Update README.txt

README.txt

@@ -7,7 +7,7 @@ T1.zip : Consists of images of time T1 i.e. changed image
 task_1_masks.zip: Consists of binary masks of task_1 i.e. Farm Pond Constructed and Farm Pond Demolished
 task_2_masks.zip: Consists of binary masks of task_2 i.e. Farm Pond Dried and Farm Pond Wetted
 task_3_masks.zip: Consists of binary masks of task_3 i.e. All 4 classes combined:  Farm Pond Constructed, Farm Pond Demolished, Farm Pond Dried and Farm Pond Wetted
-multi_class_masks.zip(new): Consists of indexed masks having each class pixel marked as an integer in the range 0-4, 
+multi_class_masks.zip(new):  Consists of indexed masks for multi class change detection. Each mask consists of pixels with values as an integer in the range 0-4, 
                             0 - Background, 1 - Farm Pond Constructed, 2 - Farm Pond Demolished, 3 - Farm Pond Dried and 4 - Farm Pond Wetted
 
 cd_dataset_train.txt: Contains file_names of train set to be taken from T0, T1 and masks of one of the tasks(task_1, task_2, task_3)