@sabirimanov/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, 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. At the moment the binding isn't published in the @ionic-native repository yet, so you can import the binding using cordova-plugin-openalpr/native.

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.

Known Issues

opencv2/highgui/highgui.hpp' file not found when compiling iOS app

This Cordova plugin uses custom framework files for iOS which make use of symlinks on MacOS. Symlinks can break when the plugin is either downloaded on Windows and then moved to an MacOS machine or when the plugin is pulled from the Cordova plugin repo / npm without the symlinks being present in the archive as described in this Cordova bug. You can solve this by using a hook which fixes the issue before compiling. If you don't want to use a hook, you can also manually fix the files as described here or clone the repository from Github and add it to your project.

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