Xamarin Native | Xamarin Document Scanner

Integration with Xamarin.Android and Xamarin.iOS

The NuGet package ScanbotSDK.Xamarin is a universal package for Android and iOS. It contains the Xamarin Bindings for the Native Scanbot SDKs for Android and iOS and the Wrappers.

Namespaces

The bindings for Native SDKs and the Wrappers are stored in different namespaces which are explained here.

Xamarin Wrapper

Namespace for Android: ScanbotSDK.Xamarin.Android
Namespace for iOS: ScanbotSDK.Xamarin.iOS

The idea of the Scanbot SDK Xamarin Wrapper is to provide a unified and convenient API for iOS and Android. However, since not all Native SDK functionalities are available in the Wrapper namespace, you can use and call them as needed directly from the native namespaces.

Currently the following Document Scanner SDK functionalities are available for the Xamarin Wrapper classes:

Document detection on images
Image processing (cropping and perspective correction, rotating, etc)
Image filters
PDF creation
TIFF creation
Text Recognition (OCR)

Native SDKs

Native SDKs for Android and iOS are provided as Xamarin Bindings Libraries and can be found in these namespaces:

Android: Net.Doo.Snap, IO.Scanbot.Sdk
iOS: ScanbotSDK.iOS

The Xamarin Bindings for the Native SDKs provide the most available functionality of the Scanbot SDK.

👉 Documentation for Native SDKs classes can be found here:

Getting started

Initialize SDK

The Scanbot SDK must be initialized before usage. Make sure to run the initialization as early as possible. We recommend implementing the initialization in the Application class of the Android app, and in the AppDelegate class of the iOS app.

In the following examples we will use the convenient wrapper class SBSDK.

Xamarin.Android
Xamarin.iOS

Add the following code to your Application class:

using ScanbotSDK.Xamarin.Android.Wrapper;

[Application(LargeHeap = true)]
public class MainApplication : Application
{
    ...
    public override void OnCreate()
    {
        // You can pass null as licenseKey for trial mode. See the "License" section for more details.
        SBSDK.Initialize(this, licenseKey, new SBSDKConfiguration { EnableLogging = true });
        ....
    }
    ...
}

Furthermore, it is highly recommended to add the flag LargeHeap = true to the Application attribute on the MainApplication since image processing is very memory-intensive.

Add the following code to your AppDelegate class:

using ScanbotSDK.Xamarin.iOS.Wrapper;

[Register("AppDelegate")]
public class AppDelegate : UIApplicationDelegate
{
    ...
    public override bool FinishedLaunching(UIApplication application, NSDictionary launchOptions)
    {
        // You can pass null as licenseKey for trial mode. See the "License" section for more details.
        SBSDK.Initialize(application, licenseKey, new SBSDKConfiguration { EnableLogging = true });
        ....
    }
    ...
}

Storage Encryption

Scanbot SDK provides the ability to store the generated image files (JPG, PNG) and PDF files encrypted. This feature provides an additional level of security to the default secure storage locations of the native SDKs.

By default the file encryption is disabled. If you use ScanbotSDK wrapper, you have to pass the following config parameters on SDK initialization:

Common Wrapper:

Common
Xamarin.Android
Xamarin.iOS

new SBSDKConfiguration
{
    Encryption = new SBSDKEncryption
    {
        Mode = EncryptionMode.AES256,
        Password = "SomeSecretPa$$w0rdForFileEncryption"
    }
};

You can also use the native bindings to enable encryption.

var initializer = new IO.Scanbot.Sdk.ScanbotSDKInitializer();
var processor = new AESEncryptedFileIOProcessor(
    "SomeSecretPa$$w0rdForFileEncryption",
    AESEncryptedFileIOProcessor.AESEncrypterMode.Aes256
);
initializer.UseFileEncryption(true, processor);

  var encryption = new SBSDKAESEncrypter(
                      "SomeSecretPa$$w0rdForFileEncryption", 
                      SBSDKAESEncrypterMode.SBSDKAESEncrypterModeAES256);
  ScanbotSDKUI.DefaultImageStoreEncrypter = encryption;
  ScanbotSDKUI.DefaultPDFEncrypter = encryption;

By activating the storage encryption the native Scanbot SDKs will use the built-in AES 128 or AES 256 encryption. All generated image files (JPG, PNG) including the preview image files, as well as the exported PDF files will be encrypted in memory and stored as encrypted data files on the flash storage of the device.

The Scanbot SDK derives the AES key from the given password, an internal salt value, and the internal number of iterations using the PBKDF2 function.

When applying image operations like cropping, rotation or image filters, Scanbot SDK will decrypt the image file in memory, apply the changes, encrypt and store it again.

Scanbot SDK UI Components

RTU UI Components

The Ready-To-Use UI (RTU UI) is a set of easy to integrate and customize high-level UI components (View Controllers for iOS and Activities for Android) for the most common tasks in Scanbot SDK. The design and behavior of these RTU UI Components are based on our many years of experience as well as the feedback from our SDK customers.

The following RTU UI Components and classes are currently provided:

Xamarin.Android
Xamarin.iOS

Document Scanner - DocumentScannerActivity
Cropping - CroppingActivity
MRZ Scanner - MRZScannerActivity
Barcode and QR-Code Scanner - BarcodeScannerActivity & BatchBarcodeScannerActivity
Generic Document Recognizer - GenericDocumentRecognizerActivity
European Health Insurance Card Scanner - HealthInsuranceCardScannerActivity
Check Recognizer - CheckRecognizerActivity
Text Data Scanner - TextDataScannerActivity
VIN Scanner - VinScannerActivity

Document Scanner - SBSDKUIDocumentScannerViewController
Cropping - SBSDKUICroppingViewController
MRZ Scanner - SBSDKUIMRZScannerViewController
Barcode and QR-Code Scanner - SBSDKUIBarcodeScannerViewController & SBSDKUIBarcodesBatchScannerViewController
European Health Insurance Card Scanner - SBSDKUIHealthInsuranceCardScannerViewController
Check Recognizer - SBSDKUICheckRecognizerViewController
Text Data Scanner - SBSDKUITextDataScannerViewController
VIN Scanner - SBSDKUIVINScannerViewController

For more details please see the corresponding API docs of the classes as well as our example app.

Customization of RTU UI:

The main idea of the RTU UI is to provide simple-to-integrate and simple-to-customize screen components. Due to this idea there are some limitations with the possibilities of customization:

UI: All colors and text resources (localization)
Behavior: Enable or disable features like Multi-Page Scanning, Auto Snapping, Flashlight

If you need more customization options you have to implement custom screens (View Controllers for iOS and Activities for Android) using our Classic UI Components.

RTU UI Examples:

Please see our example app scanbot-sdk-example-xamarin on GitHub.

Classic UI Components

Our Classic UI Components allows you to build your custom screens which are very flexible and fully customizable. It is a set of easy to integrate and customize components (Views, Buttons, Handlers, Controllers, etc.) which can be embedded and extended in your custom screens.

For more details please see the corresponding API docs for iOS and Android.

Classic UI Examples:

Please see our example app scanbot-sdk-example-xamarin on GitHub.

Document Detection

The Scanbot SDK uses digital image processing algorithms to find rectangular, document like polygons in a digital image. As input a UIImage on iOS or Bitmap on Android are accepted.

Xamarin.Android
Xamarin.iOS

Bitmap image = ...;
var detectionResult = SBSDK.DetectDocument(image);
if (detectionResult.Status == DocumentDetectionStatus.Ok)
{
  var resultImage = detectionResult.Image as Bitmap;
  var polygon = detectionResult.Polygon;
  ...
}

UIImage image = ...;
var detectionResult = SBSDK.DetectDocument(image);
if (detectionResult.Status == DocumentDetectionStatus.Ok)
{
  var resultImage = detectionResult.Image as UIImage;
  var polygon = detectionResult.Polygon;
  ...
}

The result is an object of type DocumentDetectionResult which contains the detection status and on success the warped and cropped document image as well as the detected polygon. If there was no document detected the status enum provides the reason (noisy background, too dark, etc). The polygon is a list with 4 float points (one for each corner). Each point has coordinates in the range [0..1], representing a position relative to the image size. For instance, if a point has the coordinates (0.5, 0.5), it means that it is located exactly in the center of the image.

Alternatively, you can pass a Uri on Android or NSUrl on iOS of the source image.

Xamarin.Android
Xamarin.iOS

public static DocumentDetectionResult DetectDocument(Android.Net.Uri imageUri, Android.Content.Context context)

public static DocumentDetectionResult DetectDocument(Foundation.NSUrl imageUrl)

Please note that NSUrl must be a valid file URL (file:///). Assets URLs (assets-library://) are not supported.

Image Filtering

Xamarin.Android
Xamarin.iOS

Bitmap image = ...;
var resultImage = SBSDK.ApplyImageFilter(image, ImageFilter.Binarized);

UIImage image = ...;
var resultImage = SBSDK.ApplyImageFilter(image, ImageFilter.Binarized);

Supported image filters:

ImageFilter.ColorEnhanced - Optimizes colors, contrast and brightness.
ImageFilter.Grayscale - Grayscale filter
ImageFilter.Binarized - Standard binarization filter with contrast optimization. Creates an 8-bit grayscale image with mostly black or white pixels.
ImageFilter.ColorDocument - MagicColor filter. Fixes white balance and cleans up the background.
ImageFilter.PureBinarized - A filter for binarizing an image. Creates an image with pixel values set to either pure black or pure white.
ImageFilter.BackgroundClean - Cleans up the background and tries to preserve photos within the image.
ImageFilter.BlackAndWhite - Black and white filter with background cleaning. Creates an 8-bit grayscale image with mostly black or white pixels.
ImageFilter.OtsuBinarization - A filter for black and white conversion using OTSU binarization.
ImageFilter.DeepBinarization - A filter for black and white conversion primary used for low contrast documents.
ImageFilter.EdgeHighlight - A filter that enhances edges in low contrast documents.
ImageFilter.LowLightBinarization - A binarization filter primarily intended for use on low contrast documents with hard shadows.

PDF Creation

The Scanbot SDK renders images into a PDF document and stores it as a given target file. For each image a separate page is generated.

Xamarin.Android
Xamarin.iOS

Android.Net.Uri[] images = ...;
Android.Net.Uri pdfOutputFileUri = ...;
SBSDK.CreatePDF(images, pdfOutputFileUri, PDFPageSize.A4);

NSUrl[] images = ...;
NSUrl pdfOutputFileUrl = ...;
SBSDK.CreatePDF(images, pdfOutputFileUrl, PDFPageSize.A4);

The following PDF page sizes are supported:

Letter: The page has US letter size: 8.5x11 inches. The image is fitted and centered within the page.
Legal: The page has US legal size: 8.5x14 inches. The image is fitted and centered within the page.
A3: The page has A3 size: 297x420 mm. The image is fitted and centered within the page.
A4: The page has the aspect ratio of the image, but is fitted into A4 size. Whether portrait or landscape depends on the images aspect ratio.
A5: The page has A5 size: 148x210 mm. The image is fitted and centered within the page.
B4: The page has B4 size: 250x353 mm. The image is fitted and centered within the page.
B5: The page has B5 size: 176x250 mm. The image is fitted and centered within the page.
Executive: The page has US executive size: 7.25x10.5 inches. The image is fitted and centered within the page.
US4x6: The page has US 4x6 size: 4x6 inches. The image is fitted and centered within the page.
US4x8: The page has US 4x8 size: 4x8 inches. The image is fitted and centered within the page.
US5x7: The page has US 5x7 size: 4x6 inches. The image is fitted and centered within the page.
Comm10: The page has COMM10 size: 4.125x9.5 inches. The image is fitted and centered within the page.
Custom: Each page is as large as its image at 72 dpi.

Detect barcodes from still image

The Scanbot SDK detects barcodes from an existing image (UIImage or Bitmap). Result format is equivalent to Barcode Scanner

Xamarin.Android
Xamarin.iOS

var SDK = new IO.Scanbot.Sdk.ScanbotSDK(context);
BarcodeScanningResult result = sdk.CreateBarcodeDetector().DetectFromBitmap(bitmap, 0);

var scanner = new SBSDKBarcodeScanner();
SBSDKBarcodeScannerResult[] result = scanner.DetectBarCodesOnImage(image);

European Health Insurance Card Scanner

The Scanbot SDK detects and extracts data from European Health Insurance Cards.

Xamarin.Android
Xamarin.iOS

Ready-To-Use-UI-Demo/Droid/MainActivity.cs
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Xamarin Native | Xamarin Document Scanner

Integration with Xamarin.Android and Xamarin.iOS​

Namespaces​

Xamarin Wrapper​

Native SDKs​

Getting started​

Initialize SDK​

Storage Encryption​

Scanbot SDK UI Components​

RTU UI Components​

Classic UI Components​

Document Detection​

Image Filtering​

PDF Creation​

Detect barcodes from still image​

European Health Insurance Card Scanner​

Check Recognizer UI​

OCR - Optical Character Recognition​

Preconditions to achieve a good OCR result​

Download and Provide OCR Language Files​

OCR API​

Document Quality Analyzer​

Camera UI for document scanning​

Cropping UI​

DocumentDetectionStatus enum:​

Text Data Scanner UI​

VIN Scanner UI​

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On this page

Integration with Xamarin.Android and Xamarin.iOS

Namespaces

Xamarin Wrapper

Native SDKs

Getting started

Initialize SDK

Storage Encryption

Scanbot SDK UI Components

RTU UI Components

Classic UI Components

Document Detection

Image Filtering

PDF Creation

Detect barcodes from still image

European Health Insurance Card Scanner

Check Recognizer UI

OCR - Optical Character Recognition

Preconditions to achieve a good OCR result

Download and Provide OCR Language Files

OCR API

Document Quality Analyzer

Camera UI for document scanning

Cropping UI

DocumentDetectionStatus enum:

Text Data Scanner UI

VIN Scanner UI