请问用canny检测图像轮廓后怎么把有断点的轮廓连接成一个轮廓

原图[img=https://b38.photo.store.qq.com/http_imgload.cgi?/rurl4_b=aa2abf72f17a60cdc9e345c2b538058c8e0d573df7a89f3554c7fb6af9c2bcd9d5ac78e8c257a42b6264783ea2b101ec1f48b01408061b77170beefb4f3776f796894471ab8cb355e512c56d26fe0ea983857e66&a=39&b=38][/img] 原图[img=https://b38.photo.store.qq.com/http_imgl