I am trying to use py-tesseract on google colabs to parse the following image containing readings from a meter. However it fails to get me the result expected. Looks like i need to do some pre-processing on the image. I am new to py-tesseract. Can you please help what i need to do to get this to work?
Here is my current code followed by output seen and the image:
!sudo apt install tesseract-ocr
!pip install pytesseract
import pytesseract
import shutil
import os
import random
try:
from PIL import Image
except ImportError:
import Image
image_path='drive/MyDrive/cropped_image.jpg'
print(pytesseract.image_to_string(image_path, config='--psm 13 --oem=3'))
Output
ey
Image being parsed
Cropped_image
Thanks
Try this:
print(pytesseract.image_to_string(image_path, config='-1 eng --oem 2 --psm 12'))
Output:
194735787
First, you need to preprocess the image which helps to reduce the noise and help in text extraction.
Extract text area from the image
Convert the image to grayscale and sharpen the image
Apply adaptive threshold
Clean the image by performing morphological operations and invert the image
import cv2
import numpy as np
img = cv2.imread('qKiJi.jpg')
#crop the text extraction area
crop = img[200:350, 100:400]
gray = cv2.cvtColor(crop, cv2.COLOR_BGR2GRAY)
sharpen_kernel = np.array([[-1,-1,-1], [-1,9,-1], [-1,-1,-1]])
sharpen = cv2.filter2D(gray, -1, sharpen_kernel)
thresh = cv2.threshold(sharpen, 0, 255, cv2.THRESH_BINARY_INV + cv2.THRESH_OTSU)[1]
kernel = cv2.getStructuringElement(cv2.MORPH_RECT, (2,2))
close = cv2.morphologyEx(thresh, cv2.MORPH_CLOSE, kernel, iterations=1)
result = 255 - close
cv2.imshow('img', crop)
cv2.imshow('sharpen', sharpen)
cv2.imshow('thresh', thresh)
cv2.imshow('close', close)
cv2.imshow('result', result)
cv2.waitKey()
Related
I have been working on project which involves extracting text from an image. I have researched that tesseract is one of the best libraries available and I decided to use the same along with opencv. Opencv is needed for image manipulation.
I have been playing a lot with tessaract engine and it does not seems to be giving the expected results to me. I have attached the image as an reference. Output I got is:
1] =501 [
Instead, expected output is
TM10-50%L
What I have done so far:
Remove noise
Adaptive threshold
Sending it tesseract ocr engine
Are there any other suggestions to improve the algorithm?
Thanks in advance.
Snippet of the code:
import cv2
import sys
import pytesseract
import numpy as np
from PIL import Image
if __name__ == '__main__':
if len(sys.argv) < 2:
print('Usage: python ocr_simple.py image.jpg')
sys.exit(1)
# Read image path from command line
imPath = sys.argv[1]
gray = cv2.imread(imPath, 0)
# Blur
blur = cv2.GaussianBlur(gray,(9,9), 0)
# Binarizing
thres = cv2.adaptiveThreshold(blur, 255, cv2.ADAPTIVE_THRESH_GAUSSIAN_C, cv2.THRESH_BINARY, 5, 3)
text = pytesseract.image_to_string(thresh)
print(text)
Images attached.
First image is original image. Original image
Second image is what has been fed to tessaract. Input to tessaract
Before performing OCR on an image, it's important to preprocess the image. The idea is to obtain a processed image where the text to extract is in black with the background in white. For this specific image, we need to obtain the ROI before we can OCR.
To do this, we can convert to grayscale, apply a slight Gaussian blur, then adaptive threshold to obtain a binary image. From here, we can apply morphological closing to merge individual letters together. Next we find contours, filter using contour area filtering, and then extract the ROI. We perform text extraction using the --psm 6 configuration option to assume a single uniform block of text. Take a look here for more options.
Detected ROI
Extracted ROI
Result from Pytesseract OCR
TM10=50%L
Code
import cv2
import pytesseract
pytesseract.pytesseract.tesseract_cmd = r"C:\Program Files\Tesseract-OCR\tesseract.exe"
# Grayscale, Gaussian blur, Adaptive threshold
image = cv2.imread('1.jpg')
original = image.copy()
gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
blur = cv2.GaussianBlur(gray, (3,3), 0)
thresh = cv2.adaptiveThreshold(blur, 255, cv2.ADAPTIVE_THRESH_GAUSSIAN_C, cv2.THRESH_BINARY_INV, 5, 5)
# Perform morph close to merge letters together
kernel = cv2.getStructuringElement(cv2.MORPH_RECT, (5,5))
close = cv2.morphologyEx(thresh, cv2.MORPH_CLOSE, kernel, iterations=3)
# Find contours, contour area filtering, extract ROI
cnts, _ = cv2.findContours(close, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)[-2:]
for c in cnts:
area = cv2.contourArea(c)
if area > 1800 and area < 2500:
x,y,w,h = cv2.boundingRect(c)
ROI = original[y:y+h, x:x+w]
cv2.rectangle(image, (x, y), (x + w, y + h), (36,255,12), 3)
# Perform text extraction
ROI = cv2.GaussianBlur(ROI, (3,3), 0)
data = pytesseract.image_to_string(ROI, lang='eng', config='--psm 6')
print(data)
cv2.imshow('ROI', ROI)
cv2.imshow('close', close)
cv2.imshow('image', image)
cv2.waitKey()
I am trying to detect prices using pytesseract.
However I am having very bad results.
I have one large image with several prices in different locations.
These locations are constant so I am cropping the image down and saving each area as a new image and then trying to detect the text.
I know the text will only contain 0123456789$¢.
I trained my new font using trainyourtesseract.com.
For example, I take this image.
Double it's size, and threshold it to get this.
Run it through tesseract and get an output of 8.
Any help would be appreciated.
def getnumber(self, img):
grey = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
thresh, grey = cv2.threshold(grey, 50, 255, cv2.THRESH_BINARY_INV)
filename = "{}.png".format(os.getpid())
cv2.imwrite(filename, grey)
text = pytesseract.image_to_string(Image.open(filename), lang='Droid',
config='--psm 13 --oem 3 -c tessedit_char_whitelist=0123456789.$¢')
os.remove(filename)
return(text)
You're on the right track. When preprocessing the image for OCR, you want to get the text in black with the background in white. The idea is to enlarge the image, Otsu's threshold to get a binary image, then perform OCR. We use --psm 6 to tell Pytesseract to assume a single uniform block of text. Look here for more configuration options. Here's the processed image:
Result from OCR:
2¢
Code
import cv2
import pytesseract
import imutils
pytesseract.pytesseract.tesseract_cmd = r"C:\Program Files\Tesseract-OCR\tesseract.exe"
# Resize, grayscale, Otsu's threshold
image = cv2.imread('1.png')
image = imutils.resize(image, width=500)
gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
thresh = cv2.threshold(gray, 0, 255, cv2.THRESH_BINARY_INV + cv2.THRESH_OTSU)[1]
# Perform text extraction
data = pytesseract.image_to_string(thresh, lang='eng',config='--psm 6')
print(data)
cv2.imshow('thresh', thresh)
cv2.imwrite('thresh.png', thresh)
cv2.waitKey()
Machine specs:
Windows 10
opencv-python==4.2.0.32
pytesseract==0.2.7
numpy==1.14.5
In this image tesseract is detecting the text as LOOOPCS but it is 1000PCS. Command I am using is
tesseract "item_04.png" stdout --psm 6
I have tried all psm values 0 to 13
As per suggestions by other blogs and questions on SO and internet following clipping of image as well as thresholding is also tried.
Also tried -c tessedit_char_whitelist=PCS0123456789 but that gives 00PCS.
But I am not getting 1000PCS. Can someone try these and let me know what am I missing?
Edit:
As per suggestion given by #nathancy, tried using - cv2.THRESH_BINARY_INV + cv2.THRESH_OTSU which worked on this 1 and 0 but failed for below image. It is being detected as LL8gPcs:
You need to preprocess the image. A simple approach is to Otsu's threshold then invert the image so the text is in black with the background in white. Here's the processed image and the result using Pytesseract OCR with --psm 6.
Result
1000PCS
Code
import cv2
import pytesseract
pytesseract.pytesseract.tesseract_cmd = r"C:\Program Files\Tesseract-OCR\tesseract.exe"
# Grayscale, Otsu's threshold
image = cv2.imread('1.png')
gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
thresh = cv2.threshold(gray, 0, 255, cv2.THRESH_BINARY_INV + cv2.THRESH_OTSU)[1]
# Invert and perform text extraction
thresh = 255 - thresh
data = pytesseract.image_to_string(thresh, lang='eng',config='--psm 6')
print(data)
cv2.imshow('thresh', thresh)
cv2.waitKey()
I'm trying to extract text from image using python cv2. The result is pathetic and I can't figure out a way to improve my code.
I believe the image needs to be processed before the extraction of text but not sure how.
I've tried to convert it into black and white but no luck.
import cv2
import os
import pytesseract
from PIL import Image
import time
pytesseract.pytesseract.tesseract_cmd='C:\\Program Files\\Tesseract-OCR\\tesseract.exe'
cam = cv2.VideoCapture(1,cv2.CAP_DSHOW)
cam.set(cv2.CAP_PROP_FRAME_WIDTH, 8000)
cam.set(cv2.CAP_PROP_FRAME_HEIGHT, 6000)
while True:
return_value,image = cam.read()
image=cv2.cvtColor(image,cv2.COLOR_BGR2GRAY)
image = image[127:219, 508:722]
#(thresh, image) = cv2.threshold(image, 128, 255, cv2.THRESH_BINARY | cv2.THRESH_OTSU)
cv2.imwrite('test.jpg',image)
print('Text detected: {}'.format(pytesseract.image_to_string(Image.open('test.jpg'))))
time.sleep(2)
cam.release()
#os.system('del test.jpg')
Preprocessing to clean the image before performing text extraction can help. Here's a simple approach
Convert image to grayscale and sharpen image
Adaptive threshold
Perform morpholgical operations to clean image
Invert image
First we convert to grayscale then sharpen the image using a sharpening kernel
Next we adaptive threshold to obtain a binary image
Now we perform morphological transformations to smooth the image
Finally we invert the image
import cv2
import numpy as np
image = cv2.imread('1.jpg')
gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
sharpen_kernel = np.array([[-1,-1,-1], [-1,9,-1], [-1,-1,-1]])
sharpen = cv2.filter2D(gray, -1, sharpen_kernel)
thresh = cv2.threshold(sharpen, 0, 255, cv2.THRESH_BINARY_INV + cv2.THRESH_OTSU)[1]
kernel = cv2.getStructuringElement(cv2.MORPH_RECT, (3,3))
close = cv2.morphologyEx(thresh, cv2.MORPH_CLOSE, kernel, iterations=1)
result = 255 - close
cv2.imshow('sharpen', sharpen)
cv2.imshow('thresh', thresh)
cv2.imshow('close', close)
cv2.imshow('result', result)
cv2.waitKey()
I am using pytesseract to extract text from images. Before extracting text with pytesseract, I use Pillow and cv2 to reduce noise and enhance the image:
import numpy as np
import pytesseract
from PIL import Image, ImageFilter, ImageEnhance
import cv2
img = cv2.imread('ss.png')
img = cv2.resize(img, (0,0), fx=3, fy=3)
cv2.imwrite("new.png", img)
img1 = cv2.imread("new.png", 0)
#Apply dilation and erosion
kernel = np.ones((2, 2), np.uint8)
img1 = cv2.dilate(img1, kernel, iterations=1)
img1 = cv2.erode(img1, kernel, iterations=1)
img1 = cv2.adaptiveThreshold(img1,255,cv2.ADAPTIVE_THRESH_GAUSSIAN_C, cv2.THRESH_BINARY_INV,11,2)
cv2.imwrite("new1.png", img1)
img2 = Image.open("new1.png")
#Enhance the image
img2 = im.filter(ImageFilter.MedianFilter())
enhancer = ImageEnhance.Contrast(im)
img2 = enhancer.enhance(2)
img2.save('new2.png')
result = pytesseract.image_to_string(Image.open("new2.png"))
print(result)
I mostly get good results, but when I use some low quality/resolution images, I do not get the expected output. Can I improve this in my code?
Example:
Input:
new1.png:
new2.png:
The string that I get from the console is play. What could I change in my algorithm, so that I get the whole string extracted?
Any help would be greatly appreciated.
This is a late answer, but I just came across this. we can use Pillow and cv2 to reduce noise and enhance the image before extracting text from images using pytesseract. I hope it would help someone in future.
#import required library
src_path = "C:/Users/chethan/Desktop/"
def get_string(img_path):
# Read image with opencv
img = cv2.imread(img_path)
# Convert to gray
img = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
# Apply dilation and erosion to remove some noise
kernel = np.ones((1, 1), np.uint8)
img = cv2.dilate(img, kernel, iterations=1)
img = cv2.erode(img, kernel, iterations=1)
# Write image after removed noise
cv2.imwrite(src_path + "removed_noise.png", img)
# Apply threshold to get image with only black and white
#img = cv2.adaptiveThreshold(img, 255, cv2.ADAPTIVE_THRESH_GAUSSIAN_C, cv2.THRESH_BINARY, 31, 2)
# Write the image after apply opencv to do some ...
cv2.imwrite(src_path + "thres.png", img)
# Recognize text with tesseract for python
result = pytesseract.image_to_string(Image.open(src_path + "thres.png"))
# Recognize text with tesseract for python
result = pytesseract.image_to_string(Image.open(img_path))
# Remove template file
# os.remove(temp)
return result
print(get_string(src_path + "dummy.png"))