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nerfstudio/mattport/nerf/sampler.py
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Python

"""
Collection of sampling strategies
"""
from typing import NamedTuple
from torchtyping import TensorType
from torch import nn
import torch
import nerf.cameras as cameras
RaySamples = NamedTuple(
"RaySamples", [("locations", TensorType[..., "num_samples", 3]), ("deltas", TensorType[..., "num_samples"])]
)
class Sampler(nn.Module):
"""Base Sampler. Intended to be subclassed"""
def __init__(self, near_plane: float, far_plane: float, num_samples: int) -> None:
"""Inialize sampler
Args:
near_plane (float): Minimum distance along ray to sample
far_plane (float): Maximum distance along ray to sample
num_samples (int): Number of samples per ray
"""
super().__init__()
self.near_plane = near_plane
self.far_plane = far_plane
self.num_samples = num_samples
def generate_samples(
self, camera_rays: cameras.Rays, near_plane: float, far_plane: float, num_samples: int
) -> RaySamples:
"""Encodes an input tensor.
Args:
camera_rays (cameras.Rays): Rays to generate samples for
TensorType[..., "output_dim"]: A encoded input tensor
near_plane (float): Minimum distance along ray to sample
far_plane (float): Maximum distance along ray to sample
num_samples (int): Number of samples per ray
Returns:
RaySamples: Positions and deltas for samples along a ray
"""
raise NotImplementedError
def forward(self, camera_rays: cameras.Rays, num_samples: int) -> TensorType[..., "num_samples", 3]:
"""Call forward"""
return self.Sampler(camera_rays, num_samples)
class UniformSampler(Sampler):
"""Base Sampler. Intended to be subclassed"""
def generate_samples(
self, camera_rays: cameras.Rays, near_plane: float, far_plane: float, num_samples: int
) -> TensorType[..., "num_samples", 3]:
"""Encodes an input tensor.
Args:
camera_rays (cameras.Rays): Rays to generate samples for
TensorType[..., "output_dim"]: A encoded input tensor
near_plane (float): Minimum distance along ray to sample
far_plane (float): Maximum distance along ray to sample
num_samples (int): Number of samples per ray
Returns:
RaySamples: Positions and deltas for samples along a ray
"""
near_plane = near_plane or self.near_plane
far_plane = far_plane or self.far_plane
num_samples = num_samples or self.num_samples
bins = torch.linspace(near_plane, far_plane, num_samples + 1)
positions = (bins[..., 1:] + bins[..., :-1]) / 2.0
deltas = bins[..., 1:] - bins[..., :-1]
return RaySamples(locations=positions, deltas=deltas)