diff --git a/hough_machine.cpp b/hough_machine.cpp
index 7ffaf64..a3ec510 100644
--- a/hough_machine.cpp
+++ b/hough_machine.cpp
@@ -43,7 +43,7 @@ class HoughMachine {
       this->d_ang = 0;
       this->n_rad = 0;
       this->d_rad = 0;
-      if(this->hough_arr == NULL) {
+      if(this->hough_arr != NULL) {
 	free(this->hough_arr);
 	this->hough_arr = NULL;
       }