This repository contains the official Hydra API Node.js client. The Hydra API is a text recognition service.

Quickstart

1. Install the node module.

npm install siftrics-hydra-api

1. Create a new data source on siftrics.com.
2. Grab an API key from the page of your newly created data source.
3. Create a client, passing your API key into the constructor.
4. Use the client to processes documents, passing in the id of a data source and the filepaths of the documents.

const hydra = require('siftrics-hydra-api');

const h = new hydra.Client('xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx');

h.recognize('my-data-source-id', ['invoice_1.pdf', 'my_receipt.png'])
    .then(rows => {
        console.log(rows);
    })
    .catch(error => {
        console.error(error);
    });

rows looks like this:

[
  {
    "Error": "",
    "FileIndex": 0,
    "RecognizedText": { ... }
  },
  ...
]

FileIndex is the index of this file in the original request's "files" array.

RecognizedText is an object mapping labels to values. Labels are the titles of the bounding boxes drawn during the creation of the data source. Values are the recognized text inside those bounding boxes.

Faster Results

The recognize function has a default parameter, config, which allows users to set various flags:

recognize(dataSourceId, files, config = {
    doFaster: false,
    returnTransformedImages: false,
    returnJpgs: false,
    jpgQuality: 85
})

If doFaster is set to true, then Siftrics processes the documents in half the time at the risk of lower text recognition accuracy. Experimentally, setting doFaster to true seems not to affect accuracy when all the documents to be processed have been rotated no more than 45 degrees.

Return Transformed / Pre-Processed Images

Hydra can transform input documents so they are cropped and aligned with the original image used to create the data source.

To enable this feature, set returnTransformedImages to true in config (see the "Faster Results" section above for an example of using config).

Returned images will be available in the "TransformedImages" field of each element of "Rows" in the response:

{
  "Rows": [
    {
      "Error": "",
      "FileIndex": 0,
      "RecognizedText": {
        "My Field 1": "text from your document...",
        "My Field 2": "text from your document...",
        ...
      },
      "TransformedImages": [
        {
          "Base64Image": ...,
          "PageNumber": 1
        },
        ...
      ]
    },
    ...
  ]
}

Export JPEGs instead of PNGs

If your data source returns cropped images, they are returned as PNGs encoded as base-64 strings. It is possible to return these images as JPEGs instead of PNGs, by setting returnJpgs to true in config (see the "Faster Results" section above for an example of using config). Additionally, there is a flag jpgQuality which is a number between 1 and 100 inclusive, which determines the quality of the encoded JPEGs. The default is 85. The higher the number, the higher the quality.

Returning JPEGs instead of PNGs with jpgQuality=85 typically exhibits a 7-10x reduction in image size, with minimal reduction in quality.

Official API Documentation

Here is the official documentation for the Hydra API.

Apache V2 License

This code is licensed under Apache V2.0. The full text of the license can be found in the "LICENSE" file.