Using python PIL to get the number displayed in an image

Question

I want get the number in this image, using python and PIL:

my code:

#!/usr/bin/env python
#encoding=utf-8

import Image,ImageEnhance,ImageFilter
import Data

DEBUG = False

def d_print(*msg):
    global DEBUG
    if DEBUG:
        for i in msg:
            print(i),
        print
    else:
        pass


def Get_Num(l=[]):
    min1 = []
    min2 = []
    print(l)
    for n in Data.N:
        count1=count2=count3=count4=0
        if (len(l) != len(n)):
            print("Wrong pic %s %s " %(len(l),len(n)))
            exit()
        for i in range(len(l)):
            if (l[i] == 1):
                count1+=1
                if (n[i] == 1):
                    count2+=1
        for i in range(len(l)):
            if (n[i] == 1):
                count3+=1
                if (l[i] == 1):
                    count4+=1
        d_print(count1,count2,count3,count4)

        min1.append(count1-count2)
        min2.append(count3-count4)
    d_print(min1,"\n",min2)
    for i in range(10):
        if (min1[i] <= 2 or min2[i] <= 2):
            if ((abs(min1[i] - min2[i])) < 10):
                return i
    for i in range(10):
        if (min1[i] <= 4 or min2[i] <= 4):
            if (abs(min1[i] - min2[i]) <= 2):
                return i

    for i in range(10):
        flag = False
        if (min1[i] <= 3 or min2[i] <= 3):
            for j in range(10):
                if (j != i and (min1[j] < 5 or min2[j] <5)):
                    flag = True
                else:
                    pass
            if (not flag):
                return i
    for i in range(10):
        if (min1[i] <= 5 or min2[i] <= 5):
            if (abs(min1[i] - min2[i]) <= 10):
                return i
    for i in range(10):
        if (min1[i] <= 10 or min2[i] <= 10):
            if (abs(min1[i] - min2[i]) <= 3):
                return i

#end of function Get_Num

def Pic_Reg(image_name=None):
    im = Image.open(image_name)
    im = im.filter(ImageFilter.MedianFilter())
    enhancer = ImageEnhance.Contrast(im)
    im = enhancer.enhance(5)
    im = im.convert('1')
    im.show()
                    #all by pixel
    s = 6          #start postion of first number
    w = 8          #width of each number
    h = 15          #end postion from top
    t = 2           #start postion of top
    im_new = []
    #split four numbers in the picture
    for i in range(4):
        im1 = im.crop((s+w*i+i*2,t,s+w*(i+1)+i*2,h))
        im_new.append(im1.resize((int(10),int(13)), Image.ANTIALIAS))

    s = ""
    for k in range(4):
        l = []
        im_new[k].show()
        for i in range(13):
            for j in range(10):
                if (im_new[k].getpixel((j,i)) == 255):
                    l.append(0)
                else:
                    l.append(1)
        s+=str(Get_Num(l))
    return s
if __name__ == "__main__":
    print(Pic_Reg("3.jpeg"))

The code can read some numbers, but it isn't perfect. I need better number recognition.

Answer 1

PIL is not the tool you want to use. What you are trying to do is perform image recognition, which is a typical [and quite complex] AI task.

The canonical free-as-in-freedom library for performing this kind of operations is OpenCV, for which you can find the python bindings documentation here.

BTW: the reason for which captcha use that kind of images is precisely because is extremely difficult to teach a machine how to recognise those numbers... It's a form of Turing testing specifically designed to discern humans from bots...