Text extraction (Read API) with Azure Computer Vision API (Python3.6)

Introduction

I tried to extract text from the image

Development environment

• Windows 10
• Anaconda
• Python 3.6
• OpenCV 4.4.0
• Azure Computer Vision API --Computer Vision Client Library (if needed)

Introduction

1. 1. Log in to the Azure portal (https://portal.azure.com/)

2. Create a resource for the Computer Vision API

3. 3. Make a note of the key and endpoint

Four. Please install the required libraries.

pip install matplotlib
pip install pillow
pip install opencv-python
pip install --upgrade azure-cognitiveservices-vision-computervision 

Five. Enter the key and endpoint you wrote down and run the following code!

subscription_key = "<your subscription key>"
endpoint = "<your API endpoint>"

The endpoint seems to work even if you specify the region.

endpoint = "https://<your region>.api.cognitive.microsoft.com/"

Extract text from image URL

Quick Start: Extract printed and handwritten text using Computer Vision's REST API and Python (https://docs.microsoft.com/en-us/azure/cognitive-services/computer-vision) / quickstarts / python-hand-text)

import json
import os
import os.path
import sys
import requests
import time
import matplotlib.pyplot as plt
from matplotlib.patches import Polygon
from PIL import Image
from io import BytesIO
 import cv2

subscription_key = "<your subscription key>"
endpoint = "<your API endpoint>"
 endpoint = "https://japanwest.api.cognitive.microsoft.com/"
text_recognition_url = endpoint + "vision/v3.1/read/analyze"

image_url = "https://raw.githubusercontent.com/MicrosoftDocs/azure-docs/master/articles/cognitive-services/Computer-vision/Images/readsample.jpg "
headers = {'Ocp-Apim-Subscription-Key': subscription_key}
data = {'url': image_url}
response = requests.post(text_recognition_url, headers=headers, json=data)
response.raise_for_status()

operation_url = response.headers["Operation-Location"]
analysis = {}
poll = True
while (poll):
    response_final = requests.get(response.headers["Operation-Location"], headers=headers)
    analysis = response_final.json()
    
    print(json.dumps(analysis, indent=4))

    time.sleep(1)
    if ("analyzeResult" in analysis):
        poll = False
    if ("status" in analysis and analysis['status'] == 'failed'):
        poll = False

polygons = []
if ("analyzeResult" in analysis):
    polygons = [(line["boundingBox"], line["text"])
                for line in analysis["analyzeResult"]["readResults"][0]["lines"]]

image = Image.open(BytesIO(requests.get(image_url).content))
ax = plt.imshow(image)
for polygon in polygons:
    vertices = [(polygon[0][i], polygon[0][i+1])
                for i in range(0, len(polygon[0]), 2)]
    text = polygon[1]
    patch = Polygon(vertices, closed=True, fill=False, linewidth=2, color='y')
    ax.axes.add_patch(patch)
    plt.text(vertices[0][0], vertices[0][1], text, fontsize=20, va="top")
plt.show()

input	output

Extract text from local image

import json
import os
import os.path
import sys
import requests
import time
import matplotlib.pyplot as plt
from matplotlib.patches import Polygon
from PIL import Image
from io import BytesIO
import cv2

subscription_key = "<your subscription key>"
endpoint = "<your API endpoint>"
 endpoint = "https://japanwest.api.cognitive.microsoft.com/"
text_recognition_url = endpoint + "vision/v3.1/read/analyze"

headers = {'Ocp-Apim-Subscription-Key': subscription_key, 'Content-Type': 'application/octet-stream'}
filename = "readsample.jpg "
root, ext = os.path.splitext(filename)
 image_data = open(filename, "rb").read()
color = cv2.imread(filename, cv2.IMREAD_COLOR)
cv2.namedWindow("color", cv2.WINDOW_NORMAL)
cv2.imshow("color", color)
cv2.waitKey(1)
image_data = cv2.imencode(ext, color)[1].tostring()
response = requests.post(text_recognition_url, headers=headers, data=image_data)
response.raise_for_status()

operation_url = response.headers["Operation-Location"]
analysis = {}
poll = True
while (poll):
    response_final = requests.get(
        response.headers["Operation-Location"], headers=headers)
    analysis = response_final.json()
    
    print(json.dumps(analysis, indent=4))

    time.sleep(1)
    if ("analyzeResult" in analysis):
        poll = False
    if ("status" in analysis and analysis['status'] == 'failed'):
        poll = False

polygons = []
if ("analyzeResult" in analysis):
    polygons = [(line["boundingBox"], line["text"])
                for line in analysis["analyzeResult"]["readResults"][0]["lines"]]

 image = Image.open(BytesIO(image_data))
image = Image.fromarray(color)
ax = plt.imshow(image)
for polygon in polygons:
    vertices = [(polygon[0][i], polygon[0][i+1])
                for i in range(0, len(polygon[0]), 2)]
    text = polygon[1]
    patch = Polygon(vertices, closed=True, fill=False, linewidth=2, color='y')
    ax.axes.add_patch(patch)
    plt.text(vertices[0][0], vertices[0][1], text, fontsize=20, va="top")
plt.show()

input	output

Use the Computer Vision client library

Quick Start: Use Computer Vision Client Library (https://docs.microsoft.com/en-us/azure/cognitive-services/Computer-vision/quickstarts-sdk/client-library?pivots=programming-language -python & tabs = visual-studio)

from azure.cognitiveservices.vision.computervision import ComputerVisionClient
from azure.cognitiveservices.vision.computervision.models import OperationStatusCodes
from azure.cognitiveservices.vision.computervision.models import VisualFeatureTypes
from msrest.authentication import CognitiveServicesCredentials

from array import array
import os
from PIL import Image
import sys
import time
import cv2 
from io import BytesIO

subscription_key = "<your subscription key>"
endpoint = "<your API endpoint>"
 endpoint = "https://japanwest.api.cognitive.microsoft.com/"

computervision_client = ComputerVisionClient(endpoint, CognitiveServicesCredentials(subscription_key))

print("===== Batch Read File - remote =====")
remote_image_handw_text_url = "https://raw.githubusercontent.com/MicrosoftDocs/azure-docs/master/articles/cognitive-services/Computer-vision/Images/readsample.jpg "

recognize_handw_results = computervision_client.read(remote_image_handw_text_url, raw=True)
operation_location_remote = recognize_handw_results.headers["Operation-Location"]
operation_id = operation_location_remote.split("/")[-1]

while True:
    get_handw_text_results = computervision_client.get_read_result(operation_id)
    if get_handw_text_results.status not in ['notStarted', 'running']:
        break
    time.sleep(1)

if get_handw_text_results.status == OperationStatusCodes.succeeded:
    for text_result in get_handw_text_results.analyze_result.read_results:
        for line in text_result.lines:
            print(line.text)
            print(line.bounding_box)
print()

===== Batch Read File - remote =====
The quick brown fox jumps
[38.0, 650.0, 2572.0, 699.0, 2570.0, 854.0, 37.0, 815.0]
over
[184.0, 1053.0, 508.0, 1044.0, 510.0, 1123.0, 184.0, 1128.0]
the lazy dog!
[639.0, 1011.0, 1976.0, 1026.0, 1974.0, 1158.0, 637.0, 1141.0]

Thank you for your hard work.