mediapipe-rs/mediapipe/modules/objectron/calculators/decoder.h
Victor Dudochkin 5578aa50e8 code fill
2022-03-01 19:04:01 +07:00

110 lines
4.4 KiB
C++

// Copyright 2020 The MediaPipe Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#ifndef MEDIAPIPE_MODULES_OBJECTRON_CALCULATORS_DECODER_H_
#define MEDIAPIPE_MODULES_OBJECTRON_CALCULATORS_DECODER_H_
#include <vector>
#include "Eigen/Dense"
#include "absl/status/status.h"
#include "mediapipe/framework/port/opencv_core_inc.h"
#include "mediapipe/modules/objectron/calculators/annotation_data.pb.h"
#include "mediapipe/modules/objectron/calculators/belief_decoder_config.pb.h"
namespace mediapipe {
// Decodes 3D bounding box from heatmaps and offset maps. In the future,
// if we want to develop decoder for generic skeleton, then we need to
// generalize this class, and make a few child classes.
class Decoder {
public:
static const int kNumOffsetmaps;
explicit Decoder(const BeliefDecoderConfig& config) : config_(config) {
epnp_alpha_ << 4.0f, -1.0f, -1.0f, -1.0f, 2.0f, -1.0f, -1.0f, 1.0f, 2.0f,
-1.0f, 1.0f, -1.0f, 0.0f, -1.0f, 1.0f, 1.0f, 2.0f, 1.0f, -1.0f, -1.0f,
0.0f, 1.0f, -1.0f, 1.0f, 0.0f, 1.0f, 1.0f, -1.0f, -2.0f, 1.0f, 1.0f,
1.0f;
}
// Decodes bounding boxes from predicted heatmap and offset maps.
// Input:
// heatmap: a single channel cv::Mat representing center point heatmap
// offsetmap: a 16 channel cv::Mat representing the 16 offset maps
// (2 for each of the 8 vertices)
// Output:
// Outputs 3D bounding boxes 2D vertices, represented by 'point_2d' field
// in each 'keypoints' field of object annotations.
FrameAnnotation DecodeBoundingBoxKeypoints(const cv::Mat& heatmap,
const cv::Mat& offsetmap) const;
// Lifts the estimated 2D projections of bounding box vertices to 3D.
// This function uses the EPnP approach described in this paper:
// https://icwww.epfl.ch/~lepetit/papers/lepetit_ijcv08.pdf .
// Input:
// projection_matrix: the projection matrix from 3D coordinate
// to screen coordinate.
// The 2D screen coordinate is defined as: u is along the long
// edge of the device, pointing down; v is along the short edge
// of the device, pointing right.
// portrait: a boolen variable indicating whether our images are
// obtained in portrait orientation or not.
// estimated_box: annotation with point_2d field populated with
// 2d vertices.
// Output:
// estimated_box: annotation with point_3d field populated with
// 3d vertices.
absl::Status Lift2DTo3D(
const Eigen::Matrix<float, 4, 4, Eigen::RowMajor>& projection_matrix,
bool portrait, FrameAnnotation* estimated_box) const;
private:
struct BeliefBox {
float belief;
std::vector<std::pair<float, float>> box_2d;
};
std::vector<cv::Point> ExtractCenterKeypoints(
const cv::Mat& center_heatmap) const;
// Decodes 2D keypoints at the peak point.
void DecodeByPeak(const cv::Mat& offsetmap, int center_x, int center_y,
float offset_scale_x, float offset_scale_y,
BeliefBox* box) const;
// Decodes 2D keypoints by voting around the peak.
void DecodeByVoting(const cv::Mat& heatmap, const cv::Mat& offsetmap,
int center_x, int center_y, float offset_scale_x,
float offset_scale_y, BeliefBox* box) const;
// Returns true if it is a new box. Otherwise, it may replace an existing box
// if the new box's belief is higher.
bool IsNewBox(std::vector<BeliefBox>* boxes, BeliefBox* box) const;
// Returns true if the two boxes are identical.
bool IsIdentical(const BeliefBox& box_1, const BeliefBox& box_2) const;
BeliefDecoderConfig config_;
// Following equation (1) in this paper
// https://icwww.epfl.ch/~lepetit/papers/lepetit_ijcv08.pdf,
// this variable denotes the coefficients for the 4 control points
// for each of the 8 3D box vertices.
Eigen::Matrix<float, 8, 4, Eigen::RowMajor> epnp_alpha_;
};
} // namespace mediapipe
#endif // MEDIAPIPE_MODULES_OBJECTRON_CALCULATORS_DECODER_H_