Update only if it makes sense.

oi-sensor/oi-sensor.py

@@ -161,10 +161,11 @@ async def main():
                     print("\tDetected area (px)=%.2f, result=%d, shape changes=%d" %(area, result, shape_change_counter))
 
                     # update list for last X results (FILO)
-                    result_stack.append(result)
-                    current_shape = result
-                    shape_change_counter += 1
-                    await myvar.write_value(result)
+                    if current_shape != result:
+                        result_stack.append(result)
+                        current_shape = result
+                        shape_change_counter += 1
+                        await myvar.write_value(result)
 
                     # break current countour detection loop as in this example we care
                     # for first detected SHAPE, we do not expect more shapes
@@ -173,9 +174,10 @@ async def main():
             if not contour_detected:
                 # no countours actually detected thus update OPC UA server's node attribute
                 result = 0.0
-                result_stack.append(result)
-                shape_change_counter += 1
-                await myvar.write_value(result)
+                if current_shape != result:
+                    result_stack.append(result)
+                    shape_change_counter += 1
+                    await myvar.write_value(result)
                 current_shape = result
                 print("\tNo shape detected, result=%d, shape changes=%d" %(result, shape_change_counter))