Fix MIN_CORNER threshold for asymmetric circlegrids

Author: chris-hagen

aslam_cv/aslam_cameras/include/aslam/cameras/GridCalibrationTargetCirclegrid.hpp

@@ -59,6 +59,9 @@ class GridCalibrationTargetCirclegrid : public GridCalibrationTargetBase {
   bool computeObservation(const cv::Mat &image, Eigen::MatrixXd &outImagePoints,
                           std::vector<bool> &outCornerObserved) const;
 
+  /// \brief receive the circlegrid options
+  const CirclegridOptions options() const {return _options;}
+
  private:
   /// \brief initialize the object
   void initialize();

aslam_cv/aslam_cameras/include/aslam/cameras/implementation/OmniProjection.hpp

@@ -1,3 +1,5 @@
+#include <aslam/cameras/GridCalibrationTargetCirclegrid.hpp>
+
 namespace aslam {
 
 namespace cameras {
@@ -773,7 +775,15 @@ bool OmniProjection<DISTORTION_T>::initializeIntrinsics(const std::vector<GridCa
       }
 
       // MIN_CORNERS is an arbitrary threshold for the number of corners
-      const size_t MIN_CORNERS = 4;
+      size_t MIN_CORNERS = 4;
+
+      // allow asymmetric circle grids with half of the minimum corners as 2 asymmetric columns are treated a 1
+      if (const aslam::cameras::GridCalibrationTargetCirclegrid* circleGrid = dynamic_cast<const aslam::cameras::GridCalibrationTargetCirclegrid*>(&target)){
+        if (circleGrid->options().useAsymmetricCirclegrid){
+          MIN_CORNERS = MIN_CORNERS / 2;
+        }
+      }
+
       if (count > MIN_CORNERS)
       {
         // Resize P to fit with the count of valid points.

aslam_cv/aslam_cameras/src/OmniCameraGeometry.cpp

@@ -523,7 +523,15 @@ bool OmniProjection::initializeIntrinsics(
           }
         }
 
-        const int MIN_CORNERS = 8;
+        int MIN_CORNERS = 8;
+
+        // allow asymmetric circle grids with half of the minimum corners as 2 asymmetric columns are treated a 1
+        if (const aslam::cameras::GridCalibrationTargetCirclegrid* circleGrid = dynamic_cast<const aslam::cameras::GridCalibrationTargetCirclegrid*>(&target)){
+          if (circleGrid->options().useAsymmetricCirclegrid){
+            MIN_CORNERS = MIN_CORNERS / 2;
+          }
+        }
+
         // MIN_CORNERS is an arbitrary threshold for the number of corners
         if (count > MIN_CORNERS) {
           // Resize P to fit with the count of valid points.