mediapipe/mediapipe/calculators/util/rect_projection_calculator.cc
Sebastian Schmidt fb21797611 Internal change
PiperOrigin-RevId: 494914168
2022-12-12 21:30:31 -08:00

109 lines
3.6 KiB
C++

// Copyright 2019 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.
#include <cmath>
#include "mediapipe/framework/calculator_framework.h"
#include "mediapipe/framework/formats/rect.pb.h"
namespace mediapipe {
namespace {
constexpr char kNormRectTag[] = "NORM_RECT";
constexpr char kNormReferenceRectTag[] = "NORM_REFERENCE_RECT";
using ::mediapipe::NormalizedRect;
} // namespace
// Projects rectangle from reference coordinate system (defined by reference
// rectangle) to original coordinate system (in which this reference rectangle
// is defined).
//
// Inputs:
// NORM_RECT - A NormalizedRect to be projected.
// NORM_REFERENCE_RECT - A NormalizedRect that represents reference coordinate
// system for NORM_RECT and is defined in original coordinates.
//
// Outputs:
// NORM_RECT: A NormalizedRect projected to the original coordinates.
//
// Example config:
// node {
// calculator: "RectProjectionCalculator"
// input_stream: "NORM_RECT:face_rect"
// input_stream: "NORM_REFERENCE_RECT:face_reference_rect"
// output_stream: "NORM_RECT:projected_face_rect"
// }
//
class RectProjectionCalculator : public CalculatorBase {
public:
static absl::Status GetContract(CalculatorContract* cc);
absl::Status Open(CalculatorContext* cc) override;
absl::Status Process(CalculatorContext* cc) override;
};
REGISTER_CALCULATOR(RectProjectionCalculator);
absl::Status RectProjectionCalculator::GetContract(CalculatorContract* cc) {
cc->Inputs().Tag(kNormRectTag).Set<NormalizedRect>();
cc->Inputs().Tag(kNormReferenceRectTag).Set<NormalizedRect>();
cc->Outputs().Tag(kNormRectTag).Set<NormalizedRect>();
return absl::OkStatus();
}
absl::Status RectProjectionCalculator::Open(CalculatorContext* cc) {
cc->SetOffset(TimestampDiff(0));
return absl::OkStatus();
}
absl::Status RectProjectionCalculator::Process(CalculatorContext* cc) {
if (cc->Inputs().Tag(kNormRectTag).IsEmpty()) {
return absl::OkStatus();
}
const auto& rect = cc->Inputs().Tag(kNormRectTag).Get<NormalizedRect>();
const auto& reference_rect =
cc->Inputs().Tag(kNormReferenceRectTag).Get<NormalizedRect>();
// Project center.
const float x = rect.x_center() - 0.5f;
const float y = rect.y_center() - 0.5f;
const float angle = reference_rect.rotation();
float new_x = std::cos(angle) * x - std::sin(angle) * y;
float new_y = std::sin(angle) * x + std::cos(angle) * y;
new_x = new_x * reference_rect.width() + reference_rect.x_center();
new_y = new_y * reference_rect.height() + reference_rect.y_center();
// Project size.
const float new_width = rect.width() * reference_rect.width();
const float new_height = rect.height() * reference_rect.height();
// Project rotation.
const float new_rotation = rect.rotation() + reference_rect.rotation();
auto new_rect = absl::make_unique<NormalizedRect>();
new_rect->set_x_center(new_x);
new_rect->set_y_center(new_y);
new_rect->set_width(new_width);
new_rect->set_height(new_height);
new_rect->set_rotation(new_rotation);
cc->Outputs().Tag(kNormRectTag).Add(new_rect.release(), cc->InputTimestamp());
return absl::OkStatus();
}
} // namespace mediapipe