cordova-plugin-openalpr

Cordova OpenALPR plugin

This Cordova plugin adds support for the OpenALPR (Automatic License Plate Recognition) library which provides support for retrieving the license plate from a picture. You can pass an image using Base64 or the file path to the OpenALPR plugin.

Supported platforms

The current master branch supports the following platforms:

• iOS (>= 8)
• Android (>= SDK 21)

Installation

This plugin requires Cordova 5.0+ and can be installed from the Cordova Plugin Registry. If you use Ionic 3 or Ionic 4, you should also install the @ionic-native binding.

cordova plugin add cordova-plugin-openalpr

npm install @ionic-native/openalpr

Examples

Ionic 1 / PhoneGap

This plugin defines a global cordova.plugins.OpenALPR object which provides an API for scanning license plates. It is possible to use the output of cordova-plugin-camera and pass it to the scan function of this plugin.

cordova.plugins.OpenALPR.scan(
  filepath,
  { country: "eu", amount: 3 },
  function(results) {
    console.log(results);
  },
  function(error) {
    console.log(error.code + ": " + error.message);
  }
);

Ionic 3

This plugin has a @ionic-native/openalpr binding available, which makes it easy to include it in your Ionic 3 project. You can use the output of @ionic-native/camera and pass it to the scan function of this plugin.

There is also an Ionic 3 example project available which shows the possible implementation of cordova-plugin-openalpr.

import { Camera, CameraOptions } from '@ionic-native/camera';
import { OpenALPR, OpenALPROptions, OpenALPRResult } from 'cordova-plugin-openalpr/native';
 
constructor(private camera: Camera, private openALPR: OpenALPR) {
 
}
 
const cameraOptions: CameraOptions = {
    quality: 100,
    destinationType: this.camera.DestinationType.FILE_URI,
    encodingType: this.camera.EncodingType.JPEG,
    mediaType: this.camera.MediaType.PICTURE,
    sourceType: this.camera.PictureSourceType.CAMERA
}
 
const scanOptions: OpenALPROptions = {
    country: this.openalpr.Country.EU,
    amount: 3
}
 
this.camera.getPicture(cameraOptions).then((imageData) => {
    this.openALPR.scan(imageData)
        .then((result: [OpenALPRResult]) => console.log(result[0].number))
        .catch((error: Error) => console.error(error));
});

This plugin is only supported on iOS / Android, however in order to speed up development you can make use of mocking and browser development.

Ionic 4

This plugin has a @ionic-native/openalpr binding available, which makes it easy to include it in your Ionic 4 project. You can use the output of @ionic-native/camera and pass it to the scan function of this plugin. (Check the code snippet for Ionic 3 for a reference).

There is also an Ionic 4 example project available which shows the possible implementation of cordova-plugin-openalpr.

Known Issues

Android: PictureSourceType.PHOTOLIBRARY isn't supported (yet)

In Android apps, passing the file uri from PictureSourceType.PHOTOLIBRARY isn't supported yet. This is because the photolibrary returns a different kind of path than the camera does. The cordova-plugin-filepath might provide a workaround for now but this has not been tested yet.

Notes

• This project includes prebuilt OpenALPR libraries for iOS and Android, because the compilation of the OpenALPR framework requires a lot of effort and dependencies.
• This project is not used in production anymore and won't be maintained actively. We can't guarantee that we can respond quickly to issues / pull requests, however we will keep an eye on the repository.

License

MIT, but keep in mind that OpenALPR itself is licensed under AGPL-3.0.

Credits

• License plate scanning based on OpenALPR.
• iOS platform support based on OpenALPR iOS.
• Android platform support based on OpenALPR Java bindings
• iOS Base64 implementation by @baukeroo