add API to reinterpret Mat type

modules/core/src/matrix.cpp

@@ -1261,6 +1261,16 @@ Mat Mat::reshape(int _cn, const std::vector<int>& _newshape) const
     return reshape(_cn, (int)_newshape.size(), &_newshape[0]);
 }
 
+Mat Mat::reinterpret(int type) const
+{
+    type = CV_MAT_TYPE(type);
+    CV_Assert(CV_ELEM_SIZE(this->type()) == CV_ELEM_SIZE(type));
+    Mat m = *this;
+    m.flags = (m.flags & ~CV_MAT_TYPE_MASK) | type;
+    m.updateContinuityFlag();
+    return m;
+}
+
 Mat Mat::diag(const Mat& d)
 {
     CV_Assert( d.cols == 1 || d.rows == 1 );

modules/core/src/matrix_wrap.cpp

@@ -1656,6 +1656,12 @@ void _OutputArray::create(int d, const int* sizes, int mtype, int i,
     CV_Error(Error::StsNotImplemented, "Unknown/unsupported array type");
 }
 
+Mat _OutputArray::reinterpret(int mtype) const
+{
+    mtype = CV_MAT_TYPE(mtype);
+    return getMat().reinterpret(mtype);
+}
+
 void _OutputArray::createSameSize(const _InputArray& arr, int mtype) const
 {
     int arrsz[CV_MAX_DIM], d = arr.sizend(arrsz);