image_framework_ymj/include/open3d/t/geometry/kernel/PointCloudImpl.h

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2024-12-06 16:25:16 +08:00
// ----------------------------------------------------------------------------
// - Open3D: www.open3d.org -
// ----------------------------------------------------------------------------
// Copyright (c) 2018-2023 www.open3d.org
// SPDX-License-Identifier: MIT
// ----------------------------------------------------------------------------
#include <atomic>
#include <vector>
#include "open3d/core/CUDAUtils.h"
#include "open3d/core/Dispatch.h"
#include "open3d/core/Dtype.h"
#include "open3d/core/MemoryManager.h"
#include "open3d/core/ParallelFor.h"
#include "open3d/core/SizeVector.h"
#include "open3d/core/Tensor.h"
#include "open3d/core/linalg/kernel/Matrix.h"
#include "open3d/core/linalg/kernel/SVD3x3.h"
#include "open3d/core/nns/NearestNeighborSearch.h"
#include "open3d/t/geometry/Utility.h"
#include "open3d/t/geometry/kernel/GeometryIndexer.h"
#include "open3d/t/geometry/kernel/GeometryMacros.h"
#include "open3d/t/geometry/kernel/PointCloud.h"
#include "open3d/utility/Logging.h"
namespace open3d {
namespace t {
namespace geometry {
namespace kernel {
namespace pointcloud {
#ifndef __CUDACC__
using std::abs;
using std::max;
using std::min;
using std::sqrt;
#endif
#if defined(__CUDACC__)
void UnprojectCUDA
#else
void UnprojectCPU
#endif
(const core::Tensor& depth,
utility::optional<std::reference_wrapper<const core::Tensor>>
image_colors,
core::Tensor& points,
utility::optional<std::reference_wrapper<core::Tensor>> colors,
const core::Tensor& intrinsics,
const core::Tensor& extrinsics,
float depth_scale,
float depth_max,
int64_t stride) {
const bool have_colors = image_colors.has_value();
NDArrayIndexer depth_indexer(depth, 2);
NDArrayIndexer image_colors_indexer;
core::Tensor pose = t::geometry::InverseTransformation(extrinsics);
TransformIndexer ti(intrinsics, pose, 1.0f);
// Output
int64_t rows_strided = depth_indexer.GetShape(0) / stride;
int64_t cols_strided = depth_indexer.GetShape(1) / stride;
points = core::Tensor({rows_strided * cols_strided, 3}, core::Float32,
depth.GetDevice());
NDArrayIndexer point_indexer(points, 1);
NDArrayIndexer colors_indexer;
if (have_colors) {
const auto& imcol = image_colors.value().get();
image_colors_indexer = NDArrayIndexer{imcol, 2};
colors.value().get() = core::Tensor({rows_strided * cols_strided, 3},
core::Float32, imcol.GetDevice());
colors_indexer = NDArrayIndexer(colors.value().get(), 1);
}
// Counter
#if defined(__CUDACC__)
core::Tensor count(std::vector<int>{0}, {}, core::Int32, depth.GetDevice());
int* count_ptr = count.GetDataPtr<int>();
#else
std::atomic<int> count_atomic(0);
std::atomic<int>* count_ptr = &count_atomic;
#endif
int64_t n = rows_strided * cols_strided;
DISPATCH_DTYPE_TO_TEMPLATE(depth.GetDtype(), [&]() {
core::ParallelFor(
depth.GetDevice(), n, [=] OPEN3D_DEVICE(int64_t workload_idx) {
int64_t y = (workload_idx / cols_strided) * stride;
int64_t x = (workload_idx % cols_strided) * stride;
float d = *depth_indexer.GetDataPtr<scalar_t>(x, y) /
depth_scale;
if (d > 0 && d < depth_max) {
int idx = OPEN3D_ATOMIC_ADD(count_ptr, 1);
float x_c = 0, y_c = 0, z_c = 0;
ti.Unproject(static_cast<float>(x),
static_cast<float>(y), d, &x_c, &y_c,
&z_c);
float* vertex = point_indexer.GetDataPtr<float>(idx);
ti.RigidTransform(x_c, y_c, z_c, vertex + 0, vertex + 1,
vertex + 2);
if (have_colors) {
float* pcd_pixel =
colors_indexer.GetDataPtr<float>(idx);
float* image_pixel =
image_colors_indexer.GetDataPtr<float>(x,
y);
*pcd_pixel = *image_pixel;
*(pcd_pixel + 1) = *(image_pixel + 1);
*(pcd_pixel + 2) = *(image_pixel + 2);
}
}
});
});
#if defined(__CUDACC__)
int total_pts_count = count.Item<int>();
#else
int total_pts_count = (*count_ptr).load();
#endif
#ifdef __CUDACC__
core::cuda::Synchronize();
#endif
points = points.Slice(0, 0, total_pts_count);
if (have_colors) {
colors.value().get() =
colors.value().get().Slice(0, 0, total_pts_count);
}
}
#if defined(__CUDACC__)
void GetPointMaskWithinAABBCUDA
#else
void GetPointMaskWithinAABBCPU
#endif
(const core::Tensor& points,
const core::Tensor& min_bound,
const core::Tensor& max_bound,
core::Tensor& mask) {
DISPATCH_FLOAT_DTYPE_TO_TEMPLATE(points.GetDtype(), [&]() {
const scalar_t* points_ptr = points.GetDataPtr<scalar_t>();
const int64_t n = points.GetLength();
const scalar_t* min_bound_ptr = min_bound.GetDataPtr<scalar_t>();
const scalar_t* max_bound_ptr = max_bound.GetDataPtr<scalar_t>();
bool* mask_ptr = mask.GetDataPtr<bool>();
core::ParallelFor(
points.GetDevice(), n, [=] OPEN3D_DEVICE(int64_t workload_idx) {
const scalar_t x = points_ptr[3 * workload_idx + 0];
const scalar_t y = points_ptr[3 * workload_idx + 1];
const scalar_t z = points_ptr[3 * workload_idx + 2];
if (x >= min_bound_ptr[0] && x <= max_bound_ptr[0] &&
y >= min_bound_ptr[1] && y <= max_bound_ptr[1] &&
z >= min_bound_ptr[2] && z <= max_bound_ptr[2]) {
mask_ptr[workload_idx] = true;
} else {
mask_ptr[workload_idx] = false;
}
});
});
}
#if defined(__CUDACC__)
void GetPointMaskWithinOBBCUDA
#else
void GetPointMaskWithinOBBCPU
#endif
(const core::Tensor& points,
const core::Tensor& center,
const core::Tensor& rotation,
const core::Tensor& extent,
core::Tensor& mask) {
const core::Tensor half_extent = extent.Div(2);
// Since we will extract 3 rotation axis from matrix and use it inside
// kernel, the transpose is needed.
const core::Tensor rotation_t = rotation.Transpose(0, 1).Contiguous();
const core::Tensor pd = points - center;
const int64_t n = points.GetLength();
DISPATCH_FLOAT_DTYPE_TO_TEMPLATE(points.GetDtype(), [&]() {
const scalar_t* pd_ptr = pd.GetDataPtr<scalar_t>();
// const scalar_t* center_ptr = center.GetDataPtr<scalar_t>();
const scalar_t* rotation_ptr = rotation_t.GetDataPtr<scalar_t>();
const scalar_t* half_extent_ptr = half_extent.GetDataPtr<scalar_t>();
bool* mask_ptr = mask.GetDataPtr<bool>();
core::ParallelFor(points.GetDevice(), n,
[=] OPEN3D_DEVICE(int64_t workload_idx) {
int64_t idx = 3 * workload_idx;
if (abs(core::linalg::kernel::dot_3x1(
pd_ptr + idx, rotation_ptr)) <=
half_extent_ptr[0] &&
abs(core::linalg::kernel::dot_3x1(
pd_ptr + idx, rotation_ptr + 3)) <=
half_extent_ptr[1] &&
abs(core::linalg::kernel::dot_3x1(
pd_ptr + idx, rotation_ptr + 6)) <=
half_extent_ptr[2]) {
mask_ptr[workload_idx] = true;
} else {
mask_ptr[workload_idx] = false;
}
});
});
}
#if defined(__CUDACC__)
void NormalizeNormalsCUDA
#else
void NormalizeNormalsCPU
#endif
(core::Tensor& normals) {
const core::Dtype dtype = normals.GetDtype();
const int64_t n = normals.GetLength();
DISPATCH_FLOAT_DTYPE_TO_TEMPLATE(dtype, [&]() {
scalar_t* ptr = normals.GetDataPtr<scalar_t>();
core::ParallelFor(normals.GetDevice(), n,
[=] OPEN3D_DEVICE(int64_t workload_idx) {
int64_t idx = 3 * workload_idx;
scalar_t x = ptr[idx];
scalar_t y = ptr[idx + 1];
scalar_t z = ptr[idx + 2];
scalar_t norm = sqrt(x * x + y * y + z * z);
if (norm > 0) {
x /= norm;
y /= norm;
z /= norm;
}
ptr[idx] = x;
ptr[idx + 1] = y;
ptr[idx + 2] = z;
});
});
}
#if defined(__CUDACC__)
void OrientNormalsToAlignWithDirectionCUDA
#else
void OrientNormalsToAlignWithDirectionCPU
#endif
(core::Tensor& normals, const core::Tensor& direction) {
const core::Dtype dtype = normals.GetDtype();
const int64_t n = normals.GetLength();
DISPATCH_FLOAT_DTYPE_TO_TEMPLATE(dtype, [&]() {
scalar_t* ptr = normals.GetDataPtr<scalar_t>();
const scalar_t* direction_ptr = direction.GetDataPtr<scalar_t>();
core::ParallelFor(normals.GetDevice(), n,
[=] OPEN3D_DEVICE(int64_t workload_idx) {
int64_t idx = 3 * workload_idx;
scalar_t* normal = ptr + idx;
const scalar_t norm = sqrt(normal[0] * normal[0] +
normal[1] * normal[1] +
normal[2] * normal[2]);
if (norm == 0.0) {
normal[0] = direction_ptr[0];
normal[1] = direction_ptr[1];
normal[2] = direction_ptr[2];
} else if (core::linalg::kernel::dot_3x1(
normal, direction_ptr) < 0) {
normal[0] *= -1;
normal[1] *= -1;
normal[2] *= -1;
}
});
});
}
#if defined(__CUDACC__)
void OrientNormalsTowardsCameraLocationCUDA
#else
void OrientNormalsTowardsCameraLocationCPU
#endif
(const core::Tensor& points,
core::Tensor& normals,
const core::Tensor& camera) {
const core::Dtype dtype = points.GetDtype();
const int64_t n = normals.GetLength();
DISPATCH_FLOAT_DTYPE_TO_TEMPLATE(dtype, [&]() {
scalar_t* normals_ptr = normals.GetDataPtr<scalar_t>();
const scalar_t* camera_ptr = camera.GetDataPtr<scalar_t>();
const scalar_t* points_ptr = points.GetDataPtr<scalar_t>();
core::ParallelFor(
normals.GetDevice(), n,
[=] OPEN3D_DEVICE(int64_t workload_idx) {
int64_t idx = 3 * workload_idx;
scalar_t* normal = normals_ptr + idx;
const scalar_t* point = points_ptr + idx;
const scalar_t reference[3] = {camera_ptr[0] - point[0],
camera_ptr[1] - point[1],
camera_ptr[2] - point[2]};
const scalar_t norm =
sqrt(normal[0] * normal[0] + normal[1] * normal[1] +
normal[2] * normal[2]);
if (norm == 0.0) {
normal[0] = reference[0];
normal[1] = reference[1];
normal[2] = reference[2];
const scalar_t norm_new = sqrt(normal[0] * normal[0] +
normal[1] * normal[1] +
normal[2] * normal[2]);
if (norm_new == 0.0) {
normal[0] = 0.0;
normal[1] = 0.0;
normal[2] = 1.0;
} else {
normal[0] /= norm_new;
normal[1] /= norm_new;
normal[2] /= norm_new;
}
} else if (core::linalg::kernel::dot_3x1(normal,
reference) < 0) {
normal[0] *= -1;
normal[1] *= -1;
normal[2] *= -1;
}
});
});
}
template <typename scalar_t>
OPEN3D_HOST_DEVICE void GetCoordinateSystemOnPlane(const scalar_t* query,
scalar_t* u,
scalar_t* v) {
// Unless the x and y coords are both close to zero, we can simply take
// ( -y, x, 0 ) and normalize it. If both x and y are close to zero,
// then the vector is close to the z-axis, so it's far from colinear to
// the x-axis for instance. So we take the crossed product with (1,0,0)
// and normalize it.
if (!(abs(query[0] - query[2]) < 1e-6) ||
!(abs(query[1] - query[2]) < 1e-6)) {
const scalar_t norm2_inv =
1.0 / sqrt(query[0] * query[0] + query[1] * query[1]);
v[0] = -1 * query[1] * norm2_inv;
v[1] = query[0] * norm2_inv;
v[2] = 0;
} else {
const scalar_t norm2_inv =
1.0 / sqrt(query[1] * query[1] + query[2] * query[2]);
v[0] = 0;
v[1] = -1 * query[2] * norm2_inv;
v[2] = query[1] * norm2_inv;
}
core::linalg::kernel::cross_3x1(query, v, u);
}
template <typename scalar_t>
inline OPEN3D_HOST_DEVICE void Swap(scalar_t* x, scalar_t* y) {
scalar_t tmp = *x;
*x = *y;
*y = tmp;
}
template <typename scalar_t>
inline OPEN3D_HOST_DEVICE void Heapify(scalar_t* arr, int n, int root) {
int largest = root;
int l = 2 * root + 1;
int r = 2 * root + 2;
if (l < n && arr[l] > arr[largest]) {
largest = l;
}
if (r < n && arr[r] > arr[largest]) {
largest = r;
}
if (largest != root) {
Swap<scalar_t>(&arr[root], &arr[largest]);
Heapify<scalar_t>(arr, n, largest);
}
}
template <typename scalar_t>
OPEN3D_HOST_DEVICE void HeapSort(scalar_t* arr, int n) {
for (int i = n / 2 - 1; i >= 0; i--) Heapify(arr, n, i);
for (int i = n - 1; i > 0; i--) {
Swap<scalar_t>(&arr[0], &arr[i]);
Heapify<scalar_t>(arr, i, 0);
}
}
template <typename scalar_t>
OPEN3D_HOST_DEVICE bool IsBoundaryPoints(const scalar_t* angles,
int counts,
double angle_threshold) {
scalar_t diff;
scalar_t max_diff = 0;
// Compute the maximal angle difference between two consecutive angles.
for (int i = 0; i < counts - 1; i++) {
diff = angles[i + 1] - angles[i];
max_diff = max(max_diff, diff);
}
// Get the angle difference between the last and the first.
diff = 2 * M_PI - angles[counts - 1] + angles[0];
max_diff = max(max_diff, diff);
return max_diff > angle_threshold * M_PI / 180.0 ? true : false;
}
#if defined(__CUDACC__)
void ComputeBoundaryPointsCUDA
#else
void ComputeBoundaryPointsCPU
#endif
(const core::Tensor& points,
const core::Tensor& normals,
const core::Tensor& indices,
const core::Tensor& counts,
core::Tensor& mask,
double angle_threshold) {
const int nn_size = indices.GetShape()[1];
DISPATCH_FLOAT_DTYPE_TO_TEMPLATE(points.GetDtype(), [&]() {
const scalar_t* points_ptr = points.GetDataPtr<scalar_t>();
const scalar_t* normals_ptr = normals.GetDataPtr<scalar_t>();
const int64_t n = points.GetLength();
const int32_t* indices_ptr = indices.GetDataPtr<int32_t>();
const int32_t* counts_ptr = counts.GetDataPtr<int32_t>();
bool* mask_ptr = mask.GetDataPtr<bool>();
core::Tensor angles = core::Tensor::Full(
indices.GetShape(), -10, points.GetDtype(), points.GetDevice());
scalar_t* angles_ptr = angles.GetDataPtr<scalar_t>();
core::ParallelFor(
points.GetDevice(), n, [=] OPEN3D_DEVICE(int64_t workload_idx) {
scalar_t u[3], v[3];
GetCoordinateSystemOnPlane(normals_ptr + 3 * workload_idx,
u, v);
// Ignore the point itself.
int indices_size = counts_ptr[workload_idx] - 1;
if (indices_size > 0) {
const scalar_t* query = points_ptr + 3 * workload_idx;
for (int i = 1; i < indices_size + 1; i++) {
const int idx = workload_idx * nn_size + i;
const scalar_t* point_ref =
points_ptr + 3 * indices_ptr[idx];
const scalar_t delta[3] = {point_ref[0] - query[0],
point_ref[1] - query[1],
point_ref[2] - query[2]};
const scalar_t angle = atan2(
core::linalg::kernel::dot_3x1(v, delta),
core::linalg::kernel::dot_3x1(u, delta));
angles_ptr[idx] = angle;
}
// Sort the angles in ascending order.
HeapSort<scalar_t>(
angles_ptr + workload_idx * nn_size + 1,
indices_size);
mask_ptr[workload_idx] = IsBoundaryPoints<scalar_t>(
angles_ptr + workload_idx * nn_size + 1,
indices_size, angle_threshold);
}
});
});
}
// This is a `two-pass` estimate method for covariance which is numerically more
// robust than the `textbook` method generally used for covariance computation.
template <typename scalar_t>
OPEN3D_HOST_DEVICE void EstimatePointWiseRobustNormalizedCovarianceKernel(
const scalar_t* points_ptr,
const int32_t* indices_ptr,
const int32_t& indices_count,
scalar_t* covariance_ptr) {
if (indices_count < 3) {
covariance_ptr[0] = 1.0;
covariance_ptr[1] = 0.0;
covariance_ptr[2] = 0.0;
covariance_ptr[3] = 0.0;
covariance_ptr[4] = 1.0;
covariance_ptr[5] = 0.0;
covariance_ptr[6] = 0.0;
covariance_ptr[7] = 0.0;
covariance_ptr[8] = 1.0;
return;
}
double centroid[3] = {0};
for (int32_t i = 0; i < indices_count; ++i) {
int32_t idx = 3 * indices_ptr[i];
centroid[0] += points_ptr[idx];
centroid[1] += points_ptr[idx + 1];
centroid[2] += points_ptr[idx + 2];
}
centroid[0] /= indices_count;
centroid[1] /= indices_count;
centroid[2] /= indices_count;
// cumulants must always be Float64 to ensure precision.
double cumulants[6] = {0};
for (int32_t i = 0; i < indices_count; ++i) {
int32_t idx = 3 * indices_ptr[i];
const double x = static_cast<double>(points_ptr[idx]) - centroid[0];
const double y = static_cast<double>(points_ptr[idx + 1]) - centroid[1];
const double z = static_cast<double>(points_ptr[idx + 2]) - centroid[2];
cumulants[0] += x * x;
cumulants[1] += y * y;
cumulants[2] += z * z;
cumulants[3] += x * y;
cumulants[4] += x * z;
cumulants[5] += y * z;
}
// Using Bessel's correction (dividing by (n - 1) instead of n).
// Refer:
// https://en.wikipedia.org/wiki/Algorithms_for_calculating_variance
const double normalization_factor = static_cast<double>(indices_count - 1);
for (int i = 0; i < 6; ++i) {
cumulants[i] /= normalization_factor;
}
// Covariances(0, 0)
covariance_ptr[0] = static_cast<scalar_t>(cumulants[0]);
// Covariances(1, 1)
covariance_ptr[4] = static_cast<scalar_t>(cumulants[1]);
// Covariances(2, 2)
covariance_ptr[8] = static_cast<scalar_t>(cumulants[2]);
// Covariances(0, 1) = Covariances(1, 0)
covariance_ptr[1] = static_cast<scalar_t>(cumulants[3]);
covariance_ptr[3] = covariance_ptr[1];
// Covariances(0, 2) = Covariances(2, 0)
covariance_ptr[2] = static_cast<scalar_t>(cumulants[4]);
covariance_ptr[6] = covariance_ptr[2];
// Covariances(1, 2) = Covariances(2, 1)
covariance_ptr[5] = static_cast<scalar_t>(cumulants[5]);
covariance_ptr[7] = covariance_ptr[5];
}
#if defined(__CUDACC__)
void EstimateCovariancesUsingHybridSearchCUDA
#else
void EstimateCovariancesUsingHybridSearchCPU
#endif
(const core::Tensor& points,
core::Tensor& covariances,
const double& radius,
const int64_t& max_nn) {
core::Dtype dtype = points.GetDtype();
int64_t n = points.GetLength();
core::nns::NearestNeighborSearch tree(points, core::Int32);
bool check = tree.HybridIndex(radius);
if (!check) {
utility::LogError("Building FixedRadiusIndex failed.");
}
core::Tensor indices, distance, counts;
std::tie(indices, distance, counts) =
tree.HybridSearch(points, radius, max_nn);
DISPATCH_FLOAT_DTYPE_TO_TEMPLATE(dtype, [&]() {
const scalar_t* points_ptr = points.GetDataPtr<scalar_t>();
int32_t* neighbour_indices_ptr = indices.GetDataPtr<int32_t>();
int32_t* neighbour_counts_ptr = counts.GetDataPtr<int32_t>();
scalar_t* covariances_ptr = covariances.GetDataPtr<scalar_t>();
core::ParallelFor(
points.GetDevice(), n, [=] OPEN3D_DEVICE(int64_t workload_idx) {
// NNS [Hybrid Search].
const int32_t neighbour_offset = max_nn * workload_idx;
// Count of valid correspondences per point.
const int32_t neighbour_count =
neighbour_counts_ptr[workload_idx];
// Covariance is of shape {3, 3}, so it has an
// offset factor of 9 x workload_idx.
const int32_t covariances_offset = 9 * workload_idx;
EstimatePointWiseRobustNormalizedCovarianceKernel(
points_ptr,
neighbour_indices_ptr + neighbour_offset,
neighbour_count,
covariances_ptr + covariances_offset);
});
});
core::cuda::Synchronize(points.GetDevice());
}
#if defined(__CUDACC__)
void EstimateCovariancesUsingRadiusSearchCUDA
#else
void EstimateCovariancesUsingRadiusSearchCPU
#endif
(const core::Tensor& points,
core::Tensor& covariances,
const double& radius) {
core::Dtype dtype = points.GetDtype();
int64_t n = points.GetLength();
core::nns::NearestNeighborSearch tree(points, core::Int32);
bool check = tree.FixedRadiusIndex(radius);
if (!check) {
utility::LogError("Building Radius-Index failed.");
}
core::Tensor indices, distance, counts;
std::tie(indices, distance, counts) =
tree.FixedRadiusSearch(points, radius);
DISPATCH_FLOAT_DTYPE_TO_TEMPLATE(dtype, [&]() {
const scalar_t* points_ptr = points.GetDataPtr<scalar_t>();
const int32_t* neighbour_indices_ptr = indices.GetDataPtr<int32_t>();
const int32_t* neighbour_counts_ptr = counts.GetDataPtr<int32_t>();
scalar_t* covariances_ptr = covariances.GetDataPtr<scalar_t>();
core::ParallelFor(
points.GetDevice(), n, [=] OPEN3D_DEVICE(int64_t workload_idx) {
const int32_t neighbour_offset =
neighbour_counts_ptr[workload_idx];
const int32_t neighbour_count =
(neighbour_counts_ptr[workload_idx + 1] -
neighbour_counts_ptr[workload_idx]);
// Covariance is of shape {3, 3}, so it has an offset
// factor of 9 x workload_idx.
const int32_t covariances_offset = 9 * workload_idx;
EstimatePointWiseRobustNormalizedCovarianceKernel(
points_ptr,
neighbour_indices_ptr + neighbour_offset,
neighbour_count,
covariances_ptr + covariances_offset);
});
});
core::cuda::Synchronize(points.GetDevice());
}
#if defined(__CUDACC__)
void EstimateCovariancesUsingKNNSearchCUDA
#else
void EstimateCovariancesUsingKNNSearchCPU
#endif
(const core::Tensor& points,
core::Tensor& covariances,
const int64_t& max_nn) {
core::Dtype dtype = points.GetDtype();
int64_t n = points.GetLength();
core::nns::NearestNeighborSearch tree(points, core::Int32);
bool check = tree.KnnIndex();
if (!check) {
utility::LogError("Building KNN-Index failed.");
}
core::Tensor indices, distance;
std::tie(indices, distance) = tree.KnnSearch(points, max_nn);
indices = indices.Contiguous();
int32_t nn_count = static_cast<int32_t>(indices.GetShape()[1]);
if (nn_count < 3) {
utility::LogError(
"Not enough neighbors to compute Covariances / Normals. "
"Try "
"increasing the max_nn parameter.");
}
DISPATCH_FLOAT_DTYPE_TO_TEMPLATE(dtype, [&]() {
auto points_ptr = points.GetDataPtr<scalar_t>();
auto neighbour_indices_ptr = indices.GetDataPtr<int32_t>();
auto covariances_ptr = covariances.GetDataPtr<scalar_t>();
core::ParallelFor(
points.GetDevice(), n, [=] OPEN3D_DEVICE(int64_t workload_idx) {
// NNS [KNN Search].
const int32_t neighbour_offset = nn_count * workload_idx;
// Covariance is of shape {3, 3}, so it has an offset
// factor of 9 x workload_idx.
const int32_t covariances_offset = 9 * workload_idx;
EstimatePointWiseRobustNormalizedCovarianceKernel(
points_ptr,
neighbour_indices_ptr + neighbour_offset, nn_count,
covariances_ptr + covariances_offset);
});
});
core::cuda::Synchronize(points.GetDevice());
}
template <typename scalar_t>
OPEN3D_HOST_DEVICE void ComputeEigenvector0(const scalar_t* A,
const scalar_t eval0,
scalar_t* eigen_vector0) {
scalar_t row0[3] = {A[0] - eval0, A[1], A[2]};
scalar_t row1[3] = {A[1], A[4] - eval0, A[5]};
scalar_t row2[3] = {A[2], A[5], A[8] - eval0};
scalar_t r0xr1[3], r0xr2[3], r1xr2[3];
core::linalg::kernel::cross_3x1(row0, row1, r0xr1);
core::linalg::kernel::cross_3x1(row0, row2, r0xr2);
core::linalg::kernel::cross_3x1(row1, row2, r1xr2);
scalar_t d0 = core::linalg::kernel::dot_3x1(r0xr1, r0xr1);
scalar_t d1 = core::linalg::kernel::dot_3x1(r0xr2, r0xr2);
scalar_t d2 = core::linalg::kernel::dot_3x1(r1xr2, r1xr2);
scalar_t dmax = d0;
int imax = 0;
if (d1 > dmax) {
dmax = d1;
imax = 1;
}
if (d2 > dmax) {
imax = 2;
}
if (imax == 0) {
scalar_t sqrt_d = sqrt(d0);
eigen_vector0[0] = r0xr1[0] / sqrt_d;
eigen_vector0[1] = r0xr1[1] / sqrt_d;
eigen_vector0[2] = r0xr1[2] / sqrt_d;
return;
} else if (imax == 1) {
scalar_t sqrt_d = sqrt(d1);
eigen_vector0[0] = r0xr2[0] / sqrt_d;
eigen_vector0[1] = r0xr2[1] / sqrt_d;
eigen_vector0[2] = r0xr2[2] / sqrt_d;
return;
} else {
scalar_t sqrt_d = sqrt(d2);
eigen_vector0[0] = r1xr2[0] / sqrt_d;
eigen_vector0[1] = r1xr2[1] / sqrt_d;
eigen_vector0[2] = r1xr2[2] / sqrt_d;
return;
}
}
template <typename scalar_t>
OPEN3D_HOST_DEVICE void ComputeEigenvector1(const scalar_t* A,
const scalar_t* evec0,
const scalar_t eval1,
scalar_t* eigen_vector1) {
scalar_t U[3];
if (abs(evec0[0]) > abs(evec0[1])) {
scalar_t inv_length =
1.0 / sqrt(evec0[0] * evec0[0] + evec0[2] * evec0[2]);
U[0] = -evec0[2] * inv_length;
U[1] = 0.0;
U[2] = evec0[0] * inv_length;
} else {
scalar_t inv_length =
1.0 / sqrt(evec0[1] * evec0[1] + evec0[2] * evec0[2]);
U[0] = 0.0;
U[1] = evec0[2] * inv_length;
U[2] = -evec0[1] * inv_length;
}
scalar_t V[3], AU[3], AV[3];
core::linalg::kernel::cross_3x1(evec0, U, V);
core::linalg::kernel::matmul3x3_3x1(A, U, AU);
core::linalg::kernel::matmul3x3_3x1(A, V, AV);
scalar_t m00 = core::linalg::kernel::dot_3x1(U, AU) - eval1;
scalar_t m01 = core::linalg::kernel::dot_3x1(U, AV);
scalar_t m11 = core::linalg::kernel::dot_3x1(V, AV) - eval1;
scalar_t absM00 = abs(m00);
scalar_t absM01 = abs(m01);
scalar_t absM11 = abs(m11);
scalar_t max_abs_comp;
if (absM00 >= absM11) {
max_abs_comp = max(absM00, absM01);
if (max_abs_comp > 0) {
if (absM00 >= absM01) {
m01 /= m00;
m00 = 1 / sqrt(1 + m01 * m01);
m01 *= m00;
} else {
m00 /= m01;
m01 = 1 / sqrt(1 + m00 * m00);
m00 *= m01;
}
eigen_vector1[0] = m01 * U[0] - m00 * V[0];
eigen_vector1[1] = m01 * U[1] - m00 * V[1];
eigen_vector1[2] = m01 * U[2] - m00 * V[2];
return;
} else {
eigen_vector1[0] = U[0];
eigen_vector1[1] = U[1];
eigen_vector1[2] = U[2];
return;
}
} else {
max_abs_comp = max(absM11, absM01);
if (max_abs_comp > 0) {
if (absM11 >= absM01) {
m01 /= m11;
m11 = 1 / sqrt(1 + m01 * m01);
m01 *= m11;
} else {
m11 /= m01;
m01 = 1 / sqrt(1 + m11 * m11);
m11 *= m01;
}
eigen_vector1[0] = m11 * U[0] - m01 * V[0];
eigen_vector1[1] = m11 * U[1] - m01 * V[1];
eigen_vector1[2] = m11 * U[2] - m01 * V[2];
return;
} else {
eigen_vector1[0] = U[0];
eigen_vector1[1] = U[1];
eigen_vector1[2] = U[2];
return;
}
}
}
template <typename scalar_t>
OPEN3D_HOST_DEVICE void EstimatePointWiseNormalsWithFastEigen3x3(
const scalar_t* covariance_ptr, scalar_t* normals_ptr) {
// Based on:
// https://www.geometrictools.com/Documentation/RobustEigenSymmetric3x3.pdf
// which handles edge cases like points on a plane.
scalar_t max_coeff = covariance_ptr[0];
for (int i = 1; i < 9; ++i) {
if (max_coeff < covariance_ptr[i]) {
max_coeff = covariance_ptr[i];
}
}
if (max_coeff == 0) {
normals_ptr[0] = 0.0;
normals_ptr[1] = 0.0;
normals_ptr[2] = 0.0;
return;
}
scalar_t A[9] = {0};
for (int i = 0; i < 9; ++i) {
A[i] = covariance_ptr[i] / max_coeff;
}
scalar_t norm = A[1] * A[1] + A[2] * A[2] + A[5] * A[5];
if (norm > 0) {
scalar_t eval[3];
scalar_t evec0[3];
scalar_t evec1[3];
scalar_t evec2[3];
scalar_t q = (A[0] + A[4] + A[8]) / 3.0;
scalar_t b00 = A[0] - q;
scalar_t b11 = A[4] - q;
scalar_t b22 = A[8] - q;
scalar_t p =
sqrt((b00 * b00 + b11 * b11 + b22 * b22 + norm * 2.0) / 6.0);
scalar_t c00 = b11 * b22 - A[5] * A[5];
scalar_t c01 = A[1] * b22 - A[5] * A[2];
scalar_t c02 = A[1] * A[5] - b11 * A[2];
scalar_t det = (b00 * c00 - A[1] * c01 + A[2] * c02) / (p * p * p);
scalar_t half_det = det * 0.5;
half_det = min(max(half_det, static_cast<scalar_t>(-1.0)),
static_cast<scalar_t>(1.0));
scalar_t angle = acos(half_det) / 3.0;
const scalar_t two_thrids_pi = 2.09439510239319549;
scalar_t beta2 = cos(angle) * 2.0;
scalar_t beta0 = cos(angle + two_thrids_pi) * 2.0;
scalar_t beta1 = -(beta0 + beta2);
eval[0] = q + p * beta0;
eval[1] = q + p * beta1;
eval[2] = q + p * beta2;
if (half_det >= 0) {
ComputeEigenvector0<scalar_t>(A, eval[2], evec2);
if (eval[2] < eval[0] && eval[2] < eval[1]) {
normals_ptr[0] = evec2[0];
normals_ptr[1] = evec2[1];
normals_ptr[2] = evec2[2];
return;
}
ComputeEigenvector1<scalar_t>(A, evec2, eval[1], evec1);
if (eval[1] < eval[0] && eval[1] < eval[2]) {
normals_ptr[0] = evec1[0];
normals_ptr[1] = evec1[1];
normals_ptr[2] = evec1[2];
return;
}
normals_ptr[0] = evec1[1] * evec2[2] - evec1[2] * evec2[1];
normals_ptr[1] = evec1[2] * evec2[0] - evec1[0] * evec2[2];
normals_ptr[2] = evec1[0] * evec2[1] - evec1[1] * evec2[0];
return;
} else {
ComputeEigenvector0<scalar_t>(A, eval[0], evec0);
if (eval[0] < eval[1] && eval[0] < eval[2]) {
normals_ptr[0] = evec0[0];
normals_ptr[1] = evec0[1];
normals_ptr[2] = evec0[2];
return;
}
ComputeEigenvector1<scalar_t>(A, evec0, eval[1], evec1);
if (eval[1] < eval[0] && eval[1] < eval[2]) {
normals_ptr[0] = evec1[0];
normals_ptr[1] = evec1[1];
normals_ptr[2] = evec1[2];
return;
}
normals_ptr[0] = evec0[1] * evec1[2] - evec0[2] * evec1[1];
normals_ptr[1] = evec0[2] * evec1[0] - evec0[0] * evec1[2];
normals_ptr[2] = evec0[0] * evec1[1] - evec0[1] * evec1[0];
return;
}
} else {
if (covariance_ptr[0] < covariance_ptr[4] &&
covariance_ptr[0] < covariance_ptr[8]) {
normals_ptr[0] = 1.0;
normals_ptr[1] = 0.0;
normals_ptr[2] = 0.0;
return;
} else if (covariance_ptr[0] < covariance_ptr[4] &&
covariance_ptr[0] < covariance_ptr[8]) {
normals_ptr[0] = 0.0;
normals_ptr[1] = 1.0;
normals_ptr[2] = 0.0;
return;
} else {
normals_ptr[0] = 0.0;
normals_ptr[1] = 0.0;
normals_ptr[2] = 1.0;
return;
}
}
}
#if defined(__CUDACC__)
void EstimateNormalsFromCovariancesCUDA
#else
void EstimateNormalsFromCovariancesCPU
#endif
(const core::Tensor& covariances,
core::Tensor& normals,
const bool has_normals) {
core::Dtype dtype = covariances.GetDtype();
int64_t n = covariances.GetLength();
DISPATCH_FLOAT_DTYPE_TO_TEMPLATE(dtype, [&]() {
const scalar_t* covariances_ptr = covariances.GetDataPtr<scalar_t>();
scalar_t* normals_ptr = normals.GetDataPtr<scalar_t>();
core::ParallelFor(
covariances.GetDevice(), n,
[=] OPEN3D_DEVICE(int64_t workload_idx) {
int32_t covariances_offset = 9 * workload_idx;
int32_t normals_offset = 3 * workload_idx;
scalar_t normals_output[3] = {0};
EstimatePointWiseNormalsWithFastEigen3x3<scalar_t>(
covariances_ptr + covariances_offset,
normals_output);
if ((normals_output[0] * normals_output[0] +
normals_output[1] * normals_output[1] +
normals_output[2] * normals_output[2]) == 0.0 &&
!has_normals) {
normals_output[0] = 0.0;
normals_output[1] = 0.0;
normals_output[2] = 1.0;
}
if (has_normals) {
if ((normals_ptr[normals_offset] * normals_output[0] +
normals_ptr[normals_offset + 1] *
normals_output[1] +
normals_ptr[normals_offset + 2] *
normals_output[2]) < 0.0) {
normals_output[0] *= -1;
normals_output[1] *= -1;
normals_output[2] *= -1;
}
}
normals_ptr[normals_offset] = normals_output[0];
normals_ptr[normals_offset + 1] = normals_output[1];
normals_ptr[normals_offset + 2] = normals_output[2];
});
});
core::cuda::Synchronize(covariances.GetDevice());
}
template <typename scalar_t>
OPEN3D_HOST_DEVICE void EstimatePointWiseColorGradientKernel(
const scalar_t* points_ptr,
const scalar_t* normals_ptr,
const scalar_t* colors_ptr,
const int32_t& idx_offset,
const int32_t* indices_ptr,
const int32_t& indices_count,
scalar_t* color_gradients_ptr) {
if (indices_count < 4) {
color_gradients_ptr[idx_offset] = 0;
color_gradients_ptr[idx_offset + 1] = 0;
color_gradients_ptr[idx_offset + 2] = 0;
} else {
scalar_t vt[3] = {points_ptr[idx_offset], points_ptr[idx_offset + 1],
points_ptr[idx_offset + 2]};
scalar_t nt[3] = {normals_ptr[idx_offset], normals_ptr[idx_offset + 1],
normals_ptr[idx_offset + 2]};
scalar_t it = (colors_ptr[idx_offset] + colors_ptr[idx_offset + 1] +
colors_ptr[idx_offset + 2]) /
3.0;
scalar_t AtA[9] = {0};
scalar_t Atb[3] = {0};
// approximate image gradient of vt's tangential plane
// projection (p') of a point p on a plane defined by
// normal n, where o is the closest point to p on the
// plane, is given by:
// p' = p - [(p - o).dot(n)] * n p'
// => p - [(p.dot(n) - s)] * n [where s = o.dot(n)]
// Computing the scalar s.
scalar_t s = vt[0] * nt[0] + vt[1] * nt[1] + vt[2] * nt[2];
int i = 1;
for (; i < indices_count; i++) {
int64_t neighbour_idx_offset = 3 * indices_ptr[i];
if (neighbour_idx_offset == -1) {
break;
}
scalar_t vt_adj[3] = {points_ptr[neighbour_idx_offset],
points_ptr[neighbour_idx_offset + 1],
points_ptr[neighbour_idx_offset + 2]};
// p' = p - d * n [where d = p.dot(n) - s]
// Computing the scalar d.
scalar_t d = vt_adj[0] * nt[0] + vt_adj[1] * nt[1] +
vt_adj[2] * nt[2] - s;
// Computing the p' (projection of the point).
scalar_t vt_proj[3] = {vt_adj[0] - d * nt[0], vt_adj[1] - d * nt[1],
vt_adj[2] - d * nt[2]};
scalar_t it_adj = (colors_ptr[neighbour_idx_offset + 0] +
colors_ptr[neighbour_idx_offset + 1] +
colors_ptr[neighbour_idx_offset + 2]) /
3.0;
scalar_t A[3] = {vt_proj[0] - vt[0], vt_proj[1] - vt[1],
vt_proj[2] - vt[2]};
AtA[0] += A[0] * A[0];
AtA[1] += A[1] * A[0];
AtA[2] += A[2] * A[0];
AtA[4] += A[1] * A[1];
AtA[5] += A[2] * A[1];
AtA[8] += A[2] * A[2];
scalar_t b = it_adj - it;
Atb[0] += A[0] * b;
Atb[1] += A[1] * b;
Atb[2] += A[2] * b;
}
// Orthogonal constraint.
scalar_t A[3] = {(i - 1) * nt[0], (i - 1) * nt[1], (i - 1) * nt[2]};
AtA[0] += A[0] * A[0];
AtA[1] += A[0] * A[1];
AtA[2] += A[0] * A[2];
AtA[4] += A[1] * A[1];
AtA[5] += A[1] * A[2];
AtA[8] += A[2] * A[2];
// Symmetry.
AtA[3] = AtA[1];
AtA[6] = AtA[2];
AtA[7] = AtA[5];
core::linalg::kernel::solve_svd3x3(AtA, Atb,
color_gradients_ptr + idx_offset);
}
}
#if defined(__CUDACC__)
void EstimateColorGradientsUsingHybridSearchCUDA
#else
void EstimateColorGradientsUsingHybridSearchCPU
#endif
(const core::Tensor& points,
const core::Tensor& normals,
const core::Tensor& colors,
core::Tensor& color_gradients,
const double& radius,
const int64_t& max_nn) {
core::Dtype dtype = points.GetDtype();
int64_t n = points.GetLength();
core::nns::NearestNeighborSearch tree(points, core::Int32);
bool check = tree.HybridIndex(radius);
if (!check) {
utility::LogError("NearestNeighborSearch::HybridIndex is not set.");
}
core::Tensor indices, distance, counts;
std::tie(indices, distance, counts) =
tree.HybridSearch(points, radius, max_nn);
DISPATCH_FLOAT_DTYPE_TO_TEMPLATE(dtype, [&]() {
auto points_ptr = points.GetDataPtr<scalar_t>();
auto normals_ptr = normals.GetDataPtr<scalar_t>();
auto colors_ptr = colors.GetDataPtr<scalar_t>();
auto neighbour_indices_ptr = indices.GetDataPtr<int32_t>();
auto neighbour_counts_ptr = counts.GetDataPtr<int32_t>();
auto color_gradients_ptr = color_gradients.GetDataPtr<scalar_t>();
core::ParallelFor(
points.GetDevice(), n, [=] OPEN3D_DEVICE(int64_t workload_idx) {
// NNS [Hybrid Search].
int32_t neighbour_offset = max_nn * workload_idx;
// Count of valid correspondences per point.
int32_t neighbour_count =
neighbour_counts_ptr[workload_idx];
int32_t idx_offset = 3 * workload_idx;
EstimatePointWiseColorGradientKernel(
points_ptr, normals_ptr, colors_ptr, idx_offset,
neighbour_indices_ptr + neighbour_offset,
neighbour_count, color_gradients_ptr);
});
});
core::cuda::Synchronize(points.GetDevice());
}
#if defined(__CUDACC__)
void EstimateColorGradientsUsingKNNSearchCUDA
#else
void EstimateColorGradientsUsingKNNSearchCPU
#endif
(const core::Tensor& points,
const core::Tensor& normals,
const core::Tensor& colors,
core::Tensor& color_gradients,
const int64_t& max_nn) {
core::Dtype dtype = points.GetDtype();
int64_t n = points.GetLength();
core::nns::NearestNeighborSearch tree(points, core::Int32);
bool check = tree.KnnIndex();
if (!check) {
utility::LogError("KnnIndex is not set.");
}
core::Tensor indices, distance;
std::tie(indices, distance) = tree.KnnSearch(points, max_nn);
indices = indices.To(core::Int32).Contiguous();
int64_t nn_count = indices.GetShape()[1];
if (nn_count < 4) {
utility::LogError(
"Not enough neighbors to compute Covariances / Normals. "
"Try "
"changing the search parameter.");
}
DISPATCH_FLOAT_DTYPE_TO_TEMPLATE(dtype, [&]() {
auto points_ptr = points.GetDataPtr<scalar_t>();
auto normals_ptr = normals.GetDataPtr<scalar_t>();
auto colors_ptr = colors.GetDataPtr<scalar_t>();
auto neighbour_indices_ptr = indices.GetDataPtr<int32_t>();
auto color_gradients_ptr = color_gradients.GetDataPtr<scalar_t>();
core::ParallelFor(
points.GetDevice(), n, [=] OPEN3D_DEVICE(int64_t workload_idx) {
int32_t neighbour_offset = max_nn * workload_idx;
int32_t idx_offset = 3 * workload_idx;
EstimatePointWiseColorGradientKernel(
points_ptr, normals_ptr, colors_ptr, idx_offset,
neighbour_indices_ptr + neighbour_offset, nn_count,
color_gradients_ptr);
});
});
core::cuda::Synchronize(points.GetDevice());
}
#if defined(__CUDACC__)
void EstimateColorGradientsUsingRadiusSearchCUDA
#else
void EstimateColorGradientsUsingRadiusSearchCPU
#endif
(const core::Tensor& points,
const core::Tensor& normals,
const core::Tensor& colors,
core::Tensor& color_gradients,
const double& radius) {
core::Dtype dtype = points.GetDtype();
int64_t n = points.GetLength();
core::nns::NearestNeighborSearch tree(points, core::Int32);
bool check = tree.FixedRadiusIndex(radius);
if (!check) {
utility::LogError("RadiusIndex is not set.");
}
core::Tensor indices, distance, counts;
std::tie(indices, distance, counts) =
tree.FixedRadiusSearch(points, radius);
indices = indices.To(core::Int32).Contiguous();
counts = counts.Contiguous();
DISPATCH_FLOAT_DTYPE_TO_TEMPLATE(dtype, [&]() {
auto points_ptr = points.GetDataPtr<scalar_t>();
auto normals_ptr = normals.GetDataPtr<scalar_t>();
auto colors_ptr = colors.GetDataPtr<scalar_t>();
auto neighbour_indices_ptr = indices.GetDataPtr<int32_t>();
auto neighbour_counts_ptr = counts.GetDataPtr<int32_t>();
auto color_gradients_ptr = color_gradients.GetDataPtr<scalar_t>();
core::ParallelFor(
points.GetDevice(), n, [=] OPEN3D_DEVICE(int64_t workload_idx) {
int32_t neighbour_offset =
neighbour_counts_ptr[workload_idx];
// Count of valid correspondences per point.
const int32_t neighbour_count =
(neighbour_counts_ptr[workload_idx + 1] -
neighbour_counts_ptr[workload_idx]);
int32_t idx_offset = 3 * workload_idx;
EstimatePointWiseColorGradientKernel(
points_ptr, normals_ptr, colors_ptr, idx_offset,
neighbour_indices_ptr + neighbour_offset,
neighbour_count, color_gradients_ptr);
});
});
core::cuda::Synchronize(points.GetDevice());
}
} // namespace pointcloud
} // namespace kernel
} // namespace geometry
} // namespace t
} // namespace open3d