dronescapes / dronescapes_reader /npz_representation.py
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small changes to dronescapes_reader. Added initial support for norm/std
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"""MultiTask representations stored as .npz files on the disk"""
from __future__ import annotations
from pathlib import Path
import numpy as np
import torch as tr
class NpzRepresentation:
"""Generic Task with data read from/saved to npz files. Tries to read data as-is from disk and store it as well"""
def __init__(self, name: str):
self.name = name
def load_from_disk(self, path: Path) -> tr.Tensor:
"""Reads the npz data from the disk and transforms it properly"""
data = np.load(path, allow_pickle=False)
data = data if isinstance(data, np.ndarray) else data["arr_0"] # in case on npz, we need this as well
return tr.from_numpy(data) # can be uint8, float16, float32 etc.
def save_to_disk(self, data: tr.Tensor, path: Path):
"""stores this item to the disk which can then be loaded via `load_from_disk`"""
np.save(path, data.cpu().detach().numpy(), allow_pickle=False)
def plot_fn(self, x: tr.Tensor) -> np.ndarray:
"""very basic implementation of converting this representation to a viewable image. You should overwrite this"""
assert isinstance(x, tr.Tensor), type(x)
if len(x.shape) == 2:
x = x.unsqueeze(-1)
assert len(x.shape) == 3, x.shape # guaranteed to be (H, W, C) at this point
if x.shape[-1] != 3:
x = x[..., 0:1]
if x.shape[-1] == 1:
x = x.repeat(1, 1, 3)
x = x.nan_to_num(0).cpu().detach().numpy() # guaranteed to be (H, W, 3) at this point hopefully
_min, _max = x.min((0, 1), keepdims=True), x.max((0, 1), keepdims=True)
if x.dtype != np.uint8:
x = np.nan_to_num((x - _min) / (_max - _min) * 255, 0).astype(np.uint8)
return x
def normalize(self, x: tr.Tensor, x_min: tr.Tensor, x_max: tr.Tensor) -> tr.Tensor:
"""normalizes a data point read with self.load_from_disk(path) using external min/max information"""
return ((x - x_max) / (x_max - x_min)).nan_to_num(0, 0, 0)
def standardize(self, x: tr.Tensor, x_mean: tr.Tensor, x_std: tr.Tensor) -> tr.Tensor:
"""standardizes a data point read with self.load_from_disk(path) using external min/max information"""
return ((x - x_mean) / x_std).nan_to_num(0, 0, 0)
@property
def n_channels(self) -> int:
"""return the number of channels for this representation. Must be updated by each downstream representation"""
raise NotImplementedError(f"n_channels is not implemented for {self}")
def __repr__(self):
return str(self)
def __str__(self):
return f"{str(type(self)).split('.')[-1][0:-2]}({self.name})"