diff --git a/modules/core/include/opencv2/core/mat.inl.hpp b/modules/core/include/opencv2/core/mat.inl.hpp
index ff1b9f8ee7..609f4bd57b 100644
--- a/modules/core/include/opencv2/core/mat.inl.hpp
+++ b/modules/core/include/opencv2/core/mat.inl.hpp
@@ -919,7 +919,7 @@ _Tp* Mat::ptr(int y)
 template<typename _Tp> inline
 const _Tp* Mat::ptr(int y) const
 {
-    CV_DbgAssert( y == 0 || (data && dims >= 1 && data && (unsigned)y < (unsigned)size.p[0]) );
+    CV_DbgAssert( y == 0 || (data && dims >= 1 && (unsigned)y < (unsigned)size.p[0]) );
     return (const _Tp*)(data + step.p[0] * y);
 }
 
diff --git a/modules/core/src/arithm.cpp b/modules/core/src/arithm.cpp
index 2304378355..1a464c9aec 100644
--- a/modules/core/src/arithm.cpp
+++ b/modules/core/src/arithm.cpp
@@ -270,7 +270,7 @@ static void binary_op( InputArray _src1, InputArray _src2, OutputArray _dst,
     if( !haveScalar )
     {
         const Mat* arrays[] = { &src1, &src2, &dst, &mask, 0 };
-        uchar* ptrs[4];
+        uchar* ptrs[4]{};
 
         NAryMatIterator it(arrays, ptrs);
         size_t total = it.size, blocksize = total;
@@ -306,7 +306,7 @@ static void binary_op( InputArray _src1, InputArray _src2, OutputArray _dst,
     else
     {
         const Mat* arrays[] = { &src1, &dst, &mask, 0 };
-        uchar* ptrs[3];
+        uchar* ptrs[3]{};
 
         NAryMatIterator it(arrays, ptrs);
         size_t total = it.size, blocksize = std::min(total, blocksize0);
@@ -745,7 +745,7 @@ static void arithm_op(InputArray _src1, InputArray _src2, OutputArray _dst,
     if( !haveScalar )
     {
         const Mat* arrays[] = { &src1, &src2, &dst, &mask, 0 };
-        uchar* ptrs[4];
+        uchar* ptrs[4]{};
 
         NAryMatIterator it(arrays, ptrs);
         size_t total = it.size, blocksize = total;
@@ -812,7 +812,7 @@ static void arithm_op(InputArray _src1, InputArray _src2, OutputArray _dst,
     else
     {
         const Mat* arrays[] = { &src1, &dst, &mask, 0 };
-        uchar* ptrs[3];
+        uchar* ptrs[3]{};
 
         NAryMatIterator it(arrays, ptrs);
         size_t total = it.size, blocksize = std::min(total, blocksize0);
@@ -1240,7 +1240,7 @@ void cv::compare(InputArray _src1, InputArray _src2, OutputArray _dst, int op)
     if( !haveScalar )
     {
         const Mat* arrays[] = { &src1, &src2, &dst, 0 };
-        uchar* ptrs[3];
+        uchar* ptrs[3]{};
 
         NAryMatIterator it(arrays, ptrs);
         size_t total = it.size;
@@ -1251,7 +1251,7 @@ void cv::compare(InputArray _src1, InputArray _src2, OutputArray _dst, int op)
     else
     {
         const Mat* arrays[] = { &src1, &dst, 0 };
-        uchar* ptrs[2];
+        uchar* ptrs[2]{};
 
         NAryMatIterator it(arrays, ptrs);
         size_t total = it.size, blocksize = std::min(total, blocksize0);
@@ -1748,7 +1748,7 @@ void cv::inRange(InputArray _src, InputArray _lowerb,
 
     const Mat* arrays_sc[] = { &src, &dst, 0 };
     const Mat* arrays_nosc[] = { &src, &dst, &lb, &ub, 0 };
-    uchar* ptrs[4];
+    uchar* ptrs[4]{};
 
     NAryMatIterator it(lbScalar && ubScalar ? arrays_sc : arrays_nosc, ptrs);
     size_t total = it.size, blocksize = std::min(total, blocksize0);
diff --git a/modules/core/src/convert.cpp b/modules/core/src/convert.cpp
index e5fd24dfad..7a027dd809 100644
--- a/modules/core/src/convert.cpp
+++ b/modules/core/src/convert.cpp
@@ -1347,7 +1347,7 @@ void cv::Mat::convertTo(OutputArray _dst, int _type, double alpha, double beta)
     else
     {
         const Mat* arrays[] = {&src, &dst, 0};
-        uchar* ptrs[2];
+        uchar* ptrs[2]{};
         NAryMatIterator it(arrays, ptrs);
         Size sz((int)(it.size*cn), 1);
 
@@ -1496,7 +1496,7 @@ void cv::convertFp16( InputArray _src, OutputArray _dst)
     else
     {
         const Mat* arrays[] = {&src, &dst, 0};
-        uchar* ptrs[2];
+        uchar* ptrs[2]{};
         NAryMatIterator it(arrays, ptrs);
         Size sz((int)(it.size*cn), 1);
 
diff --git a/modules/core/src/convert_scale.cpp b/modules/core/src/convert_scale.cpp
index ff8398a27b..44a968ff6c 100644
--- a/modules/core/src/convert_scale.cpp
+++ b/modules/core/src/convert_scale.cpp
@@ -1775,7 +1775,7 @@ void cv::convertScaleAbs( InputArray _src, OutputArray _dst, double alpha, doubl
     else
     {
         const Mat* arrays[] = {&src, &dst, 0};
-        uchar* ptrs[2];
+        uchar* ptrs[2]{};
         NAryMatIterator it(arrays, ptrs);
         Size sz((int)it.size*cn, 1);
 
diff --git a/modules/core/src/copy.cpp b/modules/core/src/copy.cpp
index e89a17b323..66ce393b3f 100644
--- a/modules/core/src/copy.cpp
+++ b/modules/core/src/copy.cpp
@@ -306,7 +306,7 @@ void Mat::copyTo( OutputArray _dst ) const
     if( total() != 0 )
     {
         const Mat* arrays[] = { this, &dst };
-        uchar* ptrs[2];
+        uchar* ptrs[2]{};
         NAryMatIterator it(arrays, ptrs, 2);
         size_t sz = it.size*elemSize();
 
@@ -399,7 +399,7 @@ void Mat::copyTo( OutputArray _dst, InputArray _mask ) const
     }
 
     const Mat* arrays[] = { this, &dst, &mask, 0 };
-    uchar* ptrs[3];
+    uchar* ptrs[3]{};
     NAryMatIterator it(arrays, ptrs);
     Size sz((int)(it.size*mcn), 1);
 
diff --git a/modules/core/src/count_non_zero.cpp b/modules/core/src/count_non_zero.cpp
index b703b31b27..804d46dc34 100644
--- a/modules/core/src/count_non_zero.cpp
+++ b/modules/core/src/count_non_zero.cpp
@@ -378,7 +378,7 @@ int cv::countNonZero( InputArray _src )
     CV_Assert( func != 0 );
 
     const Mat* arrays[] = {&src, 0};
-    uchar* ptrs[1];
+    uchar* ptrs[1]{};
     NAryMatIterator it(arrays, ptrs);
     int total = (int)it.size, nz = 0;
 
diff --git a/modules/core/src/lut.cpp b/modules/core/src/lut.cpp
index 71f06ea5b2..6ed26b6909 100644
--- a/modules/core/src/lut.cpp
+++ b/modules/core/src/lut.cpp
@@ -342,7 +342,7 @@ public:
         int lutcn = lut_.channels();
 
         const Mat* arrays[] = {&src, &dst, 0};
-        uchar* ptrs[2];
+        uchar* ptrs[2]{};
         NAryMatIterator it(arrays, ptrs);
         int len = (int)it.size;
 
@@ -408,7 +408,7 @@ void cv::LUT( InputArray _src, InputArray _lut, OutputArray _dst )
     CV_Assert( func != 0 );
 
     const Mat* arrays[] = {&src, &dst, 0};
-    uchar* ptrs[2];
+    uchar* ptrs[2]{};
     NAryMatIterator it(arrays, ptrs);
     int len = (int)it.size;
 
diff --git a/modules/core/src/mathfuncs.cpp b/modules/core/src/mathfuncs.cpp
index 5737e8d0b3..89fad4e734 100644
--- a/modules/core/src/mathfuncs.cpp
+++ b/modules/core/src/mathfuncs.cpp
@@ -158,7 +158,7 @@ void magnitude( InputArray src1, InputArray src2, OutputArray dst )
     Mat Mag = dst.getMat();
 
     const Mat* arrays[] = {&X, &Y, &Mag, 0};
-    uchar* ptrs[3];
+    uchar* ptrs[3]{};
     NAryMatIterator it(arrays, ptrs);
     int len = (int)it.size*cn;
 
@@ -194,7 +194,7 @@ void phase( InputArray src1, InputArray src2, OutputArray dst, bool angleInDegre
     Mat Angle = dst.getMat();
 
     const Mat* arrays[] = {&X, &Y, &Angle, 0};
-    uchar* ptrs[3];
+    uchar* ptrs[3]{};
     NAryMatIterator it(arrays, ptrs);
     int j, total = (int)(it.size*cn), blockSize = total;
     size_t esz1 = X.elemSize1();
@@ -280,7 +280,7 @@ void cartToPolar( InputArray src1, InputArray src2,
     Mat Mag = dst1.getMat(), Angle = dst2.getMat();
 
     const Mat* arrays[] = {&X, &Y, &Mag, &Angle, 0};
-    uchar* ptrs[4];
+    uchar* ptrs[4]{};
     NAryMatIterator it(arrays, ptrs);
     int j, total = (int)(it.size*cn), blockSize = std::min(total, ((BLOCK_SIZE+cn-1)/cn)*cn);
     size_t esz1 = X.elemSize1();
@@ -577,7 +577,7 @@ void polarToCart( InputArray src1, InputArray src2,
     CV_IPP_RUN(!angleInDegrees, ipp_polarToCart(Mag, Angle, X, Y));
 
     const Mat* arrays[] = {&Mag, &Angle, &X, &Y, 0};
-    uchar* ptrs[4];
+    uchar* ptrs[4]{};
     NAryMatIterator it(arrays, ptrs);
     cv::AutoBuffer<float> _buf;
     float* buf[2] = {0, 0};
@@ -676,7 +676,7 @@ void exp( InputArray _src, OutputArray _dst )
     Mat dst = _dst.getMat();
 
     const Mat* arrays[] = {&src, &dst, 0};
-    uchar* ptrs[2];
+    uchar* ptrs[2]{};
     NAryMatIterator it(arrays, ptrs);
     int len = (int)(it.size*cn);
 
@@ -709,7 +709,7 @@ void log( InputArray _src, OutputArray _dst )
     Mat dst = _dst.getMat();
 
     const Mat* arrays[] = {&src, &dst, 0};
-    uchar* ptrs[2];
+    uchar* ptrs[2]{};
     NAryMatIterator it(arrays, ptrs);
     int len = (int)(it.size*cn);
 
@@ -1241,7 +1241,7 @@ void pow( InputArray _src, double power, OutputArray _dst )
     Mat dst = _dst.getMat();
 
     const Mat* arrays[] = {&src, &dst, 0};
-    uchar* ptrs[2];
+    uchar* ptrs[2]{};
     NAryMatIterator it(arrays, ptrs);
     int len = (int)(it.size*cn);
 
@@ -1588,7 +1588,7 @@ void patchNaNs( InputOutputArray _a, double _val )
 
     Mat a = _a.getMat();
     const Mat* arrays[] = {&a, 0};
-    int* ptrs[1];
+    int* ptrs[1]{};
     NAryMatIterator it(arrays, (uchar**)ptrs);
     size_t len = it.size*a.channels();
     Cv32suf val;
diff --git a/modules/core/src/matmul.cpp b/modules/core/src/matmul.cpp
index 83607c7184..7c5655e9e6 100644
--- a/modules/core/src/matmul.cpp
+++ b/modules/core/src/matmul.cpp
@@ -2144,7 +2144,7 @@ void cv::transform( InputArray _src, OutputArray _dst, InputArray _mtx )
     CV_Assert( func != 0 );
 
     const Mat* arrays[] = {&src, &dst, 0};
-    uchar* ptrs[2];
+    uchar* ptrs[2]{};
     NAryMatIterator it(arrays, ptrs);
     size_t i, total = it.size;
 
@@ -2290,7 +2290,7 @@ void cv::perspectiveTransform( InputArray _src, OutputArray _dst, InputArray _mt
     CV_Assert( func != 0 );
 
     const Mat* arrays[] = {&src, &dst, 0};
-    uchar* ptrs[2];
+    uchar* ptrs[2]{};
     NAryMatIterator it(arrays, ptrs);
     size_t i, total = it.size;
 
@@ -2441,7 +2441,7 @@ void cv::scaleAdd( InputArray _src1, double alpha, InputArray _src2, OutputArray
     }
 
     const Mat* arrays[] = {&src1, &src2, &dst, 0};
-    uchar* ptrs[3];
+    uchar* ptrs[3]{};
     NAryMatIterator it(arrays, ptrs);
     size_t i, len = it.size*cn;
 
@@ -3301,7 +3301,7 @@ double Mat::dot(InputArray _mat) const
     }
 
     const Mat* arrays[] = {this, &mat, 0};
-    uchar* ptrs[2];
+    uchar* ptrs[2]{};
     NAryMatIterator it(arrays, ptrs);
     int len = (int)(it.size*cn);
     double r = 0;
diff --git a/modules/core/src/mean.cpp b/modules/core/src/mean.cpp
index dcf1ae206c..0badfa2f65 100644
--- a/modules/core/src/mean.cpp
+++ b/modules/core/src/mean.cpp
@@ -121,7 +121,7 @@ cv::Scalar cv::mean( InputArray _src, InputArray _mask )
     CV_Assert( cn <= 4 && func != 0 );
 
     const Mat* arrays[] = {&src, &mask, 0};
-    uchar* ptrs[2];
+    uchar* ptrs[2]{};
     NAryMatIterator it(arrays, ptrs);
     int total = (int)it.size, blockSize = total, intSumBlockSize = 0;
     int j, count = 0;
@@ -786,7 +786,7 @@ void cv::meanStdDev( InputArray _src, OutputArray _mean, OutputArray _sdv, Input
     CV_Assert( func != 0 );
 
     const Mat* arrays[] = {&src, &mask, 0};
-    uchar* ptrs[2];
+    uchar* ptrs[2]{};
     NAryMatIterator it(arrays, ptrs);
     int total = (int)it.size, blockSize = total, intSumBlockSize = 0;
     int j, count = 0, nz0 = 0;
diff --git a/modules/core/src/minmax.cpp b/modules/core/src/minmax.cpp
index d2b56646b8..371438184e 100644
--- a/modules/core/src/minmax.cpp
+++ b/modules/core/src/minmax.cpp
@@ -770,7 +770,7 @@ void cv::minMaxIdx(InputArray _src, double* minVal,
     CV_Assert( func != 0 );
 
     const Mat* arrays[] = {&src, &mask, 0};
-    uchar* ptrs[2];
+    uchar* ptrs[2]{};
     NAryMatIterator it(arrays, ptrs);
 
     size_t minidx = 0, maxidx = 0;
diff --git a/modules/core/src/norm.cpp b/modules/core/src/norm.cpp
index 6b95238af9..40d195c3f8 100644
--- a/modules/core/src/norm.cpp
+++ b/modules/core/src/norm.cpp
@@ -710,7 +710,7 @@ double cv::norm( InputArray _src, int normType, InputArray _mask )
         int cellSize = normType == NORM_HAMMING ? 1 : 2;
 
         const Mat* arrays[] = {&src, 0};
-        uchar* ptrs[1];
+        uchar* ptrs[1]{};
         NAryMatIterator it(arrays, ptrs);
         int total = (int)it.size;
         int result = 0;
@@ -727,7 +727,7 @@ double cv::norm( InputArray _src, int normType, InputArray _mask )
     CV_Assert( func != 0 );
 
     const Mat* arrays[] = {&src, &mask, 0};
-    uchar* ptrs[2];
+    uchar* ptrs[2]{};
     union
     {
         double d;
@@ -1168,7 +1168,7 @@ double cv::norm( InputArray _src1, InputArray _src2, int normType, InputArray _m
         int cellSize = normType == NORM_HAMMING ? 1 : 2;
 
         const Mat* arrays[] = {&src1, &src2, 0};
-        uchar* ptrs[2];
+        uchar* ptrs[2]{};
         NAryMatIterator it(arrays, ptrs);
         int total = (int)it.size;
         int result = 0;
@@ -1185,7 +1185,7 @@ double cv::norm( InputArray _src1, InputArray _src2, int normType, InputArray _m
     CV_Assert( func != 0 );
 
     const Mat* arrays[] = {&src1, &src2, &mask, 0};
-    uchar* ptrs[3];
+    uchar* ptrs[3]{};
     union
     {
         double d;
diff --git a/modules/core/src/parallel_impl.cpp b/modules/core/src/parallel_impl.cpp
index cf8165e3cd..1aaa56a9ee 100644
--- a/modules/core/src/parallel_impl.cpp
+++ b/modules/core/src/parallel_impl.cpp
@@ -186,9 +186,9 @@ public:
     pthread_t posix_thread;
     bool is_created;
 
-    volatile bool stop_thread;
+    std::atomic<bool> stop_thread;
 
-    volatile bool has_wake_signal;
+    std::atomic<bool> has_wake_signal;
 
     Ptr<ParallelJob> job;
 
@@ -394,7 +394,7 @@ void WorkerThread::thread_body()
         if (CV_WORKER_ACTIVE_WAIT_THREADS_LIMIT == 0)
             allow_active_wait = true;
         Ptr<ParallelJob> j_ptr; swap(j_ptr, job);
-        has_wake_signal = false;    // TODO .store(false, std::memory_order_release)
+        has_wake_signal = false;
         pthread_mutex_unlock(&mutex);
 
         if (!stop_thread)
diff --git a/modules/core/src/sum.cpp b/modules/core/src/sum.cpp
index f965823889..be68f13abd 100644
--- a/modules/core/src/sum.cpp
+++ b/modules/core/src/sum.cpp
@@ -602,7 +602,7 @@ cv::Scalar cv::sum( InputArray _src )
     CV_Assert( cn <= 4 && func != 0 );
 
     const Mat* arrays[] = {&src, 0};
-    uchar* ptrs[1];
+    uchar* ptrs[1]{};
     NAryMatIterator it(arrays, ptrs);
     Scalar s;
     int total = (int)it.size, blockSize = total, intSumBlockSize = 0;
diff --git a/modules/cudaimgproc/src/canny.cpp b/modules/cudaimgproc/src/canny.cpp
index 8c3fd4a2b5..9a1125d1cd 100644
--- a/modules/cudaimgproc/src/canny.cpp
+++ b/modules/cudaimgproc/src/canny.cpp
@@ -74,6 +74,7 @@ namespace
             low_thresh_(low_thresh), high_thresh_(high_thresh), apperture_size_(apperture_size), L2gradient_(L2gradient)
         {
             old_apperture_size_ = -1;
+            d_counter = nullptr;
         }
 
         void detect(InputArray image, OutputArray edges, Stream& stream);
diff --git a/modules/imgproc/src/accum.cpp b/modules/imgproc/src/accum.cpp
index 2b43f4e42c..fece3139e7 100644
--- a/modules/imgproc/src/accum.cpp
+++ b/modules/imgproc/src/accum.cpp
@@ -332,7 +332,7 @@ void cv::accumulate( InputArray _src, InputOutputArray _dst, InputArray _mask )
     CV_Assert( func != 0 );
 
     const Mat* arrays[] = {&src, &dst, &mask, 0};
-    uchar* ptrs[3];
+    uchar* ptrs[3]{};
     NAryMatIterator it(arrays, ptrs);
     int len = (int)it.size;
 
@@ -430,7 +430,7 @@ void cv::accumulateSquare( InputArray _src, InputOutputArray _dst, InputArray _m
     CV_Assert( func != 0 );
 
     const Mat* arrays[] = {&src, &dst, &mask, 0};
-    uchar* ptrs[3];
+    uchar* ptrs[3]{};
     NAryMatIterator it(arrays, ptrs);
     int len = (int)it.size;
 
@@ -533,7 +533,7 @@ void cv::accumulateProduct( InputArray _src1, InputArray _src2,
     CV_Assert( func != 0 );
 
     const Mat* arrays[] = {&src1, &src2, &dst, &mask, 0};
-    uchar* ptrs[4];
+    uchar* ptrs[4]{};
     NAryMatIterator it(arrays, ptrs);
     int len = (int)it.size;
 
@@ -635,7 +635,7 @@ void cv::accumulateWeighted( InputArray _src, InputOutputArray _dst,
     CV_Assert( func != 0 );
 
     const Mat* arrays[] = {&src, &dst, &mask, 0};
-    uchar* ptrs[3];
+    uchar* ptrs[3]{};
     NAryMatIterator it(arrays, ptrs);
     int len = (int)it.size;