img src="http://point-cloud-analysis.cs.ox.ac.uk/imgs/Fig1.png" width="100%"> </p>
-<p align="center"> <img src="http://point-cloud-analysis.cs.ox.ac.uk/imgs/Table1.png" width="100%"> </p>
+<p align="center"> <img src="imgs/Fig1.png" width="100%"> </p>
+<p align="center"> <img src="imgs/Table1.png" width="100%"> </p>
 
 #### 1.2 Data Collection
 
 The 3D point clouds are generated from high-quality aerial images captured by a 
 professional-grade UAV mapping system. In order to fully and evenly cover the survey area, 
 all flight paths are pre-planned in a grid fashion and automated by the flight control system (e-Motion).
 
-<p align="center"> <img src="http://point-cloud-analysis.cs.ox.ac.uk/imgs/Fig2.png" width="70%"> </p>
+<p align="center"> <img src="imgs/Fig2.png" width="70%"> </p>
 
 #### 1.3 Semantic Annotations
 
-<p align="center"> <img src="http://point-cloud-analysis.cs.ox.ac.uk/imgs/Fig3.png" width="100%"> </p>
+<p align="center"> <img src="imgs/Fig3.png" width="100%"> </p>
 
 - Ground: including impervious surfaces, grass, terrain
 - Vegetation: including trees, shrubs, hedges, bushes
@@ -48,15 +48,15 @@ all flight paths are pre-planned in a grid fashion and automated by the flight c
 
 
 #### 1.4 Statistics
-<p align="center"> <img src="http://point-cloud-analysis.cs.ox.ac.uk/imgs/Fig5.png" width="100%"> </p>
+<p align="center"> <img src="imgs/Fig5.png" width="100%"> </p>
 
 
 ### (2) Benchmarks
 We extensively evaluate the performance of state-of-the-art algorithms on our dataset 
 and provide a comprehensive analysis of the results. In particular, we identify several key challenges 
 towards urban-scale point cloud understanding. 
 
-<p align="center"> <img src="http://point-cloud-analysis.cs.ox.ac.uk/imgs/Fig6.png" width="100%"> </p>
+<p align="center"> <img src="imgs/Fig6.png" width="100%"> </p>
 
 
 ### (3) Demo