utils.py

# MIT License

# Copyright (c) 2022 Intelligent Systems Lab Org

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# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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# File author: Shariq Farooq Bhat

import matplotlib
import matplotlib.cm
import numpy as np
import torch

def colorize(value, vmin=None, vmax=None, cmap='magma_r', invalid_val=-99, invalid_mask=None, background_color=(128, 128, 128, 255), gamma_corrected=False, value_transform=None):
    """Converts a depth map to a color image.

    Args:
        value (torch.Tensor, numpy.ndarry): Input depth map. Shape: (H, W) or (1, H, W) or (1, 1, H, W). All singular dimensions are squeezed
        vmin (float, optional): vmin-valued entries are mapped to start color of cmap. If None, value.min() is used. Defaults to None.
        vmax (float, optional):  vmax-valued entries are mapped to end color of cmap. If None, value.max() is used. Defaults to None.
        cmap (str, optional): matplotlib colormap to use. Defaults to 'magma_r'.
        invalid_val (int, optional): Specifies value of invalid pixels that should be colored as 'background_color'. Defaults to -99.
        invalid_mask (numpy.ndarray, optional): Boolean mask for invalid regions. Defaults to None.
        background_color (tuple[int], optional): 4-tuple RGB color to give to invalid pixels. Defaults to (128, 128, 128, 255).
        gamma_corrected (bool, optional): Apply gamma correction to colored image. Defaults to False.
        value_transform (Callable, optional): Apply transform function to valid pixels before coloring. Defaults to None.

    Returns:
        numpy.ndarray, dtype - uint8: Colored depth map. Shape: (H, W, 4)
    """
    if isinstance(value, torch.Tensor):
        value = value.detach().cpu().numpy()

    value = value.squeeze()
    if invalid_mask is None:
        invalid_mask = value == invalid_val
    mask = np.logical_not(invalid_mask)

    # normalize
    vmin = np.percentile(value[mask],2) if vmin is None else vmin
    vmax = np.percentile(value[mask],85) if vmax is None else vmax
    if vmin != vmax:
        value = (value - vmin) / (vmax - vmin)  # vmin..vmax
    else:
        # Avoid 0-division
        value = value * 0.

    # squeeze last dim if it exists
    # grey out the invalid values

    value[invalid_mask] = np.nan
    cmapper = matplotlib.cm.get_cmap(cmap)
    if value_transform:
        value = value_transform(value)
        # value = value / value.max()
    value = cmapper(value, bytes=True)  # (nxmx4)

    # img = value[:, :, :]
    img = value[...]
    img[invalid_mask] = background_color

    # return img.transpose((2, 0, 1))
    if gamma_corrected:
        # gamma correction
        img = img / 255
        img = np.power(img, 2.2)
        img = img * 255
        img = img.astype(np.uint8)
    return img