import cv2
def crop_top(img, percent=0.15):             #对图像的上部进行裁剪，去除不必要信息
    offset = int(img.shape[0] * percent)
    return img[offset:]
def central_crop(img):              #裁剪为长宽相等且居中
    size = min(img.shape[0], img.shape[1])
    offset_h = int((img.shape[0] - size) / 2)
    offset_w = int((img.shape[1] - size) / 2)
    return img[offset_h:offset_h + size, offset_w:offset_w + size]   #切片表示
def process_image_file(filepath, size, top_percent=0.08, crop=True):
    img = cv2.imread(filepath)    #返回三维列表 长 宽 通道
    img = crop_top(img, percent=top_percent)
    if crop:
        img = central_crop(img)
    img = cv2.resize(img, (size, size))   #默认双线性插值 调整长宽大小为size
    return img