Distinguished leads by its direction, quad leads could consider two dual leads, therefore the method is also availablefor QFP (quad flat packages) and QFN (quad flat No-lead).

• 通过区分引脚的细长度方向将两边带引脚推广到四边带引脚，该方法对QFP、QFN等封装类型的形位检测也是有效的。