CODEWITHSUNDEEP
pythonimage-processingocrtesseractpython-tesseract
Abtin Rasoulian
Abtin Rasoulian

Reputation: 919

Getting the bounding box of the recognized words using python-tesseract

I am using python-tesseract to extract words from an image. This is a python wrapper for tesseract which is an OCR code.

I am using the following code for getting the words:

import tesseract

api = tesseract.TessBaseAPI()
api.Init(".","eng",tesseract.OEM_DEFAULT)
api.SetVariable("tessedit_char_whitelist", "0123456789abcdefghijklmnopqrstuvwxyz")
api.SetPageSegMode(tesseract.PSM_AUTO)

mImgFile = "test.jpg"
mBuffer=open(mImgFile,"rb").read()
result = tesseract.ProcessPagesBuffer(mBuffer,len(mBuffer),api)
print "result(ProcessPagesBuffer)=",result

This returns only the words and not their location/size/orientation (or in other words a bounding box containing them) in the image. I was wondering if there is any way to get that as well

Upvotes: 66

Views: 152988

Answers (9)

Bex T.
Bex T.

Reputation: 1786

This is the ONLY solution that draws a rectangle around each word. Other working solutions draw boxes around blocks of text as well, which results in a mess if the image contains too many words. Here is the image I am using:

enter image description here

And here is the code:

import cv2
import pytesseract  # version '0.3.10'
from pytesseract import Output

img = cv2.imread("images/easy_text.png")

# Extract recognized data
data = pytesseract.image_to_data(img, output_type=Output.DICT)
n_boxes = len(data["text"])

for i in range(n_boxes):
    # Skip -1 confidence, because they correspond with blocks of text
    if data["conf"][i] == -1:
        continue
    # Coordinates
    x, y = data["left"][i], data["top"][i]
    w, h = data["width"][i], data["height"][i]

    # Corners
    top_left = (x, y)
    bottom_right = (x + w, y + h)

    # Box params
    green = (0, 255, 0)
    thickness = 3  # pixels

    cv2.rectangle(img, top_left, bottom_right, green, thickness)

# Save the image
output_image_path = "images/image_with_boxes.jpg"
cv2.imwrite(output_image_path, img)

And here is the result:

enter image description here

Upvotes: 0

Abhishek Gautam
Abhishek Gautam

Reputation: 71

To get bounding boxes over words:

import cv2
import pytesseract
from pytesseract import Output

img = cv2.imread('test-01.jpg')
d = pytesseract.image_to_data(img, output_type=Output.DICT)
n_boxes = len(d['level'])
for i in range(n_boxes):
    if (d['text'][i] != ""):
        (x, y, w, h) = (d['left'][i], d['top'][i], d['width'][i], d['height'][i])
        cv2.rectangle(img, (x, y), (x + w, y + h), (0, 255, 0), 2) # in-place operation

cv2.imwrite('result.png', img)

Upvotes: 4

himanshu_chawla
himanshu_chawla

Reputation: 120

Some examples are answered aove which can be used with pytesseract, however to use tesserocr python library you can use code given below to find individual word and their bounding boxes:-

    with PyTessBaseAPI(psm=6, oem=1) as api:
            level = RIL.WORD
            api.SetImageFile(imagePath)
            api.Recognize()
            ri = api.GetIterator()
            while True::
                word = ri.GetUTF8Text(level)
                boxes = ri.BoundingBox(level)
                print(word,"word")
                print(boxes,"coords")
                if not ri.Next(level):
                     break

Upvotes: 2

Milan Hlinák
Milan Hlinák

Reputation: 4430

As already mentioned, you can use pytesseract's image_to_boxes. You can check my Docker Hub repo https://hub.docker.com/r/milanhlinak/tesseract-image-to-boxes - a simple Flask application with Tesseract 5.0.0.

Upvotes: 0

stwykd
stwykd

Reputation: 2874

Use pytesseract.image_to_data()

import pytesseract
from pytesseract import Output
import cv2
img = cv2.imread('image.jpg')

d = pytesseract.image_to_data(img, output_type=Output.DICT)
n_boxes = len(d['level'])
for i in range(n_boxes):
    (x, y, w, h) = (d['left'][i], d['top'][i], d['width'][i], d['height'][i])
    cv2.rectangle(img, (x, y), (x + w, y + h), (0, 255, 0), 2)

cv2.imshow('img', img)
cv2.waitKey(0)

Among the data returned by pytesseract.image_to_data():

  • left is the distance from the upper-left corner of the bounding box, to the left border of the image.
  • top is the distance from the upper-left corner of the bounding box, to the top border of the image.
  • width and height are the width and height of the bounding box.
  • conf is the model's confidence for the prediction for the word within that bounding box. If conf is -1, that means that the corresponding bounding box contains a block of text, rather than just a single word.

The bounding boxes returned by pytesseract.image_to_boxes() enclose letters so I believe pytesseract.image_to_data() is what you're looking for.

Upvotes: 134

Endyd
Endyd

Reputation: 1279

Would comment under lennon310 but don't have enough reputation to comment...

To run his command line command tesseract test.jpg result hocr in a python script:

from subprocess import check_call

tesseractParams = ['tesseract', 'test.jpg', 'result', 'hocr']
check_call(tesseractParams)

Upvotes: 4

jtbr
jtbr

Reputation: 1179

Python tesseract can do this without writing to file, using the image_to_boxes function:

import cv2
import pytesseract

filename = 'image.png'

# read the image and get the dimensions
img = cv2.imread(filename)
h, w, _ = img.shape # assumes color image

# run tesseract, returning the bounding boxes
boxes = pytesseract.image_to_boxes(img) # also include any config options you use

# draw the bounding boxes on the image
for b in boxes.splitlines():
    b = b.split(' ')
    img = cv2.rectangle(img, (int(b[1]), h - int(b[2])), (int(b[3]), h - int(b[4])), (0, 255, 0), 2)

# show annotated image and wait for keypress
cv2.imshow(filename, img)
cv2.waitKey(0)

Upvotes: 17

khushhall
khushhall

Reputation: 77

Using the below code you can get the bounding box corresponding to each character.

import csv
import cv2
from pytesseract import pytesseract as pt

pt.run_tesseract('bw.png', 'output', lang=None, boxes=True, config="hocr")

# To read the coordinates
boxes = []
with open('output.box', 'rb') as f:
    reader = csv.reader(f, delimiter = ' ')
    for row in reader:
        if(len(row)==6):
            boxes.append(row)

# Draw the bounding box
img = cv2.imread('bw.png')
h, w, _ = img.shape
for b in boxes:
    img = cv2.rectangle(img,(int(b[1]),h-int(b[2])),(int(b[3]),h-int(b[4])),(255,0,0),2)

cv2.imshow('output',img)

Upvotes: 7

lennon310
lennon310

Reputation: 12689

tesseract.GetBoxText() method returns the exact position of each character in an array.

Besides, there is a command line option tesseract test.jpg result hocr that will generate a result.html file with each recognized word's coordinates in it. But I'm not sure whether it can be called through python script.

Upvotes: 21

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