Fix ref-counting issue in python wrapper. Fixes #171

apriltag_pywrap.c

@@ -235,7 +235,7 @@ static PyObject* apriltag_detect(apriltag_py_t* self,
         PyErr_Format(PyExc_RuntimeError, "Error creating output tuple of size %d", N);
         goto done;
     }
-
+    
     for (int i=0; i < N; i++)
     {
         xy_c = (PyArrayObject*)PyArray_SimpleNew(1, ((npy_intp[]){2}), NPY_FLOAT64);
@@ -264,7 +264,7 @@ static PyObject* apriltag_detect(apriltag_py_t* self,
         }
 
         PyTuple_SET_ITEM(detections_tuple, i,
-                         Py_BuildValue("{s:i,s:f,s:i,s:O,s:O}",
+                         Py_BuildValue("{s:i,s:f,s:i,s:N,s:N}",
                                        "hamming", det->hamming,
                                        "margin",  det->decision_margin,
                                        "id",      det->id,
@@ -278,7 +278,7 @@ static PyObject* apriltag_detect(apriltag_py_t* self,
     result = detections_tuple;
     detections_tuple = NULL;
 
- done:
+  done:
     Py_XDECREF(xy_c);
     Py_XDECREF(xy_lb_rb_rt_lt);
     Py_XDECREF(image);