OCR with Django

The purpose of this project is to illustrate how to implement a simple OCR web form using Django and tesserocr. Tesserocr is a Python wrapper for the Tesseract C++ API.

Installation

Tesserocr requires a fairly recent versions of tesseract-ocr and leptonica. On Ubuntu these can be installed with:

$ apt install tesseract-ocr libtesseract-dev libleptonica-dev

Depending on your environment, you might have to install these packages from the source code. Follow their respective documentations on instructions on how to do it. Next, you have to install the project's requirements:

(venv) $ pip3 install Cython==0.24.1
(venv) $ pip3 install -r ocr_with_django/requirements.txt

and run the necessary steps to set-up the Django site:

(venv) $ cd ocr_with_django/
(venv) $ python manage.py migrate
(venv) $ python manage.py collectstatic --noinput

We've included a Vagrantfile script for you to see the site in action by yourself.

OCRView

The OCR process is done in the OcrView

# documents/views.py

class OcrView(View):
    def post(self, request, *args, **kwargs):
        with PyTessBaseAPI() as api:
            with Image.open(request.FILES['image']) as image:
                sharpened_image = image.filter(ImageFilter.SHARPEN)
                api.SetImage(sharpened_image)
                utf8_text = api.GetUTF8Text()

        return JsonResponse({'utf8_text': utf8_text})

We take the uploaded image, process it using a Pillow filter, and pass along the result to the Tesseract OCR API through tesserocr.

We tried to keep the view as simple as possible (no Form, no validation) to focus only on the OCR processes. If you read PyTessBaseAPI docstrings you'll see that there are tons of things you can do with the image and recognition result.