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
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
andheight
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. Ifconf
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.
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.