OCR: Google Cloud Vision vs Tesseract
Google Cloud Vision
Google Cloud Vision includes OCR services. It also includes an OCR engine to extract text from documents.
The Vision API can detect and extract text from images. There are two annotation features that support optical character recognition (OCR):
1- TEXT_DETECTION detects and extracts text from any image. For example, a photograph might contain a street sign or traffic sign. The JSON includes the entire extracted string, as well as individual words, and their bounding boxes.
2-DOCUMENT_TEXT_DETECTION also extracts text from an image, but the response is optimized for dense text and documents. The JSON includes page, block, paragraph, word, and break information.
Tesseract is an open source text recognition (OCR) Engine, available under the Apache 2.0 license. It can be used directly, or (for programmers) using an API to extract text from images or even extract text from PDFs. It supports a wide variety of languages. Tesseract doesn’t have a built-in GUI, but there are several available from the 3rdParty page. Tesseract is compatible with many programming languages and frameworks through wrappers that can be found here. It can be used with the existing layout analysis to recognize text within a large document, or it can be used in conjunction with an external text detector to recognize text from an image of a single text line.
Tesseract 4.00 includes a new neural network subsystem configured as a text line recognizer. It has its origins in OCRopus’ Python-based LSTM implementation but has been redesigned for Tesseract in C++. The neural network system in Tesseract pre-dates TensorFlow but is compatible with it, as there is a network description language called Variable Graph Specification Language (VGSL), that is also available for TensorFlow.
The most effective way to compare these two engines is to test them: the performance can truely depend on your data and your needs. It is to facilitate the testing and use of this type of engine that we have developed Eden AI: a unique API connected to the best AI engines and combined with a powerful management platform.