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VIN Scanner Integration Guide

In this guide, we will explore the VIN Scanner features of the Dynamsoft Capture Vision SDK.

Description

Scan the VIN code from a barcode or a text line and extract the vehicle information.

Requirements

Dev tools

  • Latest Flutter SDK
  • For Android apps: Android SDK (API Level 21+), platforms and developer tools
  • For iOS apps: iOS 13+, macOS with latest Xcode and command line tools

Mobile platforms

  • Android 5.0 (API Level 21) and higher
  • iOS 13 and higher

Installation

Run the following commands in the root directory of your flutter project to add dynamsoft_capture_vision_flutter into dependencies

flutter pub add dynamsoft_capture_vision_flutter

then run the command to install all dependencies:

flutter pub get

Camera permissions

The Dynamsoft Capture Vision SDK needs the camera permission to use the camera device, so it can capture from video stream.

Android

Before opening camera to start capturing, you need to request camera permission from system.

import 'package:dynamsoft_capture_vision_flutter/dynamsoft_capture_vision_flutter.dart';

PermissionUtil.requestCameraPermission();

iOS

Add this camera permission description to ios/{projectName}/Info.plist inside the element:

<key>NSCameraUsageDescription</key>
    <string></string>

Append Model Into Your Project

Scanning the VIN code from a Text line needs to load the model(VINCharRecognition.data).

Android

You can get VINCharRecognition.data from here.

Then copy the VINCharRecognition.data into android/app/src/main/assets/Models/ of your Flutter Project.

iOS

You can get the 'DynamsoftResources.bundle' containing 'VINCharRecognition.data' from here.

Then reference DynamsoftResources.bundle of your Flutter Project.

Build the VIN Scanner Widget

Now that the package is added, it's time to start building the VIN Scanner Widget using the SDK.

Initialize License

The first step in code configuration is to initialize a valid license via LicenseManager.initLicense.

import 'package:dynamsoft_capture_vision_flutter/dynamsoft_capture_vision_flutter.dart';

LicenseManager.initLicense('DLS2eyJvcmdhbml6YXRpb25JRCI6IjIwMDAwMSJ9').then((data) {
      final (isSuccess, message) = data;
      if (!isSuccess) {
        print("license error: $message");
      }
    });

Note

  • The license string here grants a time-limited free trial which requires network connection to work.
  • You can request a 30-day trial license via the Request a Trial License link.

Implement VIN Scanning from Video Stream

The basic workflow of scanning VIN code from video stream is as follows:

  • Initialize the CameraEnhancer object
  • Initialize the CaptureVisionRouter object
  • Bind the CameraEnhancer object to the CaptureVisionRouter object
  • Add a 'MultiFrameResultCrossFilter' object to enable the verification for text recognition
  • Register a CapturedResultReceiver object to listen for parsed VIN code via the callback function onParsedResultsReceived
  • Open the camera
  • Start VIN scanning via startCapturing
import 'package:dynamsoft_capture_vision_flutter/dynamsoft_capture_vision_flutter.dart';
import 'package:flutter/material.dart';

class ScannerPage extends StatefulWidget {
  const ScannerPage({super.key});

  @override
  State<ScannerPage> createState() => _ScannerPageState();
}

class _ScannerPageState extends State<ScannerPage> {
  final String _templateName = "ReadVIN";
  final CaptureVisionRouter _cvr = CaptureVisionRouter.instance
    ..addResultFilter(
      MultiFrameResultCrossFilter()
        ..enableResultCrossVerification(EnumCapturedResultItemType.textLine.value | EnumCapturedResultItemType.barcode.value, true),
    );
  final CameraEnhancer _camera = CameraEnhancer.instance;
  late final CapturedResultReceiver _receiver = CapturedResultReceiver()
    ..onParsedResultsReceived = (ParsedResult result) async {
      if (result.items?.isNotEmpty ?? false) {
        //stopCapturing is used to prevent frequent callbacks of results from affecting your actions on results
        _cvr.stopCapturing();
        VINData? data;
        if (result.items!.length == 1) {
          data = VINData.fromParsedResultItem(result.items![0]);
        } else {
          // result.items!.length>1
          for (var item in result.items!) {
            if (item.targetROIDefName.contains('vin-barcode')) {
              //Means this item is pared from a barcode, which is more accurate than textLine.
              data = VINData.fromParsedResultItem(item);
              break;
            }
          }
        }
        if (data != null) {
          //Do something with data
        } else {
          _cvr.startCapturing(_templateName); // restart capturing
        }
      }
    };

  @override
  void initState() {
    super.initState();
    PermissionUtil.requestCameraPermission();
    LicenseManager.initLicense('DLS2eyJvcmdhbml6YXRpb25JRCI6IjIwMDAwMSJ9').then((data) {
      final (isSuccess, message) = data;
      if (!isSuccess) {
        print("license error: $message");
      }
    });
    initSdk();
  }

  void initSdk() async {
    await _cvr.setInput(_camera); //bind CameraEnhancer and CaptureVisonRouter
    _cvr.addResultReceiver(_receiver); //Register `CapturedResultReceiver` object to listen for parsed VIN code
    _camera.open();
    try {
      await _cvr.startCapturing(_templateName); //Start capturing
    } catch (e) {
      print(e);
    }
  }

  @override
  void dispose() {
    super.dispose();
    _cvr.stopCapturing();
    _camera.close();
    _cvr.removeResultReceiver(_receiver);
    _cvr.dispose();
    _camera.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(backgroundColor: Theme.of(context).colorScheme.inversePrimary, title: Text(widget.title)),
      body: Center(child: CameraView(cameraEnhancer: _camera)), // Bind CameraView and CameraEnhancer
    );
  }
}

Note

  • The VINData.fromParsedResultItem() function is a helper function to convert ParsedResultItem into an easier-to-read structure(VINData). You can get the source code from vin_scan_result.dart

Customize the Vin Scanner

Specify the Scan Region

You can also limit the scan region of the SDK so that it doesn't exhaust resources trying to read from the entire image or frame.

import 'package:dynamsoft_capture_vision_flutter/dynamsoft_capture_vision_flutter.dart';

final CameraEnhancer _camera = CameraEnhancer.instance;

void initSdk() async {
  //......
  final scanRegion = DSRect(left: 0.1, top: 0.4, right: 0.9, bottom: 0.6, measuredInPercentage: true);
  _camera.setScanRegion(scanRegion);
}

Run the project

Android:

flutter run -d <DEVICE_ID>

You can get the IDs of all connected devices with flutter devices.

iOS:

Install Pods dependencies:

cd ios/
pod install --repo-update

Open the workspace(!) ios/Runner.xcworkspace in Xcode and adjust the Signing / Developer Account settings. Then, build and run the app in Xcode.

If everything is set up correctly, you should see your new app running on your device.

Full Sample Code

The full sample code is available here.

License

Contact

https://www.dynamsoft.com/company/contact/