Source code for rastervision.pytorch_learner.dataset.visualizer.classification_visualizer

from typing import (Sequence, Optional)
from textwrap import wrap

import torch

from rastervision.pytorch_learner.dataset.visualizer import Visualizer  # NOQA
from rastervision.pytorch_learner.utils import (plot_channel_groups,

[docs]class ClassificationVisualizer(Visualizer): """Plots samples from image classification Datasets."""
[docs] def plot_xyz(self, axs: Sequence, x: torch.Tensor, y: int, z: Optional[int] = None) -> None: channel_groups = self.get_channel_display_groups(x.shape[1]) img_axes = axs[:-1] label_ax = axs[-1] # plot image imgs = channel_groups_to_imgs(x, channel_groups) plot_channel_groups(img_axes, imgs, channel_groups) # plot label class_names = self.class_names class_names = ['-\n-'.join(wrap(c, width=8)) for c in class_names] if z is None: # just display the class name as text class_name = class_names[y] label_ax.text( .5, .5, class_name, ha='center', va='center', fontdict={ 'size': 24, 'family': 'sans-serif' }) label_ax.set_xlim((0, 1)) label_ax.set_ylim((0, 1)) label_ax.axis('off') else: # display predicted class probabilities as a horizontal bar plot # legend: green = ground truth, dark-red = wrong prediction, # light-gray = other. In case predicted class matches ground truth, # only one bar will be green and the others will be light-gray. class_probabilities = z.softmax(dim=-1) class_index_pred = z.argmax(dim=-1) class_index_gt = y bar_colors = ['lightgray'] * len(z) if class_index_pred == class_index_gt: bar_colors[class_index_pred] = 'green' else: bar_colors[class_index_pred] = 'darkred' bar_colors[class_index_gt] = 'green' label_ax.barh( y=class_names, width=class_probabilities, color=bar_colors, edgecolor='black') label_ax.set_xlim((0, 1)) label_ax.xaxis.grid(linestyle='--', alpha=1) label_ax.set_xlabel('Probability') label_ax.set_title('Prediction')
[docs] def get_plot_ncols(self, **kwargs) -> int: x = kwargs['x'] nb_img_channels = x.shape[1] ncols = len(self.get_channel_display_groups(nb_img_channels)) + 1 return ncols