Detect faces in a local file

Perform face detection on a local file.

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For detailed documentation that includes this code sample, see the following:

Code sample

Go

Before trying this sample, follow the Go setup instructions in the Vision quickstart using client libraries. For more information, see the Vision Go API reference documentation.

To authenticate to Vision, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.


// detectFaces gets faces from the Vision API for an image at the given file path.
func detectFaces(w io.Writer, file string) error {
	ctx := context.Background()

	client, err := vision.NewImageAnnotatorClient(ctx)
	if err != nil {
		return err
	}
	defer client.Close()

	f, err := os.Open(file)
	if err != nil {
		return err
	}
	defer f.Close()

	image, err := vision.NewImageFromReader(f)
	if err != nil {
		return err
	}
	annotations, err := client.DetectFaces(ctx, image, nil, 10)
	if err != nil {
		return err
	}
	if len(annotations) == 0 {
		fmt.Fprintln(w, "No faces found.")
	} else {
		fmt.Fprintln(w, "Faces:")
		for i, annotation := range annotations {
			fmt.Fprintln(w, "  Face", i)
			fmt.Fprintln(w, "    Anger:", annotation.AngerLikelihood)
			fmt.Fprintln(w, "    Joy:", annotation.JoyLikelihood)
			fmt.Fprintln(w, "    Surprise:", annotation.SurpriseLikelihood)
		}
	}
	return nil
}

Java

Before trying this sample, follow the Java setup instructions in the Vision quickstart using client libraries. For more information, see the Vision Java API reference documentation.

To authenticate to Vision, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.


import com.google.cloud.vision.v1.AnnotateImageRequest;
import com.google.cloud.vision.v1.AnnotateImageResponse;
import com.google.cloud.vision.v1.BatchAnnotateImagesResponse;
import com.google.cloud.vision.v1.FaceAnnotation;
import com.google.cloud.vision.v1.Feature;
import com.google.cloud.vision.v1.Image;
import com.google.cloud.vision.v1.ImageAnnotatorClient;
import com.google.protobuf.ByteString;
import java.io.FileInputStream;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

public class DetectFaces {

  public static void detectFaces() throws IOException {
    // TODO(developer): Replace these variables before running the sample.
    String filePath = "path/to/your/image/file.jpg";
    detectFaces(filePath);
  }

  // Detects faces in the specified local image.
  public static void detectFaces(String filePath) throws IOException {
    List<AnnotateImageRequest> requests = new ArrayList<>();

    ByteString imgBytes = ByteString.readFrom(new FileInputStream(filePath));

    Image img = Image.newBuilder().setContent(imgBytes).build();
    Feature feat = Feature.newBuilder().setType(Feature.Type.FACE_DETECTION).build();
    AnnotateImageRequest request =
        AnnotateImageRequest.newBuilder().addFeatures(feat).setImage(img).build();
    requests.add(request);

    // Initialize client that will be used to send requests. This client only needs to be created
    // once, and can be reused for multiple requests. After completing all of your requests, call
    // the "close" method on the client to safely clean up any remaining background resources.
    try (ImageAnnotatorClient client = ImageAnnotatorClient.create()) {
      BatchAnnotateImagesResponse response = client.batchAnnotateImages(requests);
      List<AnnotateImageResponse> responses = response.getResponsesList();

      for (AnnotateImageResponse res : responses) {
        if (res.hasError()) {
          System.out.format("Error: %s%n", res.getError().getMessage());
          return;
        }

        // For full list of available annotations, see http://g.co/cloud/vision/docs
        for (FaceAnnotation annotation : res.getFaceAnnotationsList()) {
          System.out.format(
              "anger: %s%njoy: %s%nsurprise: %s%nposition: %s",
              annotation.getAngerLikelihood(),
              annotation.getJoyLikelihood(),
              annotation.getSurpriseLikelihood(),
              annotation.getBoundingPoly());
        }
      }
    }
  }
}

Node.js

Before trying this sample, follow the Node.js setup instructions in the Vision quickstart using client libraries. For more information, see the Vision Node.js API reference documentation.

To authenticate to Vision, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

// Imports the Google Cloud client library
const vision = require('@google-cloud/vision');

// Creates a client
const client = new vision.ImageAnnotatorClient();

async function detectFaces() {
  /**
   * TODO(developer): Uncomment the following line before running the sample.
   */
  // const fileName = 'Local image file, e.g. /path/to/image.png';

  const [result] = await client.faceDetection(fileName);
  const faces = result.faceAnnotations;
  console.log('Faces:');
  faces.forEach((face, i) => {
    console.log(`  Face #${i + 1}:`);
    console.log(`    Joy: ${face.joyLikelihood}`);
    console.log(`    Anger: ${face.angerLikelihood}`);
    console.log(`    Sorrow: ${face.sorrowLikelihood}`);
    console.log(`    Surprise: ${face.surpriseLikelihood}`);
  });
}
detectFaces();

PHP

Before trying this sample, follow the PHP setup instructions in the Vision quickstart using client libraries. For more information, see the Vision PHP API reference documentation.

To authenticate to Vision, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

namespace Google\Cloud\Samples\Vision;

use Google\Cloud\Vision\V1\ImageAnnotatorClient;

/**
 * @param string $path    Path to the image, e.g. "path/to/your/image.jpg"
 * @param string $outFile Saves a copy of the image supplied in $path with a
 *                        rectangle drawn around the detected faces.
 */
function detect_face(string $path, string $outFile = null)
{
    $imageAnnotator = new ImageAnnotatorClient();

    # annotate the image
    // $path = 'path/to/your/image.jpg'
    $image = file_get_contents($path);
    $response = $imageAnnotator->faceDetection($image);
    $faces = $response->getFaceAnnotations();

    # names of likelihood from google.cloud.vision.enums
    $likelihoodName = ['UNKNOWN', 'VERY_UNLIKELY', 'UNLIKELY',
    'POSSIBLE', 'LIKELY', 'VERY_LIKELY'];

    printf('%d faces found:' . PHP_EOL, count($faces));
    foreach ($faces as $face) {
        $anger = $face->getAngerLikelihood();
        printf('Anger: %s' . PHP_EOL, $likelihoodName[$anger]);

        $joy = $face->getJoyLikelihood();
        printf('Joy: %s' . PHP_EOL, $likelihoodName[$joy]);

        $surprise = $face->getSurpriseLikelihood();
        printf('Surprise: %s' . PHP_EOL, $likelihoodName[$surprise]);

        # get bounds
        $vertices = $face->getBoundingPoly()->getVertices();
        $bounds = [];
        foreach ($vertices as $vertex) {
            $bounds[] = sprintf('(%d,%d)', $vertex->getX(), $vertex->getY());
        }
        print('Bounds: ' . join(', ', $bounds) . PHP_EOL);
        print(PHP_EOL);
    }
}

Python

Before trying this sample, follow the Python setup instructions in the Vision quickstart using client libraries. For more information, see the Vision Python API reference documentation.

To authenticate to Vision, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

def detect_faces(path):
    """Detects faces in an image."""
    from google.cloud import vision

    client = vision.ImageAnnotatorClient()

    with open(path, "rb") as image_file:
        content = image_file.read()

    image = vision.Image(content=content)

    response = client.face_detection(image=image)
    faces = response.face_annotations

    # Names of likelihood from google.cloud.vision.enums
    likelihood_name = (
        "UNKNOWN",
        "VERY_UNLIKELY",
        "UNLIKELY",
        "POSSIBLE",
        "LIKELY",
        "VERY_LIKELY",
    )
    print("Faces:")

    for face in faces:
        print(f"anger: {likelihood_name[face.anger_likelihood]}")
        print(f"joy: {likelihood_name[face.joy_likelihood]}")
        print(f"surprise: {likelihood_name[face.surprise_likelihood]}")

        vertices = [
            f"({vertex.x},{vertex.y})" for vertex in face.bounding_poly.vertices
        ]

        print("face bounds: {}".format(",".join(vertices)))

    if response.error.message:
        raise Exception(
            "{}\nFor more info on error messages, check: "
            "https://cloud.google.com/apis/design/errors".format(response.error.message)
        )

What's next

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