To set the stage: training and tuning. This means that we’re going to teach our model how to recognize different types of land cover by showing it a bunch of examples (called “training data”) and then testing its accuracy on new, unseen images (“test data”). To do this, we split the dataset into two parts:
– Training set: This is where the magic happens. We feed our model thousands of satellite images with their corresponding labels (e.g., forest, water, urban) and let it learn how to classify them based on certain features like color, texture, and shape. The goal here is to minimize the error rate between what the computer thinks should be classified as a particular land cover type versus what actually is.
– Test set: Once our model has been trained, we use this test data to see how well it can generalize to new images that it hasn’t seen before. This helps us evaluate its performance and identify any areas where it might need further improvement (e.g., if it consistently misclassifies certain types of land cover).
So let’s say we have a dataset with 10,000 satellite images labeled as either forest or non-forest. We split this into a training set of 8,000 and a test set of 2,000. During the training phase, our model will learn to distinguish between these two classes based on various features like color (green for forests) and texture (dense canopy vs. open fields). Once it’s done learning, we use the test data to see how well it performs on new images that it hasn’t seen before.
Now UNet specifically. This is a type of deep learning architecture designed for segmentation tasks (i.e., dividing an image into smaller segments and labeling each one). It consists of two main parts: the encoder, which compresses the input image to extract features at different scales; and the decoder, which expands these features back out to produce a segmented output.
The UNet model works by first passing our satellite images through several layers (called “convolutional” or “pooling”) that progressively reduce their size while preserving important features like edges and corners. This helps us identify patterns in the data that might be useful for classification purposes. Once we’ve extracted these features, we pass them through a series of fully connected layers to produce our final output (i.e., the predicted land cover type).
That’s how UNet works for land cover classification using satellite images. It might sound complicated at first, but once you break it down into simpler terms like “training” and “tuning,” it becomes a lot easier to understand.