I wrote a program to remove the line from this captcha:
first of all, I improve image visibility by median filter
def apply_median_filter(self,img):
img_gray=img.convert('L')
img_gray=cv2.medianBlur(np.asarray(img_gray),3)
img_bw=(img_gray>np.mean(img_gray))*255
return img_bw
then I try to remove line:
def eliminate_zeros(self,vector):
return [(dex,v) for (dex,v) in enumerate(vector) if v!=0 ]
def get_line_position(self,img):
sumx=img.sum(axis=0)
list_without_zeros=self.eliminate_zeros(sumx)
min1,min2=heapq.nsmallest(2,list_without_zeros,key=itemgetter(1))
l=[dex for [dex,val] in enumerate(sumx) if val==min1[1] or val==min2[1]]
mindex=[l[0],l[len(l)-1]]
cols=img[:,mindex[:]]
col1=cols[:,0]
col2=cols[:,1]
col1_without_0=self.eliminate_zeros(col1)
col2_without_0=self.eliminate_zeros(col2)
line_length=len(col1_without_0)
dex1=col1_without_0[round(len(col1_without_0)/2)][0]
dex2=col2_without_0[round(len(col2_without_0)/2)][0]
p1=[dex1,mindex[0]]
p2=[dex2,mindex[1]]
return p1,p2,line_length
finally I remove line by its position:
def remove_line(self,p1,p2,LL,img):
m=(p2[0]-p1[0])/(p2[1]-p1[1]) if p2[1]!=p1[1] else np.inf
w,h=len(img),len(img[0])
x=[x for x in range(w)]
y=[p1[0]+k for k in [m*t for t in [v-p1[1] for v in x]]]
img_removed_line=img
for dex in range(w):
i,j=np.round([y[dex],x[dex]])
i=int(i)
j=int(j)
rlist=[]
while True:
f1=i
if img_removed_line[i,j]==0 and img_removed_line[i-1,j]==0:
break
rlist.append(i)
i=i-1
i,j=np.round([y[dex],x[dex]])
i=int(i)
j=int(j)
while True:
f2=i
if img_removed_line[i,j]==0 and img_removed_line[i+1,j]==0:
break
rlist.append(i)
i=i+1
print([np.abs(f2-f1),[LL+1,LL,LL-1]])
if np.abs(f2-f1) in [LL+1,LL,LL-1]:
rlist=list(set(rlist))
img_removed_line[rlist,j]=0
return img_removed_line
but line isn't removed completely in some cases and I get the captcha image with some noise:
Thank you very much for your help!
elahe
The problem is solved! Here is my edited python code. this removes line from captcha. I hope it helps:
from PIL import Image,ImageFilter
from scipy.misc import toimage
from operator import itemgetter
from skimage import measure
import numpy as np
import copy
import heapq
import cv2
import matplotlib.pyplot as plt
from scipy.ndimage.filters import median_filter
#----------------------------------------------------------------
class preprocessing:
def pre_proc_image(self,img):
#img_removed_noise=self.apply_median_filter(img)
img_removed_noise=self.remove_noise(img)
p1,p2,LL=self.get_line_position(img_removed_noise)
img=self.remove_line(p1,p2,LL,img_removed_noise)
img=median_filter(np.asarray(img),1)
return img
def remove_noise(self,img):
img_gray=img.convert('L')
w,h=img_gray.size
max_color=np.asarray(img_gray).max()
pix_access_img=img_gray.load()
row_img=list(map(lambda x:255 if x in range(max_color-15,max_color+1) else 0,np.asarray(img_gray.getdata())))
img=np.reshape(row_img,[h,w])
return img
def apply_median_filter(self,img):
img_gray=img.convert('L')
img_gray=cv2.medianBlur(np.asarray(img_gray),3)
img_bw=(img_gray>np.mean(img_gray))*255
return img_bw
def eliminate_zeros(self,vector):
return [(dex,v) for (dex,v) in enumerate(vector) if v!=0 ]
def get_line_position(self,img):
sumx=img.sum(axis=0)
list_without_zeros=self.eliminate_zeros(sumx)
min1,min2=heapq.nsmallest(2,list_without_zeros,key=itemgetter(1))
l=[dex for [dex,val] in enumerate(sumx) if val==min1[1] or val==min2[1]]
mindex=[l[0],l[len(l)-1]]
cols=img[:,mindex[:]]
col1=cols[:,0]
col2=cols[:,1]
col1_without_0=self.eliminate_zeros(col1)
col2_without_0=self.eliminate_zeros(col2)
line_length=len(col1_without_0)
dex1=col1_without_0[round(len(col1_without_0)/2)][0]
dex2=col2_without_0[round(len(col2_without_0)/2)][0]
p1=[dex1,mindex[0]]
p2=[dex2,mindex[1]]
return p1,p2,line_length
def remove_line(self,p1,p2,LL,img):
m=(p2[0]-p1[0])/(p2[1]-p1[1]) if p2[1]!=p1[1] else np.inf
w,h=len(img),len(img[0])
x=list(range(h))
y=list(map(lambda z : int(np.round(p1[0]+m*(z-p1[1]))),x))
img_removed_line=list(img)
for dex in range(h):
i,j=y[dex],x[dex]
i=int(i)
j=int(j)
rlist=[]
while True:
f1=i
if img_removed_line[i][j]==0 and img_removed_line[i-1][j]==0:
break
rlist.append(i)
i=i-1
i,j=y[dex],x[dex]
i=int(i)
j=int(j)
while True:
f2=i
if img_removed_line[i][j]==0 and img_removed_line[i+1][j]==0:
break
rlist.append(i)
i=i+1
if np.abs(f2-f1) in [LL+1,LL,LL-1]:
rlist=list(set(rlist))
for k in rlist:
img_removed_line[k][j]=0
return img_removed_line
来源：https://stackoverflow.com/questions/42736616/how-to-remove-line-from-captcha-completely