no really, I fixed the initialization bug

main.go

@@ -56,12 +56,13 @@ func main() {
 
 	fmt.Printf("Start reading device: %v\n", deviceID)
 
-	// This is a warm up ladies and gentlemen.  
+	// This is a warm up ladies and gentlemen.
 	for i := 0; i < 20; i++ {
 		if ok := webcam.Read(&img); !ok {
 			fmt.Printf("Device closed: %v\n", deviceID)
 			return
 		}
+		detectMotion(img)
 	}
 
 	// main loop