preprocessing.md

Preprocessing API

Spectral Indices

compute_ndvi

def compute_ndvi(nir: torch.Tensor, red: torch.Tensor) -> torch.Tensor

Computes Normalized Difference Vegetation Index.

$$\text{NDVI} = \frac{\text{NIR} - \text{Red}}{\text{NIR} + \text{Red}}$$

compute_ndwi

def compute_ndwi(green: torch.Tensor, nir: torch.Tensor) -> torch.Tensor

Computes Normalized Difference Water Index.

$$\text{NDWI} = \frac{\text{Green} - \text{NIR}}{\text{Green} + \text{NIR}}$$

Normalization

min_max_scale

def min_max_scale(
    tensor: torch.Tensor, 
    min_val: float, 
    max_val: float
) -> torch.Tensor

Scale values to [0, 1].

standardize

def standardize(
    tensor: torch.Tensor, 
    mean: list[float], 
    std: list[float]
) -> torch.Tensor

Z-score normalization.

$$z = \frac{x - \mu}{\sigma}$$