Detect lines in image

line_detect.py

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

image = cv2.imread('input2.png', 0)

# find lines by horizontally blurring the image and thresholding
blur = cv2.blur(image, (80, 9))
#cv2.imshow('y', blur)
#cv2.waitKey(0)
b_mean = np.mean(blur, axis=1)/256

#hist, bin_edges = np.histogram(b_mean, bins=100)
#threshold = bin_edges[66]
#print(hist)
#print(threshold)
threshold = np.percentile(b_mean, 2)

t = b_mean > threshold

'''
get the image row numbers that has text (non zero)
a text line is a consecutive group of image rows that 
are above the threshold and are defined by the first and 
last row numbers
'''
tix = np.where(1-t)
tix = tix[0]
lines = []
start_ix = tix[0]
for ix in range(1, tix.shape[0]-1):
    if tix[ix] == tix[ix-1] + 1:
        continue
    # identified gap between lines, close previous line and start a new one
    end_ix = tix[ix-1]
    lines.append([start_ix, end_ix])
    start_ix = tix[ix]
end_ix = tix[-1]
lines.append([start_ix, end_ix])

#l_starts = []
#for line in lines:
#    xx = 500
#    for x in range(0,500):
#        col = image[line[0]:line[1], x]
#        print(col)
#        if np.min(col) <100: 
#            xx = x
#            break
#    l_starts.append(xx)
#print(l_starts)
#median_ls = np.median(l_starts)

line_seg = []
for line in lines:
	line_seg.append(line[1]-line[0])
print(line_seg)
median_ls = np.mean(line_seg)
print(np.mean(line_seg))
paragraphs = []
p_start = lines[0][0]

para = []
inc = line_seg[1]
for ix in range(2, len(lines)):
	if line_seg[ix] > inc and line_seg[ix] > median_ls + 1:
		inc = line_seg[ix]
		break
dec = inc
for ix in range(line_seg.index(dec), len(lines)):
        if line_seg[ix] < dec  and line_seg[ix] < median_ls + 1:
                dec = line_seg[ix]
                break
#for ix in range(1, len(lines)):
#    if line_seg[ix] > median_ls+1:
#        p_end = lines[ix][0] - 10
#        paragraphs.append([p_start, p_end])
#        p_start = lines[ix][0]
inci = line_seg.index(inc)
deci = line_seg.index(dec)
print(inci)
print(deci)
paragraphs.append([p_start-10, lines[inci][1]+20])
paragraphs.append([lines[inci][1]+10, lines[deci][1]+20])
paragraphs.append([lines[deci][1]+10, lines[-1][0]])

print(paragraphs)
p_img = np.array(image)
n_cols = p_img.shape[1]
for paragraph in paragraphs:
    cv2.rectangle(p_img, (5, paragraph[0]), (n_cols - 5, paragraph[1]), (0, 255, 0), 3)

cv2.imwrite('paragraphs_out.png', p_img)