STDM

代码说明：

  利用STDM方法嵌入水印信息，可设置量化步长，选择各种经典的攻击方式，控制攻击强弱，返回误码率和峰值信噪比(Stdm method using embedded watermark information, to set the quantization step size, choose a variety of classic attacks, controlling the strength of the attack and returned to the bit error rate and peak signal to noise ratio)