add feature extractor abstract class

laserchicken/feature_extractor.py

@@ -0,0 +1,26 @@
+class FeatureExtractor(object):
+    def get_requirements(self):
+        """
+        Get a list of names of the point attributes that are needed for this feature extraction. For simple features,
+        this could be just x, y, and z. Other features can build on again other features to have been computed first.
+        :return: List of feature names
+        """
+        NotImplementedError("Class %s doesn't implement aMethod()" % (self.__class__.__name__))
+
+    def get_names(self):
+        """
+        Get a list of names of the feature values. This will return as many names as as the number feature values
+        that will be returned. For instance, if a feature extractor returns the first 3 Eigen values, this method
+        should return 3 names, for instance 'eigen_value_1', 'eigen_value_2' and 'eigen_value_3'.
+        :return: List of feature names
+        """
+        NotImplementedError("Class %s doesn't implement aMethod()" % (self.__class__.__name__))
+
+    def extract_features(self, point_cloud, target):
+        """
+        Extract the feature value(s) of the point cloud at location of the target.
+        :param point_cloud:
+        :param target:
+        :return:
+        """
+        NotImplementedError("Class %s doesn't implement aMethod()" % (self.__class__.__name__))