 病理学实验室的技术人员需要分析幻灯片的数字图象。幻灯片上有许多要分析的目标，由鼠标单击确定一个目标。目标边界的周长是一个有用的测量参数。 编程任务：确定选中目标的周长。 - pathology laboratory technicians need to analyze the digital image of the slide. There are many goals to be analyzed on a slide, click the mou