diff --git a/modules/calib3d/src/solvepnp.cpp b/modules/calib3d/src/solvepnp.cpp
index 07780c4b17..d9e2664877 100644
--- a/modules/calib3d/src/solvepnp.cpp
+++ b/modules/calib3d/src/solvepnp.cpp
@@ -152,12 +152,13 @@ public:
     int runKernel( InputArray _m1, InputArray _m2, OutputArray _model ) const CV_OVERRIDE
     {
         Mat opoints = _m1.getMat(), ipoints = _m2.getMat();
-
+        Mat iter_rvec = rvec.clone();
+        Mat iter_tvec = tvec.clone();
         bool correspondence = solvePnP( _m1, _m2, cameraMatrix, distCoeffs,
-                                            rvec, tvec, useExtrinsicGuess, flags );
+                                            iter_rvec, iter_tvec, useExtrinsicGuess, flags );
 
         Mat _local_model;
-        hconcat(rvec, tvec, _local_model);
+        hconcat(iter_rvec, iter_tvec, _local_model);
         _local_model.copyTo(_model);
 
         return correspondence;
@@ -336,7 +337,13 @@ bool solvePnPRansac(InputArray _opoints, InputArray _ipoints,
     ipoints_inliers.resize(npoints1);
     try
     {
-        result = solvePnP(opoints_inliers, ipoints_inliers, cameraMatrix,
+       if (flags == SOLVEPNP_ITERATIVE && !useExtrinsicGuess)
+       {
+          rvec = _local_model.col(0).clone();
+          tvec = _local_model.col(1).clone();
+          useExtrinsicGuess = true;
+       }
+       result = solvePnP(opoints_inliers, ipoints_inliers, cameraMatrix,
                           distCoeffs, rvec, tvec, useExtrinsicGuess,
                           (flags == SOLVEPNP_P3P || flags == SOLVEPNP_AP3P) ? SOLVEPNP_EPNP : flags) ? 1 : -1;
     }
diff --git a/modules/core/src/parallel_impl.cpp b/modules/core/src/parallel_impl.cpp
index 3abd054743..b18204ce84 100644
--- a/modules/core/src/parallel_impl.cpp
+++ b/modules/core/src/parallel_impl.cpp
@@ -45,9 +45,8 @@ DECLARE_CV_PAUSE
       static inline void cv_non_sse_mm_pause() { __asm__ __volatile__ ("rep; nop"); }
 #     define _mm_pause cv_non_sse_mm_pause
 #   endif
-// 5 * v is meants for backward compatibility: with pre-Skylake CPUs, _mm_pause took 4 or 5 cycles.
-// With post-Skylake CPUs, _mm_pause takes 140 cycles.
-#   define CV_PAUSE(v) do { const uint64_t __delay = 5 * v; uint64_t __init = __rdtsc(); do { _mm_pause(); } while ((__rdtsc() - __init) < __delay); } while (0)
+// With Skylake CPUs and above, _mm_pause takes 140 cycles so no need for a loop.
+#   define CV_PAUSE(v) do { (void)v; _mm_pause(); } while (0)
 # elif defined __GNUC__ && defined __aarch64__
 #   define CV_PAUSE(v) do { for (int __delay = (v); __delay > 0; --__delay) { asm volatile("yield" ::: "memory"); } } while (0)
 # elif defined __GNUC__ && defined __arm__
diff --git a/modules/imgproc/src/color.hpp b/modules/imgproc/src/color.hpp
index e3c25f08d9..abbd65ec06 100644
--- a/modules/imgproc/src/color.hpp
+++ b/modules/imgproc/src/color.hpp
@@ -115,6 +115,12 @@ inline int dstChannels(int code)
         case COLOR_YUV2BGR_YV12: case COLOR_YUV2RGB_YV12: case COLOR_YUV2BGR_IYUV: case COLOR_YUV2RGB_IYUV:
         case COLOR_YUV2RGB_UYVY: case COLOR_YUV2BGR_UYVY: case COLOR_YUV2RGB_YVYU: case COLOR_YUV2BGR_YVYU:
         case COLOR_YUV2RGB_YUY2: case COLOR_YUV2BGR_YUY2:
+        case COLOR_Lab2BGR: case COLOR_Lab2RGB: case COLOR_BGR2Lab: case COLOR_RGB2Lab:
+        case COLOR_Lab2LBGR: case COLOR_Lab2LRGB:
+        case COLOR_Luv2BGR: case COLOR_Luv2RGB: case COLOR_BGR2Luv: case COLOR_RGB2Luv:
+        case COLOR_Luv2LBGR: case COLOR_Luv2LRGB:
+        case COLOR_YCrCb2BGR: case COLOR_YCrCb2RGB: case COLOR_BGR2YCrCb: case COLOR_RGB2YCrCb:
+        case COLOR_XYZ2BGR: case COLOR_XYZ2RGB: case COLOR_BGR2XYZ: case COLOR_RGB2XYZ:
 
             return 3;