Detecting labels in an image
You can use the DetectLabels operation to detect labels in an image.
For an example, see Analyzing images stored in an Amazon S3 bucket.
The following examples use various AWS SDKs and the AWS CLI to call
DetectLabels. For information about the DetectLabels
operation response, see DetectLabels response.
To detect labels in an image
If you haven't already:
Create or update an IAM user with AmazonRekognitionFullAccess and
AmazonS3ReadOnlyAccess permissions. For more
information, see Step 1: Set up an AWS account and create an IAM
user.
Install and configure the AWS CLI and the AWS SDKs. For more information, see
Step 2: Set up the AWS CLI and AWS SDKs.
-
Upload an image that contains one or more objects—such as trees,
houses, and boat—to your S3 bucket. The image must be in
.jpg or .png format.
For instructions, see Uploading Objects into Amazon S3 in the Amazon Simple Storage Service User Guide.
-
Use the following examples to call the DetectLabels operation.
- Java
This example displays a list of labels that were detected in the input image. Replace the
values of bucket and photo with the names
of the Amazon S3 bucket and image that you used in step 2.
package com.amazonaws.samples;
import java.util.List;
import com.amazonaws.services.rekognition.model.BoundingBox;
import com.amazonaws.services.rekognition.model.DetectLabelsRequest;
import com.amazonaws.services.rekognition.model.DetectLabelsResult;
import com.amazonaws.services.rekognition.model.Image;
import com.amazonaws.services.rekognition.model.Instance;
import com.amazonaws.services.rekognition.model.Label;
import com.amazonaws.services.rekognition.model.Parent;
import com.amazonaws.services.rekognition.model.S3Object;
import com.amazonaws.services.rekognition.AmazonRekognition;
import com.amazonaws.services.rekognition.AmazonRekognitionClientBuilder;
import com.amazonaws.services.rekognition.model.AmazonRekognitionException;
public class DetectLabels {
public static void main(String[] args) throws Exception {
String photo = "photo";
String bucket = "bucket";
AmazonRekognition rekognitionClient = AmazonRekognitionClientBuilder.defaultClient();
DetectLabelsRequest request = new DetectLabelsRequest()
.withImage(new Image().withS3Object(new S3Object().withName(photo).withBucket(bucket)))
.withMaxLabels(10).withMinConfidence(75F);
try {
DetectLabelsResult result = rekognitionClient.detectLabels(request);
List<Label> labels = result.getLabels();
System.out.println("Detected labels for " + photo + "\n");
for (Label label : labels) {
System.out.println("Label: " + label.getName());
System.out.println("Confidence: " + label.getConfidence().toString() + "\n");
List<Instance> instances = label.getInstances();
System.out.println("Instances of " + label.getName());
if (instances.isEmpty()) {
System.out.println(" " + "None");
} else {
for (Instance instance : instances) {
System.out.println(" Confidence: " + instance.getConfidence().toString());
System.out.println(" Bounding box: " + instance.getBoundingBox().toString());
}
}
System.out.println("Parent labels for " + label.getName() + ":");
List<Parent> parents = label.getParents();
if (parents.isEmpty()) {
System.out.println(" None");
} else {
for (Parent parent : parents) {
System.out.println(" " + parent.getName());
}
}
System.out.println("--------------------");
System.out.println();
}
} catch (AmazonRekognitionException e) {
e.printStackTrace();
}
}
}
- AWS CLI
-
This example displays the JSON output from the
detect-labels CLI operation. Replace the values of
bucket and photo with the names of the
Amazon S3 bucket and image that you used in Step 2.
aws rekognition detect-labels \
--image '{"S3Object":{"Bucket":"bucket","Name":"file"}}'
- Python
This example displays the labels that were detected in the input image. In the function main,
replace the values of bucket and photo with the names of the
Amazon S3 bucket and image that you used in Step 2.
#Copyright 2018 Amazon.com, Inc. or its affiliates. All Rights Reserved.
#PDX-License-Identifier: MIT-0 (For details, see https://github.com/awsdocs/amazon-rekognition-developer-guide/blob/master/LICENSE-SAMPLECODE.)
import boto3
def detect_labels(photo, bucket):
client=boto3.client('rekognition')
response = client.detect_labels(Image={'S3Object':{'Bucket':bucket,'Name':photo}},
MaxLabels=10)
print('Detected labels for ' + photo)
print()
for label in response['Labels']:
print ("Label: " + label['Name'])
print ("Confidence: " + str(label['Confidence']))
print ("Instances:")
for instance in label['Instances']:
print (" Bounding box")
print (" Top: " + str(instance['BoundingBox']['Top']))
print (" Left: " + str(instance['BoundingBox']['Left']))
print (" Width: " + str(instance['BoundingBox']['Width']))
print (" Height: " + str(instance['BoundingBox']['Height']))
print (" Confidence: " + str(instance['Confidence']))
print()
print ("Parents:")
for parent in label['Parents']:
print (" " + parent['Name'])
print ("----------")
print ()
return len(response['Labels'])
def main():
photo=''
bucket=''
label_count=detect_labels(photo, bucket)
print("Labels detected: " + str(label_count))
if __name__ == "__main__":
main()
- .NET
This example displays a list of labels that were detected in the input image. Replace the
values of bucket and photo with the names
of the Amazon S3 bucket and image that you used in Step 2.
//Copyright 2018 Amazon.com, Inc. or its affiliates. All Rights Reserved.
//PDX-License-Identifier: MIT-0 (For details, see https://github.com/awsdocs/amazon-rekognition-developer-guide/blob/master/LICENSE-SAMPLECODE.)
using System;
using Amazon.Rekognition;
using Amazon.Rekognition.Model;
public class DetectLabels
{
public static void Example()
{
String photo = "input.jpg";
String bucket = "bucket";
AmazonRekognitionClient rekognitionClient = new AmazonRekognitionClient();
DetectLabelsRequest detectlabelsRequest = new DetectLabelsRequest()
{
Image = new Image()
{
S3Object = new S3Object()
{
Name = photo,
Bucket = bucket
},
},
MaxLabels = 10,
MinConfidence = 75F
};
try
{
DetectLabelsResponse detectLabelsResponse = rekognitionClient.DetectLabels(detectlabelsRequest);
Console.WriteLine("Detected labels for " + photo);
foreach (Label label in detectLabelsResponse.Labels)
Console.WriteLine("{0}: {1}", label.Name, label.Confidence);
}
catch (Exception e)
{
Console.WriteLine(e.Message);
}
}
}
- Ruby
This example displays a list of labels that were detected in the input image. Replace the
values of bucket and photo with the names
of the Amazon S3 bucket and image that you used in Step 2.
#Copyright 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
#PDX-License-Identifier: MIT-0 (For details, see https://github.com/awsdocs/amazon-rekognition-developer-guide/blob/master/LICENSE-SAMPLECODE.)
# Add to your Gemfile
# gem 'aws-sdk-rekognition'
require 'aws-sdk-rekognition'
credentials = Aws::Credentials.new(
ENV['AWS_ACCESS_KEY_ID'],
ENV['AWS_SECRET_ACCESS_KEY']
)
bucket = 'bucket' # the bucket name without s3://
photo = 'photo' # the name of file
client = Aws::Rekognition::Client.new credentials: credentials
attrs = {
image: {
s3_object: {
bucket: bucket,
name: photo
},
},
max_labels: 10
}
response = client.detect_labels attrs
puts "Detected labels for: #{photo}"
response.labels.each do |label|
puts "Label: #{label.name}"
puts "Confidence: #{label.confidence}"
puts "Instances:"
label['instances'].each do |instance|
box = instance['bounding_box']
puts " Bounding box:"
puts " Top: #{box.top}"
puts " Left: #{box.left}"
puts " Width: #{box.width}"
puts " Height: #{box.height}"
puts " Confidence: #{instance.confidence}"
end
puts "Parents:"
label.parents.each do |parent|
puts " #{parent.name}"
end
puts "------------"
puts ""
end
- Node.js
This example displays a list of labels that were detected in the input image. Replace the
values of bucket and photo with the names
of the Amazon S3 bucket and image that you used in Step 2.
If you are using TypeScript definitions, you may need to use
import AWS from 'aws-sdk' instead of const
AWS = require('aws-sdk'), in order to run the program
with Node.js. You can consult the AWS
SDK for Javascript for more details. Depending on how
you have your configurations set up, you also may need to specify
your region with
AWS.config.update({region:region});.
//Copyright 2018 Amazon.com, Inc. or its affiliates. All Rights Reserved.
//PDX-License-Identifier: MIT-0 (For details, see https://github.com/awsdocs/amazon-rekognition-developer-guide/blob/master/LICENSE-SAMPLECODE.)
// Load the SDK
var AWS = require('aws-sdk');
const bucket = 'bucket' // the bucketname without s3://
const photo = 'photo' // the name of file
const config = new AWS.Config({
accessKeyId: process.env.AWS_ACCESS_KEY_ID,
secretAccessKey: process.env.AWS_SECRET_ACCESS_KEY,
region: process.env.AWS_REGION
})
const client = new AWS.Rekognition();
const params = {
Image: {
S3Object: {
Bucket: bucket,
Name: photo
},
},
MaxLabels: 10
}
client.detectLabels(params, function(err, response) {
if (err) {
console.log(err, err.stack); // if an error occurred
} else {
console.log(`Detected labels for: ${photo}`)
response.Labels.forEach(label => {
console.log(`Label: ${label.Name}`)
console.log(`Confidence: ${label.Confidence}`)
console.log("Instances:")
label.Instances.forEach(instance => {
let box = instance.BoundingBox
console.log(" Bounding box:")
console.log(` Top: ${box.Top}`)
console.log(` Left: ${box.Left}`)
console.log(` Width: ${box.Width}`)
console.log(` Height: ${box.Height}`)
console.log(` Confidence: ${instance.Confidence}`)
})
console.log("Parents:")
label.Parents.forEach(parent => {
console.log(` ${parent.Name}`)
})
console.log("------------")
console.log("")
}) // for response.labels
} // if
});
- Java V2
-
This code is taken from the AWS Documentation SDK examples GitHub repository. See the full example
here.
public static void detectImageLabels(RekognitionClient rekClient, String sourceImage) {
try {
InputStream sourceStream = new FileInputStream(sourceImage);
SdkBytes sourceBytes = SdkBytes.fromInputStream(sourceStream);
// Create an Image object for the source image.
Image souImage = Image.builder()
.bytes(sourceBytes)
.build();
DetectLabelsRequest detectLabelsRequest = DetectLabelsRequest.builder()
.image(souImage)
.maxLabels(10)
.build();
DetectLabelsResponse labelsResponse = rekClient.detectLabels(detectLabelsRequest);
List<Label> labels = labelsResponse.labels();
System.out.println("Detected labels for the given photo");
for (Label label: labels) {
System.out.println(label.name() + ": " + label.confidence().toString());
}
} catch (RekognitionException | FileNotFoundException e) {
System.out.println(e.getMessage());
System.exit(1);
}
}
DetectLabels operation request
The input to DetectLabel is an image. In this example JSON input, the source image is loaded from an Amazon S3 Bucket.
MaxLabels is the maximum number of labels to return in the response. MinConfidence is the minimum confidence
that Amazon Rekognition Image must have in the accuracy of the detected label for it to be returned in the response.
{
"Image": {
"S3Object": {
"Bucket": "bucket",
"Name": "input.jpg"
}
},
"MaxLabels": 10,
"MinConfidence": 75
}
DetectLabels response
The response from DetectLabels is an array of labels detected in the image and the level of confidence by which they were detected.
The following is an example
response from DetectLabels.
The response shows that the operation detected multiple labels including Person,
Vehicle, and Car. Each label has an associated level of
confidence. For example, the detection algorithm is 98.991432% confident that the
image contains a person.
The response also includes the ancestor labels for a label in the Parents
array. For example, the label Automobile has two parent labels named Vehicle and Transportation.
The response for common object labels includes bounding box information for the location of
the label on the input image. For example, the Person label has an instances array
containing two bounding boxes. These are the locations of two people detected in the image.
The field LabelModelVersion contains the version number of the detection model used
by DetectLabels.
{
{
"Labels": [
{
"Name": "Vehicle",
"Confidence": 99.15271759033203,
"Instances": [],
"Parents": [
{
"Name": "Transportation"
}
]
},
{
"Name": "Transportation",
"Confidence": 99.15271759033203,
"Instances": [],
"Parents": []
},
{
"Name": "Automobile",
"Confidence": 99.15271759033203,
"Instances": [],
"Parents": [
{
"Name": "Vehicle"
},
{
"Name": "Transportation"
}
]
},
{
"Name": "Car",
"Confidence": 99.15271759033203,
"Instances": [
{
"BoundingBox": {
"Width": 0.10616336017847061,
"Height": 0.18528179824352264,
"Left": 0.0037978808395564556,
"Top": 0.5039216876029968
},
"Confidence": 99.15271759033203
},
{
"BoundingBox": {
"Width": 0.2429988533258438,
"Height": 0.21577216684818268,
"Left": 0.7309805154800415,
"Top": 0.5251884460449219
},
"Confidence": 99.1286392211914
},
{
"BoundingBox": {
"Width": 0.14233611524105072,
"Height": 0.15528248250484467,
"Left": 0.6494812965393066,
"Top": 0.5333095788955688
},
"Confidence": 98.48368072509766
},
{
"BoundingBox": {
"Width": 0.11086395382881165,
"Height": 0.10271988064050674,
"Left": 0.10355594009160995,
"Top": 0.5354844927787781
},
"Confidence": 96.45606231689453
},
{
"BoundingBox": {
"Width": 0.06254628300666809,
"Height": 0.053911514580249786,
"Left": 0.46083059906959534,
"Top": 0.5573825240135193
},
"Confidence": 93.65448760986328
},
{
"BoundingBox": {
"Width": 0.10105438530445099,
"Height": 0.12226245552301407,
"Left": 0.5743985772132874,
"Top": 0.534368634223938
},
"Confidence": 93.06217193603516
},
{
"BoundingBox": {
"Width": 0.056389667093753815,
"Height": 0.17163699865341187,
"Left": 0.9427769780158997,
"Top": 0.5235804319381714
},
"Confidence": 92.6864013671875
},
{
"BoundingBox": {
"Width": 0.06003860384225845,
"Height": 0.06737709045410156,
"Left": 0.22409997880458832,
"Top": 0.5441341400146484
},
"Confidence": 90.4227066040039
},
{
"BoundingBox": {
"Width": 0.02848697081208229,
"Height": 0.19150497019290924,
"Left": 0.0,
"Top": 0.5107086896896362
},
"Confidence": 86.65286254882812
},
{
"BoundingBox": {
"Width": 0.04067881405353546,
"Height": 0.03428703173995018,
"Left": 0.316415935754776,
"Top": 0.5566273927688599
},
"Confidence": 85.36471557617188
},
{
"BoundingBox": {
"Width": 0.043411049991846085,
"Height": 0.0893595889210701,
"Left": 0.18293385207653046,
"Top": 0.5394920110702515
},
"Confidence": 82.21705627441406
},
{
"BoundingBox": {
"Width": 0.031183116137981415,
"Height": 0.03989990055561066,
"Left": 0.2853088080883026,
"Top": 0.5579366683959961
},
"Confidence": 81.0157470703125
},
{
"BoundingBox": {
"Width": 0.031113790348172188,
"Height": 0.056484755128622055,
"Left": 0.2580395042896271,
"Top": 0.5504819750785828
},
"Confidence": 56.13441467285156
},
{
"BoundingBox": {
"Width": 0.08586374670267105,
"Height": 0.08550430089235306,
"Left": 0.5128012895584106,
"Top": 0.5438792705535889
},
"Confidence": 52.37760925292969
}
],
"Parents": [
{
"Name": "Vehicle"
},
{
"Name": "Transportation"
}
]
},
{
"Name": "Human",
"Confidence": 98.9914321899414,
"Instances": [],
"Parents": []
},
{
"Name": "Person",
"Confidence": 98.9914321899414,
"Instances": [
{
"BoundingBox": {
"Width": 0.19360728561878204,
"Height": 0.2742200493812561,
"Left": 0.43734854459762573,
"Top": 0.35072067379951477
},
"Confidence": 98.9914321899414
},
{
"BoundingBox": {
"Width": 0.03801717236638069,
"Height": 0.06597328186035156,
"Left": 0.9155802130699158,
"Top": 0.5010883808135986
},
"Confidence": 85.02790832519531
}
],
"Parents": []
}
],
"LabelModelVersion": "2.0"
}
}
