diff --git a/modules/core/include/opencv2/core/cuda.hpp b/modules/core/include/opencv2/core/cuda.hpp
index bc6dd31438..fe7c0a8c48 100644
--- a/modules/core/include/opencv2/core/cuda.hpp
+++ b/modules/core/include/opencv2/core/cuda.hpp
@@ -261,8 +261,8 @@ public:
     int* refcount;
 
     //! helper fields used in locateROI and adjustROI
-    uchar* datastart;
-    uchar* dataend;
+    const uchar* datastart;
+    const uchar* dataend;
 
     //! allocator
     Allocator* allocator;
@@ -349,8 +349,8 @@ public:
     uchar* data;
     int* refcount;
 
-    uchar* datastart;
-    uchar* dataend;
+    const uchar* datastart;
+    const uchar* dataend;
 
     AllocType alloc_type;
 };
diff --git a/modules/core/include/opencv2/core/mat.hpp b/modules/core/include/opencv2/core/mat.hpp
index 945b450303..44501f6de9 100644
--- a/modules/core/include/opencv2/core/mat.hpp
+++ b/modules/core/include/opencv2/core/mat.hpp
@@ -395,7 +395,7 @@ struct CV_EXPORTS UMatData
 
 struct CV_EXPORTS UMatDataAutoLock
 {
-    UMatDataAutoLock(UMatData* u);
+    explicit UMatDataAutoLock(UMatData* u);
     ~UMatDataAutoLock();
     UMatData* u;
 };
@@ -403,7 +403,7 @@ struct CV_EXPORTS UMatDataAutoLock
 
 struct CV_EXPORTS MatSize
 {
-    MatSize(int* _p);
+    explicit MatSize(int* _p);
     Size operator()() const;
     const int& operator[](int i) const;
     int& operator[](int i);
@@ -417,7 +417,7 @@ struct CV_EXPORTS MatSize
 struct CV_EXPORTS MatStep
 {
     MatStep();
-    MatStep(size_t s);
+    explicit MatStep(size_t s);
     const size_t& operator[](int i) const;
     size_t& operator[](int i);
     operator size_t() const;
@@ -918,9 +918,9 @@ public:
     uchar* data;
 
     //! helper fields used in locateROI and adjustROI
-    uchar* datastart;
-    uchar* dataend;
-    uchar* datalimit;
+    const uchar* datastart;
+    const uchar* dataend;
+    const uchar* datalimit;
 
     //! custom allocator
     MatAllocator* allocator;
@@ -1804,9 +1804,9 @@ public:
     //! copy operator
     MatConstIterator& operator = (const MatConstIterator& it);
     //! returns the current matrix element
-    uchar* operator *() const;
+    const uchar* operator *() const;
     //! returns the i-th matrix element, relative to the current
-    uchar* operator [](ptrdiff_t i) const;
+    const uchar* operator [](ptrdiff_t i) const;
 
     //! shifts the iterator forward by the specified number of elements
     MatConstIterator& operator += (ptrdiff_t ofs);
@@ -1831,9 +1831,9 @@ public:
 
     const Mat* m;
     size_t elemSize;
-    uchar* ptr;
-    uchar* sliceStart;
-    uchar* sliceEnd;
+    const uchar* ptr;
+    const uchar* sliceStart;
+    const uchar* sliceEnd;
 };
 
 
@@ -1917,9 +1917,9 @@ public:
     //! constructor that sets the iterator to the specified element of the matrix
     MatIterator_(Mat_<_Tp>* _m, int _row, int _col=0);
     //! constructor that sets the iterator to the specified element of the matrix
-    MatIterator_(const Mat_<_Tp>* _m, Point _pt);
+    MatIterator_(Mat_<_Tp>* _m, Point _pt);
     //! constructor that sets the iterator to the specified element of the matrix
-    MatIterator_(const Mat_<_Tp>* _m, const int* _idx);
+    MatIterator_(Mat_<_Tp>* _m, const int* _idx);
     //! copy constructor
     MatIterator_(const MatIterator_& it);
     //! copy operator
diff --git a/modules/core/include/opencv2/core/mat.inl.hpp b/modules/core/include/opencv2/core/mat.inl.hpp
index dae0e137a8..6923146f94 100644
--- a/modules/core/include/opencv2/core/mat.inl.hpp
+++ b/modules/core/include/opencv2/core/mat.inl.hpp
@@ -438,7 +438,7 @@ Mat::Mat(const std::vector<_Tp>& vec, bool copyData)
     if( !copyData )
     {
         step[0] = step[1] = sizeof(_Tp);
-        data = datastart = (uchar*)&vec[0];
+        datastart = data = (uchar*)&vec[0];
         datalimit = dataend = datastart + rows * step[0];
     }
     else
@@ -453,7 +453,7 @@ Mat::Mat(const Vec<_Tp, n>& vec, bool copyData)
     if( !copyData )
     {
         step[0] = step[1] = sizeof(_Tp);
-        data = datastart = (uchar*)vec.val;
+        datastart = data = (uchar*)vec.val;
         datalimit = dataend = datastart + rows * step[0];
     }
     else
@@ -470,7 +470,7 @@ Mat::Mat(const Matx<_Tp,m,n>& M, bool copyData)
     {
         step[0] = cols * sizeof(_Tp);
         step[1] = sizeof(_Tp);
-        data = datastart = (uchar*)M.val;
+        datastart = data = (uchar*)M.val;
         datalimit = dataend = datastart + rows * step[0];
     }
     else
@@ -485,7 +485,7 @@ Mat::Mat(const Point_<_Tp>& pt, bool copyData)
     if( !copyData )
     {
         step[0] = step[1] = sizeof(_Tp);
-        data = datastart = (uchar*)&pt.x;
+        datastart = data = (uchar*)&pt.x;
         datalimit = dataend = datastart + rows * step[0];
     }
     else
@@ -504,7 +504,7 @@ Mat::Mat(const Point3_<_Tp>& pt, bool copyData)
     if( !copyData )
     {
         step[0] = step[1] = sizeof(_Tp);
-        data = datastart = (uchar*)&pt.x;
+        datastart = data = (uchar*)&pt.x;
         datalimit = dataend = datastart + rows * step[0];
     }
     else
@@ -642,7 +642,7 @@ inline void Mat::release()
     if( u && CV_XADD(&u->refcount, -1) == 1 )
         deallocate();
     u = NULL;
-    data = datastart = dataend = datalimit = 0;
+    datastart = dataend = datalimit = data = 0;
     size.p[0] = 0;
 }
 
@@ -1044,7 +1044,7 @@ void Mat::push_back(const _Tp& elem)
     }
     CV_Assert(DataType<_Tp>::type == type() && cols == 1
               /* && dims == 2 (cols == 1 implies dims == 2) */);
-    uchar* tmp = dataend + step[0];
+    const uchar* tmp = dataend + step[0];
     if( !isSubmatrix() && isContinuous() && tmp <= datalimit )
     {
         *(_Tp*)(data + (size.p[0]++) * step.p[0]) = elem;
@@ -2148,7 +2148,7 @@ MatConstIterator& MatConstIterator::operator = (const MatConstIterator& it )
 }
 
 inline
-uchar* MatConstIterator::operator *() const
+const uchar* MatConstIterator::operator *() const
 {
     return ptr;
 }
@@ -2281,7 +2281,7 @@ MatConstIterator operator - (const MatConstIterator& a, ptrdiff_t ofs)
 
 
 inline
-uchar* MatConstIterator::operator [](ptrdiff_t i) const
+const uchar* MatConstIterator::operator [](ptrdiff_t i) const
 {
     return *(*this + i);
 }
@@ -2453,12 +2453,12 @@ MatIterator_<_Tp>::MatIterator_(Mat_<_Tp>* _m, int _row, int _col)
 {}
 
 template<typename _Tp> inline
-MatIterator_<_Tp>::MatIterator_(const Mat_<_Tp>* _m, Point _pt)
+MatIterator_<_Tp>::MatIterator_(Mat_<_Tp>* _m, Point _pt)
     : MatConstIterator_<_Tp>(_m, _pt)
 {}
 
 template<typename _Tp> inline
-MatIterator_<_Tp>::MatIterator_(const Mat_<_Tp>* _m, const int* _idx)
+MatIterator_<_Tp>::MatIterator_(Mat_<_Tp>* _m, const int* _idx)
     : MatConstIterator_<_Tp>(_m, _idx)
 {}
 
@@ -2592,7 +2592,7 @@ inline SparseMatConstIterator& SparseMatConstIterator::operator = (const SparseM
 template<typename _Tp> inline
 const _Tp& SparseMatConstIterator::value() const
 {
-    return *(_Tp*)ptr;
+    return *(const _Tp*)ptr;
 }
 
 inline
diff --git a/modules/core/src/dxt.cpp b/modules/core/src/dxt.cpp
index c1551acb41..c74d87dcba 100644
--- a/modules/core/src/dxt.cpp
+++ b/modules/core/src/dxt.cpp
@@ -2635,8 +2635,8 @@ void cv::dft( InputArray _src0, OutputArray _dst, int flags, int nonzero_rows )
 
             for( i = 0; i < nonzero_rows; i++ )
             {
-                uchar* sptr = src.data + i*src.step;
-                uchar* dptr0 = dst.data + i*dst.step;
+                const uchar* sptr = src.ptr(i);
+                uchar* dptr0 = dst.ptr(i);
                 uchar* dptr = dptr0;
 
                 if( tmp_buf )
@@ -2649,7 +2649,7 @@ void cv::dft( InputArray _src0, OutputArray _dst, int flags, int nonzero_rows )
 
             for( ; i < count; i++ )
             {
-                uchar* dptr0 = dst.data + i*dst.step;
+                uchar* dptr0 = dst.ptr(i);
                 memset( dptr0, 0, dst_full_len );
             }
 
@@ -2661,7 +2661,7 @@ void cv::dft( InputArray _src0, OutputArray _dst, int flags, int nonzero_rows )
         {
             int a = 0, b = count;
             uchar *buf0, *buf1, *dbuf0, *dbuf1;
-            uchar* sptr0 = src.data;
+            const uchar* sptr0 = src.data;
             uchar* dptr0 = dst.data;
             buf0 = ptr;
             ptr += len*complex_elem_size;
@@ -2800,7 +2800,7 @@ void cv::dft( InputArray _src0, OutputArray _dst, int flags, int nonzero_rows )
                     int n = dst.cols;
                     if( elem_size == (int)sizeof(float) )
                     {
-                        float* p0 = (float*)dst.data;
+                        float* p0 = dst.ptr<float>();
                         size_t dstep = dst.step/sizeof(p0[0]);
                         for( i = 0; i < len; i++ )
                         {
@@ -2816,7 +2816,7 @@ void cv::dft( InputArray _src0, OutputArray _dst, int flags, int nonzero_rows )
                     }
                     else
                     {
-                        double* p0 = (double*)dst.data;
+                        double* p0 = dst.ptr<double>();
                         size_t dstep = dst.step/sizeof(p0[0]);
                         for( i = 0; i < len; i++ )
                         {
diff --git a/modules/core/src/lapack.cpp b/modules/core/src/lapack.cpp
index 8895a56593..45881c3d55 100644
--- a/modules/core/src/lapack.cpp
+++ b/modules/core/src/lapack.cpp
@@ -955,10 +955,10 @@ double cv::invert( InputArray _src, OutputArray _dst, int method )
         SVD::compute(src, w, u, vt);
         SVD::backSubst(w, u, vt, Mat(), _dst);
         return type == CV_32F ?
-            (((float*)w.data)[0] >= FLT_EPSILON ?
-             ((float*)w.data)[n-1]/((float*)w.data)[0] : 0) :
-            (((double*)w.data)[0] >= DBL_EPSILON ?
-             ((double*)w.data)[n-1]/((double*)w.data)[0] : 0);
+            (w.ptr<float>()[0] >= FLT_EPSILON ?
+             w.ptr<float>()[n-1]/w.ptr<float>()[0] : 0) :
+            (w.ptr<double>()[0] >= DBL_EPSILON ?
+             w.ptr<double>()[n-1]/w.ptr<double>()[0] : 0);
     }
 
     CV_Assert( m == n );
@@ -975,10 +975,10 @@ double cv::invert( InputArray _src, OutputArray _dst, int method )
         transpose(vt, u);
         SVD::backSubst(w, u, vt, Mat(), _dst);
         return type == CV_32F ?
-        (((float*)w.data)[0] >= FLT_EPSILON ?
-         ((float*)w.data)[n-1]/((float*)w.data)[0] : 0) :
-        (((double*)w.data)[0] >= DBL_EPSILON ?
-         ((double*)w.data)[n-1]/((double*)w.data)[0] : 0);
+        (w.ptr<float>()[0] >= FLT_EPSILON ?
+         w.ptr<float>()[n-1]/w.ptr<float>()[0] : 0) :
+        (w.ptr<double>()[0] >= DBL_EPSILON ?
+         w.ptr<double>()[n-1]/w.ptr<double>()[0] : 0);
     }
 
     CV_Assert( method == DECOMP_LU || method == DECOMP_CHOLESKY );
@@ -988,7 +988,7 @@ double cv::invert( InputArray _src, OutputArray _dst, int method )
 
     if( n <= 3 )
     {
-        uchar* srcdata = src.data;
+        const uchar* srcdata = src.data;
         uchar* dstdata = dst.data;
         size_t srcstep = src.step;
         size_t dststep = dst.step;
@@ -1212,8 +1212,8 @@ bool cv::solve( InputArray _src, InputArray _src2arg, OutputArray _dst, int meth
         #define bf(y) ((float*)(bdata + y*src2step))[0]
         #define bd(y) ((double*)(bdata + y*src2step))[0]
 
-        uchar* srcdata = src.data;
-        uchar* bdata = _src2.data;
+        const uchar* srcdata = src.data;
+        const uchar* bdata = _src2.data;
         uchar* dstdata = dst.data;
         size_t srcstep = src.step;
         size_t src2step = _src2.step;
@@ -1709,7 +1709,7 @@ cvEigenVV( CvArr* srcarr, CvArr* evectsarr, CvArr* evalsarr, double,
         eigen(src, evals, evects);
         if( evects0.data != evects.data )
         {
-            uchar* p = evects0.data;
+            const uchar* p = evects0.data;
             evects.convertTo(evects0, evects0.type());
             CV_Assert( p == evects0.data );
         }
@@ -1718,7 +1718,7 @@ cvEigenVV( CvArr* srcarr, CvArr* evectsarr, CvArr* evalsarr, double,
         eigen(src, evals);
     if( evals0.data != evals.data )
     {
-        uchar* p = evals0.data;
+        const uchar* p = evals0.data;
         if( evals0.size() == evals.size() )
             evals.convertTo(evals0, evals0.type());
         else if( evals0.type() == evals.type() )
diff --git a/modules/core/src/matrix.cpp b/modules/core/src/matrix.cpp
index 7eff30660c..af0fe2219b 100644
--- a/modules/core/src/matrix.cpp
+++ b/modules/core/src/matrix.cpp
@@ -346,7 +346,7 @@ static void finalizeHdr(Mat& m)
     if( d > 2 )
         m.rows = m.cols = -1;
     if(m.u)
-        m.data = m.datastart = m.u->data;
+        m.datastart = m.data = m.u->data;
     if( m.data )
     {
         m.datalimit = m.datastart + m.size[0]*m.step[0];
@@ -510,7 +510,7 @@ Mat::Mat(int _dims, const int* _sizes, int _type, void* _data, const size_t* _st
       datalimit(0), allocator(0), u(0), size(&rows)
 {
     flags |= CV_MAT_TYPE(_type);
-    data = datastart = (uchar*)_data;
+    datastart = data = (uchar*)_data;
     setSize(*this, _dims, _sizes, _steps, true);
     finalizeHdr(*this);
 }
@@ -549,7 +549,7 @@ static Mat cvMatNDToMat(const CvMatND* m, bool copyData)
 
     if( !m )
         return thiz;
-    thiz.data = thiz.datastart = m->data.ptr;
+    thiz.datastart = thiz.data = m->data.ptr;
     thiz.flags |= CV_MAT_TYPE(m->type);
     int _sizes[CV_MAX_DIM];
     size_t _steps[CV_MAX_DIM];
@@ -587,7 +587,7 @@ static Mat cvMatToMat(const CvMat* m, bool copyData)
         thiz.dims = 2;
         thiz.rows = m->rows;
         thiz.cols = m->cols;
-        thiz.data = thiz.datastart = m->data.ptr;
+        thiz.datastart = thiz.data = m->data.ptr;
         size_t esz = CV_ELEM_SIZE(m->type), minstep = thiz.cols*esz, _step = m->step;
         if( _step == 0 )
             _step = minstep;
@@ -597,7 +597,7 @@ static Mat cvMatToMat(const CvMat* m, bool copyData)
     }
     else
     {
-        thiz.data = thiz.datastart = thiz.dataend = 0;
+        thiz.datastart = thiz.dataend = thiz.data = 0;
         Mat(m->rows, m->cols, m->type, m->data.ptr, m->step).copyTo(thiz);
     }
 
@@ -636,7 +636,7 @@ static Mat iplImageToMat(const IplImage* img, bool copyData)
         m.rows = img->roi->height;
         m.cols = img->roi->width;
         esz = CV_ELEM_SIZE(m.flags);
-        m.data = m.datastart = (uchar*)img->imageData +
+        m.datastart = m.data = (uchar*)img->imageData +
             (selectedPlane ? (img->roi->coi - 1)*m.step*img->height : 0) +
             img->roi->yOffset*m.step[0] + img->roi->xOffset*esz;
     }
@@ -5532,14 +5532,14 @@ double norm( const SparseMat& src, int normType )
     {
         if( normType == NORM_INF )
             for( i = 0; i < N; i++, ++it )
-                result = std::max(result, std::abs((double)*(const float*)it.ptr));
+                result = std::max(result, std::abs((double)it.value<float>()));
         else if( normType == NORM_L1 )
             for( i = 0; i < N; i++, ++it )
-                result += std::abs(*(const float*)it.ptr);
+                result += std::abs(it.value<float>());
         else
             for( i = 0; i < N; i++, ++it )
             {
-                double v = *(const float*)it.ptr;
+                double v = it.value<float>();
                 result += v*v;
             }
     }
@@ -5547,14 +5547,14 @@ double norm( const SparseMat& src, int normType )
     {
         if( normType == NORM_INF )
             for( i = 0; i < N; i++, ++it )
-                result = std::max(result, std::abs(*(const double*)it.ptr));
+                result = std::max(result, std::abs(it.value<double>()));
         else if( normType == NORM_L1 )
             for( i = 0; i < N; i++, ++it )
-                result += std::abs(*(const double*)it.ptr);
+                result += std::abs(it.value<double>());
         else
             for( i = 0; i < N; i++, ++it )
             {
-                double v = *(const double*)it.ptr;
+                double v = it.value<double>();
                 result += v*v;
             }
     }
@@ -5578,7 +5578,7 @@ void minMaxLoc( const SparseMat& src, double* _minval, double* _maxval, int* _mi
         float minval = FLT_MAX, maxval = -FLT_MAX;
         for( i = 0; i < N; i++, ++it )
         {
-            float v = *(const float*)it.ptr;
+            float v = it.value<float>();
             if( v < minval )
             {
                 minval = v;
@@ -5600,7 +5600,7 @@ void minMaxLoc( const SparseMat& src, double* _minval, double* _maxval, int* _mi
         double minval = DBL_MAX, maxval = -DBL_MAX;
         for( i = 0; i < N; i++, ++it )
         {
-            double v = *(const double*)it.ptr;
+            double v = it.value<double>();
             if( v < minval )
             {
                 minval = v;
diff --git a/modules/core/src/stat.cpp b/modules/core/src/stat.cpp
index 7abbde543e..20e8aa5a79 100644
--- a/modules/core/src/stat.cpp
+++ b/modules/core/src/stat.cpp
@@ -782,7 +782,7 @@ cv::Scalar cv::mean( InputArray _src, InputArray _mask )
         int type = src.type();
         if( !mask.empty() )
         {
-            typedef IppStatus (CV_STDCALL* ippiMaskMeanFuncC1)(const void *, int, void *, int, IppiSize, Ipp64f *);
+            typedef IppStatus (CV_STDCALL* ippiMaskMeanFuncC1)(const void *, int, const void *, int, IppiSize, Ipp64f *);
             ippiMaskMeanFuncC1 ippFuncC1 =
             type == CV_8UC1 ? (ippiMaskMeanFuncC1)ippiMean_8u_C1MR :
             type == CV_16UC1 ? (ippiMaskMeanFuncC1)ippiMean_16u_C1MR :
@@ -795,7 +795,7 @@ cv::Scalar cv::mean( InputArray _src, InputArray _mask )
                     return Scalar(res);
                 setIppErrorStatus();
             }
-            typedef IppStatus (CV_STDCALL* ippiMaskMeanFuncC3)(const void *, int, void *, int, IppiSize, int, Ipp64f *);
+            typedef IppStatus (CV_STDCALL* ippiMaskMeanFuncC3)(const void *, int, const void *, int, IppiSize, int, Ipp64f *);
             ippiMaskMeanFuncC3 ippFuncC3 =
             type == CV_8UC3 ? (ippiMaskMeanFuncC3)ippiMean_8u_C3CMR :
             type == CV_16UC3 ? (ippiMaskMeanFuncC3)ippiMean_16u_C3CMR :
@@ -1071,7 +1071,7 @@ void cv::meanStdDev( InputArray _src, OutputArray _mean, OutputArray _sdv, Input
         int type = src.type();
         if( !mask.empty() )
         {
-            typedef IppStatus (CV_STDCALL* ippiMaskMeanStdDevFuncC1)(const void *, int, void *, int, IppiSize, Ipp64f *, Ipp64f *);
+            typedef IppStatus (CV_STDCALL* ippiMaskMeanStdDevFuncC1)(const void *, int, const void *, int, IppiSize, Ipp64f *, Ipp64f *);
             ippiMaskMeanStdDevFuncC1 ippFuncC1 =
             type == CV_8UC1 ? (ippiMaskMeanStdDevFuncC1)ippiMean_StdDev_8u_C1MR :
             type == CV_16UC1 ? (ippiMaskMeanStdDevFuncC1)ippiMean_StdDev_16u_C1MR :
@@ -1083,7 +1083,7 @@ void cv::meanStdDev( InputArray _src, OutputArray _mean, OutputArray _sdv, Input
                     return;
                 setIppErrorStatus();
             }
-            typedef IppStatus (CV_STDCALL* ippiMaskMeanStdDevFuncC3)(const void *, int, void *, int, IppiSize, int, Ipp64f *, Ipp64f *);
+            typedef IppStatus (CV_STDCALL* ippiMaskMeanStdDevFuncC3)(const void *, int, const void *, int, IppiSize, int, Ipp64f *, Ipp64f *);
             ippiMaskMeanStdDevFuncC3 ippFuncC3 =
             type == CV_8UC3 ? (ippiMaskMeanStdDevFuncC3)ippiMean_StdDev_8u_C3CMR :
             type == CV_16UC3 ? (ippiMaskMeanStdDevFuncC3)ippiMean_StdDev_16u_C3CMR :
diff --git a/modules/core/src/umatrix.cpp b/modules/core/src/umatrix.cpp
index ab8865d047..a128bcd01d 100644
--- a/modules/core/src/umatrix.cpp
+++ b/modules/core/src/umatrix.cpp
@@ -582,7 +582,7 @@ Mat UMat::getMat(int accessFlags) const
     hdr.flags = flags;
     hdr.u = u;
     hdr.datastart = u->data;
-    hdr.data = hdr.datastart + offset;
+    hdr.data = u->data + offset;
     hdr.datalimit = hdr.dataend = u->data + u->size;
     CV_XADD(&hdr.u->refcount, 1);
     return hdr;
diff --git a/modules/features2d/src/brisk.cpp b/modules/features2d/src/brisk.cpp
index f4690eb170..213dd60413 100644
--- a/modules/features2d/src/brisk.cpp
+++ b/modules/features2d/src/brisk.cpp
@@ -427,7 +427,7 @@ BRISK::smoothedIntensity(const cv::Mat& image, const cv::Mat& integral, const fl
   if (dx + dy > 2)
   {
     // now the calculation:
-    uchar* ptr = image.data + x_left + imagecols * y_top;
+    const uchar* ptr = image.data + x_left + imagecols * y_top;
     // first the corners:
     ret_val = A * int(*ptr);
     ptr += dx + 1;
@@ -475,7 +475,7 @@ BRISK::smoothedIntensity(const cv::Mat& image, const cv::Mat& integral, const fl
   }
 
   // now the calculation:
-  uchar* ptr = image.data + x_left + imagecols * y_top;
+  const uchar* ptr = image.data + x_left + imagecols * y_top;
   // first row:
   ret_val = A * int(*ptr);
   ptr++;
@@ -487,7 +487,7 @@ BRISK::smoothedIntensity(const cv::Mat& image, const cv::Mat& integral, const fl
   ret_val += B * int(*ptr);
   // middle ones:
   ptr += imagecols - dx - 1;
-  uchar* end_j = ptr + dy * imagecols;
+  const uchar* end_j = ptr + dy * imagecols;
   for (; ptr < end_j; ptr += imagecols - dx - 1)
   {
     ret_val += r_x_1_i * int(*ptr);
@@ -607,7 +607,7 @@ BRISK::computeDescriptorsAndOrOrientation(InputArray _image, InputArray _mask, s
   int t2;
 
   // the feature orientation
-  uchar* ptr = descriptors.data;
+  const uchar* ptr = descriptors.data;
   for (size_t k = 0; k < ksize; k++)
   {
     cv::KeyPoint& kp = keypoints[k];
@@ -1070,7 +1070,7 @@ BriskScaleSpace::isMax2D(const int layer, const int x_layer, const int y_layer)
 {
   const cv::Mat& scores = pyramid_[layer].scores();
   const int scorescols = scores.cols;
-  uchar* data = scores.data + y_layer * scorescols + x_layer;
+  const uchar* data = scores.data + y_layer * scorescols + x_layer;
   // decision tree:
   const uchar center = (*data);
   data--;
@@ -2140,7 +2140,7 @@ BriskLayer::value(const cv::Mat& mat, float xf, float yf, float scale_in) const
     const int r_y = (int)((yf - y) * 1024);
     const int r_x_1 = (1024 - r_x);
     const int r_y_1 = (1024 - r_y);
-    uchar* ptr = image.data + x + y * imagecols;
+    const uchar* ptr = image.data + x + y * imagecols;
     // just interpolate:
     ret_val = (r_x_1 * r_y_1 * int(*ptr));
     ptr++;
@@ -2186,7 +2186,7 @@ BriskLayer::value(const cv::Mat& mat, float xf, float yf, float scale_in) const
   const int r_y1_i = (int)(r_y1 * scaling);
 
   // now the calculation:
-  uchar* ptr = image.data + x_left + imagecols * y_top;
+  const uchar* ptr = image.data + x_left + imagecols * y_top;
   // first row:
   ret_val = A * int(*ptr);
   ptr++;
@@ -2198,7 +2198,7 @@ BriskLayer::value(const cv::Mat& mat, float xf, float yf, float scale_in) const
   ret_val += B * int(*ptr);
   // middle ones:
   ptr += imagecols - dx - 1;
-  uchar* end_j = ptr + dy * imagecols;
+  const uchar* end_j = ptr + dy * imagecols;
   for (; ptr < end_j; ptr += imagecols - dx - 1)
   {
     ret_val += r_x_1_i * int(*ptr);
diff --git a/modules/imgcodecs/src/grfmt_jpeg2000.cpp b/modules/imgcodecs/src/grfmt_jpeg2000.cpp
index d711846ce8..83fd55a594 100644
--- a/modules/imgcodecs/src/grfmt_jpeg2000.cpp
+++ b/modules/imgcodecs/src/grfmt_jpeg2000.cpp
@@ -154,7 +154,7 @@ bool  Jpeg2KDecoder::readData( Mat& img )
 {
     bool result = false;
     int color = img.channels() > 1;
-    uchar* data = img.data;
+    uchar* data = img.ptr();
     int step = (int)img.step;
     jas_stream_t* stream = (jas_stream_t*)m_stream;
     jas_image_t* image = (jas_image_t*)m_image;
@@ -478,7 +478,7 @@ bool  Jpeg2KEncoder::writeComponent8u( void *__img, const Mat& _img )
 
     for( int y = 0; y < h; y++ )
     {
-        uchar* data = _img.data + _img.step*y;
+        const uchar* data = _img.ptr(y);
         for( int i = 0; i < ncmpts; i++ )
         {
             for( int x = 0; x < w; x++)
@@ -502,7 +502,7 @@ bool  Jpeg2KEncoder::writeComponent16u( void *__img, const Mat& _img )
 
     for( int y = 0; y < h; y++ )
     {
-        uchar* data = _img.data + _img.step*y;
+        const uchar* data = _img.ptr(y);
         for( int i = 0; i < ncmpts; i++ )
         {
             for( int x = 0; x < w; x++)
diff --git a/modules/imgproc/test/test_filter.cpp b/modules/imgproc/test/test_filter.cpp
index a0927b0f39..6b8cb8c472 100644
--- a/modules/imgproc/test/test_filter.cpp
+++ b/modules/imgproc/test/test_filter.cpp
@@ -228,7 +228,7 @@ int CV_MorphologyBaseTest::prepare_test_case( int test_case_idx )
     if( shape == CV_SHAPE_CUSTOM )
     {
         eldata.resize(aperture_size.width*aperture_size.height);
-        uchar* src = test_mat[INPUT][1].data;
+        const uchar* src = test_mat[INPUT][1].data;
         int srcstep = (int)test_mat[INPUT][1].step;
         int i, j, nonzero = 0;
 
diff --git a/modules/imgproc/test/test_imgwarp.cpp b/modules/imgproc/test/test_imgwarp.cpp
index b0897483a2..e08020dbed 100644
--- a/modules/imgproc/test/test_imgwarp.cpp
+++ b/modules/imgproc/test/test_imgwarp.cpp
@@ -344,7 +344,7 @@ static void test_remap( const Mat& src, Mat& dst, const Mat& mapx, const Mat& ma
     int x, y, k;
     int drows = dst.rows, dcols = dst.cols;
     int srows = src.rows, scols = src.cols;
-    uchar* sptr0 = src.data;
+    const uchar* sptr0 = src.data;
     int depth = src.depth(), cn = src.channels();
     int elem_size = (int)src.elemSize();
     int step = (int)(src.step / CV_ELEM_SIZE(depth));
diff --git a/modules/imgproc/test/test_imgwarp_strict.cpp b/modules/imgproc/test/test_imgwarp_strict.cpp
index 034d89014b..02016fb3da 100644
--- a/modules/imgproc/test/test_imgwarp_strict.cpp
+++ b/modules/imgproc/test/test_imgwarp_strict.cpp
@@ -532,7 +532,7 @@ void CV_Resize_Test::resize_1d(const Mat& _src, Mat& _dst, int dy, const dim& _d
             ofs = 3, ksize = 8;
 
         Mat _extended_src_row(1, _src.cols + ksize * 2, _src.type());
-        uchar* srow = _src.data + dy * _src.step;
+        const uchar* srow = _src.ptr(dy);
         memcpy(_extended_src_row.data + elemsize * ksize, srow, _src.step);
         for (int k = 0; k < ksize; ++k)
         {