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// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//
// * Redistributions in binary form must reproduce the above copyright
// notice, this list of conditions and the following disclaimer in the
// documentation and/or other materials provided with the distribution.
//
// * Neither the name of ETH Zurich and UNC Chapel Hill nor the names of
// its contributors may be used to endorse or promote products derived
// from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE
// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
// POSSIBILITY OF SUCH DAMAGE.
//
// Author: Johannes L. Schoenberger (jsch-at-demuc-dot-de)
#include "feature/utils.h"
#include "util/math.h"
namespace colmap {
std::vector<Eigen::Vector2d> FeatureKeypointsToPointsVector(
const FeatureKeypoints& keypoints) {
std::vector<Eigen::Vector2d> points(keypoints.size());
for (size_t i = 0; i < keypoints.size(); ++i) {
points[i] = Eigen::Vector2d(keypoints[i].x, keypoints[i].y);
}
return points;
}
Eigen::MatrixXf L2NormalizeFeatureDescriptors(
const Eigen::MatrixXf& descriptors) {
return descriptors.rowwise().normalized();
}
Eigen::MatrixXf L1RootNormalizeFeatureDescriptors(
const Eigen::MatrixXf& descriptors) {
Eigen::MatrixXf descriptors_normalized(descriptors.rows(),
descriptors.cols());
for (Eigen::MatrixXf::Index r = 0; r < descriptors.rows(); ++r) {
const float norm = descriptors.row(r).lpNorm<1>();
descriptors_normalized.row(r) = descriptors.row(r) / norm;
descriptors_normalized.row(r) =
descriptors_normalized.row(r).array().sqrt();
}
return descriptors_normalized;
}
FeatureDescriptors FeatureDescriptorsToUnsignedByte(
const Eigen::MatrixXf& descriptors) {
FeatureDescriptors descriptors_unsigned_byte(descriptors.rows(),
descriptors.cols());
for (Eigen::MatrixXf::Index r = 0; r < descriptors.rows(); ++r) {
for (Eigen::MatrixXf::Index c = 0; c < descriptors.cols(); ++c) {
const float scaled_value = std::round(512.0f * descriptors(r, c));
descriptors_unsigned_byte(r, c) =
TruncateCast<float, uint8_t>(scaled_value);
}
}
return descriptors_unsigned_byte;
}
void ExtractTopScaleFeatures(FeatureKeypoints* keypoints,
FeatureDescriptors* descriptors,
const size_t num_features) {
CHECK_EQ(keypoints->size(), descriptors->rows());
CHECK_GT(num_features, 0);
if (static_cast<size_t>(descriptors->rows()) <= num_features) {
return;
}
FeatureKeypoints top_scale_keypoints;
FeatureDescriptors top_scale_descriptors;
std::vector<std::pair<size_t, float>> scales;
scales.reserve(static_cast<size_t>(keypoints->size()));
for (size_t i = 0; i < keypoints->size(); ++i) {
scales.emplace_back(i, (*keypoints)[i].ComputeScale());
}
std::partial_sort(scales.begin(), scales.begin() + num_features, scales.end(),
[](const std::pair<size_t, float> scale1,
const std::pair<size_t, float> scale2) {
return scale1.second > scale2.second;
});
top_scale_keypoints.resize(num_features);
top_scale_descriptors.resize(num_features, descriptors->cols());
for (size_t i = 0; i < num_features; ++i) {
top_scale_keypoints[i] = (*keypoints)[scales[i].first];
top_scale_descriptors.row(i) = descriptors->row(scales[i].first);
}
*keypoints = top_scale_keypoints;
*descriptors = top_scale_descriptors;
}
} // namespace colmap
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