don't use constructors for C API structures

modules/stitching/src/motion_estimators.cpp

@@ -255,10 +255,10 @@ bool BundleAdjusterBase::estimate(const std::vector<ImageFeatures> &features,
 
     CvLevMarq solver(num_images_ * num_params_per_cam_,
                      total_num_matches_ * num_errs_per_measurement_,
-                     term_criteria_);
+                     cvTermCriteria(term_criteria_));
 
     Mat err, jac;
-    CvMat matParams = cam_params_;
+    CvMat matParams = cvMat(cam_params_);
     cvCopy(&matParams, solver.param);
 
     int iter = 0;
@@ -278,7 +278,7 @@ bool BundleAdjusterBase::estimate(const std::vector<ImageFeatures> &features,
         if (_jac)
         {
             calcJacobian(jac);
-            CvMat tmp = jac;
+            CvMat tmp = cvMat(jac);
             cvCopy(&tmp, _jac);
         }
 
@@ -287,7 +287,7 @@ bool BundleAdjusterBase::estimate(const std::vector<ImageFeatures> &features,
             calcError(err);
             LOG_CHAT(".");
             iter++;
-            CvMat tmp = err;
+            CvMat tmp = cvMat(err);
             cvCopy(&tmp, _err);
         }
     }