diff --git a/canny_edge_machine.cpp b/canny_edge_machine.cpp
index 00cd60f..eeb7724 100644
--- a/canny_edge_machine.cpp
+++ b/canny_edge_machine.cpp
@@ -255,7 +255,7 @@ class CannyEdgeMachine {
       int y_l = std::max(y-1, 0);
       int y_r = std::min(y+1, this->height-1);
       for(int x=x_l; x<=x_r; x++) {
-	for(int y=y_l; y<y_r; y++) {
+	for(int y=y_l; y<=y_r; y++) {
 	  if((this->maximum_magnitude[y*this->width + x] >= this->t_high)
 	    && (this->binary_edge_pixels[y*this->width + x] == 0)) {
 	    this->traceAndThreshold(x, y);