# 主体识别示例
本章节对主体识别AK/SK方式使用SDK进行示例说明。
- 主体识别示例代码只需将AK/SK信息替换为实际AK/SK，代码中可以使用ImageMainObjectDetectionReq中的url或image方法配置图像信息（image和url参数二选一），示例中以url为例，配置完成后运行即可。
- endpoint是华为云各服务应用区域和各服务的终端节点，详情请查看 [地区和终端节点](https://developer.huaweicloud.com/endpoint?Image)。
1. 主体识别调用示例代码如下：
   ```
   using System;
   using System.Collections.Generic;
   using HuaweiCloud.SDK.Core;
   using HuaweiCloud.SDK.Core.Auth;
   using HuaweiCloud.SDK.Image;
   using HuaweiCloud.SDK.Image.V2;
   using HuaweiCloud.SDK.Image.V2.Model;
    
   namespace RunImageMainObjectDetectionSolution
   {
       class Program
       {
           static void Main(string[] args) {
          //认证用的ak和sk硬编码到代码中或者明文存储都有很大的安全风险，建议在配置文件或者环境变量中密文存放，使用时解密，确保安全
         //本示例以ak和sk保存在环境变量中来实现身份验证为例，运行本示例前请先在本地环境中设置环境变量HUAWEICLOUD_SDK_AK和HUAWEICLOUD_SDK_SK  
           string accessKey= Environment.GetEnvironmentVariable("HUAWEICLOUD_SDK_AK", EnvironmentVariableTarget.Machine);
           string secretKey= Environment.GetEnvironmentVariable("HUAWEICLOUD_SDK_SK", EnvironmentVariableTarget.Machine);
    
               var config = HttpConfig.GetDefaultConfig();
               config.IgnoreSslVerification = true;
               var auth = new BasicCredentials(ak, sk);
    
               var client = ImageClient.NewBuilder()
                       .WithCredential(auth)
                       .WithRegion(ImageRegion.ValueOf("cn-north-4"))  //此处替换为您开通服务的区域，详情请查看地区和终端节点.
                       .WithHttpConfig(config)
                       .Build();
    
               var req = new RunImageMainObjectDetectionRequest
               {
               };
               req.Body = new ImageMainObjectDetectionReq()
               {
                   Threshold = 30,
                   Url = "https://XXX.jpg"  //替换为公网可以访问的图片地址
               };
               try
               {
                   var resp = client.RunImageMainObjectDetection(req);
                   var respStatusCode = resp.HttpStatusCode;
                   Console.WriteLine(respStatusCode);
               }
               catch (RequestTimeoutException requestTimeoutException)
               {
                   Console.WriteLine(requestTimeoutException.ErrorMessage);
               }
               catch (ServiceResponseException clientRequestException)
               {
                   Console.WriteLine(clientRequestException.HttpStatusCode);
                   Console.WriteLine(clientRequestException.ErrorCode);
                   Console.WriteLine(clientRequestException.ErrorMsg);
               }
               catch (ConnectionException connectionException)
               {
                   Console.WriteLine(connectionException.ErrorMessage);
               }
           }
       }
   }
   ```
   
2. 执行示例代码文件，控制台输出主体识别结果即表示程序执行成功。相关参数说明请参考[主体识别API](https://support.huaweicloud.com/api-image/image_03_0042.html#section4)。
   ```
   {
   "result": [{
   "confidence": "95.73",
   "label": "bounding_box",
   "location": {
   "height": 327.77,
   "top_left_x": 3.7,
   "top_left_y": 1.72,
   "width": 463.03}},
   {
   "confidence": "88.35",
   "label": "main_object_box",
   "location": {
   "height": 328.35,
   "top_left_x": 3.22,
   "top_left_y": 1.5,
   "width": 456.63}
   }]
   }
   ```