calib3d: findChessboardCornersSB() minor updates

- avoid updating of input image during equalizeHist() call
- avoid for() with double variable (use 'int' instead)
- more CV_Check*() macros
- use Mat_<T>, Matx
- static for local variables

modules/core/src/check.cpp

@@ -113,6 +113,10 @@ void check_failed_auto(const double v1, const double v2, const CheckContext& ctx
 {
     check_failed_auto_<double>(v1, v2, ctx);
 }
+void check_failed_auto(const Size_<int> v1, const Size_<int> v2, const CheckContext& ctx)
+{
+    check_failed_auto_< Size_<int> >(v1, v2, ctx);
+}
 
 
 template<typename T> static CV_NORETURN
@@ -163,6 +167,10 @@ void check_failed_auto(const double v, const CheckContext& ctx)
 {
     check_failed_auto_<double>(v, ctx);
 }
+void check_failed_auto(const Size_<int> v, const CheckContext& ctx)
+{
+    check_failed_auto_< Size_<int> >(v, ctx);
+}
 
 
 }} // namespace