Recognize Landmarks with Firebase ML on iOS

You can use Firebase ML to recognize well-known landmarks in an image.

Before you begin

If you have not already added Firebase to your app, do so by following the steps in the getting started guide.

Use Swift Package Manager to install and manage Firebase dependencies.

1. In Xcode, with your app project open, navigate to File> Add Packages.
2. When prompted, add the Firebase Apple platforms SDK repository:

 https://github.com/firebase/firebase-ios-sdk.git

3. Choose the Firebase ML library.
4. Add the -ObjC flag to the Other Linker Flags section of your target's build settings.
5. When finished, Xcode will automatically begin resolving and downloading your dependencies in the background.

Next, perform some in-app setup:

1. In your app, import Firebase:

   Swift

   importFirebaseMLModelDownloader

   Objective-C

   @importFirebaseMLModelDownloader;

1. If you haven't already enabled Cloud-based APIs for your project, do so now:

   1. Open the Firebase ML APIs page in the Firebase console.

   2. If you haven't already upgraded your project to the pay-as-you-go Blaze pricing plan, click Upgrade to do so. (You'll be prompted to upgrade only if your project isn't on the Blaze pricing plan.)

      Only projects on the Blaze pricing plan can use Cloud-based APIs.

   3. If Cloud-based APIs aren't already enabled, click Enable Cloud-based APIs.

Configure the landmark detector

By default, the Cloud detector uses the stable version of the model and returns up to 10 results. If you want to change either of these settings, specify them with a VisionCloudDetectorOptions object as in the following example:

letoptions=VisionCloudDetectorOptions()
options.modelType=.latest
options.maxResults=20
ViewController.swift 

FIRVisionCloudDetectorOptions*options=
[[FIRVisionCloudDetectorOptionsalloc]init];
options.modelType=FIRVisionCloudModelTypeLatest;
options.maxResults=20;

In the next step, pass the VisionCloudDetectorOptions object when you create the Cloud detector object.

Run the landmark detector

1. Get an instance of VisionCloudLandmarkDetector:

   Swift

   lazyvarvision=Vision.vision()
   letcloudDetector=vision.cloudLandmarkDetector(options:options)
   // Or, to use the default settings:
   // let cloudDetector = vision.cloudLandmarkDetector()
   ViewController.swift 

   Objective-C

   FIRVision*vision=[FIRVisionvision];
   FIRVisionCloudLandmarkDetector*landmarkDetector=[visioncloudLandmarkDetector];
   // Or, to change the default settings:
   // FIRVisionCloudLandmarkDetector *landmarkDetector =
   // [vision cloudLandmarkDetectorWithOptions:options];

2. In order to call Cloud Vision, the image must be formatted as a base64-encoded string. To process a UIImage:

   Swift

   guardletimageData=uiImage.jpegData(compressionQuality:1.0)else{return}
   letbase64encodedImage=imageData.base64EncodedString()

   Objective-C

   NSData*imageData=UIImageJPEGRepresentation(uiImage,1.0f);
   NSString*base64encodedImage=
   [imageDatabase64EncodedStringWithOptions:NSDataBase64Encoding76CharacterLineLength];

3. Then, pass the image to the detect(in:) method:

   Swift

   cloudDetector.detect(in:visionImage){landmarks,errorin
   guarderror==nil,letlandmarks=landmarks,!landmarks.isEmptyelse{
   // ...
   return
   }
   // Recognized landmarks
   // ...
   }
   ViewController.swift 

   Objective-C

   [landmarkDetectordetectInImage:image
   completion:^(NSArray<FIRVisionCloudLandmark*>*landmarks,
   NSError*error){
   if(error!=nil){
   return;
   }elseif(landmarks!=nil){
   // Got landmarks
   }
   }];

Get information about the recognized landmarks

For example:

forlandmarkinlandmarks{
letlandmarkDesc=landmark.landmark
letboundingPoly=landmark.frame
letentityId=landmark.entityId
// A landmark can have multiple locations: for example, the location the image
// was taken, and the location of the landmark depicted.
forlocationinlandmark.locations{
letlatitude=location.latitude
letlongitude=location.longitude
}
letconfidence=landmark.confidence
}

for(FIRVisionCloudLandmark*landmarkinlandmarks){
NSString*landmarkDesc=landmark.landmark;
CGRectframe=landmark.frame;
NSString*entityId=landmark.entityId;
// A landmark can have multiple locations: for example, the location the image
// was taken, and the location of the landmark depicted.
for(FIRVisionLatitudeLongitude*locationinlandmark.locations){
doublelatitude=[location.latitudedoubleValue];
doublelongitude=[location.longitudedoubleValue];
}
floatconfidence=[landmark.confidencefloatValue];
}

Next steps

• Before you deploy to production an app that uses a Cloud API, you should take some additional steps to prevent and mitigate the effect of unauthorized API access.