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# 搜索用户（图像）
`SearchUsersByImage` 在指定集合 ID 中搜索与所提供图像中检测到的最大人脸相匹配的用户。默认情况下， SearchUsersByImage 返回相似度分数大于 80% 的用户 ID。相似度表示用户 ID 与所提供图像中检测到的最大面孔的匹配程度。如果返回多个用户 ID，则按相似度最高到最低的顺序列出。或者，您可以使用 UserMatchThreshold 来指定不同的值。有关更多信息，请参阅 [在集合中管理用户](managing-face-collections.md#collections-manage-users)。
**按图片搜索用户 (SDK)**
1. 如果您尚未执行以下操作，请：
1. 使用 `AmazonRekognitionFullAccess` 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](setting-up.md#setting-up-iam)。
1. 安装和配置 AWS CLI 和 AWS SDK。有关更多信息，请参阅 [第 2 步：设置 AWS CLI and AWS 软件开发工具包](setup-awscli-sdk.md)。
1. 使用以下示例调用 `SearchUsersByImage` 操作。
------
#### [ Java ]
此 Java 示例使用 `SearchUsersByImage` 操作根据输入图像搜索集合中的用户。
```
import com.amazonaws.services.rekognition.AmazonRekognition;
import com.amazonaws.services.rekognition.AmazonRekognitionClientBuilder;
import com.amazonaws.services.rekognition.model.Image;
import com.amazonaws.services.rekognition.model.S3Object;
import com.amazonaws.services.rekognition.model.SearchUsersByImageRequest;
import com.amazonaws.services.rekognition.model.SearchUsersByImageResult;
import com.amazonaws.services.rekognition.model.UserMatch;
public class SearchUsersByImage {
//Replace bucket, collectionId and photo with your values.
public static final String collectionId = "MyCollection";
public static final String s3Bucket = "bucket";
public static final String s3PhotoFileKey = "input.jpg";
public static void main(String[] args) throws Exception {
AmazonRekognition rekognitionClient = AmazonRekognitionClientBuilder.defaultClient();
// Get an image object from S3 bucket.
Image image = new Image()
.withS3Object(new S3Object()
.withBucket(s3Bucket)
.withName(s3PhotoFileKey));
// Search collection for users similar to the largest face in the image.
SearchUsersByImageRequest request = new SearchUsersByImageRequest()
.withCollectionId(collectionId)
.withImage(image)
.withUserMatchThreshold(70F)
.withMaxUsers(2);
SearchUsersByImageResult result =
rekognitionClient.searchUsersByImage(request);
System.out.println("Printing search result with matched user and similarity score");
for (UserMatch match: result.getUserMatches()) {
System.out.println(match.getUser().getUserId() + " with similarity score " + match.getSimilarity());
}
}
}
```
------
#### [ AWS CLI ]
此 AWS CLI 命令通过`SearchUsersByImage`操作根据输入图像在集合中搜索用户。
```
aws rekognition search-users-by-image --image '{"S3Object":{"Bucket":"{{s3BucketName}}","Name":"{{file-name}}"}}' --collection-id {{MyCollectionId}} --region {{region-name}}
```
------
#### [ Python ]
以下示例使用 `SearchUsersByImage` 操作根据输入图像搜索集合中的用户。
```
# 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
from botocore.exceptions import ClientError
import logging
import os
logger = logging.getLogger(__name__)
session = boto3.Session(profile_name='profile-name')
client = session.client('rekognition')
def load_image(file_name):
"""
helper function to load the image for indexFaces call from local disk
:param image_file_name: The image file location that will be used by indexFaces call.
:return: The Image in bytes
"""
print(f'- loading image: {file_name}')
with open(file_name, 'rb') as file:
return {'Bytes': file.read()}
def search_users_by_image(collection_id, image_file):
"""
SearchUsersByImage operation with user ID provided as the search source
:param collection_id: The ID of the collection where user and faces are stored.
:param image_file: The image that contains the reference face to search for.
:return: response of SearchUsersByImage API
"""
logger.info(f'Searching for users using an image: {image_file}')
try:
response = client.search_users_by_image(
CollectionId=collection_id,
Image=load_image(image_file)
)
print(f'- found {len(response["UserMatches"])} matches')
print([f'- {x["User"]["UserId"]} - {x["Similarity"]}%' for x in response["UserMatches"]])
except ClientError:
logger.exception(f'Failed to perform SearchUsersByImage with given image: {image_file}')
raise
else:
print(response)
return response
def main():
collection_id = "collection-id"
IMAGE_SEARCH_SOURCE = os.getcwd() + '/image_path'
search_users_by_image(collection_id, IMAGE_SEARCH_SOURCE)
if __name__ == "__main__":
main()
```
------
## SearchUsersByImage 操作请求
对 `SearchUsersByImage` 的请求包括要在其中进行搜索的集合和源图像位置。在此示例中，源图像存储在 Amazon S3 存储桶（`S3Object`）中。另外还指定了要返回的用户最大数量（`MaxUsers`）和要与返回的用户匹配所必须达到的最低置信度（`UserMatchThreshold`）。
```
{
"CollectionId": "MyCollection",
"Image": {
"S3Object": {
"Bucket": "bucket",
"Name": "input.jpg"
}
},
"MaxUsers": 2,
"UserMatchThreshold": 99
}
```
## SearchUsersByImage 操作响应
的响应`SearchUsersByImage`包括一个对应的`FaceDetail`对象`SearchedFace`，以及每个对象 UserMatches 的列表，均`UserStatus`为`UserId``Similarity`、和。如果输入图像包含多张脸，则还 UnsearchedFaces 会返回一个列表。
```
{
"SearchedFace": {
"FaceDetail": {
"BoundingBox": {
"Width": 0.23692893981933594,
"Top": 0.19235000014305115,
"Left": 0.39177176356315613,
"Height": 0.5437348484992981
}
}
},
"UserMatches": [
{
"User": {
"UserId": "demoUser1",
"UserStatus": "ACTIVE"
},
"Similarity": 100.0
},
{
"User": {
"UserId": "demoUser2",
"UserStatus": "ACTIVE"
},
"Similarity": 99.97946166992188
}
],
"FaceModelVersion": "6",
"UnsearchedFaces": [
{
"FaceDetails": {
"BoundingBox": {
"Width": 0.031677018851041794,
"Top": 0.5593535900115967,
"Left": 0.6102562546730042,
"Height": 0.0682177022099495
}
},
"Reasons": [
"FACE_NOT_LARGEST"
]
},
{
"FaceDetails": {
"BoundingBox": {
"Width": 0.03254449740052223,
"Top": 0.6080358028411865,
"Left": 0.516062319278717,
"Height": 0.06347997486591339
}
},
"Reasons": [
"FACE_NOT_LARGEST"
]
}
]
}
```