Merge "Undistort april detection corners"
diff --git a/y2023/vision/BUILD b/y2023/vision/BUILD
index 5c98d7c..2cc4367 100644
--- a/y2023/vision/BUILD
+++ b/y2023/vision/BUILD
@@ -66,6 +66,7 @@
     srcs = ["vision_util.cc"],
     hdrs = ["vision_util.h"],
     deps = [
+        "//third_party:opencv",
         "//y2023/constants:constants_fbs",
         "@com_github_google_glog//:glog",
     ],
diff --git a/y2023/vision/aprilrobotics.cc b/y2023/vision/aprilrobotics.cc
index cb6a5bc..a98f269 100644
--- a/y2023/vision/aprilrobotics.cc
+++ b/y2023/vision/aprilrobotics.cc
@@ -6,6 +6,9 @@
     debug, false,
     "If true, dump a ton of debug and crash on the first valid detection.");
 
+DEFINE_double(min_decision_margin, 30.0,
+              "Minimum decision margin (confidence) for an apriltag detection");
+
 namespace y2023 {
 namespace vision {
 
@@ -40,8 +43,16 @@
   // Check team string is valid
   calibration_ = FindCameraCalibration(
       calibration_data_.constants(), event_loop->node()->name()->string_view());
+
+  extrinsics_ = CameraExtrinsics(calibration_);
+
   intrinsics_ = CameraIntrinsics(calibration_);
-  camera_distortion_coeffs_ = CameraDistCoeffs(calibration_);
+  // Create an undistort projection matrix using the intrinsics
+  projection_matrix_ = cv::Mat::zeros(3, 4, CV_64F);
+  intrinsics_.rowRange(0, 3).colRange(0, 3).copyTo(
+      projection_matrix_.rowRange(0, 3).colRange(0, 3));
+
+  dist_coeffs_ = CameraDistCoeffs(calibration_);
 
   image_callback_.set_format(frc971::vision::ImageCallback::Format::GRAYSCALE);
 }
@@ -66,10 +77,10 @@
   }
 }
 
-void AprilRoboticsDetector::HandleImage(cv::Mat image_color_mat,
+void AprilRoboticsDetector::HandleImage(cv::Mat image_grayscale,
                                         aos::monotonic_clock::time_point eof) {
   std::vector<std::pair<apriltag_detection_t, apriltag_pose_t>> detections =
-      DetectTags(image_color_mat);
+      DetectTags(image_grayscale);
 
   auto builder = target_map_sender_.MakeBuilder();
   std::vector<flatbuffers::Offset<frc971::vision::TargetPoseFbs>> target_poses;
@@ -102,6 +113,28 @@
                                              orientation_offset);
 }
 
+void AprilRoboticsDetector::UndistortDetection(
+    apriltag_detection_t *det) const {
+  // 4 corners
+  constexpr size_t kRows = 4;
+  // 2d points
+  constexpr size_t kCols = 2;
+
+  cv::Mat distorted_points(kRows, kCols, CV_64F, det->p);
+  cv::Mat undistorted_points = cv::Mat::zeros(kRows, kCols, CV_64F);
+
+  // Undistort the april tag points
+  cv::undistortPoints(distorted_points, undistorted_points, intrinsics_,
+                      dist_coeffs_, cv::noArray(), projection_matrix_);
+
+  // Copy the undistorted points into det
+  for (size_t i = 0; i < kRows; i++) {
+    for (size_t j = 0; j < kCols; j++) {
+      det->p[i][j] = undistorted_points.at<double>(i, j);
+    }
+  }
+}
+
 std::vector<std::pair<apriltag_detection_t, apriltag_pose_t>>
 AprilRoboticsDetector::DetectTags(cv::Mat image) {
   const aos::monotonic_clock::time_point start_time =
@@ -128,7 +161,7 @@
     apriltag_detection_t *det;
     zarray_get(detections, i, &det);
 
-    if (det->decision_margin > 30) {
+    if (det->decision_margin > FLAGS_min_decision_margin) {
       VLOG(1) << "Found tag number " << det->id << " hamming: " << det->hamming
               << " margin: " << det->decision_margin;
 
@@ -139,6 +172,7 @@
       apriltag_detection_info_t info;
       info.det = det;
       info.tagsize = 0.1524;
+
       info.fx = intrinsics_.at<double>(0, 0);
       info.fy = intrinsics_.at<double>(1, 1);
       info.cx = intrinsics_.at<double>(0, 2);
@@ -147,6 +181,7 @@
       apriltag_pose_t pose;
       double err = estimate_tag_pose(&info, &pose);
 
+      UndistortDetection(det);
       VLOG(1) << "err: " << err;
 
       results.emplace_back(*det, pose);
diff --git a/y2023/vision/aprilrobotics.h b/y2023/vision/aprilrobotics.h
index 8c2c0ad..4477856 100644
--- a/y2023/vision/aprilrobotics.h
+++ b/y2023/vision/aprilrobotics.h
@@ -5,6 +5,7 @@
 #include "aos/events/shm_event_loop.h"
 #include "aos/network/team_number.h"
 #include "aos/realtime.h"
+#include "frc971/constants/constants_sender_lib.h"
 #include "frc971/vision/calibration_generated.h"
 #include "frc971/vision/charuco_lib.h"
 #include "frc971/vision/target_map_generated.h"
@@ -15,9 +16,8 @@
 #include "third_party/apriltag/apriltag.h"
 #include "third_party/apriltag/apriltag_pose.h"
 #include "third_party/apriltag/tag16h5.h"
-#include "y2023/vision/april_debug_generated.h"
 #include "y2023/constants/constants_generated.h"
-#include "frc971/constants/constants_sender_lib.h"
+#include "y2023/vision/april_debug_generated.h"
 
 DECLARE_int32(team_number);
 
@@ -28,14 +28,20 @@
  public:
   AprilRoboticsDetector(aos::EventLoop *event_loop,
                         std::string_view channel_name);
-
   ~AprilRoboticsDetector();
 
   void SetWorkerpoolAffinities();
 
+  // Undistorts the april tag corners using the camera calibration
+  void UndistortDetection(apriltag_detection_t *det) const;
+
   std::vector<std::pair<apriltag_detection_t, apriltag_pose_t>> DetectTags(
       cv::Mat image);
 
+  const cv::Mat extrinsics() const { return extrinsics_; }
+  const cv::Mat intrinsics() const { return intrinsics_; }
+  const cv::Mat dist_coeffs() const { return dist_coeffs_; }
+
  private:
   void HandleImage(cv::Mat image, aos::monotonic_clock::time_point eof);
 
@@ -44,36 +50,15 @@
       frc971::vision::TargetMapper::TargetId target_id,
       flatbuffers::FlatBufferBuilder *fbb);
 
-
-  static cv::Mat CameraIntrinsics(
-      const frc971::vision::calibration::CameraCalibration
-          *camera_calibration) {
-    cv::Mat result(3, 3, CV_32F,
-                   const_cast<void *>(static_cast<const void *>(
-                       camera_calibration->intrinsics()->data())));
-    result.convertTo(result, CV_64F);
-    CHECK_EQ(result.total(), camera_calibration->intrinsics()->size());
-
-    return result;
-  }
-
-  static cv::Mat CameraDistCoeffs(
-      const frc971::vision::calibration::CameraCalibration
-          *camera_calibration) {
-    const cv::Mat result(5, 1, CV_32F,
-                         const_cast<void *>(static_cast<const void *>(
-                             camera_calibration->dist_coeffs()->data())));
-    CHECK_EQ(result.total(), camera_calibration->dist_coeffs()->size());
-    return result;
-  }
-
   apriltag_family_t *tag_family_;
   apriltag_detector_t *tag_detector_;
 
   const frc971::constants::ConstantsFetcher<Constants> calibration_data_;
   const frc971::vision::calibration::CameraCalibration *calibration_;
   cv::Mat intrinsics_;
-  cv::Mat camera_distortion_coeffs_;
+  cv::Mat projection_matrix_;
+  cv::Mat extrinsics_;
+  cv::Mat dist_coeffs_;
 
   aos::Ftrace ftrace_;
 
diff --git a/y2023/vision/calib_files/calibration_pi-971-1_cam-23-01_2013-01-18_08-56-17.194305339.json b/y2023/vision/calib_files/calibration_pi-971-1_cam-23-01_2013-01-18_08-56-17.194305339.json
new file mode 100755
index 0000000..1f30579
--- /dev/null
+++ b/y2023/vision/calib_files/calibration_pi-971-1_cam-23-01_2013-01-18_08-56-17.194305339.json
@@ -0,0 +1,42 @@
+{
+ "node_name": "pi1",
+ "team_number": 971,
+ "intrinsics": [
+  913.133728,
+  0.0,
+  575.592285,
+  0.0,
+  917.686462,
+  364.544403,
+  0.0,
+  0.0,
+  1.0
+ ],
+ "dist_coeffs": [
+  -0.454162,
+  0.255307,
+  -0.000166,
+  0.008949,
+  -0.079813
+ ],
+ "fixed_extrinsics": [
+  1.0,
+  0.0,
+  0.0,
+  0.0,
+  0.0,
+  1.0,
+  0.0,
+  0.0,
+  0.0,
+  0.0,
+  1.0,
+  0.0,
+  0.0,
+  0.0,
+  0.0,
+  1.0
+ ],
+ "calibration_timestamp": 1358499377194305339,
+ "camera_id": "23-01"
+}
diff --git a/y2023/vision/target_mapping.cc b/y2023/vision/target_mapping.cc
index 4f10499..18be258 100644
--- a/y2023/vision/target_mapping.cc
+++ b/y2023/vision/target_mapping.cc
@@ -75,41 +75,23 @@
   }
 }
 
-Eigen::Affine3d CameraExtrinsics(
-    const calibration::CameraCalibration *camera_calibration) {
-  const frc971::vision::calibration::TransformationMatrix *transform =
-      camera_calibration->has_turret_extrinsics()
-          ? camera_calibration->turret_extrinsics()
-          : camera_calibration->fixed_extrinsics();
-
-  cv::Mat result(
-      4, 4, CV_32F,
-      const_cast<void *>(static_cast<const void *>(transform->data()->data())));
-  result.convertTo(result, CV_64F);
-  CHECK_EQ(result.total(), transform->data()->size());
-
-  Eigen::Matrix4d result_eigen;
-  cv::cv2eigen(result, result_eigen);
-  return Eigen::Affine3d(result_eigen);
-}
-
 // Get images from pi and pass apriltag positions to HandleAprilTag()
 void HandlePiCaptures(
-    const frc971::constants::ConstantsFetcher<Constants> &constants,
     aos::EventLoop *pi_event_loop, aos::logger::LogReader *reader,
     std::vector<DataAdapter::TimestampedDetection>
         *timestamped_target_detections,
     std::vector<std::unique_ptr<AprilRoboticsDetector>> *detectors) {
-
-  const auto node_name = pi_event_loop->node()->name()->string_view();
-  const calibration::CameraCalibration *calibration =
-      FindCameraCalibration(constants.constants(), node_name);
-  const auto extrinsics = CameraExtrinsics(calibration);
-
   // TODO(milind): change to /camera once we log at full frequency
   static constexpr std::string_view kImageChannel = "/camera/decimated";
-  detectors->emplace_back(
-      std::make_unique<AprilRoboticsDetector>(pi_event_loop, kImageChannel));
+  auto detector_ptr =
+      std::make_unique<AprilRoboticsDetector>(pi_event_loop, kImageChannel);
+  // Get the camera extrinsics
+  cv::Mat extrinsics_cv = detector_ptr->extrinsics();
+  Eigen::Matrix4d extrinsics_matrix;
+  cv::cv2eigen(extrinsics_cv, extrinsics_matrix);
+  const auto extrinsics = Eigen::Affine3d(extrinsics_matrix);
+
+  detectors->emplace_back(std::move(detector_ptr));
 
   pi_event_loop->MakeWatcher("/camera", [=](const TargetMap &map) {
     aos::distributed_clock::time_point pi_distributed_time =
@@ -139,36 +121,28 @@
       aos::configuration::GetNode(reader.configuration(), "pi1");
   std::unique_ptr<aos::EventLoop> pi1_event_loop =
       reader.event_loop_factory()->MakeEventLoop("pi1", pi1);
-  frc971::constants::ConstantsFetcher<Constants> pi1_constants(
-      pi1_event_loop.get());
-  HandlePiCaptures(pi1_constants, pi1_event_loop.get(), &reader,
+  HandlePiCaptures(pi1_event_loop.get(), &reader,
                    &timestamped_target_detections, &detectors);
 
   const aos::Node *pi2 =
       aos::configuration::GetNode(reader.configuration(), "pi2");
   std::unique_ptr<aos::EventLoop> pi2_event_loop =
       reader.event_loop_factory()->MakeEventLoop("pi2", pi2);
-  frc971::constants::ConstantsFetcher<Constants> pi2_constants(
-      pi2_event_loop.get());
-  HandlePiCaptures(pi2_constants, pi2_event_loop.get(), &reader,
+  HandlePiCaptures(pi2_event_loop.get(), &reader,
                    &timestamped_target_detections, &detectors);
 
   const aos::Node *pi3 =
       aos::configuration::GetNode(reader.configuration(), "pi3");
   std::unique_ptr<aos::EventLoop> pi3_event_loop =
       reader.event_loop_factory()->MakeEventLoop("pi3", pi3);
-  frc971::constants::ConstantsFetcher<Constants> pi3_constants(
-      pi3_event_loop.get());
-  HandlePiCaptures(pi3_constants, pi3_event_loop.get(), &reader,
+  HandlePiCaptures(pi3_event_loop.get(), &reader,
                    &timestamped_target_detections, &detectors);
 
   const aos::Node *pi4 =
       aos::configuration::GetNode(reader.configuration(), "pi4");
   std::unique_ptr<aos::EventLoop> pi4_event_loop =
       reader.event_loop_factory()->MakeEventLoop("pi4", pi4);
-  frc971::constants::ConstantsFetcher<Constants> pi4_constants(
-      pi4_event_loop.get());
-  HandlePiCaptures(pi4_constants, pi4_event_loop.get(), &reader,
+  HandlePiCaptures(pi4_event_loop.get(), &reader,
                    &timestamped_target_detections, &detectors);
 
   reader.event_loop_factory()->Run();
diff --git a/y2023/vision/vision_util.cc b/y2023/vision/vision_util.cc
index eed315a..f4937e5 100644
--- a/y2023/vision/vision_util.cc
+++ b/y2023/vision/vision_util.cc
@@ -3,6 +3,7 @@
 #include "glog/logging.h"
 
 namespace y2023::vision {
+
 const frc971::vision::calibration::CameraCalibration *FindCameraCalibration(
     const y2023::Constants &calibration_data, std::string_view node_name) {
   CHECK(calibration_data.has_cameras());
@@ -16,4 +17,40 @@
   }
   LOG(FATAL) << ": Failed to find camera calibration for " << node_name;
 }
+
+cv::Mat CameraExtrinsics(
+    const frc971::vision::calibration::CameraCalibration *camera_calibration) {
+  CHECK(!camera_calibration->has_turret_extrinsics())
+      << "No turret on 2023 robot";
+
+  cv::Mat result(4, 4, CV_32F,
+                 const_cast<void *>(static_cast<const void *>(
+                     camera_calibration->fixed_extrinsics()->data()->data())));
+  result.convertTo(result, CV_64F);
+  CHECK_EQ(result.total(),
+           camera_calibration->fixed_extrinsics()->data()->size());
+
+  return result;
+}
+
+cv::Mat CameraIntrinsics(
+    const frc971::vision::calibration::CameraCalibration *camera_calibration) {
+  cv::Mat result(3, 3, CV_32F,
+                 const_cast<void *>(static_cast<const void *>(
+                     camera_calibration->intrinsics()->data())));
+  result.convertTo(result, CV_64F);
+  CHECK_EQ(result.total(), camera_calibration->intrinsics()->size());
+
+  return result;
+}
+
+cv::Mat CameraDistCoeffs(
+    const frc971::vision::calibration::CameraCalibration *camera_calibration) {
+  const cv::Mat result(5, 1, CV_32F,
+                       const_cast<void *>(static_cast<const void *>(
+                           camera_calibration->dist_coeffs()->data())));
+  CHECK_EQ(result.total(), camera_calibration->dist_coeffs()->size());
+  return result;
+}
+
 }  // namespace y2023::vision
diff --git a/y2023/vision/vision_util.h b/y2023/vision/vision_util.h
index 58f9a7f..ce1a69d 100644
--- a/y2023/vision/vision_util.h
+++ b/y2023/vision/vision_util.h
@@ -2,10 +2,23 @@
 #define Y2023_VISION_VISION_UTIL_H_
 #include <string_view>
 
+#include "opencv2/imgproc.hpp"
 #include "y2023/constants/constants_generated.h"
+
 namespace y2023::vision {
 
 const frc971::vision::calibration::CameraCalibration *FindCameraCalibration(
     const y2023::Constants &calibration_data, std::string_view node_name);
-}
+
+cv::Mat CameraExtrinsics(
+    const frc971::vision::calibration::CameraCalibration *camera_calibration);
+
+cv::Mat CameraIntrinsics(
+    const frc971::vision::calibration::CameraCalibration *camera_calibration);
+
+cv::Mat CameraDistCoeffs(
+    const frc971::vision::calibration::CameraCalibration *camera_calibration);
+
+}  // namespace y2023::vision
+
 #endif  // Y2023_VISION_VISION_UTIL_H_