Algorithm Framework       Procedure of Point Symbol Recognition

Step 1 Prescreening the topographic maps.

Step 1.1 The topographic map is processed to extract the black sub-layouts.

Step 1.2 Based on the method of judging the minimum bounding rectangle, the connected region of suspected point symbols should be obtained.

Step 2 Training the model.

Step 2.1 Pretraining the AlexNet networks based on MNIST database by transfer learning to obtain the pretraining model.

Step 2.2 Pretaining the pretraining model based on the point-symbols data to obtain the final model.

Step 3 Recognition of the point-symbols.

The test images of point symbols input the final model to test the recognition accuracy.