import cv2
import numpy as np
import matplotlib.pyplot as plt

img = cv2.imread('image.jpg',0)

def remove_horizontal_lines(img, threshold):    
    # 原图像形状
    height, width = img.shape

    # Canny算法去除水平线
    canny = cv2.Canny(img, threshold[0], threshold[1], apertureSize=3)

    # 计算每行中包含的边缘点数量
    histogram = np.sum(canny,axis=1)

    # 存储最多的数量和对应的行数
    max_value,max_index = 0,0

    # 计算中心点最多的行
    for i in range(height):
        if histogram[i]>max_value:
            max_index = i
            max_value = histogram[i]

    # 替换水平线为白色
    canny[max_index,:] = 255

    # 显示结果
    plt.subplot(1,2,1),plt.imshow(img,cmap = 'gray')
    plt.title('Original Image'), plt.xticks([]), plt.yticks([])
    plt.subplot(1,2,2),plt.imshow(canny,cmap = 'gray')
    plt.title('Result Image'), plt.xticks([]), plt.yticks([])    

# 调整阈值，以便看到更清晰的水平线
remove_horizontal_lines(img, [50, 150])