import matplotlib.pyplot as plt
import matplotlib.patches as patches

# 根据坐标作图
def plot_pic():
    img_path = "000000000650.jpg"
    txt_path = "000000000650.txt"

    img = plt.imread(img_path)
    h,w,c = img.shape
    txt_lines = open(txt_path).readlines()
    
    coords = []
    for line in txt_lines:
        new_line = line.strip().split(" ")[1:]
        # [x_center,y_center,width,hieght]坐标转换成[left,top,width,height]
        width = float(new_line[2]) * w
        height = float(new_line[3]) * h
        left = float(new_line[0]) * w - width / 2
        bottom = float(new_line[1]) * h + height / 2

        coords.append([left,bottom ,width,height])


    fig, ax = plt.subplots(1, 1)
    ax.imshow(img)
    currentAxis = fig.gca()
    
    #
    for index, coord in enumerate(coords):
        rect = patches.Rectangle((coord[0], coord[1]), coord[2], coord[3], 
        						linewidth=1, edgecolor='r',facecolor='none')
        currentAxis.add_patch(rect)

        plt.show()
    print(0)
if __name__ == "__main__":
    plot_pic()

其中
000000000650.jpg图片如下：

000000000650.txt内容如下：

15 0.519398 0.544087 0.476359 0.572061
2 0.501859 0.820726 0.996281 0.332178
#[class x_center y_center width height] 复制请删除这一行

通过运行上面的程序，得到如下结果：

rectangle函数的参数解释如下：

Rectangle(xy,width,heigth,angle=0,**kwargs)
参数
xy:2元组，矩形左下角坐标
width：矩形的宽度
height：矩形的高度
angle：float，可选，矩形相对于x轴逆时针旋转角度，默认0
fill：bool，可选，是否填充矩形