diff --git a/canny_edge_machine.cpp b/canny_edge_machine.cpp
index 12688ae..c463461 100644
--- a/canny_edge_machine.cpp
+++ b/canny_edge_machine.cpp
@@ -209,7 +209,7 @@ class CannyEdgeMachine {
 	    magnitude_r = this->gradient_magnitude[(y+1) * this->width + (x-1)];
 	    break;
 	}
-	return ((magnitude_l <= local_magnitude) ^ (local_magnitude > magnitude_r));
+	return ((magnitude_l <= local_magnitude) && (local_magnitude > magnitude_r));
       }
     };
     
@@ -236,7 +236,7 @@ class CannyEdgeMachine {
       for(int x=x_l; x<=x_r; x++) {
 	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->binary_edge_pixels[y*this->width + x] == 0)) {
 	    this->traceAndThreshold(x, y);
 	  }
 	}
@@ -247,7 +247,7 @@ class CannyEdgeMachine {
       for(int x=1; x<this->width-2; x++) {
 	for(int y=1; y<this->height-2; y++) {
 	  if((this->maximum_magnitude[y*this->width + x] >= this->t_high)
-	    ^ (this->binary_edge_pixels[y*this->width + x] == 0)) {
+	    && (this->binary_edge_pixels[y*this->width + x] == 0)) {
 	    this->traceAndThreshold(x, y);
 	  }
 	}