Changed initial estimation for F in fisheye calibration.

modules/calib3d/src/fisheye.cpp

@@ -799,7 +799,7 @@ double cv::fisheye::calibrate(InputArrayOfArrays objectPoints, InputArrayOfArray
     }
     else
     {
-        finalParam.Init(Vec2d(max(image_size.width, image_size.height) / CV_PI, max(image_size.width, image_size.height) / CV_PI),
+        finalParam.Init(Vec2d(max(image_size.width, image_size.height) / 2., max(image_size.width, image_size.height) / 2.),
                         Vec2d(image_size.width  / 2.0 - 0.5, image_size.height / 2.0 - 0.5));
     }
 

modules/calib3d/test/test_fisheye.cpp

@@ -410,6 +410,11 @@ TEST_F(fisheyeTest, Calibration)
 {
     const int n_images = 34;
 
+    const cv::Matx33d goldK(558.4780870585967, 0, 620.4585053962692,
+                            0, 560.5067667343917, 381.9394122875291,
+                            0, 0, 1);
+    const cv::Vec4d goldD(-0.00146136, -0.00329847, 0.00605742, -0.00374201);
+
     std::vector<std::vector<cv::Point2d> > imagePoints(n_images);
     std::vector<std::vector<cv::Point3d> > objectPoints(n_images);
 
@@ -437,8 +442,8 @@ TEST_F(fisheyeTest, Calibration)
     cv::fisheye::calibrate(objectPoints, imagePoints, imageSize, theK, theD,
                            cv::noArray(), cv::noArray(), flag, cv::TermCriteria(3, 20, 1e-6));
 
-    EXPECT_MAT_NEAR(theK, this->K, 1e-10);
-    EXPECT_MAT_NEAR(theD, this->D, 1e-10);
+    EXPECT_MAT_NEAR(theK, goldK, 1e-8);
+    EXPECT_MAT_NEAR(theD, goldD, 1e-8);
 }
 
 TEST_F(fisheyeTest, CalibrationWithFixedFocalLength)
@@ -597,10 +602,10 @@ TEST_F(fisheyeTest, EstimateUncertainties)
     cv::internal::EstimateUncertainties(objectPoints, imagePoints, param,  rvec, tvec,
                                         errors, err_std, thresh_cond, check_cond, rms);
 
-    EXPECT_MAT_NEAR(errors.f, cv::Vec2d(1.34250246865020720, 1.36037536429654530), 1e-10);
-    EXPECT_MAT_NEAR(errors.c, cv::Vec2d(0.92070526160049848, 0.84383585812851514), 1e-10);
-    EXPECT_MAT_NEAR(errors.k, cv::Vec4d(0.0053379581373996041, 0.017389792901700545, 0.022036256089491224, 0.0094714594258908952), 1e-10);
-    EXPECT_MAT_NEAR(err_std, cv::Vec2d(0.187475975266883, 0.185678953263995), 1e-10);
+    EXPECT_MAT_NEAR(errors.f, cv::Vec2d(1.34250246865020720, 1.36037536429654530), 1e-6);
+    EXPECT_MAT_NEAR(errors.c, cv::Vec2d(0.92070526160049848, 0.84383585812851514), 1e-6);
+    EXPECT_MAT_NEAR(errors.k, cv::Vec4d(0.0053379581373996041, 0.017389792901700545, 0.022036256089491224, 0.0094714594258908952), 1e-7);
+    EXPECT_MAT_NEAR(err_std, cv::Vec2d(0.187475975266883, 0.185678953263995), 1e-7);
     CV_Assert(fabs(rms - 0.263782587133546) < 1e-10);
     CV_Assert(errors.alpha == 0);
 }