分析从本地文件系统加载的图像

Amazon Rekognition Image 操作可以分析作为图像字节提供的图像或存储在 Amazon S3 存储桶中的图像。

这些主题提供如下示例：通过使用从本地文件系统加载的文件，将图像字节提供给 Amazon Rekognition Image API 操作。使用图像输入参数将图像字节传递给 Amazon Rekognition API 操作。在 Image 中，您指定 Bytes 属性以传递 base64 编码的图像字节。

使用Bytes输入参数传递给 Amazon Rekognition API 操作的图像字节必须为 base64 编码。这些示例使用的 AWS 软件开发工具包自动对图像执行 base64 编码。在调用 Amazon Rekognition API 操作之前，您无需对图像字节进行编码。有关更多信息，请参阅图像规格。

在 DetectLabels的此示例 JSON 请求中，源图像字节在 Bytes 输入参数中传递。


{
    "Image": {
        "Bytes": "/9j/4AAQSk....."
    },
    "MaxLabels": 10,
    "MinConfidence": 77
}

以下示例使用不同 AWS 开发工具包和 AWS CLI 来调用 DetectLabels。有关 DetectLabels 操作响应的信息，请参阅DetectLabels 响应。

有关客户端 JavaScript 示例，请参阅使用 JavaScript。

检测本地图像中的标签

如果您尚未执行以下操作，请：
1. 使用 AmazonRekognitionFullAccess 和 AmazonS3ReadOnlyAccess 权限创建或更新用户。有关更多信息，请参阅步骤 1：设置 AWS 账户并创建用户。
2. 安装并配置 AWS CLI 和 AWS SDK。有关更多信息，请参阅步骤 2：设置 AWS CLI 和 AWS SDK。

使用以下示例调用 DetectLabels 操作。

Java

以下 Java 示例说明如何从本地文件系统加载图像，并使用 detectLabels AWS 软件开发工具包操作来检测标签。将 photo 的值更改为图像文件（.jpg 或 .png 格式）的路径和文件名。


//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.)

package aws.example.rekognition.image;
import java.io.File;
import java.io.FileInputStream;
import java.io.InputStream;
import java.nio.ByteBuffer;
import java.util.List;
import com.amazonaws.services.rekognition.AmazonRekognition;
import com.amazonaws.services.rekognition.AmazonRekognitionClientBuilder;
import com.amazonaws.AmazonClientException;
import com.amazonaws.services.rekognition.model.AmazonRekognitionException;
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.Label;
import com.amazonaws.util.IOUtils;

public class DetectLabelsLocalFile {
    public static void main(String[] args) throws Exception {
    	String photo="input.jpg";


        ByteBuffer imageBytes;
        try (InputStream inputStream = new FileInputStream(new File(photo))) {
            imageBytes = ByteBuffer.wrap(IOUtils.toByteArray(inputStream));
        }


        AmazonRekognition rekognitionClient = AmazonRekognitionClientBuilder.defaultClient();

        DetectLabelsRequest request = new DetectLabelsRequest()
                .withImage(new Image()
                        .withBytes(imageBytes))
                .withMaxLabels(10)
                .withMinConfidence(77F);

        try {

            DetectLabelsResult result = rekognitionClient.detectLabels(request);
            List <Label> labels = result.getLabels();

            System.out.println("Detected labels for " + photo);
            for (Label label: labels) {
               System.out.println(label.getName() + ": " + label.getConfidence().toString());
            }

        } catch (AmazonRekognitionException e) {
            e.printStackTrace();
        }

    }
}

Python

以下 AWS SDK for Python 示例说明如何从本地文件系统加载图像并调用 detect_labels 操作。将 photo 的值更改为图像文件（.jpg 或 .png 格式）的路径和文件名。


#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_local_file(photo):


    client=boto3.client('rekognition')
   
    with open(photo, 'rb') as image:
        response = client.detect_labels(Image={'Bytes': image.read()})
        
    print('Detected labels in ' + photo)    
    for label in response['Labels']:
        print (label['Name'] + ' : ' + str(label['Confidence']))

    return len(response['Labels'])

def main():
    photo='photo'

    label_count=detect_labels_local_file(photo)
    print("Labels detected: " + str(label_count))


if __name__ == "__main__":
    main()

.NET

以下示例说明如何从本地文件系统加载图像和使用 DetectLabels 操作来检测标签。将 photo 的值更改为图像文件（.jpg 或 .png 格式）的路径和文件名。


//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 System.IO;
using Amazon.Rekognition;
using Amazon.Rekognition.Model;

public class DetectLabelsLocalfile
{
    public static void Example()
    {
        String photo = "input.jpg";

        Amazon.Rekognition.Model.Image image = new Amazon.Rekognition.Model.Image();
        try
        {
            using (FileStream fs = new FileStream(photo, FileMode.Open, FileAccess.Read))
            {
                byte[] data = null;
                data = new byte[fs.Length];
                fs.Read(data, 0, (int)fs.Length);
                image.Bytes = new MemoryStream(data);
            }
        }
        catch (Exception)
        {
            Console.WriteLine("Failed to load file " + photo);
            return;
        }

        AmazonRekognitionClient rekognitionClient = new AmazonRekognitionClient();

        DetectLabelsRequest detectlabelsRequest = new DetectLabelsRequest()
        {
            Image = image,
            MaxLabels = 10,
            MinConfidence = 77F
        };

        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);
        }
    }
}

PHP

以下适用于 PHP 的 AWS SDK 示例演示如何从本地文件系统加载图像并调用 DetectFaces API 操作。将 photo 的值更改为图像文件（.jpg 或 .png 格式）的路径和文件名。



<?php
//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.)

    require 'vendor/autoload.php';

    use Aws\Rekognition\RekognitionClient;

    $options = [
       'region'            => 'us-west-2',
        'version'           => 'latest'
    ];

    $rekognition = new RekognitionClient($options);
	
    // Get local image
    $photo = 'input.jpg';
    $fp_image = fopen($photo, 'r');
    $image = fread($fp_image, filesize($photo));
    fclose($fp_image);


    // Call DetectFaces
    $result = $rekognition->DetectFaces(array(
       'Image' => array(
          'Bytes' => $image,
       ),
       'Attributes' => array('ALL')
       )
    );

    // Display info for each detected person
    print 'People: Image position and estimated age' . PHP_EOL;
    for ($n=0;$n<sizeof($result['FaceDetails']); $n++){

      print 'Position: ' . $result['FaceDetails'][$n]['BoundingBox']['Left'] . " "
      . $result['FaceDetails'][$n]['BoundingBox']['Top']
      . PHP_EOL
      . 'Age (low): '.$result['FaceDetails'][$n]['AgeRange']['Low']
      .  PHP_EOL
      . 'Age (high): ' . $result['FaceDetails'][$n]['AgeRange']['High']
      .  PHP_EOL . PHP_EOL;
    }
?>

Ruby

此示例显示在输入图像中检测到的标签的列表。将 photo 的值更改为图像文件（.jpg 或 .png 格式）的路径和文件名。


#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.)

    # gem 'aws-sdk-rekognition'
    require 'aws-sdk-rekognition'
    credentials = Aws::Credentials.new(
       ENV['AWS_ACCESS_KEY_ID'],
       ENV['AWS_SECRET_ACCESS_KEY']
    )
    client   = Aws::Rekognition::Client.new credentials: credentials
    photo = 'photo.jpg'
    path = File.expand_path(photo) # expand path relative to the current directory
    file = File.read(path)
    attrs = {
      image: {
        bytes: file
      },
      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

Java V2

此代码取自 AWS 文档 SDK 示例 GitHub 存储库。请在此处查看完整示例。


import software.amazon.awssdk.core.SdkBytes;
import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.rekognition.RekognitionClient;
import software.amazon.awssdk.services.rekognition.model.*;

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.InputStream;
import java.util.List;

/**
 * Before running this Java V2 code example, set up your development
 * environment, including your credentials.
 *
 * For more information, see the following documentation topic:
 *
 * https://docs.aws.amazon.com/sdk-for-java/latest/developer-guide/get-started.html
 */
public class DetectLabels {
    public static void main(String[] args) {
        final String usage = """
            Usage: <bucketName> <sourceImage>

            Where:
                bucketName - The name of the Amazon S3 bucket where the image is stored
                sourceImage - The name of the image file (for example, pic1.png).\s
            """;

        if (args.length != 2) {
            System.out.println(usage);
            System.exit(1);
        }

        String bucketName = args[0] ;
        String sourceImage = args[1] ;
        Region region = Region.US_WEST_2;
        RekognitionClient rekClient = RekognitionClient.builder()
                .region(region)
                .build();

        detectImageLabels(rekClient, bucketName, sourceImage);
        rekClient.close();
    }

    /**
     * Detects the labels in an image stored in an Amazon S3 bucket using the Amazon Rekognition service.
     *
     * @param rekClient     the Amazon Rekognition client used to make the detection request
     * @param bucketName    the name of the Amazon S3 bucket where the image is stored
     * @param sourceImage   the name of the image file to be analyzed
     */
    public static void detectImageLabels(RekognitionClient rekClient, String bucketName, String sourceImage) {
        try {
            S3Object s3ObjectTarget = S3Object.builder()
                    .bucket(bucketName)
                    .name(sourceImage)
                    .build();

            Image souImage = Image.builder()
                    .s3Object(s3ObjectTarget)
                    .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 e) {
            System.out.println(e.getMessage());
            System.exit(1);
        }
    }
}

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要使用 Amazon Web Services 文档，必须启用 Javascript。请参阅浏览器的帮助页面以了解相关说明。

文档惯例

分析 Amazon S3 存储桶中的图像

使用 JavaScript