Merge remote-tracking branch 'upstream/3.4' into merge-3.4

Author: alalek

CMakeLists.txt

@@ -999,6 +999,12 @@ if(COMMAND ocv_pylint_finalize)
   ocv_pylint_add_directory_recurse(${CMAKE_CURRENT_LIST_DIR}/samples/python/tutorial_code)
   ocv_pylint_finalize()
 endif()
+if(TARGET check_pylint)
+  message(STATUS "Registered 'check_pylint' target: using ${PYLINT_EXECUTABLE} (ver: ${PYLINT_VERSION}), checks: ${PYLINT_TOTAL_TARGETS}")
+endif()
+if(TARGET check_flake8)
+  message(STATUS "Registered 'check_flake8' target: using ${FLAKE8_EXECUTABLE} (ver: ${FLAKE8_VERSION})")
+endif()
 
 if(OPENCV_GENERATE_SETUPVARS)
   include(cmake/OpenCVGenSetupVars.cmake)
@@ -1628,12 +1634,6 @@ endif()
 
 status("")
 status("  Python (for build):"  PYTHON_DEFAULT_AVAILABLE THEN "${PYTHON_DEFAULT_EXECUTABLE}" ELSE NO)
-if(PYLINT_FOUND AND PYLINT_EXECUTABLE)
-  status("    Pylint:"  PYLINT_FOUND THEN "${PYLINT_EXECUTABLE} (ver: ${PYLINT_VERSION}, checks: ${PYLINT_TOTAL_TARGETS})" ELSE NO)
-endif()
-if(FLAKE8_FOUND AND FLAKE8_EXECUTABLE)
-  status("    Flake8:"  FLAKE8_FOUND THEN "${FLAKE8_EXECUTABLE} (ver: ${FLAKE8_VERSION})" ELSE NO)
-endif()
 
 # ========================== java ==========================
 if(BUILD_JAVA)

cmake/FindPylint.cmake

@@ -16,7 +16,7 @@ if(PYLINT_EXECUTABLE AND NOT DEFINED PYLINT_VERSION)
   execute_process(COMMAND ${PYLINT_EXECUTABLE} --version RESULT_VARIABLE _result OUTPUT_VARIABLE PYLINT_VERSION_RAW)
   if(NOT _result EQUAL 0)
     ocv_clear_vars(PYLINT_EXECUTABLE PYLINT_VERSION)
-  elseif(PYLINT_VERSION_RAW MATCHES "pylint([^,]*) ([0-9\\.]+[0-9])")
+  elseif(PYLINT_VERSION_RAW MATCHES "pylint([^,\n]*) ([0-9\\.]+[0-9])")
     set(PYLINT_VERSION "${CMAKE_MATCH_2}")
   else()
     set(PYLINT_VERSION "unknown")

cmake/OpenCVPylint.cmake

@@ -122,7 +122,6 @@ function(ocv_pylint_finalize)
 
   list(LENGTH PYLINT_TARGET_ID __total)
   set(PYLINT_TOTAL_TARGETS "${__total}" CACHE INTERNAL "")
-  message(STATUS "Pylint: registered ${__total} targets. Build 'check_pylint' target to run checks (\"cmake --build . --target check_pylint\" or \"make check_pylint\")")
   configure_file("${OpenCV_SOURCE_DIR}/cmake/templates/pylint.cmake.in" "${CMAKE_BINARY_DIR}/pylint.cmake" @ONLY)
 
   add_custom_target(check_pylint

modules/calib3d/src/polynom_solver.cpp

@@ -65,7 +65,8 @@ int solve_deg3(double a, double b, double c, double d,
       return 3;
     }
     else {
-      x0 = pow(2 * R, 1 / 3.0) - b_a_3;
+      double cube_root = cv::cubeRoot(2 * R);
+      x0 = cube_root - b_a_3;
       return 1;
     }
   }
@@ -82,8 +83,15 @@ int solve_deg3(double a, double b, double c, double d,
   }
 
   // D > 0, only one real root
-  double AD = pow(fabs(R) + sqrt(D), 1.0 / 3.0) * (R > 0 ? 1 : (R < 0 ? -1 : 0));
-  double BD = (AD == 0) ? 0 : -Q / AD;
+  double AD = 0.;
+  double BD = 0.;
+  double R_abs = fabs(R);
+  if (R_abs > DBL_EPSILON)
+  {
+    AD = cv::cubeRoot(R_abs + sqrt(D));
+    AD = (R >= 0) ? AD : -AD;
+    BD = -Q / AD;
+  }
 
   // Calculate the only real root
   x0 = AD + BD - b_a_3;

modules/core/include/opencv2/core/base.hpp

@@ -538,6 +538,16 @@ _AccTp normInf(const _Tp* a, const _Tp* b, int n)
  */
 CV_EXPORTS_W float cubeRoot(float val);
 
+/** @overload
+
+cubeRoot with argument of `double` type calls `std::cbrt(double)`
+*/
+static inline
+double cubeRoot(double val)
+{
+    return std::cbrt(val);
+}
+
 /** @brief Calculates the angle of a 2D vector in degrees.
 
  The function fastAtan2 calculates the full-range angle of an input 2D vector. The angle is measured