Source code for rastervision.core.data.raster_transformer.min_max_transformer

import numpy as np

from rastervision.core.data.raster_transformer import RasterTransformer


[docs]class MinMaxTransformer(RasterTransformer):
    """Transforms chips by scaling values in each channel to span 0-255."""

[docs]    def transform(self, chip: np.ndarray) -> np.ndarray:
        c = chip.shape[-1]
        pixels = chip.reshape(-1, c)
        channel_mins = pixels.min(axis=0)
        channel_maxs = pixels.max(axis=0)
        chip_normalized = (chip - channel_mins) / (channel_maxs - channel_mins)
        chip_normalized = (255 * chip_normalized).astype(np.uint8)
        return chip_normalized

[docs]    def get_out_dtype(self, in_dtype: np.dtype) -> np.dtype:
        return np.dtype(np.uint8)