图像处理之填充多边形

大致流程：

1. 新建一个全是一的掩膜；
2. 减去多边形的边界，得到两个块状物；
3. 判断块状物是否在边界，在边界的块状物去掉，得到填充后的效果

def segmentation_pipe(img ,cfg):
    gray = cv.cvtColor(img, cv.COLOR_BGR2GRAY)
    ret, thresh = cv.threshold(gray, 240, 255, cv.THRESH_BINARY)
    thresh[thresh > 0] = 1
    out = dilation(thresh, square(20))
    out = erosion(out, square(10))
    # remove small objects
    labels = ndi.label(out, output=np.uint32)[0]
    unique, counts = np.unique(labels, return_counts=True)
    for (k, v) in dict(zip(unique, counts)).items():
        if v < cfg.remove_area:
            out[labels == k] = 0
    
    # fill the hole
    out[out > 0] = 1
    temp = np.ones_like(out) - out
    labels = ndi.label(temp, output=np.uint32)[0]
    unique, counts = np.unique(labels, return_counts=True)

    for (k, v) in dict(zip(unique, counts)).items():
        temp_ = np.zeros_like(out)
        temp_[labels == k] = 1
        if temp_[0, 0] == 1:
            temp[labels == k] = 0

    return temp