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nerfstudio/pyrad/nerf/image_sampler.py
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Ethan Weber 146332cfb6 Refactoring (data loading, semantic-nerf/nerf-w fixes, ...) (#8)
* in progress. camera_indices broken

* faster dataloader. starting on pixel sampler logic

* imagesampler and pixelsampler

* lint and black

* continuing merge

* pytest working

* fixed docs

* docs

* minor changes
2022-06-02 14:58:46 -04:00

76 lines
2.4 KiB
Python

"""
Code for sampling images.
"""
import random
import torch
from torch.utils.data import default_collate
from pyrad.utils.misc import get_dict_to_torch
class ImageSampler(torch.utils.data.IterableDataset):
"""Samples 'image_batch's."""
def __getitem__(self, idx):
raise NotImplementedError()
def __iter__(self):
raise NotImplementedError()
class CacheImageSampler(ImageSampler):
"""Collated image dataset that implements caching of images.
Creates batches of the ImageDataset return type.
"""
def __init__(
self,
dataset: torch.utils.data.Dataset,
num_samples_to_collate: int,
num_times_to_repeat_images: int = 0,
device="cpu",
):
super().__init__()
self.dataset = dataset
self.num_samples_to_collate = num_samples_to_collate
self.num_times_to_repeat_images = num_times_to_repeat_images
self.device = device
self.num_repeated = self.num_times_to_repeat_images # starting value
self.cached_collated_batch = None
self.first_time = True
def __getitem__(self, idx):
return self.dataset.__getitem__(idx)
def get_batch_list(self):
"""Returns a list of batches from the dataset attribute."""
indices = random.sample(range(len(self.dataset)), k=self.num_samples_to_collate)
batch_list = [self.dataset.__getitem__(idx) for idx in indices]
return batch_list
def get_collated_batch(self):
"""Returns a collated batch."""
batch_list = self.get_batch_list()
collated_batch = default_collate(batch_list)
collated_batch = get_dict_to_torch(collated_batch, device=self.device)
return collated_batch
def __iter__(self):
while True:
if self.first_time or (
self.num_times_to_repeat_images != -1 and self.num_repeated >= self.num_times_to_repeat_images
):
# trigger a reset
self.num_repeated = 0
collated_batch = self.get_collated_batch()
# possibly save a cached item
self.cached_collated_batch = collated_batch if self.num_times_to_repeat_images != 0 else None
self.first_time = False
else:
collated_batch = self.cached_collated_batch
self.num_repeated += 1
yield collated_batch